IPAC2015 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOXGB2	Commissioning and Operation of 12 GeV CEBAF	operation, cryomodule, cavity, SRF	1
	A. Freyberger JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 The Continuous Electron Beam Accelerator Facility (CEBAF) located at the Thomas Jefferson National Accelerator Laboratory (JLab) has been recently upgraded to deliver continuous electron beams to the experimental users at a maximum energy of 12 GeV, three times the original design energy of 4 GeV. This paper will present an overview of the upgrade, referred to as the 12GeV upgrade, and highlights from recent beam commissioning results.
	Slides MOXGB2 [4.359 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOXGB2
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MOAB2	Overview of Beam Instrumentation for the CADS Injector I Proton Linac	rfq, emittance, diagnostics, proton	21
	Y.F. Sui, J.S. Cao, Q.Y. Deng, J. He, H.Z. Ma, L. Wang, Q. Ye, L. Yu, J.H. Yue, X.Y. Zhao, Y. Zhao IHEP, People's Republic of China
	The driver linac of the China Accelerator Driven Subcritical system (C-ADS), which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam phase as well as beam current and beam losses. Though many are conventional design, They can provide efficient operation of drive linac. This paper gives an overview of C-ADS linac beam instrumentation.
	Slides MOAB2 [2.755 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOAB2
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MOPWA006	Core-Halo Limit as an Indicator of High Intensity Beam Internal Dynamics	space-charge, emittance, simulation, vacuum	86
	P.A.P. Nghiem, N. Chauvin, N. Pichoff, D. Uriot, M. Valette CEA/DSM/IRFU, France
	The dynamics of high-intensity beams is mainly governed by their internal space charge forces. These forces induce emittance growth and halo generation. They contribute to shape the beam density profile. As a consequence, a careful analysis of this profile can help revealing the internal dynamics of the beam. This paper recalls the precise core-halo limit determination proposed earlier , then studies its behavior through a wide range of beam profiles and finally shows its relevance as an indicator of the limit separating the two specific space charge field regimes of the core and the halo. P. A. P. Nghiem et al., Appl. Phys. Lett. 104, 074109 (2014)
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MOPWA007	The SARAF-LINAC Beam Dynamics	rfq, emittance, proton, simulation	89
	N. Pichoff, D. Uriot CEA/DSM/IRFU, France B. Dalena CEA/IRFU, Gif-sur-Yvette, France
	SNRC and CEA collaborate to the upgrade of the SARAF Accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). This paper presents the beam dynamics in the reference design of the SARAF-LINAC (from the 4 m long 176 MHz RFQ to the HWR Superconducting linac’s end). The beam losses, mostly in longitudinal direction, estimated from error studies, are compared with acceptable losses defined for hands-on maintenance.
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MOPWA008	Status of TraceWin Code	simulation, space-charge, cavity, diagnostics	92
	D. Uriot, N. Pichoff CEA/DSM/IRFU, France
	Well known in the community of high-intensity linear accelerators, the transport code TraceWin * is able to simulate a beam from the source to the target using either simple linear model or multiparticle simulations including 2D or 3D space-charge. Continuously developed at CEA Saclay since 15 years, it is today the reference code for projects such IFMIF, ESS, MYRRHA, SPIRAL2, IPHI … The accuracy of his predictions associated with an original and powerful GUI and its numerous features have made its success, with a community of 200 users worldwide. It is now used on a larger perimeter that its initial skills. The aim of this paper is to summarize the TraceWin capabilities, including implemented last ones. * http://irfu.cea.fr/Sacm/logiciels/
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MOPWA010	Emittances of the Core and of the Halo	emittance, space-charge, extraction, simulation	99
	M. Valette, P.A.P. Nghiem CEA/IRFU, Gif-sur-Yvette, France
	In high intensity accelerators, the beam is often space charge dominated. The density profile then takes a shape very different from a Gaussian one, with a more or less sharp core and a more or less compact halo. Furthermore, the core and the halo can be differently focused and thus differently oriented in the phase spaces. In these conditions, classically characterizing the beam by a global set of rms values, namely Emittance and Twiss parameters, is no more meaningful. This paper extends the core-halo limit defined ealier in 1D real space * to the 2D phase space, allowing to define for the very first time Emittances and Twiss parameters for the core and the halo separately. Applications to the IFMIF accelerators are given as an example of more appropriate beam characterization for high intensity linacs. * P. A. P. Nghiem et al., Appl. Phys. Lett. 104, 074109 (2014)
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MOPWA038	Sensitivity of Linac Optics to Focusing and Energy Errors	optics, focusing, operation, quadrupole	193
	V. Balandin, W. Decking, N. Golubeva DESY, Hamburg, Germany
	The ability to control beam optics in the presence of such imperfections as focusing and energy gain errors is essential for a successful operation of high brightness electron linacs providing beams for free-electron lasers. We characterize the cumulative effect of these imperfections using the value of mismatch parameter calculated at the linac exit and show how it depends on the design of the focusing lattice.
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MOPWA046	Lattice and Beam Dynamics of the Energy Recovery Mode of the Mainz Energy-recovering Superconducting Accelerator MESA	cryomodule, lattice, experiment, simulation	220
	D. Simon, K. Aulenbacher, R.G. Heine, F. Schlander IKP, Mainz, Germany
	Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence PRISMA. The mainz energy recovering superconducting accelerator (MESA) is a proposed multi-turn energy recovery linac for particle physics experiments. It will be built at the institute for nuclear physics (KPH) at Mainz University. Because of the multi-turn energy recovery mode there are particular demands at the beam dynamics. We present the current status of the lattice development.
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MOPWA047	Start to End Simulation of High Current Injector using TRACEWIN Code	ion, DTL, rfq, optics	223
	S. Kumar, A. Mandal IUAC, New Delhi, India
	High Current Injector (HCI) is an alternate injector to superconducting linac at IUAC in addition to pelletron. It consists mainly of high temperature superconducting ECR ion source (PKDELIS), radio frequency quadrupole (RFQ)* and a drift tube linac (DTL). The ions of mass to charge (A/q) ratio of 6 are analysed initially and accelerated through RFQ and DTL to a total energy of 1.8 MeV/u. The different energy regimes connecting the accelerating stages are named as low, medium and high energy beam transport section (LEBT, MEBT and HEBT). The energy spread of beam increases from 0.02% at ECR source to 0.5% at the DTL exit. An ion beam of normalized transverse and longitudinal emittance of 0.03 pi mm-mrad and 0.3 keV/u-ns has been considered at the start for the simulation of ion optics using TRACEWIN* code. The whole beam transport system has been designed using GICOSY, TRANSPORT and TRACE 3D codes piecewise and TRACEWIN code is used to simulate whole ion optics from start to end including acceleration stages such as RFQ and DTL. Simulation results shows that beam can be injected through LEBT, MEBT and HEBT into LINAC without significant emittance growth and beam loss. * Sugam Kumar et al., Proc. of InPAC-2011, IUAC, New Delhi B.P. Ajith Kumar et al., Proc. of InPAC-2009, RRCAT, Indore * http://irfu.cea.fr/Sacm/logiciels/index3.php
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MOPWA053	Emittance Preservation in SuperKEKB Injector	emittance, wakefield, simulation, injection	239
	S. Kazama, Y. Ogawa, M. Satoh, H. Sugimoto, M. Yoshida KEK, Ibaraki, Japan
	Injector linac at KEK is now under the way to produce high current and low emittance beams for SuperKEKB. The target luminosity for SuperKEKB is 40 times higher than that of KEKB. Short-range transverse wakefield and dispersive effects at the linac cause an emittance growth, and longitudinal wakefield effect enlarges an energy spread of the beams. In this presentation, we will report simulation studies of the emittance preservation issues and how to suppress the increase of the energy spread of the beams.
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MOPWA054	Effect of Number of Macro Particles on Resolution in Phase Space Distribution	electron, simulation, operation	242
	T. Miyajima KEK, Ibaraki, Japan
	Funding: This work was supported by JSPS KAKENHI Grant Number 26600147. In order to analyze charged particle beam in an accelerator, a beam model is used to reduce number of degrees of freedom, e.g. charged disk model, charged cylinder model and macro-particle model. In numerical simulation, the macro-particle model, which has same mass-to-charge ratio, is widely used, since it does not require any symmetry of beam shape. However, the estimation of proper number of macro-particles is one of the important issues. In order to study the effect of the number of macro-particles for the numerical model, we defined a simple transformation to generate reduced distribution. The transformation was applied for one dimensional and two dimensional particle distributions. The static electric fields due to the transformed distributions were calculated. As a result, we confirmed the effectiveness of the transformation.
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MOPWA056	Transverse Multi-Pass Beam Breakup Simulation for KEK ERL Light Source	HOM, cavity, simulation, cryomodule	248
	S. Chen, N. Nakamura, M. Shimada, D. Zhou KEK, Ibaraki, Japan S. Huang, K.X. Liu PKU, Beijing, People's Republic of China
	In this paper, the multi-pass BBU of such a high energy ERL is studied based on the simulation on a 3 GeV ERL light source proposed by KEK.
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MOPWA061	ADS Injector I Frequency Choice at IHEP	rfq, emittance, space-charge, proton	265
	F. Yan, H. Geng, C. Meng, H.F. Ouyang, S. Pei, Y.L. Zhao IHEP, Beijing, People's Republic of China
	Funding: Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System) The China ADS driver linac is composed of two major parts: the injector and the main linac. There are two frequency choices for the injector: 325 MHz and 162.5 MHz. The former choice is benefit for the same frequency with the front end of the main linac. For half frequency choice, to obtain the same longitudinal acceptance of the main linac comparing with 325MHz injector, the tune depression of the beam reaches the lower design limit of 0.5, no current upgrade opportunity is reserved; contrarily to get the same space charge effect, 16 more cavities would be the cost to get the same acceptance. However the disadvantage of the 325MHz injector choice is the bigger power density of the copper structure CW RFQ and the smaller longitudinal acceptance of the SC section. The details of the comparing for the two frequency choices are introduced and presented. *Work supported by Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System)
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MOPJE006	Electron Gun Longitudinal Jitter: Simulation and Analysis	gun, electron, timing, simulation	297
	M.S. Liu, Y.L. Chi, S. Pei, Y.F. Sui IHEP, Bejing, People's Republic of China
	The beam longitudinal jitter is fatal not only for the electron beam performance but also for the positron yield in routine operation of the Beijing Electron Positron Collider II (BEPCII) linear accelerator (Linac). Practically, longitudinal jitter has been observed many times which decreased the beam performance. We simulated the electron gun longitudinal jitter effect by PARMELA software in bunch capture process and analyzed its results about beam performance including average energy, energy spread, emittance and longitudinal phase of reference particle. We adjusted the electron gun trigger time during one cycle without changing other parameters. The percentage difference between maximum and minimum of average energy, energy spread, emittance and longitudinal phase of reference particle was 11.3%, 42%, 98% and 6.4%, respectively. It is observed and analyzed that gun trigger time longitudinal jitter is fatal for maintaining good beam performance. This analysis also gives a salutary lesson to any other longitudinal jitter which can affect the beam bunching in pre-injector .
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MOPJE008	Suppression of Microbunching Instability via a Transverse Gradient Undulator	electron, simulation, FEL, laser	300
	D. Huang, H.X. Deng, C. Feng, D. Gu, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Funding: the Major State Basic Research Development Program of China (2011CB808300) and the National Natural Science Foundation of China (11275253, 11475250 and 11322550). The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by turning the strength of the undulator magnet field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an X-Ray free-electron laser.
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MOPJE016	Start-to-End Simulation for RAON Superconducting Linac	ion, cryomodule, lattice, emittance	311
	H. Jang, J.-H. Jang, H. Jin IBS, Daejeon, Republic of Korea
	An ion accelerator, RAON is going to be built in Daejeon, Korea by Rare Isotope Science Project(RISP) team in Institute of Basic Science(IBS). The linac part of RAON consists of two low energy linacs, one high energy linac and two bending section for transporting accelerated low energy ions to high energy linac. It is planned to accelerate many diverse ions like proton, carbon, calcium, uranium, etc. which have different A/q values. Consequently the lattice design for each ion and to investigate beam dynamics issues for each case are one of the important topics for this project. For enhancement of beam acceleration a study to suppress emittance growth and to maximize the longitudinal acceptance is conducted while designing the RAON lattice. In this presentation the designed linac lattices for various ions and start-to-end simulation results will be described.
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MOPJE030	Non-linear Dynamics model for the ESS Linac Simulator	octupole, sextupole, proton, space-charge	345
	E. Laface ESS, Lund, Sweden
	The ESS Proton Linac will run a beam with 62.5 mA of current. In the first meters of the accelerator, the non- linear space-charge force dominates the dynamics of the beam. The Drift Tube Linac, the Spoke resonators and the elliptical cavities, which are responsible for the 99.8% of the total energy gained by the beam along the accelerator, produce a significant longitudinal non-linear force on the proton beam. In this paper, we introduce a new theory to transport the probability density function of the beam under the effect of non-linear forces. A model based on this theory can be implemented in the ESS Linac Simulator for the fast simulations to be performed during the operations of the proton Linac.
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MOPJE031	Field Map Model for the ESS Linac Simulator	cavity, proton, framework, space-charge	348
	E. Laface ESS, Lund, Sweden I. List Cosylab, Ljubljana, Slovenia
	The proton beam driving the spallation process at the European Spallation Source, in Lund, will be accelerated and delivered onto a tungsten target by a linac. This linac is composed of four different families of accelerating structures: adrift tube linac, a section of spoke resonators and two sections of elliptical cavities for the particles’ medium and high relativistic β. These structures provide 99.8% of the total energy gained by the beam along the accelerator. It is necessary, then, to have an accurate model describing the physics of the cavities in the ESS Linac Simulator (ELS), which isthe online model that will simulate the accelerator during operation. Here, we present an RF-cavity model based on the field maps that we implemented in ELS, showing a maximum 10% deviation from TraceWin in the horizontal, vertical and longitudinal planes.
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MOPJE032	A Steering Study for the ESS Normal Conducting Linac	DTL, quadrupole, lattice, beam-losses	351
	R. Miyamoto ESS, Lund, Sweden
	Construction of the European Spallation Source is rapidly progressing in Lund, Sweden, and preparations for commissioning of its proton linac has been underway for some time now. Accurate adjustment of accelerator components to achieve ideal beam parameters is the key to maximizing performance and safe operation for any machine. This paper presents a study of beam steering for the normal conducting part of the proton linac of ESS.
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MOPJE042	Longitudinal Injection Schemes For the CERN PS Booster at 160 MeV Including Space Charge Effects	space-charge, injection, simulation, emittance	378
	V. Forte, E. Benedetto, A.M. Lombardi, D. Quartullo CERN, Geneva, Switzerland
	In the frame of the LHC Injectors Upgrade project, the CERN PS Booster will be equipped with a H⁻ injection system at 160 MeV to tailor the initial transverse and longitudinal profiles. We are here reviewing the different multi-turn longitudinal injection schemes, from the beam dynamics point of view, taking into account the needs of the large variety of the PSB users, spanning in intensity from 5·10⁹ to about 1.6·10¹³ protons per bunch. The baseline of the longitudinal injection has always been the longitudinal stacking with central energy modulation: this scheme has the advantage of filling uniformly the RF bucket and mitigate transverse space charge, but it requires at least 40 turns of injection. A simpler injection protocol without energy modulation is here analyzed in detail to find the optimum initial conditions in terms of bucket filling and reduction of transverse and longitudinal space charge effects, with the advantage of minimizing the number of turns for the LHC beams. Simulations with space charge of the longitudinal injection process from different Linac4 trains are presented to fix possible longitudinal injection scenarios during the future commissioning and operation with Linac4.
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MOPJE058	FLUKA Modeling of the ESS Accelerator	cryomodule, proton, target, radiation	434
	L. Lari, M. Eshraqi, L.S. Esposito, L. Tchelidze ESS, Lund, Sweden F. Cerutti, L.S. Esposito, L. Lari, A. Mereghetti CERN, Geneva, Switzerland
	In order to evaluate the energy deposition and radiation issues concerning the ESS accelerator, a FLUKA model of the machine has been created. The geometry of the superconducting beam line is built according to the machine optics, described in the TraceWin file and the CATIA drawings of the beam elements, using the LineBuilder tool developed at CERN. The objective is to create a flexible FLUKA model that is able to be adapted to the optimization of the optics, design modifications and machine integration constraints. Preliminary results are also presented.
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MOPJE066	Single and Multi-bunch End-to-end Tracking in the LHeC	lattice, synchrotron, radiation, synchrotron-radiation	459
	D. Pellegrini, A. Latina, D. Schulte CERN, Geneva, Switzerland S.A. Bogacz JLab, Newport News, Virginia, USA
	The LHeC study aims at delivering an electron beam for collision with the LHC proton beam. The current baseline design consists of a multi-pass superconductive energy-recovery linac operating in a continuous wave mode. The high current beam (~100 mA) in the linacs excites long-range wake-fields between bunches of different turns, which induce instabilities and might cause beam losses. PLACET2, a novel version of the tracking code PLACET, capable to handle recirculation and time dependencies, has been employed to perform the first LHeC end-to-end tracking. The impact of long-range wake-fields, synchrotron radiation, and beam-beam effects has been assessed. The simulation results and recent improvements in the lattice design are presented and discussed in this paper.
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MOPJE068	PLACET2: A Novel Code for Beam Dynamics in Recirculating Machines	dipole, simulation, lattice, operation	465
	D. Pellegrini, A. Latina, D. Schulte CERN, Geneva, Switzerland
	Efforts have been taken to enable the simulation of recirculating machines in PLACET. The new version, PLACET2, allows handling multiple interconnected beamlines in order to obtain a realistic model of a machine. Two new elements, injectors and dumps, have been introduced and are active components of any working machine. Trains of bunches are routed through beamlines and tracked simultaneously in a parallel manner. Tracking through time-dependent elements is possible, and care is made to preserve the correct time-structure of the beam in case of beam recombination. This allows straightforward computations of multi-bunch effects arising with high-charge and shortly spaced bunch trains, even with variable train structure. The main features of the code are presented together with its working principles and its key ideas. Two case studies are introduced: LHeC and the CTF3 combiner ring.
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MOPJE073	The Extreme Beams Initiative in EuCARD-2	collider, polarization, hadron, diagnostics	483
	G. Franchetti, J. Struckmeier GSI, Darmstadt, Germany K. Aulenbacher IKP, Mainz, Germany F. Zimmermann CERN, Geneva, Switzerland
	EuCARD-2 is an Integration Activity on accelerator R&D co-funded within the European Union’s 7th Framework Programme. The Extreme Beams (XBEAM) network of EuCARD-2 extends, and goes beyond the scope of, the previous Networking Activities of CARE-HHH and EuCARD(-1) EuroLumi. XBEAM addresses, and pushes, all accelerator frontiers: luminosity, energy, beam power, beam intensity, and polarization. This is realized through five tasks: Coordination and Communication, Extreme Colliders (XCOL)m Extreme Performance Rings (XRING), Extreme SC Linacs (XLINAC), and Extreme Polarization (XPOL), respectively. In the first two years of EuCARD-2, XBEAM (co-)organised more than 15 topical workshops: the upgrade of KEKB in Japan, crystal channelling, the advancement of the CERN facilities, e.g. LHC upgrades and the Future Circular Collider, magnet optimization, space-charge effects, the commissioning of proton linacs, with emphasis on the ESS, key questions for lepton spin polarization, storage rings for measuring the electric dipole moment of electrons or protons. This presentation reports the major achievements of the XBEAM activity from 2013 to 2015, and outlines the further plans through 2017.
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MOPJE083	Implications of Manufacturing Errors on Higher Order Modes and on Beam Dynamics in the ESS Linac	HOM, cavity, coupling, wakefield	514
	A. Farricker, R.M. Jones UMAN, Manchester, United Kingdom S. Molloy ESS, Lund, Sweden
	The European Spallation Source (ESS) in Lund, Sweden, will be a facility for fundamental physics studies of atomic structure using a spallation source of unparalleled brightness. To achieve this end, protons will be accelerated up to 2 GeV using a suite of cavities. Here we focus on the Medium Beta (β =0.67) elliptical superconducting cavities and we assess the influence of potential errors in fabrication to shift eigenmode frequencies onto an harmonic of the bunch frequency. If this occurs, and countermeasures are not adopted, the beam quality will be appreciably diluted . We provide details on the geometrical parameters which are particularly sensitive to frequency errors from intensive finite element simulations of the electromagnetic fields. A circuit model is also employed to rapidly assess the shift in the eigenmodes from their anticipated design values due a variety of potential errors. Aaron Farricker et al, Physics Procedia, Proceedings of HOMSC14 (in press), 2014.
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MOPMA014	Design of Superconducting CW linac for PIP-II	cryomodule, beam-losses, optics, operation	565
	A. Saini, V.A. Lebedev, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Proton Improvement Plan (PIP) -II is a proposed roadmap to upgrade existing proton accelerator complex at Fermilab. It is primarily based on construction of superconducting (SC) linear accelerator (linac) that would be capable to operate in continuous wave (CW) mode. This paper will present reference design of SC linac and discuss motivations and requirements resulting in this layout and beam optics.
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MOPMA018	Simulation of Multipacting in SC Low Beta Cavities at FNAL	simulation, cavity, niobium, operation	579
	G.V. Romanov, P. Berrutti, T.N. Khabiboulline Fermilab, Batavia, Illinois, USA
	Proton Improvement Plan-II at Fermilab is a plan for improvements to the accelerator complex aimed at providing a beam power capability of at least 1 MW on target at the initiation of LBNE (Long Base Neutrino Experiment) operations. The central element of the PIP-II is a new 800 MeV superconducting linac, injecting into the existing Booster. Multipacting affects superconducting RF cavities in the entire range from high energy elliptical cavities to coaxial resonators for low-beta applications. This work is focused on multipacting study in the low-beta 325 MHz spoke cavities; namely SSR1 and SSR2, which are especially susceptible to the phenomena. The extensive simulations of multipacting in the cavities with updated material properties and comparison of the results with experimental data helped us to improve overall reliability and accuracy of these simulations. Our practical approach to the simulations is described in details. For SSR2, which has a high multipacting barrier right at the operating power level, some changes of the cavity shape to mitigate this harmful phenomenon are proposed.
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MOPMA041	Experimental Observation of Head-Tail Modes for Fermilab Booster	booster, space-charge, dipole, betatron	636
	T. Zolkin University of Chicago, Chicago, Illinois, USA A.V. Burov, V.A. Lebedev Fermilab, Batavia, Illinois, USA
	The Fermilab Booster is known to suffer from beam transverse instabilities. An experimental attempt of head-tail modes extraction from the stable beam motion by periodic excitement of betatron motion has been performed. The shapes of head-tail modes have been successfully obtained while eigenfrequencies separation from the betatron tune were too small to be resolved. The qualitative agreement between the theory and an experimental data has been demonstrated. This is an important step towards the understanding of general theory of collective instabilities for strong space charge case, which is a rather typical case for hadron machines.
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MOPMA043	Longitudinal Bunch Shaping at Picosecond Scales using Alpha-BBO Crystals at the Advanced Superconducting Test Accelerator	gun, electron, laser, space-charge	643
	B. Beaudoin UMD, College Park, Maryland, USA D.R. Edstrom, A.H. Lumpkin, J. Ruan, J.C.T. Thangaraj Fermilab, Batavia, Illinois, USA
	Funding: This works is supported by the University Research Association, Inc. Operated by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy The Integrable Optics Test Accelerator (IOTA) electron injector at Fermilab will enable a broad range of experiments at a national laboratory in order to study and develop solutions to the limitations that prevent the propagation of high intensity beams at picosecond lengths. One of the most significant complications towards increasing short-beam intensity is space-charge, especially in the vicinity of the gun. A few applications that require a longitudinally shaped electron beam at high intensities are for, the generation of THz waves and dielectric wakefields, each of which will encounter the effects of longitudinal space-charge. This paper investigates the effects of longitudinal space-charge on alpha-BBO UV laser shaped electron bunches in the vicinity of the 1½cell 1.3 GHz cylindrically symmetric RF photocathode gun.
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MOPMA054	Start-to-end Simulation of Free-electron Lasers	FEL, simulation, wiggler, electron	675
	C.C. Hall, S. Biedron, H. Freund, S.V. Milton CSU, Fort Collins, Colorado, USA
	Start-to-end (S2E) modeling of free-electron lasers (FELs) normally requires the use of multiple codes to correctly capture the physics in each region of the machine. Codes such as PARMELA, IMPACT-T or MICHELLE, for instance, may be used to simulate the injector. From there the linac and transport line may be handled by codes such as DIMAD, ELEGANT or IMPACT-Z. Finally, at the FEL a wiggler interaction code such as GENESIS, GINGER, or MINERVA must be used. These codes may be optimized to work with a wide range in magnitude of macro-particle numbers (from 10⁴-10⁸ in different codes) and have different input formats. It is therefore necessary to have translator codes to provide a bridge between each section. It is essential that these translators be able to preserve the statistical properties of the bunch while raising or lowering the number of macro-particles used between codes. In this work we show a suite of such translators designed to facilitate S2E simulations of an FEL with a new wiggler code, MINERVA, and use these codes to provide benchmarking of MINERVA against other common wiggler simulation codes.
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MOPMN007	An Alternate Ring-Ring Design for eRHIC	electron, ion, collider, proton	713
	Y. Zhang JLab, Newport News, Virginia, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357 I present here a new ring-ring design of eRHIC. It utilizes high repetition rate colliding beams and is likely able to deliver the performance to meet the requirements of the science program with low technical risk and modest accelerator R&D. The expected performance includes high luminosities over multiple collision points and a broad CM energy range with a maximum value up to 2×1034 cm^-2s⁻¹ per detector, and polarization higher than 70% for the colliding electron and light ion beams. This new design calls for reuse of decommissioned facilities in the US, namely, the PEP-II high energy ring and one section of the SLAC linac as a full energy injector.
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MOPMN028	Design of Bunch Compressing System with Suppression of Coherent Synchrotron Radiation for ATF Upgrade	emittance, electron, dipole, simulation	760
	Y.C. Jing, M.G. Fedurin, D. Stratakis BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Brookhaven National Laboratory Accelerator Test Facility (BNL ATF) is in the process of upgrading to ATF2 with higher electron beam energy thus expanding its capabilities. For the fully upgraded electron beam (500 MeV), it will be of great interest to compress the bunch to femto-seconds scale while maintaining high peak current (~7,800 amps) for users. A bunch compressor composed of magnetic chicanes can be utilized for this purpose. However, during such strong compression, beam quality can easily be deteriorated by Coherent Synchrotron Radiation (CSR). In this paper, we present our study for a bunch compressor where this CSR effect is compensated through careful manipulation of phase space. We also show a beam with good quality is preserved through the system by presenting a start to end simulation.
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MOPHA013	Superconducting Radio Frequency Cavity Degradation Due to Errant Beam	cavity, ion, ion-source, vacuum	805
	C.C. Peters, D. Curry, G.D. Johns ORNL RAD, Oak Ridge, Tennessee, USA A.V. Aleksandrov, W. Blokland, M.T. Crofford, C. Deibele, G.W. Dodson, J. Galambos, T.A. Justice, S.-H. Kim, T.A. Pelaia II, M.A. Plum, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy. In 2009, the Superconducting Radio Frequency (SRF) cavities at the Spallation Neutron Source (SNS) began to experience significant operational degradation [1]. The source of the degradation was found to be repeated striking of cavity surfaces with errant beam pulses. The Machine Protection System (MPS) was designed to turn the beam off during a fault condition in less than 20 μseconds [2] as these errant beam pulses were not unexpected. Unfortunately an improperly operating MPS was not turning off the beam within the designed 20 μseconds, and the SRF cavities were being damaged. The MPS issues were corrected, and the SRF performance was restored with cavity thermal cycling and RF processing. However, the SRF cavity performance has continued to degrade, though at a reduced rate compared to 2009. This paper will detail further study of errant beam frequency, amount lost per event, causes, and the corrective actions imposed since the initial event.
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MOPHA035	Beam Optics Measurements at FLASH2	extraction, undulator, optics, FEL	863
	M. Scholz, M. Vogt, J. Zemella DESY, Hamburg, Germany
	FLASH2 is a newly build second beamline at FLASH, a soft X-ray FEL at DESY, Hamburg. Unlike the existing beamline FLASH1, it is equipped with variable gap undulators. This beamline is currently being commissioned. Both undulator beamlines of FLASH are driven by a common linear accelerator. Fast kickers and a septum are installed at the end of the linac to distribute the electron bunches of every train between FLASH1 and FLASH2. A specific beam optics in the extraction arc with horizontal beam waists in the bending magnets is mandatory in order to mitigate effects from coherent synchrotron radiation (CSR). We performed various beam optics measurements to ensure that the conditions for FEL operation at FLASH2 are fulfilled. Here we will show results of measurements.
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MOPHA047	RF System Design for the TOP-IMPLART Accelerator	controls, LLRF, proton, klystron	897
	V. Surrenti, G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle ENEA C.R. Frascati, Frascati (Roma), Italy F. Ambrosini Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
	In the ENEA-Frascati research center a linear accelerator for proton therapy is under development in the framework of TOP-IMPLART Project carried out by ENEA in collaboration with ISS and IRE-IFO. The machine is based on a 7 MeV injector operating at a frequency of 425 MHz followed by a sequence of 2997.92 MHz accelerating modules. Five 10 MW klystrons will be used to power all high frequency structures up to a beam energy of 150 MeV. The maximum repetition frequency is 100 Hz and the pulse duration is 4 μs. The RF amplitude and phase stability requirements of the accelerating field are within ±2% and ±2 degrees respectively. For therapeutic use the beam energy will be varied between 85 and 150 MeV by switching off the last modules and varying the electric field amplitude in the last module switched on. Fast control of the RF power supplied to the individual structures allows an energy variation on a pulse by pulse basis; furthermore the system must be able to control the RF phase between accelerating structures. This work describes the RF power distribution scheme and the RF phase and amplitude monitoring system implemented into an embedded control system.
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MOPHA048	Beam Optimization of the DAΦNE Beam Test Facility	diagnostics, software, electron, detector	901
	L.G. Foggetta, B. Buonomo INFN/LNF, Frascati (Roma), Italy P. Valente INFN-Roma, Roma, Italy
	The DAΦNE Beam Test Facility delivers electron and positron beam with a wide spread of parameters in charge, energy, transverse dimensions and time width. Thanks to the recent improvements of the diagnostics, all the beam parameters have been measured and optimized. In particular we report here some results on beam transverse size, divergence, and position stability for different energy and intensity configurations. After the upgrade of the electronic gun of the DAΦNE LINAC, the pulse time width and charge distribution have been also characterized.
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MOPHA049	Evolution of Diagnostics and Services of the DAΦNE Beam Test Facility	vacuum, detector, controls, diagnostics	904
	L.G. Foggetta, B. Buonomo INFN/LNF, Frascati (Roma), Italy P. Valente INFN-Roma, Roma, Italy
	The DAΦNE Beam Test Facility (BTF) is operational in Frascati since 2003. In the last years the beam diagnostics tools have been completely renewed and the services for users have been largely improved. We describe here the new transverse beam diagnostics based on new GEM TPC detectors and Timepix/FitPix, the new BTF network layout, the renewed DAQ system including the BCM detectors, the data caching system based on MEMCached and the integration of the new sub-systems in the new data-logging. All other services, such as the environmental monitoring system, vacuum system, payload remote handling, and gas distribution have been also improved.
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MOPHA053	Radiation Measurements of a Medical Particle Accelerator Through a Passive Resonant Cavity	cavity, detector, coupling, radiation	917
	A. Leggieri, F. Di Paolo, D. Passi Università degli Studi di Roma "Tor Vergata", Roma, Italy A. Ciccotelli, S. De Stefano, G. Felici, F. Marangoni S.I.T., Aprilia, Italy
	Beam monitoring system are required by technical standards for the real time measurement of the dose delivered to the target while the beam is crossing them * . Traditional beam current monitoring systems are based on ionization chambers and requires high voltage biases * **. This study investigates on the measurements of the electron beam current emitted by a medical electron linear accelerator using the power exchange of the beam current with a passive resonant cavity *** placed at the output interface of the accelerator. The cavity is magnetically coupled with a coaxial transmission line loaded on a microwave envelope detector and its output signal has been documented while receiving several electron currents. This paper shows the complete equivalency, in terms of global performance, of the current revelation performed by exploiting the cavity-beam interaction principle with the classical technology, based on ionization chambers, however without need of high voltage. The most important point is that the resonant cavity system, by measuring the beam current, gives a direct measurement of a physical observable quantity directly related with the dose deposed by the beam. * EN 60601-2-1, 2009. A.P. Turner, 1979. * V.L. Uvarov, 1997. ** M. Ruf∗, 2014. *** J.B. Rosenzweig, 2003
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MOPHA059	Control System Upgrade for SuperKEKB Injector Linac	controls, operation, EPICS, Linux	930
	M. Satoh, K. Furukawa, K. Mikawa, F. Miyahara, Y. Seimiya, T. Suwada KEK, Ibaraki, Japan T. Kudou, S. Kusano Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan H.S. Saotome, M. Takagi Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
	Toward SuperKEKB project, the electron/positron injector linac upgrade is ongoing at KEK in order to deliver the low emittance electron/positron beams with high bunched charge intensity and small emittance. A large number of accelerator components and control devices will be newly installed before the autumn of 2014. Finally, we are aiming at the simultaneous top-up operation for the four independent storage rings including two light sources. The high availability and reliability of control system is strongly required for the long-term stable beam operation under such complex operation schemes. In this presentation, we will describe the control system upgrade plan and status.
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MOPTY002	Bunch Length Measurement of Femtosecond Electron Beam by Monitoring Coherent Transition Radiation	electron, detector, radiation, gun	940
	I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, A. Ogata, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Ultrashort electron bunches with durations of femtoseconds and attoseconds are essential for time-resolved measurements, including pulse radiolysis and ultrafast electron microscopy. However, generation of the ultrashort electron bunches is commonly difficult because of bunch length growth due to space charge effect, nonlinear momentum dispersion and so on. Several bunch length measurement methods for the ultrashort electron beams have also been considered so far, which have not been established yet. In this study, the femtosecond electron beams were generated using a laser photocathode radio-frequency gun linac and a magnetic bunch compressor. The bunch length measurement was carried out using a Michelson interferometer based on monitoring coherent transition radiation (CTR), which is characterized by square modulus of the Fourier transform of the longitudinal bunch distribution. Analyzing the experimentally obtained interferograms of CTR, the electron beams with the average duration of 5 fs were generated and measured successfully at the condition of bunch charge of 1 pC. Consideration of the longitudinal bunch shapes was also carried out using the Kramers-Kronig relation.
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MOPTY003	Measurement of Momentum Spread of the Injection Beam with Longitudinal Tomography Method in the J-PARC RCS	injection, acceleration, operation, synchrotron	944
	M. Yoshimoto, H. Harada, H. Hotchi, M. Kinsho, P.K. Saha, F. Tamura, M. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the J-PARC RCS, the beam tuning toward the design output beam power of 1MW were started after the completing of the beam energy and beam current upgrades in the LINAC. One of the important issues to achieve the 1MW beam operation is the optimization of the injection beam from the LINAC. Due to the longitudinal beam tuning in the LINAC, the momentum spread of the injected beam into the RCS was measured with the longitudinal tomography method. Our longitudinal tomography tool had been developed using the simple algorithm with the Convolution Back-Projection (CBP) method for the beam storage mode of the RCS. Accordingly, we improved this tool to expand into the acceleration mode.
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MOPTY004	Wakefield Monitor Experiments with X-Band Accelerating Structures	wakefield, pick-up, hardware, dipole	947
	R.L. Lillestøl, E. Adli, J. Pfingstner University of Oslo, Oslo, Norway R. Corsini, S. Döbert, W. Farabolini, L. Malina, W. Wuensch CERN, Geneva, Switzerland
	The accelerating structures for CLIC must be aligned with a precision of a few um with respect to the beam trajectory in order to mitigate emittance growth due to transverse wake fields. We report on first results from wake field monitor tests in an X-band structure, with a probe beam at the CLIC Test Facility. The monitors are currently installed in the CLIC Two-Beam Module. In order to fully demonstrate the feasibility of using wakefield monitors for CLIC, the precision of the monitors must be verified using a probe beam while simultaneously filling the structure with high power rf used to drive the accelerating mode. We outline plans to perform such a demonstration in the CLIC Test Facility.
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MOPTY006	Study on the Injection Beam Commissioning Software for CSNS/RCS	injection, controls, software, interface	950
	M.Y. Huang, L. Huang, W.B. Liu, J. Qiu, S. Wang IHEP, Beijing, People's Republic of China
	Funding: Funding Agency: Work supported by National Natural Science Foundation of China (11205185, 11175020, 11175193 ) The China Spallation Neutron Source (CSNS) accelerator uses H⁻ stripping and phase space painting method of filling large ring acceptance with the linac beam of small emittance. The beam commissioning software system is the key part of CSNS accelerator. The injection beam commissioning software for CSNS contains three parts currently: painting curve control, injection beam control and injection orbit correction. The injection beam control contains two subsections: single bunch beam calculation and LRBT beam control at the foil. The injection orbit correction also contains two subsections: injection orbit correction by the calculation and injection trim power control.
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MOPTY008	Preliminary Hardware Implementation of Compensation Mechanism of Superconducting Cavity Failure in C-ADS Linac	FPGA, hardware, cavity, proton	953
	Z. Xue, J.P. Dai IHEP, Beijing, People's Republic of China L. Cheng, Y. Yang SINANO, Suzhou, People's Republic of China
	For the proton linear accelerators used in applications such as ADS, due to the nature of the operation, it is essential to have beam failures at the rate several orders of magnitude lower than usual performance of similar accelerators. In order to achieve this extremely high performance reliability requirement, in addition to hardware improvement, a failure tolerant design is mandatory. A compensation mechanism to cope with hardware failure, mainly RF failures of superconducting cavities, will be in place in order to maintain the high uptime, short recovery time and extremely low frequency of beam loss. The hardware implementation of the mechanism poses high challenges due to the extremely tight timing constraints, high logic complexity, and mostly important, high flexibility and short turnaround time due to varying operation contexts. We will explore the hardware implementation of the scheme using fast electronic devices and Field Programmable Gate Array (FPGA). In order to achieve the goals of short recovery time and flexibility in compensation algorithms, an advanced hardware design methodology including high-level synthesis will be used.
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MOPTY012	Design and Test of Prototype of LLRF System for KIPT Neutron Source LINAC	LLRF, controls, EPICS, FPGA	959
	X.P. Ma, Y.L. Chi, R.L. Liu IHEP, Beijing, People's Republic of China S. Shu Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China
	A 100 MeV/100 kW electron LINAC is being constructed by IHEP, China for the NSC KIPT Neutron Source project in Ukraine. A LLRF system is required to produce the driver RF input of the klystron and maintain the accelerating phase and amplitude stability of the machine. The LLRF system consists of an RF reference distribution system, six identical control units, and the fast RF interlock module. The main part of control unit is the PXI-bus crate implemented with PXI9846 - 4 ADC digitizer board and ICS572 - high speed 2 ADC/2 DAC signal process board. An EPICS IOC based on WinDriver as the PCI device driver is developed and tested. Preliminary results show phase detect resolution of 0.03 degree (rms) of 2856 MHz signal has been achieved. *Mail Address: maxp@ihep.ac.cn
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MOPTY023	Beam Diagnostic of the LINAC for the Compact High-Performance THz-FEL	gun, FEL, emittance, target	987
	T. Hu, Q.S. Chen, K.F. Liu, B. Qin, P. Tan, Y.Q. Xiong, J. Yang HUST, Wuhan, People's Republic of China W. Chen Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People's Republic of China J. Liu, Y.J. Pei, Z.X. Tang USTC/NSRL, Hefei, Anhui, People's Republic of China Z.M. Wang Chinagray, Hefei, Anhui, People's Republic of China
	With the aim to obtain short-pulse bunches with high peak current for a terahertz radiation source, an FEL-based LINAC is employed in HUST THz-FEL, and the LINAC consists of an EC-ITC RF gun, a disk-loaed waveguide structure with a constant gradient and collinear absorbing loads with focusing coils surrounded and so on. To achieve a balance between compactness and high performance, beam diagnostic system should be simple and high-precision. So that a cost-effective measurement scheme for the high-brightness beam extracted by the LINAC is needed. This paper will describe the beam line and beam diagnostic system of the LINAC in the HUST THz-FEL in detail and give corresponding assembly scheme. In addition, online monitor system is introduced.
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MOPTY044	Machine Protection Systems and their Impact on Beam Availability and Accelerator Reliability	operation, storage-ring, software, proton	1029
	R. Andersson, E. Bargalló, A. Nordt ESS, Lund, Sweden E. Adli University of Oslo, Oslo, Norway
	Over the last decades, the complexity and performance levels of machine protection have developed. The level of reliability and availability analysis prior to operation differs between facilities, just as the pragmatic changes of the machine protection during operation. This paper studies the experience and development of machine protection for some of the state of the art proton and ion accelerators, and how it relates to reducing damage to and downtime of the machine. The findings are discussed and categorized, with emphasis on proton accelerators. The paper is concluded with some recommendations for a future high power linear proton accelerator.
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MOPTY047	ESS Cold LINAC BLM Locations Determination	detector, simulation, quadrupole, proton	1039
	M. Jarosz, A. Jansson, J.C. Kazantzidis, T.J. Shea, L. Tchelidze ESS, Lund, Sweden
	Funding: This project (oPAC) is funded by the European Union under contract PITN-GA-2011-289485. The linear accelerator of ESS will produce a 5 MW proton beam. Beam of this power must be strictly monitored by a specialized Beam Loss Monitoring (BLM) System to detect any abnormal losses and to ensure that operational losses do not lead to excessive activation. A long series of beam loss simulations was performed using MARS Monte Carlo code system in order to optimize the number and setting mounting locations of the detectors for best coverage, distinguishability and sensitivity. Simulations anticipated multiple possible beam loss scenarios resulting in different loss patterns. The results of energy deposition in air in the linac tunnel in multiple locations were analysed in several different ways. Incorporated methods varied from simple brute force approach to more sophisticated singular value decomposition based algorithms, all resulting in detector layout proposals. Locations selected for BLMs were evaluated for all methods.
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MOPTY060	Pulse Compressor Phase and Amplitude Modulation Based on Iterative Learning Control	klystron, controls, operation, experiment	1076
	A. Řežaeizadeh, R. Kalt, T. Schilcher PSI, Villigen PSI, Switzerland R. Smith Automatic Control Laboratory, ETH Zurich, Zurich, Switzerland
	This paper presents an alternative way to produce flat-topped RF pulses at the pulse compressor output. Flat-topped RF pulses are suitable for multi-bunch operation where it is often required that beams experience the same accelerating gradient. Moreover, the energy gain, in this case, is less sensitive to timing jitters. The proposed approach is based on Iterative Learning Control technique, which iteratively updates the input waveforms, in order to generate the desired output waveforms.
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MOPTY061	Beam-Based Power Distribution Over Multiple Klystrons in a Linear Accelerator	klystron, high-voltage, controls, LLRF	1079
	A. Řežaeizadeh, R. Kalt, T. Schilcher PSI, Villigen PSI, Switzerland R. Smith Automatic Control Laboratory, ETH Zurich, Zurich, Switzerland
	A linear accelerator including several klystron driver RF stations can be viewed as a single virtual RF station with a certain accelerating RF voltage (in amplitude and phase). This paper develops an optimization scheme that, for a specified beam energy gain, determines the klystrons output powers and the modulators high voltages optimally. The algorithm employs the klystron nonlinear static characteristics curves to calculate the input RF amplitude of the drive chain. A. Řežaeizadeh, et al, Model-based klystron linearization in the SwissFEL test facility, 36th International Free Electron Laser Conference, Basel, Switzerland
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPTY061
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MOPWI002	Bunch Length Measurements using Synchrotron Light Monitor	emittance, synchrotron, injection, dipole	1143
	M.M. Ali, M.G. Tiefenback JLab, Newport News, Virginia, USA
	The bunch length is measured at CEBAF using an invasive technique. The technique depends on applying an energy chirp for the electron bunch and imaging it through a dispersive region. The measurements are taken through Arc1 and Arc2 at CEBAF. The fundamental equations, procedure and the latest results are given.
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MOPWI003	Laserwire Emittance Scanner at CERN Linac 4	laser, detector, emittance, ion	1146
	K.O. Kruchinin, G.E. Boorman, A. Bosco, S.M. Gibson, P. Karataev Royal Holloway, University of London, Surrey, United Kingdom E. Bravin, T. Hofmann, U. Raich, F. Roncarolo, F. Zocca CERN, Geneva, Switzerland A.P. Letchford STFC/RAL, Chilton, Didcot, Oxon, United Kingdom J.K. Pozimski Imperial College of Science and Technology, Department of Physics, London, United Kingdom
	Linac 4 presently under construction at CERN is designed to replace the existing 50 MeV Linac 2 in the LHC injector chain and will accelerate the beam of high current negative hydrogen ions to 160 MeV. During the commissioning a laserwire emittance scanner has been installed allowing noninvasive measuring of the emittance at 3 MeV and 12 MeV setups. A low power infrared fibre coupled laser was focused in the interaction region down to ~150 um and collided with the ion beam neutralising negative ions. At each transverse laser position with respect to the ion beam the angular distribution of the neutral particle beamlets was recorded by scanning a diamond detector across the beamlet at a certain distance from the IP while the main beam of the H⁻ ions was deflected using dipole magnet installed upstream the detector. Measuring the profile of the beamlet by scanning the laser across the beam allows to directly measure the transverse phase-space distribution and reconstruct the transverse beam emittance. In this report we will describe the analysis of the data collected during the 3 MeV and 12 MeV operation of the Linac 4. We will discuss the hardware status and future plans.
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MOPWI016	Development of a Versatile Bunch-length Monitor for Electron Beams at ASTA	laser, radiation, electron, optics	1181
	A.H. Lumpkin, D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA
	Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy. The generation of bright electron beams at the ASTA/IOTA facility at Fermilab includes implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The station will include both a Hamamatsu C5680 synchroscan streak camera and a Martin-Puplett interferometer (MPI). An Al-coated Si screen will be used to generate both optical transition radiation (OTR) and coherent transition radiation (CTR) during the beam’s interaction with the screen. A chicane bypass beamline will allow the measurement of the initial bunch length at the same downstream beamline location using OTR and the streak camera. The UV component of the drive laser has previously been characterized with a Gaussian fit σ of 3.5 ps, and the uncompressed electron beam is expected to be similar to this value at low charge per micropulse. In addition, OTR will be transported to the streak camera from the focal plane of the downstream spectrometer to provide an E-t distribution within the micropulse time scale. Commissioning of the system and initial results with beam will be presented as available. A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org.
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MOPWI021	The LCLS-II LLRF System	cavity, controls, LLRF, cryomodule	1195
	C. Hovater, R. Bachimanchi JLab, Newport News, Virginia, USA S. Babel, B. Hong, D. Van Winkle SLAC, Menlo Park, California, USA B.E. Chase, E. Cullerton, P. Varghese Fermilab, Batavia, Illinois, USA L.R. Doolittle, G. Huang, A. Ratti, C. Serrano LBNL, Berkeley, California, USA
	Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515. The SLAC National Accelerator Laboratory is planning an upgrade (LCLS-II) to the Linear Coherent Light Source with a 4 GeV CW superconducting (SCRF) linac. The SCRF linac consists of 35 ILC style cryomodules (eight cavities each) for a total of 280 cavities. Expected cavity gradients are 16 MV/m with a loaded QL of ~ 4x10⁷. The RF system will have 3.8 kW solid state amplifiers driving single cavities. To ensure optimum field stability a single source single cavity control system has been chosen. It consists of a precision four channel cavity receiver and RF stations (Forward, Reflected and Drive signals). In order to regulate the resonant frequency variations of the cavities due to He pressure, the tuning of each cavity is controlled by a Piezo actuator and a slow stepper motor. In addition the system (LLRF-amplifier-cavity) is being modeled and cavity microphonic testing has started. This paper describes the LLRF system under consideration, including recent modeling and cavity tests.
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MOPWI023	Development Plan for Physics Application Software for FRIB Driver Linac	software, ion, EPICS, operation	1201
	M. Ikegami, G. Shen FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. FRIB is a heavy ion linac facility presently under construction at Michigan State University, USA, and its driver linac accelerates CW beams of all stable ions up to uranium to the energy of 200 MeV/u with the beam power of 400 kW. We plan to start beam commissioning of the driver linac from December 2017. An adequate software environment and infrastructure is critical for our commissioning and operation. Recently, a middle layer based architecture, EPICS V4 based services for example, for physics application has been rapidly developed at other facilities like NSLS II. It has been showing its flexibility, and portability. After reviewing those recent developments, we decided to adopt these services as software infrastructure for FRIB driver linac commissioning. It enables us to take advantage of their cutting edge technologies and maturity as a system sustained by the experience accumulated in the commissioning of NSLS-II. In this paper, we present a plan to develop physics application software for FRIB driver linac based on EPICS V4 services and related software. We also present a plan to adjust these EPICS V4 related software to meet the FRIB specific requirements.
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MOPWI025	Phase and Amplitude Tuning Algorithms for the FRIB Superconducting Cavities	cavity, acceleration, simulation, SRF	1207
	Y. Zhang, P. Chu, Z.Q. He FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 FRIB driver linac will deliver all heavy ion beams up to uranium with energy above 200 MeV/u, and maximum beam power on target 400 kW for nuclear physics research. Phase and amplitude tuning of the FRIB superconducting cavities – totally about 330 of them, are important to the linac beam commissioning at low power and normal operation at high power. Because relatively low beam energy and high acceleration gradient, beam velocity changes significantly in the cavity RF gaps and the beam bunch cannot preserve perfectly in the further downstream beam diagnostics systems, beam longitudinal tuning algorithms are studied for different FRIB cavities and at different beam energy, which include the acceleration cavities as well as the re-buncher cavities.
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MOPWI026	Transverse Matching of Horizontal-Vertical Coupled Beams for the FRIB Linac	quadrupole, simulation, lattice, solenoid	1211
	Y. Zhang, P. Chu, Z.Q. He, S.M. Lund, D.G. Maxwell FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 FRIB driver linac will deliver all heavy ion beams up to uranium with energy above 200 MeV/u, and maximum beam power on target 400 kW for nuclear physics research. Strong horizontal-vertical beam coupling exists in the FRIB linac since superconducting solenoids are applied to focus multi charge state beams. Further, the FRIB low beta SRF cavities have raised quadrupole field components. The combined effects make beam transverse matching challenging. In this paper, we study transverse matching of horizontal-vertical coupled beams based on beam profile measurements with multiple wire scanners. There are multiple solutions for the initial linac beams with coupling, and errors of the beam diagnostics and magnet power supplies introduce further complication. Nonetheless, simulation studies show that satisfactory transverse matching can be achieved with proper linac beam tuning.
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MOPWI033	Advantages to an Online Multi-particle Beam Dynamics Model for High-power Proton Linacs	operation, emittance, proton, beam-losses	1234
	L. Rybarcyk, S.A. Baily, X. Pang LANL, Los Alamos, New Mexico, USA
	High-power proton linacs like the 800-MeV LANSCE accelerator typically use a physics-based approach and online single-particle and envelope beam dynamics models to establish nominal set points for operation. However, these models are not good enough to enable immediate transition to high-power operation. Instead, some amount of empirical adjustment is necessary to achieve stable, low beam-loss operation. At Los Alamos, we have been developing a new online model, which employs multiparticle beam dynamics, as a tool for providing more information and insight to the operations staff, especially during this transition to high-power operations. This presentation will discuss some of the advantages and benefits of using this type of tool in the tune-up and operation of a high-power proton linac.
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MOPWI046	eDT and Model-based Configuration of 12 GeV CEBAF	operation, controls, radiation, synchrotron	1259
	D.L. Turner JLab, Newport News, Virginia, USA
	Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. This poster will discuss model-driven setup of CEBAF for the 12GeV era, focusing on the elegant Download Tool (eDT). eDT is a new operator tool that generates magnet design setpoints for various machine energies and pass configurations. eDT was developed in the effort towards a process for reducing machine configuration time and reproducibility by way of an accurate accelerator model.
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TUXB2	Upgrade of the Unilac for Fair	DTL, proton, ion, emittance	1281
	L. Groening, A. Adonin, R. M. Brodhage, X. Du, R. Hollinger, O.K. Kester, S. Mickat, A. Orzhekhovskaya, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao GSI, Darmstadt, Germany H. Hähnel, U. Ratzinger, A. Seibel, R. Tiede IAP, Frankfurt am Main, Germany
	The UNIversal Linear Accelerator (UNILAC) at GSI serves as injector for all ion species from protons to uranium since four decades. Its 10⁸ MHz Alvarez type DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue. The DTL will be replaced by a completely new section with almost same design parameters, i.e. pulsed current of up to 15 mA of 238U²⁸⁺ at 11.4 MeV/u. A dedicated terminal & LEBT for operation with 238U⁴⁺ is currently constructed. The uranium sources need to be upgraded in order to provide increased beam brilliances and for operation at 3 Hz. In parallel a 70 MeV / 70 mA proton linac based on H-mode cavities is under design and construction. This contribution will also give a brief summary of the overall status of the FAIR project.
	Slides TUXB2 [4.634 MB]
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TUYB1	Progress of SuperKEKB	emittance, positron, electron, gun	1291
	T. Miura, T. Abe, T. Adachi, K. Akai, M. Akemoto, A. Akiyama, D.A. Arakawa, Y. Arakida, Y. Arimoto, M. Arinaga, K. Ebihara, K. Egawa, A. Enomoto, J.W. Flanagan, S. Fukuda, H. Fukuma, Y. Funakoshi, K. Furukawa, T. Furuya, K. Hara, T. Higo, H. Hisamatsu, H. Honma, T. Honma, R. Ichimiya, N. Iida, H. Iinuma, H. Ikeda, M. Ikeda, T. Ishibashi, H. Ishii, M. Iwasaki, A. Kabe, T. Kageyama, H. Kaji, K. Kakihara, S. Kamada, T. Kamitani, S. Kanaeda, K. Kanazawa, H. Katagiri, S. Kato, S. Kazama, M. Kikuchi, T. Kobayashi, H. Koiso, Y. Kojima, M. Kurashina, K. Marutsuka, M. Masuzawa, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, F. Miyahara, K. Mori, T. Mori, A. Morita, Y. Morita, H. Nakai, H. Nakajima, T.T. Nakamura, K. Nakanishi, K. Nakao, H. Nakayama, T. Natsui, M. Nishiwaki, J.-I. Odagiri, Y. Ogawa, K. Ohmi, Y. Ohnishi, S. Ohsawa, Y. Ohsawa, N. Ohuchi, K. Oide, T. Oki, M. Ono, H. Sakai, Y. Sakamoto, S. Sasaki, M. Sato, M. Satoh, K. Shibata, T. Shidara, M. Shirai, A. Shirakawa, M. Suetake, Y. Suetsugu, R. Sugahara, H. Sugimoto, T. Suwada, S. Takasaki, T. Takatomi, T. Takenaka, Y. Takeuchi, M. Tanaka, M. Tawada, S. Terui, M. Tobiyama, N. Tokuda, K. Tsuchiya, X. Wang, K. Watanabe, H. Yamaoka, Y. Yano, K. Yokoyama, Ma. Yoshida, M. Yoshida, S.I. Yoshimoto, K. Yoshino, R. Zhang, D. Zhou, X. Zhou, Z.G. Zong KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	This presentation will cover the status of the installation and the injector commissioning status of SuperKEKB. The IR optics and design with very low β^* of less than 1 mm will be discussed.
	Slides TUYB1 [6.588 MB]
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TUYB2	Accelerator Physics in ERL Based Polarized Electron Ion Collider	electron, ion, luminosity, radiation	1296
	Y. Hao BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.
	Slides TUYB2 [14.101 MB]
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TUBB1	Charge Stripper Development for FRIB	ion, heavy-ion, proton, plasma	1339
	F. Marti, P. Guetschow, J.A. Nolen FRIB, East Lansing, Michigan, USA A. Hershcovitch, P. Thieberger BNL, Upton, Long Island, New York, USA Y. Momozaki, J.A. Nolen, C.B. Reed ANL, Argonne, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and NSF grant PHY-1102511 The Facility for Rare Isotope Beams (FRIB) at Michigan State University is building a heavy ion linac to produce rare isotopes by the fragmentation method. The linac will accelerate ions up to U to energies above 200 MeV/u with beam powers up to 400 kW. At energies between 16 and 20 MeV/u the ions will be stripped to higher charge states to increase the energy gain downstream in the linac. The main challenges in the stripper design are due to the high power deposited by the ions in the stripping media (~ 30 MW/cm³) and radiation damage if solids are used. For that reason self-recovering stripper media must be used. The baseline stripper choice is a high-velocity, thin film of liquid lithium with an alternative option of a helium gas stripper. We present in this paper the status of the R&D and construction of the final stripper. Extensive experimental work has been performed on both options.
	Slides TUBB1 [3.534 MB]
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TUAD3	LLRF Commissioning of the European XFEL RF Gun and Its First Linac RF Station	LLRF, cryomodule, gun, electronics	1377
	J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, M. Omet, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang DESY, Hamburg, Germany S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, K. Oliwa, J. Piekarski, K.T. Pozniak, I. Rutkowski, R. Rybaniec, D. Sikora, W. Wierba, L.Z. Zembala, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek TUL-DMCS, Łódź, Poland A. Piotrowski FastLogic Sp. z o.o., Łódź, Poland
	The European X-ray free electron laser (XFEL) at the Deutsches Elektronen-Synchrotron (DESY), Hamburg Germany is in its construction phase. Approximately a third of the super-conductive cryomodules have been produced and tested. The RF gun is installed since 2013; periods of commissioning are regularly scheduled between installation phases of the rest of the injector. The first linac, L1, consisting of 4 cryomodules powered by one 10 MW klystron is installed and being commissioned. This contribution reports on the installation and preparation work of the low-level radio frequency system (LLRF) to perform the commissioning of the XFEL first components. The commissioning plans, schedule and first results are presented.
	Slides TUAD3 [14.016 MB]
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TUBD2	Final Cooling For a High-luminosity High-energy Lepton Collider	emittance, collider, luminosity, solenoid	1384
	D.V. Neuffer Fermilab, Batavia, Illinois, USA T.L. Hart, D.J. Summers UMiss, University, Mississippi, USA H. K. Sayed BNL, Upton, Long Island, New York, USA
	Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy. The final cooling system for a high-energy high-luminosity muon collider requires reduction of the transverse emittance by an order of magnitude to ~0.00003 m (rms, N), while allowing longitudinal emittance increase to ~0.1m. In the present baseline approach, this is obtained by transverse cooling of low-energy muons within a sequence of high field solenoids with low-frequency rf systems. Recent studies of such systems are presented. Since the final cooling steps are actually emittance exchange a variant form of that final system can be obtained by a round to flat transform in x-y, with transverse slicing of the enlarged flat transverse dimension followed by longitudinal recombination of the sliced bunchlets. Development of final exchange following lowest-emittance cooling is discussed.
	Slides TUBD2 [1.976 MB]
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TUBD3	Effects of Accelerating Structures on On-line DFS in the Main Linac of CLIC	wakefield, emittance, dipole, simulation	1387
	J. Pfingstner, E. Adli University of Oslo, Oslo, Norway D. Schulte CERN, Geneva, Switzerland
	Long-term ground motion will create significant dispersion in the time-scale of hours in the main linac of CLIC. To preserve the emittance to an acceptable level, a dispersion correction with on-line dispersion-free steering (DFS) is inevitable. For this on-line technique, the dispersion has to be measured using beam energy variations of only about one per mil in order to not disturb the operation of the accelerator. For such small energy variations, the interaction of the particle beam and the accelerating structures creates large enough additional signals components in the measured dispersion to cause the dispersion correction to not work properly anymore. In this paper, the additional signals are described and their effect on the DFS algorithm is analysed. Finally, methods for the mitigation of the deteriorating signal components are presented and studied via simulations.
	Slides TUBD3 [1.697 MB]
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TUPWA002	Layout Options for the AXXS Injector and XFEL	storage-ring, FEL, lattice, dipole	1394
	M.J. Boland, Y.E. Tan, D. Zhu SLSA, Clayton, Australia
	A new injector is being planned for the Australian Synchrotron that is designed to feed both an upgraded storage ring and an XFEL. The desire to fit the AXXS project on the same site as the existing light source presents several layout difficulties. Several options are studied and simulations are performed to check the impact each choice has on the beam performance.
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TUPWA005	Comparison of Bunch Compression Schemes for the AXXS FEL	simulation, FEL, electron, synchrotron	1399
	T.K. Charles, D.M. Paganin Monash University, Faculty of Science, Clayton, Victoria, Australia A.A. Aksoy Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey M.J. Boland, R.T. Dowd SLSA, Clayton, Australia A. Latina, D. Schulte CERN, Geneva, Switzerland
	Different types of electron bunch compression schemes are compared for the AXXS FEL design study. The main linac for the proposed machine is based on CLIC x-band structures. This choice leaves several options for the bunch compression schemes which impact the injection system RF band. Both harmonic linearization and phase modulation linearization are considered and their relative strengths and weaknesses compared. Simulations were performed to compare the performance of an s-band injector with a higher harmonic RF linearization and an x-band injector. One motivation for the study is to optimise the length of the AXXS machine, allowing the linac to fit onto the proposed and also act as the injector to the existing storage ring at the Australian Synchrotron.
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TUPWA009	50 MeV Electron Linac with a RF Gun and a Thermoionic Cathode	gun, cavity, focusing, cathode	1413
	A.S. Setty, A.S. Chauchat, D. Fasse, D. Jousse, P. Sirot Thales Communications & Security (TCS), Gennevilliers Cedex, France
	The low energy part of our pre injectors is made up of a 90 kV DC themoionic trioode gun, followed by a 500 MHz sub harmonic prebuncher and a 3 GHz prebuncher. We propose a new design for a 50 MeV linac with a RF gun . this study will compare the beam dynamics simulations for the new design and for our previous pre injectors. A. Setty et al. "Study of a RF gun with a Thermoionic Cathode", Proceeding IPAC 2014, Germany, Dresden, June 2014.
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TUPWA020	BNL ATF II Beamlines Design	experiment, electron, laser, cavity	1445
	M.G. Fedurin, Y.C. Jing, D. Stratakis, C. Swinson BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The Brookhaven National Lab. Accelerator Test Facility (BNL ATF) is currently undergoing a major upgrade (ATF-II). Together with a new location and much improved facilities, the ATF will see an upgrade in its major capabilities: electron beam energy and quality and CO2 laser power. The electron beam energy will be increased in stages, first to 100-150 MeV followed by a further increase to 500 MeV. Combined with the planned increase in CO2 laser power (from 1-100 TW), the ATF-II will be a powerful tool for Advanced Accelerator research. A high-brightness electron beam, produced by a photocathode gun, will be accelerated and optionally delivered to multiple beamlines. Besides the energy range (up to a possible 500 MeV in the final stage) the electron beam can be tailored to each experiment with options such as: small transverse beam size (<10 um), flat beam, short bunch length (<100 fs) and, combined short and small bunch options. This report gives a detailed overview of the ATF-II capabilities and beamlines configuration.
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TUPWA028	Simulation Results of the Beam Transport of Ultra-Short Electron Bunches in Existing Beam Transfer Lines to Sinbad	optics, gun, electron, synchrotron	1466
	U. Dorda, R.W. Aßmann, K. Flöttmann, B. Marchetti, Y.C. Nie, J. Zhu DESY, Hamburg, Germany
	SINBAD, the upcoming accelerator R&D facility at DESY, will host multiple independent experiments on the production and acceleration of ultra-short bunches including plasma wakefield experiments. As a possible later upgrade the option to transport higher energy electrons (up to 800 MeV) or positrons (up to 400 MeV) from the existing DESY Linac 2 to the facility is studied. Though existing a possible connection using e.g. a part of the DESY synchrotron as a transfer line and other currently unused transfer-line, these machines were not designed for the desired longitudinal bunch compression and high peak current required by e.g. beam driven plasma wake-field experiments. Simulation results illustrate the modifications to the current layout that would have to be implemented and the corresponding achievable beam parameters are given.
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TUPWA029	ARES: Accelerator Research Experiment at SINBAD	electron, cavity, bunching, experiment	1469
	B. Marchetti, R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, J. Grebenyuk, M. Hüning, Y.C. Nie, H. Schlarb, J. Zhu DESY, Hamburg, Germany
	ARES is a planned linear accelerator for R&D for production of ultra-short electron bunches. It will be hosted at the SINBAD facility, at DESY in Hamburg. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with high arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The baseline layout of the accelerator foresees an S-band photo-injector which compresses low charge electron bunches via velocity bunching and accelerates them to 100 MeV energy. In the second stage, it is planned to install a third S-band accelerating cavity to reach 200 MeV as well as two X-band cavities: One for the linearization of the longitudinal phase space (subsequently allowing an improved bunch compression) and another one as a transverse deflecting cavity for longitudinal beam diagnostics. Moreover a magnetic bunch compressor is envisaged allowing to cut out the central slice of the beam** or hybrid bunch compression. * R. Assmann et al., TUPME047, Proceedings of IPAC 2014. R. Assmann, J. Grebenyuk, TUOBB01, Proceedings of IPAC 2014. * P. Emma et al., PRL 92 7 (2004).
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TUPWA031	Compression of Train of Bunches with Ramped Intensity Profile at SPARC_LAB	laser, cathode, plasma, electron	1476
	B. Marchetti DESY, Hamburg, Germany A. Bacci Istituto Nazionale di Fisica Nucleare, Milano, Italy E. Chiadroni, M. Ferrario, R. Pompili INFN/LNF, Frascati (Roma), Italy A. Cianchi Università di Roma II Tor Vergata, Roma, Italy
	The production and acceleration of train of bunches with variable spacing in the ps/sub-ps range having ramped intensity profile are interesting to drive a plasma wave in the so-called resonant Plasma Wake-Fields Acceleration (r-PWFA). At SPARC_LAB trains having a constant intensity profile have been produced for the first time by using a shaped photo-cathode laser combined with the use of the velocity bunching compression technique,,*. If the sub-bunches have ramped intensity, i.e. they have different charge density, the space charge force affects differently the development of the longitudinal phase space of each one of them during the compression. In this paper we present preliminary simulations for the compression of a ramped train of bunches. The differences between the beam dynamics for a train of bunches having constant intensity profile and the ramped train are underlined. We discuss also the possibility of properly tuning the shaping of the photocathode laser to balance the space charge effect. SLAC-PUB-3528 M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010). * M. Ferrario et al. NIM A 637, S43-S46 (2011). **** E. Chiadroni et al., Rev. Sci. Instrum. 84, 022703
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TUPWA032	Progress in the Injector Upgrade of the LINAC II at DESY	electron, gun, simulation, solenoid	1479
	Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz DESY, Hamburg, Germany
	A new injection system is under development for the LINAC II at DESY to improve the reliability of the machine and mitigate the radiological problem due to electron losses at energy of hundreds of MeV. It consists of a 100 kV triode DC gun, a 2.998 GHz pre-buncher, a novel 2.998 GHz hybrid buncher, and the dedicated beam transport and diagnostic elements. As the key components, the pre-buncher and the hybrid buncher realize a two-stage velocity bunching process including the ballistic bunching and the phase space rotation. Therefore, they produce a certain number of well-bunched 5 MeV micro-bunches from the input 2 ns-50 ns electron pulse for the downstream LINAC II. The overall upgrade plan, developments of the critical components, as well as the latest beam test results will be reported.
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TUPWA035	Progress in Optics Studies at FLASH	optics, quadrupole, FEL, free-electron-laser	1488
	J. Zemella, T. Hellert, M. Scholz, M. Vogt DESY, Hamburg, Germany
	FLASH is the superconducting soft X-ray Free Electron Laser in Hamburg at DESY, Germany. Good control over the beam optics is a key aspect of the operation of a SASE FEL. In 2013 a second beam line, FLASH2, was assembled and the modifications necessary to feed the two beam lines were installed downstream of the FLASH linac. As reported before * we started a campaign of optics consolidation. We give an update on the progress of this effort and on results. * J. Zemella, T. Hellert, M.Scholz, M.Vogt, "Measurements of the Optical Functions at FLASH", Proc. of IPAC'14, TUPRO050.
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TUPWA042	Status of the Accelerator Physics Test Facility FLUTE	electron, gun, diagnostics, laser	1506
	M.J. Nasse, A. Bernhard, I. Birkel, A. Borysenko, A. Böhm, S. Hillenbrand, N. Hiller, S. Höninger, S. Marsching, A.-S. Müller, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, B. Smit, S. Walther, M. Weber, P. Wesolowski KIT, Karlsruhe, Germany R.W. Aßmann, M. Felber, K. Flöttmann, C. Gerth, M. Hoffmann, P. Peier, H. Schlarb, B. Steffen DESY, Hamburg, Germany R. Ischebeck, B. Keil, V. Schlott, L. Stingelin PSI, Villigen PSI, Switzerland
	A new compact versatile linear accelerator named FLUTE (Ferninfrarot Linac Und Test Experiment) is currently under construction at the Karlsruhe Institute of Technology (KIT). It will serve as an accelerator test facility and allow conducting a variety of accelerator physics studies. In addition, it will be used to generate intense, ultra-short THz pulses for photon science experiments. FLUTE consists of a ~7 MeV photo-injector gun, a ~41 MeV S-band linac and a D-shaped chicane to compress bunches to a few femtoseconds. This contribution presents an overview of the project status and the accompanying simulation studies.
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TUPWA045	Further Investigations on the MESA injector	coupling, simulation, space-charge, experiment	1515
	R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander IKP, Mainz, Germany
	Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA" The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster).
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TUPWA053	Influence of a Non-uniform Longitudinal Heating on High Brightness Electron Beams for FEL	electron, laser, FEL, undulator	1535
	E. Roussel, E. Allaria, M.B. Danailov, G. De Ninno, S. Di Mitri, E. Ferrari, D. Gauthier, L. Giannessi, G. Penco Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Laser-heater systems are essential tools to control and optimize high-gain free electron lasers (FELs), working in the x-ray wavelength range. Indeed, these systems induce a controllable heating of the energy spread of the electron bunch. The heating allows in turn to suppress longitudinal microbunching instabilities limiting the FEL performance. In this communication, we show that a long-wavelength energy modulation of the electron beam induced by the laser heater can persist until the beam entrance in the undulators, affecting the FEL emission process. This non-uniform longitudinal heating can be exploited to investigate the electron-beam microbunching in the linac, as well as to control the FEL spectral properties. Here, we present experimental, analytical and numerical studies carried out at FERMI.
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TUPWA056	New Gun Implementation and Performance of the DAΦNE LINAC	gun, cathode, electron, operation	1546
	B. Buonomo, L.G. Foggetta, G. Piermarini INFN/LNF, Frascati (Roma), Italy
	A new electron gun system has been developed for DAΦNE LINAC, and put into operation since January 2014. Several elements of the system were upgraded, including a new grid pulser, an improved bias voltage system and a renewed cathode socket. The new LINAC gun has now a wider range of parameters, i.e. the emission pulse length spans from 1.4ns up to 40ns, while the better control of the grid and bias voltage allows a maximum peak current of 5A with a pulse repetition rate of 50 Hz. This paper describes the details of the pulser, the power supply, the socket, all the service components of the upgraded gun and its integration in the main LINAC control system. A report on the performance of the LINAC with the new gun will follow.
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TUPWA057	DAΦNE LINAC: Beam Diagnostics and Outline of the Last Improvements	klystron, electron, positron, operation	1549
	B. Buonomo, L.G. Foggetta INFN/LNF, Frascati (Roma), Italy
	The LINAC of the DAΦNE complex is in operation since 1996, both as injector of the e⁺ e⁻ phi-factory, and, since 2003, for the extraction of electron beam to the Beam Test Facility. In the last years, many improvements has been developed in different sub-systems of the LINAC, aiming at a wider, tunable range of beam parameters, in particular the pulse time width and the pulse charge. A long term measurement campaign has been recently started to characterize the LINAC performance after that many sub-systems has been overhauled and improved, starting from RF power (i.e. klystron substitution, modulator re-newing, RF driver layout, SLED tuning) as well as the timing system, magnets, cooling, vacuum, control system and energy/position diagnostics. This work reports the latest results on the optimization of the fully consolidated system.
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TUPWA058	Study of a C-band Harmonic RF System to Optimize the RF Bunch Compression Process of the SPARC Beam	cavity, gun, experiment, emittance	1552
	A. Gallo, D. Alesini, M. Bellaveglia, M. Ferrario INFN/LNF, Frascati (Roma), Italy A. Bacci, V. Petrillo, A.R. Rossi, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy F. Cardelli, L. Piersanti INFN-Roma1, Rome, Italy B. Marchetti DESY, Hamburg, Germany M. Rossetti Conti Universita' degli Studi di Milano & INFN, Milano, Italy
	The SPARC linac at the INFN Frascati Labs is a high brilliance electron source with a wide scientific program including production of THz and Thomson backscattering radiation, FEL studies and plasma wave acceleration experiments. The linac is based on S-band RF and consists in an RF Gun followed by 3 accelerating structures, while an energy upgrade based on 2 C-band accelerating structures is ready to be implemented. Short bunches are ordinarily produced by using the linear RF bunch compression concept. A harmonic RF structure interposed between the Gun and the 1st accelerating structure can be used to optimize the RF compression by a longitudinal phase space pre-correction, allowing to reach shorter bunches, a much more uniform current distribution and in general to control better the whole compression process. Here we report the results of numerical studies on the SPARC bunch compression optimization through the use of a harmonic cavity, and the design of a C-band RF system to implement it. The proposed system consists in a multi-cell SW cavity powered by a moderate portion of the total RF power spilled from the C-band power plant already installed for the linac energy upgrade.
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TUPWA069	Simulation Study on Bunch Compression and Decompression for the Compact ERL	sextupole, simulation, optics, emittance	1591
	N. Nakamura, K. Harada, T. Miyajima, S. Sakanaka, M. Shimada, O. Tanaka KEK, Ibaraki, Japan
	Generation of THz coherent radiation (THz-CSR) is planned for the near future at the Compact Energy Recovery Linac (cERL) in KEK where the beam recirculation and energy recovery were already achieved in February 2014 and an experiment for generation of laser-Compton scattering X-rays (LCS-X) is being prepared to start in February 2015. To achieve a ultra-short bunch less than 100 fs for generation of the THz-CSR up to 5 THz, we have studied bunch compression and decompression in the cERL mainly by using a simulation code ELEGANT. In this study, off-crest acceleration in the main superconducting linac and non-zero R56 optics in the two arc sections are used and sextupole magnets are introduced into the two arc sections for correcting T566 of the arc sections. In this paper, we will present the simulation results and the requirements for the sextupole magnets including their number and layout.
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Paper

Title

Other Keywords

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MOXGB2

Commissioning and Operation of 12 GeV CEBAF

operation, cryomodule, cavity, SRF

1

A. Freyberger
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The Continuous Electron Beam Accelerator Facility (CEBAF) located at the Thomas Jefferson National Accelerator Laboratory (JLab) has been recently upgraded to deliver continuous electron beams to the experimental users at a maximum energy of 12 GeV, three times the original design energy of 4 GeV. This paper will present an overview of the upgrade, referred to as the 12GeV upgrade, and highlights from recent beam commissioning results.

Slides MOXGB2 [4.359 MB]

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MOAB2

Overview of Beam Instrumentation for the CADS Injector I Proton Linac

rfq, emittance, diagnostics, proton

21

Y.F. Sui, J.S. Cao, Q.Y. Deng, J. He, H.Z. Ma, L. Wang, Q. Ye, L. Yu, J.H. Yue, X.Y. Zhao, Y. Zhao
IHEP, People's Republic of China

The driver linac of the China Accelerator Driven Subcritical system (C-ADS), which is composed of an ECR ion source, a low energy beam transport line (LEBT), a radio frequency quadrupole accelerator (RFQ), a medium energy beam transport line (MEBT) and cryomodules with SRF cavities to boost the energy up to 10 MeV. The injector linac will be equipped with beam diagnostics to measure the beam position, the transverse profile and emittance, the beam phase as well as beam current and beam losses. Though many are conventional design, They can provide efficient operation of drive linac. This paper gives an overview of C-ADS linac beam instrumentation.

Slides MOAB2 [2.755 MB]

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MOPWA006

Core-Halo Limit as an Indicator of High Intensity Beam Internal Dynamics

space-charge, emittance, simulation, vacuum

86

P.A.P. Nghiem, N. Chauvin, N. Pichoff, D. Uriot, M. Valette
CEA/DSM/IRFU, France

The dynamics of high-intensity beams is mainly governed by their internal space charge forces. These forces induce emittance growth and halo generation. They contribute to shape the beam density profile. As a consequence, a careful analysis of this profile can help revealing the internal dynamics of the beam. This paper recalls the precise core-halo limit determination proposed earlier *, then studies its behavior through a wide range of beam profiles and finally shows its relevance as an indicator of the limit separating the two specific space charge field regimes of the core and the halo.
* P. A. P. Nghiem et al., Appl. Phys. Lett. 104, 074109 (2014)

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MOPWA007

The SARAF-LINAC Beam Dynamics

rfq, emittance, proton, simulation

89

N. Pichoff, D. Uriot
CEA/DSM/IRFU, France
B. Dalena
CEA/IRFU, Gif-sur-Yvette, France

SNRC and CEA collaborate to the upgrade of the SARAF Accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). This paper presents the beam dynamics in the reference design of the SARAF-LINAC (from the 4 m long 176 MHz RFQ to the HWR Superconducting linac’s end). The beam losses, mostly in longitudinal direction, estimated from error studies, are compared with acceptable losses defined for hands-on maintenance.

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MOPWA008

Status of TraceWin Code

simulation, space-charge, cavity, diagnostics

92

D. Uriot, N. Pichoff
CEA/DSM/IRFU, France

Well known in the community of high-intensity linear accelerators, the transport code TraceWin * is able to simulate a beam from the source to the target using either simple linear model or multiparticle simulations including 2D or 3D space-charge. Continuously developed at CEA Saclay since 15 years, it is today the reference code for projects such IFMIF, ESS, MYRRHA, SPIRAL2, IPHI … The accuracy of his predictions associated with an original and powerful GUI and its numerous features have made its success, with a community of 200 users worldwide. It is now used on a larger perimeter that its initial skills. The aim of this paper is to summarize the TraceWin capabilities, including implemented last ones.
* http://irfu.cea.fr/Sacm/logiciels/

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MOPWA010

Emittances of the Core and of the Halo

emittance, space-charge, extraction, simulation

99

M. Valette, P.A.P. Nghiem
CEA/IRFU, Gif-sur-Yvette, France

In high intensity accelerators, the beam is often space charge dominated. The density profile then takes a shape very different from a Gaussian one, with a more or less sharp core and a more or less compact halo. Furthermore, the core and the halo can be differently focused and thus differently oriented in the phase spaces. In these conditions, classically characterizing the beam by a global set of rms values, namely Emittance and Twiss parameters, is no more meaningful. This paper extends the core-halo limit defined ealier in 1D real space * to the 2D phase space, allowing to define for the very first time Emittances and Twiss parameters for the core and the halo separately. Applications to the IFMIF accelerators are given as an example of more appropriate beam characterization for high intensity linacs.
* P. A. P. Nghiem et al., Appl. Phys. Lett. 104, 074109 (2014)

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MOPWA038

Sensitivity of Linac Optics to Focusing and Energy Errors

optics, focusing, operation, quadrupole

193

V. Balandin, W. Decking, N. Golubeva
DESY, Hamburg, Germany

The ability to control beam optics in the presence of such imperfections as focusing and energy gain errors is essential for a successful operation of high brightness electron linacs providing beams for free-electron lasers. We characterize the cumulative effect of these imperfections using the value of mismatch parameter calculated at the linac exit and show how it depends on the design of the focusing lattice.

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MOPWA046

Lattice and Beam Dynamics of the Energy Recovery Mode of the Mainz Energy-recovering Superconducting Accelerator MESA

cryomodule, lattice, experiment, simulation

220

D. Simon, K. Aulenbacher, R.G. Heine, F. Schlander
IKP, Mainz, Germany

Funding: Work supported by the German Federal Ministry of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence PRISMA.
The mainz energy recovering superconducting accelerator (MESA) is a proposed multi-turn energy recovery linac for particle physics experiments. It will be built at the institute for nuclear physics (KPH) at Mainz University. Because of the multi-turn energy recovery mode there are particular demands at the beam dynamics. We present the current status of the lattice development.

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MOPWA047

Start to End Simulation of High Current Injector using TRACEWIN Code

ion, DTL, rfq, optics

223

S. Kumar, A. Mandal
IUAC, New Delhi, India

High Current Injector (HCI) is an alternate injector to superconducting linac at IUAC in addition to pelletron. It consists mainly of high temperature superconducting ECR ion source (PKDELIS), radio frequency quadrupole (RFQ)* and a drift tube linac (DTL)**. The ions of mass to charge (A/q) ratio of 6 are analysed initially and accelerated through RFQ and DTL to a total energy of 1.8 MeV/u. The different energy regimes connecting the accelerating stages are named as low, medium and high energy beam transport section (LEBT, MEBT and HEBT). The energy spread of beam increases from 0.02% at ECR source to 0.5% at the DTL exit. An ion beam of normalized transverse and longitudinal emittance of 0.03 pi mm-mrad and 0.3 keV/u-ns has been considered at the start for the simulation of ion optics using TRACEWIN*** code. The whole beam transport system has been designed using GICOSY, TRANSPORT and TRACE 3D codes piecewise and TRACEWIN code is used to simulate whole ion optics from start to end including acceleration stages such as RFQ and DTL. Simulation results shows that beam can be injected through LEBT, MEBT and HEBT into LINAC without significant emittance growth and beam loss.
* Sugam Kumar et al., Proc. of InPAC-2011, IUAC, New Delhi
** B.P. Ajith Kumar et al., Proc. of InPAC-2009, RRCAT, Indore
*** http://irfu.cea.fr/Sacm/logiciels/index3.php

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MOPWA053

Emittance Preservation in SuperKEKB Injector

emittance, wakefield, simulation, injection

239

S. Kazama, Y. Ogawa, M. Satoh, H. Sugimoto, M. Yoshida
KEK, Ibaraki, Japan

Injector linac at KEK is now under the way to produce high current and low emittance beams for SuperKEKB. The target luminosity for SuperKEKB is 40 times higher than that of KEKB. Short-range transverse wakefield and dispersive effects at the linac cause an emittance growth, and longitudinal wakefield effect enlarges an energy spread of the beams. In this presentation, we will report simulation studies of the emittance preservation issues and how to suppress the increase of the energy spread of the beams.

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MOPWA054

Effect of Number of Macro Particles on Resolution in Phase Space Distribution

electron, simulation, operation

242

T. Miyajima
KEK, Ibaraki, Japan

Funding: This work was supported by JSPS KAKENHI Grant Number 26600147.
In order to analyze charged particle beam in an accelerator, a beam model is used to reduce number of degrees of freedom, e.g. charged disk model, charged cylinder model and macro-particle model. In numerical simulation, the macro-particle model, which has same mass-to-charge ratio, is widely used, since it does not require any symmetry of beam shape. However, the estimation of proper number of macro-particles is one of the important issues. In order to study the effect of the number of macro-particles for the numerical model, we defined a simple transformation to generate reduced distribution. The transformation was applied for one dimensional and two dimensional particle distributions. The static electric fields due to the transformed distributions were calculated. As a result, we confirmed the effectiveness of the transformation.

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MOPWA056

Transverse Multi-Pass Beam Breakup Simulation for KEK ERL Light Source

HOM, cavity, simulation, cryomodule

248

S. Chen, N. Nakamura, M. Shimada, D. Zhou
KEK, Ibaraki, Japan
S. Huang, K.X. Liu
PKU, Beijing, People's Republic of China

In this paper, the multi-pass BBU of such a high energy ERL is studied based on the simulation on a 3 GeV ERL light source proposed by KEK.

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MOPWA061

ADS Injector I Frequency Choice at IHEP

rfq, emittance, space-charge, proton

265

F. Yan, H. Geng, C. Meng, H.F. Ouyang, S. Pei, Y.L. Zhao
IHEP, Beijing, People's Republic of China

Funding: Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System)
The China ADS driver linac is composed of two major parts: the injector and the main linac. There are two frequency choices for the injector: 325 MHz and 162.5 MHz. The former choice is benefit for the same frequency with the front end of the main linac. For half frequency choice, to obtain the same longitudinal acceptance of the main linac comparing with 325MHz injector, the tune depression of the beam reaches the lower design limit of 0.5, no current upgrade opportunity is reserved; contrarily to get the same space charge effect, 16 more cavities would be the cost to get the same acceptance. However the disadvantage of the 325MHz injector choice is the bigger power density of the copper structure CW RFQ and the smaller longitudinal acceptance of the SC section. The details of the comparing for the two frequency choices are introduced and presented.
*Work supported by Chinese Academy of Science (CAS) strategic Priority Research Program-Future Advanced Nuclear Fission Energy (Accelerator-Driven Sub-critical System)

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MOPJE006

Electron Gun Longitudinal Jitter: Simulation and Analysis

gun, electron, timing, simulation

297

M.S. Liu, Y.L. Chi, S. Pei, Y.F. Sui
IHEP, Bejing, People's Republic of China

The beam longitudinal jitter is fatal not only for the electron beam performance but also for the positron yield in routine operation of the Beijing Electron Positron Collider II (BEPCII) linear accelerator (Linac). Practically, longitudinal jitter has been observed many times which decreased the beam performance. We simulated the electron gun longitudinal jitter effect by PARMELA software in bunch capture process and analyzed its results about beam performance including average energy, energy spread, emittance and longitudinal phase of reference particle. We adjusted the electron gun trigger time during one cycle without changing other parameters. The percentage difference between maximum and minimum of average energy, energy spread, emittance and longitudinal phase of reference particle was 11.3%, 42%, 98% and 6.4%, respectively. It is observed and analyzed that gun trigger time longitudinal jitter is fatal for maintaining good beam performance. This analysis also gives a salutary lesson to any other longitudinal jitter which can affect the beam bunching in pre-injector .

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MOPJE008

Suppression of Microbunching Instability via a Transverse Gradient Undulator

electron, simulation, FEL, laser

300

D. Huang, H.X. Deng, C. Feng, D. Gu, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Funding: the Major State Basic Research Development Program of China (2011CB808300) and the National Natural Science Foundation of China (11275253, 11475250 and 11322550).
The microbunching instability in the linear accelerator (linac) of a free-electron laser facility has always been a problem that degrades the electron beam quality. In this paper, a quite simple and inexpensive technique is proposed to smooth the electron beam current profile to suppress the instability. By directly adding a short undulator with transverse gradient field right after the injector to couple the transverse spread into the longitudinal direction, additional density mixing in the electron beam is introduced to smooth the current profile, which results in the reduction of the gain of the microbunching instability. The magnitude of the density mixing can be easily controlled by turning the strength of the undulator magnet field. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in the accelerator of an X-Ray free-electron laser.

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MOPJE016

Start-to-End Simulation for RAON Superconducting Linac

ion, cryomodule, lattice, emittance

311

H. Jang, J.-H. Jang, H. Jin
IBS, Daejeon, Republic of Korea

An ion accelerator, RAON is going to be built in Daejeon, Korea by Rare Isotope Science Project(RISP) team in Institute of Basic Science(IBS). The linac part of RAON consists of two low energy linacs, one high energy linac and two bending section for transporting accelerated low energy ions to high energy linac. It is planned to accelerate many diverse ions like proton, carbon, calcium, uranium, etc. which have different A/q values. Consequently the lattice design for each ion and to investigate beam dynamics issues for each case are one of the important topics for this project. For enhancement of beam acceleration a study to suppress emittance growth and to maximize the longitudinal acceptance is conducted while designing the RAON lattice. In this presentation the designed linac lattices for various ions and start-to-end simulation results will be described.

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MOPJE030

Non-linear Dynamics model for the ESS Linac Simulator

octupole, sextupole, proton, space-charge

345

E. Laface
ESS, Lund, Sweden

The ESS Proton Linac will run a beam with 62.5 mA of current. In the first meters of the accelerator, the non- linear space-charge force dominates the dynamics of the beam. The Drift Tube Linac, the Spoke resonators and the elliptical cavities, which are responsible for the 99.8% of the total energy gained by the beam along the accelerator, produce a significant longitudinal non-linear force on the proton beam. In this paper, we introduce a new theory to transport the probability density function of the beam under the effect of non-linear forces. A model based on this theory can be implemented in the ESS Linac Simulator for the fast simulations to be performed during the operations of the proton Linac.

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MOPJE031

Field Map Model for the ESS Linac Simulator

cavity, proton, framework, space-charge

348

E. Laface
ESS, Lund, Sweden
I. List
Cosylab, Ljubljana, Slovenia

The proton beam driving the spallation process at the European Spallation Source, in Lund, will be accelerated and delivered onto a tungsten target by a linac. This linac is composed of four different families of accelerating structures: adrift tube linac, a section of spoke resonators and two sections of elliptical cavities for the particles’ medium and high relativistic β. These structures provide 99.8% of the total energy gained by the beam along the accelerator. It is necessary, then, to have an accurate model describing the physics of the cavities in the ESS Linac Simulator (ELS), which isthe online model that will simulate the accelerator during operation. Here, we present an RF-cavity model based on the field maps that we implemented in ELS, showing a maximum 10% deviation from TraceWin in the horizontal, vertical and longitudinal planes.

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MOPJE032

A Steering Study for the ESS Normal Conducting Linac

DTL, quadrupole, lattice, beam-losses

351

R. Miyamoto
ESS, Lund, Sweden

Construction of the European Spallation Source is rapidly progressing in Lund, Sweden, and preparations for commissioning of its proton linac has been underway for some time now. Accurate adjustment of accelerator components to achieve ideal beam parameters is the key to maximizing performance and safe operation for any machine. This paper presents a study of beam steering for the normal conducting part of the proton linac of ESS.

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MOPJE042

Longitudinal Injection Schemes For the CERN PS Booster at 160 MeV Including Space Charge Effects

space-charge, injection, simulation, emittance

378

V. Forte, E. Benedetto, A.M. Lombardi, D. Quartullo
CERN, Geneva, Switzerland

In the frame of the LHC Injectors Upgrade project, the CERN PS Booster will be equipped with a H⁻ injection system at 160 MeV to tailor the initial transverse and longitudinal profiles. We are here reviewing the different multi-turn longitudinal injection schemes, from the beam dynamics point of view, taking into account the needs of the large variety of the PSB users, spanning in intensity from 5·10⁹ to about 1.6·10¹³ protons per bunch. The baseline of the longitudinal injection has always been the longitudinal stacking with central energy modulation: this scheme has the advantage of filling uniformly the RF bucket and mitigate transverse space charge, but it requires at least 40 turns of injection. A simpler injection protocol without energy modulation is here analyzed in detail to find the optimum initial conditions in terms of bucket filling and reduction of transverse and longitudinal space charge effects, with the advantage of minimizing the number of turns for the LHC beams. Simulations with space charge of the longitudinal injection process from different Linac4 trains are presented to fix possible longitudinal injection scenarios during the future commissioning and operation with Linac4.

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MOPJE058

FLUKA Modeling of the ESS Accelerator

cryomodule, proton, target, radiation

434

L. Lari, M. Eshraqi, L.S. Esposito, L. Tchelidze
ESS, Lund, Sweden
F. Cerutti, L.S. Esposito, L. Lari, A. Mereghetti
CERN, Geneva, Switzerland

In order to evaluate the energy deposition and radiation issues concerning the ESS accelerator, a FLUKA model of the machine has been created. The geometry of the superconducting beam line is built according to the machine optics, described in the TraceWin file and the CATIA drawings of the beam elements, using the LineBuilder tool developed at CERN. The objective is to create a flexible FLUKA model that is able to be adapted to the optimization of the optics, design modifications and machine integration constraints. Preliminary results are also presented.

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MOPJE066

Single and Multi-bunch End-to-end Tracking in the LHeC

lattice, synchrotron, radiation, synchrotron-radiation

459

D. Pellegrini, A. Latina, D. Schulte
CERN, Geneva, Switzerland
S.A. Bogacz
JLab, Newport News, Virginia, USA

The LHeC study aims at delivering an electron beam for collision with the LHC proton beam. The current baseline design consists of a multi-pass superconductive energy-recovery linac operating in a continuous wave mode. The high current beam (~100 mA) in the linacs excites long-range wake-fields between bunches of different turns, which induce instabilities and might cause beam losses. PLACET2, a novel version of the tracking code PLACET, capable to handle recirculation and time dependencies, has been employed to perform the first LHeC end-to-end tracking. The impact of long-range wake-fields, synchrotron radiation, and beam-beam effects has been assessed. The simulation results and recent improvements in the lattice design are presented and discussed in this paper.

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MOPJE068

PLACET2: A Novel Code for Beam Dynamics in Recirculating Machines

dipole, simulation, lattice, operation

465

D. Pellegrini, A. Latina, D. Schulte
CERN, Geneva, Switzerland

Efforts have been taken to enable the simulation of recirculating machines in PLACET. The new version, PLACET2, allows handling multiple interconnected beamlines in order to obtain a realistic model of a machine. Two new elements, injectors and dumps, have been introduced and are active components of any working machine. Trains of bunches are routed through beamlines and tracked simultaneously in a parallel manner. Tracking through time-dependent elements is possible, and care is made to preserve the correct time-structure of the beam in case of beam recombination. This allows straightforward computations of multi-bunch effects arising with high-charge and shortly spaced bunch trains, even with variable train structure. The main features of the code are presented together with its working principles and its key ideas. Two case studies are introduced: LHeC and the CTF3 combiner ring.

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MOPJE073

The Extreme Beams Initiative in EuCARD-2

collider, polarization, hadron, diagnostics

483

G. Franchetti, J. Struckmeier
GSI, Darmstadt, Germany
K. Aulenbacher
IKP, Mainz, Germany
F. Zimmermann
CERN, Geneva, Switzerland

EuCARD-2 is an Integration Activity on accelerator R&D co-funded within the European Union’s 7th Framework Programme. The Extreme Beams (XBEAM) network of EuCARD-2 extends, and goes beyond the scope of, the previous Networking Activities of CARE-HHH and EuCARD(-1) EuroLumi. XBEAM addresses, and pushes, all accelerator frontiers: luminosity, energy, beam power, beam intensity, and polarization. This is realized through five tasks: Coordination and Communication, Extreme Colliders (XCOL)m Extreme Performance Rings (XRING), Extreme SC Linacs (XLINAC), and Extreme Polarization (XPOL), respectively. In the first two years of EuCARD-2, XBEAM (co-)organised more than 15 topical workshops: the upgrade of KEKB in Japan, crystal channelling, the advancement of the CERN facilities, e.g. LHC upgrades and the Future Circular Collider, magnet optimization, space-charge effects, the commissioning of proton linacs, with emphasis on the ESS, key questions for lepton spin polarization, storage rings for measuring the electric dipole moment of electrons or protons. This presentation reports the major achievements of the XBEAM activity from 2013 to 2015, and outlines the further plans through 2017.

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MOPJE083

Implications of Manufacturing Errors on Higher Order Modes and on Beam Dynamics in the ESS Linac

HOM, cavity, coupling, wakefield

514

A. Farricker, R.M. Jones
UMAN, Manchester, United Kingdom
S. Molloy
ESS, Lund, Sweden

The European Spallation Source (ESS) in Lund, Sweden, will be a facility for fundamental physics studies of atomic structure using a spallation source of unparalleled brightness. To achieve this end, protons will be accelerated up to 2 GeV using a suite of cavities. Here we focus on the Medium Beta (β =0.67) elliptical superconducting cavities and we assess the influence of potential errors in fabrication to shift eigenmode frequencies onto an harmonic of the bunch frequency. If this occurs, and countermeasures are not adopted, the beam quality will be appreciably diluted *. We provide details on the geometrical parameters which are particularly sensitive to frequency errors from intensive finite element simulations of the electromagnetic fields. A circuit model is also employed to rapidly assess the shift in the eigenmodes from their anticipated design values due a variety of potential errors.
* Aaron Farricker et al, Physics Procedia, Proceedings of HOMSC14 (in press), 2014.

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MOPMA014

Design of Superconducting CW linac for PIP-II

cryomodule, beam-losses, optics, operation

565

A. Saini, V.A. Lebedev, J.-F. Ostiguy, N. Solyak, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan (PIP) -II is a proposed roadmap to upgrade existing proton accelerator complex at Fermilab. It is primarily based on construction of superconducting (SC) linear accelerator (linac) that would be capable to operate in continuous wave (CW) mode. This paper will present reference design of SC linac and discuss motivations and requirements resulting in this layout and beam optics.

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MOPMA018

Simulation of Multipacting in SC Low Beta Cavities at FNAL

simulation, cavity, niobium, operation

579

G.V. Romanov, P. Berrutti, T.N. Khabiboulline
Fermilab, Batavia, Illinois, USA

Proton Improvement Plan-II at Fermilab is a plan for improvements to the accelerator complex aimed at providing a beam power capability of at least 1 MW on target at the initiation of LBNE (Long Base Neutrino Experiment) operations. The central element of the PIP-II is a new 800 MeV superconducting linac, injecting into the existing Booster. Multipacting affects superconducting RF cavities in the entire range from high energy elliptical cavities to coaxial resonators for low-beta applications. This work is focused on multipacting study in the low-beta 325 MHz spoke cavities; namely SSR1 and SSR2, which are especially susceptible to the phenomena. The extensive simulations of multipacting in the cavities with updated material properties and comparison of the results with experimental data helped us to improve overall reliability and accuracy of these simulations. Our practical approach to the simulations is described in details. For SSR2, which has a high multipacting barrier right at the operating power level, some changes of the cavity shape to mitigate this harmful phenomenon are proposed.

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MOPMA041

Experimental Observation of Head-Tail Modes for Fermilab Booster

booster, space-charge, dipole, betatron

636

T. Zolkin
University of Chicago, Chicago, Illinois, USA
A.V. Burov, V.A. Lebedev
Fermilab, Batavia, Illinois, USA

The Fermilab Booster is known to suffer from beam transverse instabilities. An experimental attempt of head-tail modes extraction from the stable beam motion by periodic excitement of betatron motion has been performed. The shapes of head-tail modes have been successfully obtained while eigenfrequencies separation from the betatron tune were too small to be resolved. The qualitative agreement between the theory and an experimental data has been demonstrated. This is an important step towards the understanding of general theory of collective instabilities for strong space charge case, which is a rather typical case for hadron machines.

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MOPMA043

Longitudinal Bunch Shaping at Picosecond Scales using Alpha-BBO Crystals at the Advanced Superconducting Test Accelerator

gun, electron, laser, space-charge

643

B. Beaudoin
UMD, College Park, Maryland, USA
D.R. Edstrom, A.H. Lumpkin, J. Ruan, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

Funding: This works is supported by the University Research Association, Inc. Operated by the Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
The Integrable Optics Test Accelerator (IOTA) electron injector at Fermilab will enable a broad range of experiments at a national laboratory in order to study and develop solutions to the limitations that prevent the propagation of high intensity beams at picosecond lengths. One of the most significant complications towards increasing short-beam intensity is space-charge, especially in the vicinity of the gun. A few applications that require a longitudinally shaped electron beam at high intensities are for, the generation of THz waves and dielectric wakefields, each of which will encounter the effects of longitudinal space-charge. This paper investigates the effects of longitudinal space-charge on alpha-BBO UV laser shaped electron bunches in the vicinity of the 1½cell 1.3 GHz cylindrically symmetric RF photocathode gun.

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MOPMA054

Start-to-end Simulation of Free-electron Lasers

FEL, simulation, wiggler, electron

675

C.C. Hall, S. Biedron, H. Freund, S.V. Milton
CSU, Fort Collins, Colorado, USA

Start-to-end (S2E) modeling of free-electron lasers (FELs) normally requires the use of multiple codes to correctly capture the physics in each region of the machine. Codes such as PARMELA, IMPACT-T or MICHELLE, for instance, may be used to simulate the injector. From there the linac and transport line may be handled by codes such as DIMAD, ELEGANT or IMPACT-Z. Finally, at the FEL a wiggler interaction code such as GENESIS, GINGER, or MINERVA must be used. These codes may be optimized to work with a wide range in magnitude of macro-particle numbers (from 10⁴-10⁸ in different codes) and have different input formats. It is therefore necessary to have translator codes to provide a bridge between each section. It is essential that these translators be able to preserve the statistical properties of the bunch while raising or lowering the number of macro-particles used between codes. In this work we show a suite of such translators designed to facilitate S2E simulations of an FEL with a new wiggler code, MINERVA, and use these codes to provide benchmarking of MINERVA against other common wiggler simulation codes.

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MOPMN007

An Alternate Ring-Ring Design for eRHIC

electron, ion, collider, proton

713

Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Work supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC05-06OR23177 and No. DE-AC02-06CH11357
I present here a new ring-ring design of eRHIC. It utilizes high repetition rate colliding beams and is likely able to deliver the performance to meet the requirements of the science program with low technical risk and modest accelerator R&D. The expected performance includes high luminosities over multiple collision points and a broad CM energy range with a maximum value up to 2×1034 cm^-2s⁻¹ per detector, and polarization higher than 70% for the colliding electron and light ion beams. This new design calls for reuse of decommissioned facilities in the US, namely, the PEP-II high energy ring and one section of the SLAC linac as a full energy injector.

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MOPMN028

Design of Bunch Compressing System with Suppression of Coherent Synchrotron Radiation for ATF Upgrade

emittance, electron, dipole, simulation

760

Y.C. Jing, M.G. Fedurin, D. Stratakis
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Brookhaven National Laboratory Accelerator Test Facility (BNL ATF) is in the process of upgrading to ATF2 with higher electron beam energy thus expanding its capabilities. For the fully upgraded electron beam (500 MeV), it will be of great interest to compress the bunch to femto-seconds scale while maintaining high peak current (~7,800 amps) for users. A bunch compressor composed of magnetic chicanes can be utilized for this purpose. However, during such strong compression, beam quality can easily be deteriorated by Coherent Synchrotron Radiation (CSR). In this paper, we present our study for a bunch compressor where this CSR effect is compensated through careful manipulation of phase space. We also show a beam with good quality is preserved through the system by presenting a start to end simulation.

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MOPHA013

Superconducting Radio Frequency Cavity Degradation Due to Errant Beam

cavity, ion, ion-source, vacuum

805

C.C. Peters, D. Curry, G.D. Johns
ORNL RAD, Oak Ridge, Tennessee, USA
A.V. Aleksandrov, W. Blokland, M.T. Crofford, C. Deibele, G.W. Dodson, J. Galambos, T.A. Justice, S.-H. Kim, T.A. Pelaia II, M.A. Plum, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL is managed by UT-Battelle, LLC, under contract DE-AC05- 00OR22725 for the U.S. Department of Energy.
In 2009, the Superconducting Radio Frequency (SRF) cavities at the Spallation Neutron Source (SNS) began to experience significant operational degradation [1]. The source of the degradation was found to be repeated striking of cavity surfaces with errant beam pulses. The Machine Protection System (MPS) was designed to turn the beam off during a fault condition in less than 20 μseconds [2] as these errant beam pulses were not unexpected. Unfortunately an improperly operating MPS was not turning off the beam within the designed 20 μseconds, and the SRF cavities were being damaged. The MPS issues were corrected, and the SRF performance was restored with cavity thermal cycling and RF processing. However, the SRF cavity performance has continued to degrade, though at a reduced rate compared to 2009. This paper will detail further study of errant beam frequency, amount lost per event, causes, and the corrective actions imposed since the initial event.

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MOPHA035

Beam Optics Measurements at FLASH2

extraction, undulator, optics, FEL

863

M. Scholz, M. Vogt, J. Zemella
DESY, Hamburg, Germany

FLASH2 is a newly build second beamline at FLASH, a soft X-ray FEL at DESY, Hamburg. Unlike the existing beamline FLASH1, it is equipped with variable gap undulators. This beamline is currently being commissioned. Both undulator beamlines of FLASH are driven by a common linear accelerator. Fast kickers and a septum are installed at the end of the linac to distribute the electron bunches of every train between FLASH1 and FLASH2. A specific beam optics in the extraction arc with horizontal beam waists in the bending magnets is mandatory in order to mitigate effects from coherent synchrotron radiation (CSR). We performed various beam optics measurements to ensure that the conditions for FEL operation at FLASH2 are fulfilled. Here we will show results of measurements.

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MOPHA047

RF System Design for the TOP-IMPLART Accelerator

controls, LLRF, proton, klystron

897

V. Surrenti, G. Bazzano, P. Nenzi, L. Picardi, C. Ronsivalle
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy

In the ENEA-Frascati research center a linear accelerator for proton therapy is under development in the framework of TOP-IMPLART Project carried out by ENEA in collaboration with ISS and IRE-IFO. The machine is based on a 7 MeV injector operating at a frequency of 425 MHz followed by a sequence of 2997.92 MHz accelerating modules. Five 10 MW klystrons will be used to power all high frequency structures up to a beam energy of 150 MeV. The maximum repetition frequency is 100 Hz and the pulse duration is 4 μs. The RF amplitude and phase stability requirements of the accelerating field are within ±2% and ±2 degrees respectively. For therapeutic use the beam energy will be varied between 85 and 150 MeV by switching off the last modules and varying the electric field amplitude in the last module switched on. Fast control of the RF power supplied to the individual structures allows an energy variation on a pulse by pulse basis; furthermore the system must be able to control the RF phase between accelerating structures. This work describes the RF power distribution scheme and the RF phase and amplitude monitoring system implemented into an embedded control system.

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MOPHA048

Beam Optimization of the DAΦNE Beam Test Facility

diagnostics, software, electron, detector

901

L.G. Foggetta, B. Buonomo
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The DAΦNE Beam Test Facility delivers electron and positron beam with a wide spread of parameters in charge, energy, transverse dimensions and time width. Thanks to the recent improvements of the diagnostics, all the beam parameters have been measured and optimized. In particular we report here some results on beam transverse size, divergence, and position stability for different energy and intensity configurations. After the upgrade of the electronic gun of the DAΦNE LINAC, the pulse time width and charge distribution have been also characterized.

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MOPHA049

Evolution of Diagnostics and Services of the DAΦNE Beam Test Facility

vacuum, detector, controls, diagnostics

904

L.G. Foggetta, B. Buonomo
INFN/LNF, Frascati (Roma), Italy
P. Valente
INFN-Roma, Roma, Italy

The DAΦNE Beam Test Facility (BTF) is operational in Frascati since 2003. In the last years the beam diagnostics tools have been completely renewed and the services for users have been largely improved. We describe here the new transverse beam diagnostics based on new GEM TPC detectors and Timepix/FitPix, the new BTF network layout, the renewed DAQ system including the BCM detectors, the data caching system based on MEMCached and the integration of the new sub-systems in the new data-logging. All other services, such as the environmental monitoring system, vacuum system, payload remote handling, and gas distribution have been also improved.

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MOPHA053

Radiation Measurements of a Medical Particle Accelerator Through a Passive Resonant Cavity

cavity, detector, coupling, radiation

917

A. Leggieri, F. Di Paolo, D. Passi
Università degli Studi di Roma "Tor Vergata", Roma, Italy
A. Ciccotelli, S. De Stefano, G. Felici, F. Marangoni
S.I.T., Aprilia, Italy

Beam monitoring system are required by technical standards for the real time measurement of the dose delivered to the target while the beam is crossing them * **. Traditional beam current monitoring systems are based on ionization chambers and requires high voltage biases *** ****. This study investigates on the measurements of the electron beam current emitted by a medical electron linear accelerator using the power exchange of the beam current with a passive resonant cavity ***** placed at the output interface of the accelerator. The cavity is magnetically coupled with a coaxial transmission line loaded on a microwave envelope detector and its output signal has been documented while receiving several electron currents. This paper shows the complete equivalency, in terms of global performance, of the current revelation performed by exploiting the cavity-beam interaction principle with the classical technology, based on ionization chambers, however without need of high voltage. The most important point is that the resonant cavity system, by measuring the beam current, gives a direct measurement of a physical observable quantity directly related with the dose deposed by the beam.
* EN 60601-2-1, 2009.
** A.P. Turner, 1979.
*** V.L. Uvarov, 1997.
**** M. Ruf∗, 2014.
***** J.B. Rosenzweig, 2003

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MOPHA059

Control System Upgrade for SuperKEKB Injector Linac

controls, operation, EPICS, Linux

930

M. Satoh, K. Furukawa, K. Mikawa, F. Miyahara, Y. Seimiya, T. Suwada
KEK, Ibaraki, Japan
T. Kudou, S. Kusano
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
H.S. Saotome, M. Takagi
Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan

Toward SuperKEKB project, the electron/positron injector linac upgrade is ongoing at KEK in order to deliver the low emittance electron/positron beams with high bunched charge intensity and small emittance. A large number of accelerator components and control devices will be newly installed before the autumn of 2014. Finally, we are aiming at the simultaneous top-up operation for the four independent storage rings including two light sources. The high availability and reliability of control system is strongly required for the long-term stable beam operation under such complex operation schemes. In this presentation, we will describe the control system upgrade plan and status.

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MOPTY002

Bunch Length Measurement of Femtosecond Electron Beam by Monitoring Coherent Transition Radiation

electron, detector, radiation, gun

940

I. Nozawa, M. Gohdo, K. Kan, T. Kondoh, A. Ogata, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Ultrashort electron bunches with durations of femtoseconds and attoseconds are essential for time-resolved measurements, including pulse radiolysis and ultrafast electron microscopy. However, generation of the ultrashort electron bunches is commonly difficult because of bunch length growth due to space charge effect, nonlinear momentum dispersion and so on. Several bunch length measurement methods for the ultrashort electron beams have also been considered so far, which have not been established yet. In this study, the femtosecond electron beams were generated using a laser photocathode radio-frequency gun linac and a magnetic bunch compressor. The bunch length measurement was carried out using a Michelson interferometer based on monitoring coherent transition radiation (CTR), which is characterized by square modulus of the Fourier transform of the longitudinal bunch distribution. Analyzing the experimentally obtained interferograms of CTR, the electron beams with the average duration of 5 fs were generated and measured successfully at the condition of bunch charge of 1 pC. Consideration of the longitudinal bunch shapes was also carried out using the Kramers-Kronig relation.

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MOPTY003

Measurement of Momentum Spread of the Injection Beam with Longitudinal Tomography Method in the J-PARC RCS

injection, acceleration, operation, synchrotron

944

M. Yoshimoto, H. Harada, H. Hotchi, M. Kinsho, P.K. Saha, F. Tamura, M. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the J-PARC RCS, the beam tuning toward the design output beam power of 1MW were started after the completing of the beam energy and beam current upgrades in the LINAC. One of the important issues to achieve the 1MW beam operation is the optimization of the injection beam from the LINAC. Due to the longitudinal beam tuning in the LINAC, the momentum spread of the injected beam into the RCS was measured with the longitudinal tomography method. Our longitudinal tomography tool had been developed using the simple algorithm with the Convolution Back-Projection (CBP) method for the beam storage mode of the RCS. Accordingly, we improved this tool to expand into the acceleration mode.

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MOPTY004

Wakefield Monitor Experiments with X-Band Accelerating Structures

wakefield, pick-up, hardware, dipole

947

R.L. Lillestøl, E. Adli, J. Pfingstner
University of Oslo, Oslo, Norway
R. Corsini, S. Döbert, W. Farabolini, L. Malina, W. Wuensch
CERN, Geneva, Switzerland

The accelerating structures for CLIC must be aligned with a precision of a few um with respect to the beam trajectory in order to mitigate emittance growth due to transverse wake fields. We report on first results from wake field monitor tests in an X-band structure, with a probe beam at the CLIC Test Facility. The monitors are currently installed in the CLIC Two-Beam Module. In order to fully demonstrate the feasibility of using wakefield monitors for CLIC, the precision of the monitors must be verified using a probe beam while simultaneously filling the structure with high power rf used to drive the accelerating mode. We outline plans to perform such a demonstration in the CLIC Test Facility.

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MOPTY006

Study on the Injection Beam Commissioning Software for CSNS/RCS

injection, controls, software, interface

950

M.Y. Huang, L. Huang, W.B. Liu, J. Qiu, S. Wang
IHEP, Beijing, People's Republic of China

Funding: Funding Agency: Work supported by National Natural Science Foundation of China (11205185, 11175020, 11175193 )
The China Spallation Neutron Source (CSNS) accelerator uses H⁻ stripping and phase space painting method of filling large ring acceptance with the linac beam of small emittance. The beam commissioning software system is the key part of CSNS accelerator. The injection beam commissioning software for CSNS contains three parts currently: painting curve control, injection beam control and injection orbit correction. The injection beam control contains two subsections: single bunch beam calculation and LRBT beam control at the foil. The injection orbit correction also contains two subsections: injection orbit correction by the calculation and injection trim power control.

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MOPTY008

Preliminary Hardware Implementation of Compensation Mechanism of Superconducting Cavity Failure in C-ADS Linac

FPGA, hardware, cavity, proton

953

Z. Xue, J.P. Dai
IHEP, Beijing, People's Republic of China
L. Cheng, Y. Yang
SINANO, Suzhou, People's Republic of China

For the proton linear accelerators used in applications such as ADS, due to the nature of the operation, it is essential to have beam failures at the rate several orders of magnitude lower than usual performance of similar accelerators. In order to achieve this extremely high performance reliability requirement, in addition to hardware improvement, a failure tolerant design is mandatory. A compensation mechanism to cope with hardware failure, mainly RF failures of superconducting cavities, will be in place in order to maintain the high uptime, short recovery time and extremely low frequency of beam loss. The hardware implementation of the mechanism poses high challenges due to the extremely tight timing constraints, high logic complexity, and mostly important, high flexibility and short turnaround time due to varying operation contexts. We will explore the hardware implementation of the scheme using fast electronic devices and Field Programmable Gate Array (FPGA). In order to achieve the goals of short recovery time and flexibility in compensation algorithms, an advanced hardware design methodology including high-level synthesis will be used.

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MOPTY012

Design and Test of Prototype of LLRF System for KIPT Neutron Source LINAC

LLRF, controls, EPICS, FPGA

959

X.P. Ma, Y.L. Chi, R.L. Liu
IHEP, Beijing, People's Republic of China
S. Shu
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

A 100 MeV/100 kW electron LINAC is being constructed by IHEP, China for the NSC KIPT Neutron Source project in Ukraine. A LLRF system is required to produce the driver RF input of the klystron and maintain the accelerating phase and amplitude stability of the machine. The LLRF system consists of an RF reference distribution system, six identical control units, and the fast RF interlock module. The main part of control unit is the PXI-bus crate implemented with PXI9846 - 4 ADC digitizer board and ICS572 - high speed 2 ADC/2 DAC signal process board. An EPICS IOC based on WinDriver as the PCI device driver is developed and tested. Preliminary results show phase detect resolution of 0.03 degree (rms) of 2856 MHz signal has been achieved.
*Mail Address: maxp@ihep.ac.cn

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MOPTY023

Beam Diagnostic of the LINAC for the Compact High-Performance THz-FEL

gun, FEL, emittance, target

987

T. Hu, Q.S. Chen, K.F. Liu, B. Qin, P. Tan, Y.Q. Xiong, J. Yang
HUST, Wuhan, People's Republic of China
W. Chen
Huazhong University of Science and Technology, State Key Laboratory of Advanced Electromagnetic Engineering and Technology,, Hubei, People's Republic of China
J. Liu, Y.J. Pei, Z.X. Tang
USTC/NSRL, Hefei, Anhui, People's Republic of China
Z.M. Wang
Chinagray, Hefei, Anhui, People's Republic of China

With the aim to obtain short-pulse bunches with high peak current for a terahertz radiation source, an FEL-based LINAC is employed in HUST THz-FEL, and the LINAC consists of an EC-ITC RF gun, a disk-loaed waveguide structure with a constant gradient and collinear absorbing loads with focusing coils surrounded and so on. To achieve a balance between compactness and high performance, beam diagnostic system should be simple and high-precision. So that a cost-effective measurement scheme for the high-brightness beam extracted by the LINAC is needed. This paper will describe the beam line and beam diagnostic system of the LINAC in the HUST THz-FEL in detail and give corresponding assembly scheme. In addition, online monitor system is introduced.

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MOPTY044

Machine Protection Systems and their Impact on Beam Availability and Accelerator Reliability

operation, storage-ring, software, proton

1029

R. Andersson, E. Bargalló, A. Nordt
ESS, Lund, Sweden
E. Adli
University of Oslo, Oslo, Norway

Over the last decades, the complexity and performance levels of machine protection have developed. The level of reliability and availability analysis prior to operation differs between facilities, just as the pragmatic changes of the machine protection during operation. This paper studies the experience and development of machine protection for some of the state of the art proton and ion accelerators, and how it relates to reducing damage to and downtime of the machine. The findings are discussed and categorized, with emphasis on proton accelerators. The paper is concluded with some recommendations for a future high power linear proton accelerator.

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MOPTY047

ESS Cold LINAC BLM Locations Determination

detector, simulation, quadrupole, proton

1039

M. Jarosz, A. Jansson, J.C. Kazantzidis, T.J. Shea, L. Tchelidze
ESS, Lund, Sweden

Funding: This project (oPAC) is funded by the European Union under contract PITN-GA-2011-289485.
The linear accelerator of ESS will produce a 5 MW proton beam. Beam of this power must be strictly monitored by a specialized Beam Loss Monitoring (BLM) System to detect any abnormal losses and to ensure that operational losses do not lead to excessive activation. A long series of beam loss simulations was performed using MARS Monte Carlo code system in order to optimize the number and setting mounting locations of the detectors for best coverage, distinguishability and sensitivity. Simulations anticipated multiple possible beam loss scenarios resulting in different loss patterns. The results of energy deposition in air in the linac tunnel in multiple locations were analysed in several different ways. Incorporated methods varied from simple brute force approach to more sophisticated singular value decomposition based algorithms, all resulting in detector layout proposals. Locations selected for BLMs were evaluated for all methods.

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MOPTY060

Pulse Compressor Phase and Amplitude Modulation Based on Iterative Learning Control

klystron, controls, operation, experiment

1076

A. Řežaeizadeh, R. Kalt, T. Schilcher
PSI, Villigen PSI, Switzerland
R. Smith
Automatic Control Laboratory, ETH Zurich, Zurich, Switzerland

This paper presents an alternative way to produce flat-topped RF pulses at the pulse compressor output. Flat-topped RF pulses are suitable for multi-bunch operation where it is often required that beams experience the same accelerating gradient. Moreover, the energy gain, in this case, is less sensitive to timing jitters. The proposed approach is based on Iterative Learning Control technique, which iteratively updates the input waveforms, in order to generate the desired output waveforms.

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MOPTY061

Beam-Based Power Distribution Over Multiple Klystrons in a Linear Accelerator

klystron, high-voltage, controls, LLRF

1079

A. Řežaeizadeh, R. Kalt, T. Schilcher
PSI, Villigen PSI, Switzerland
R. Smith
Automatic Control Laboratory, ETH Zurich, Zurich, Switzerland

A linear accelerator including several klystron driver RF stations can be viewed as a single virtual RF station with a certain accelerating RF voltage (in amplitude and phase). This paper develops an optimization scheme that, for a specified beam energy gain, determines the klystrons output powers and the modulators high voltages optimally. The algorithm employs the klystron nonlinear static characteristics curves to calculate the input RF amplitude of the drive chain.
A. Řežaeizadeh, et al, Model-based klystron linearization in the SwissFEL test facility, 36th International Free Electron Laser Conference, Basel, Switzerland

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MOPWI002

Bunch Length Measurements using Synchrotron Light Monitor

emittance, synchrotron, injection, dipole

1143

M.M. Ali, M.G. Tiefenback
JLab, Newport News, Virginia, USA

The bunch length is measured at CEBAF using an invasive technique. The technique depends on applying an energy chirp for the electron bunch and imaging it through a dispersive region. The measurements are taken through Arc1 and Arc2 at CEBAF. The fundamental equations, procedure and the latest results are given.

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MOPWI003

Laserwire Emittance Scanner at CERN Linac 4

laser, detector, emittance, ion

1146

K.O. Kruchinin, G.E. Boorman, A. Bosco, S.M. Gibson, P. Karataev
Royal Holloway, University of London, Surrey, United Kingdom
E. Bravin, T. Hofmann, U. Raich, F. Roncarolo, F. Zocca
CERN, Geneva, Switzerland
A.P. Letchford
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
J.K. Pozimski
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Linac 4 presently under construction at CERN is designed to replace the existing 50 MeV Linac 2 in the LHC injector chain and will accelerate the beam of high current negative hydrogen ions to 160 MeV. During the commissioning a laserwire emittance scanner has been installed allowing noninvasive measuring of the emittance at 3 MeV and 12 MeV setups. A low power infrared fibre coupled laser was focused in the interaction region down to ~150 um and collided with the ion beam neutralising negative ions. At each transverse laser position with respect to the ion beam the angular distribution of the neutral particle beamlets was recorded by scanning a diamond detector across the beamlet at a certain distance from the IP while the main beam of the H⁻ ions was deflected using dipole magnet installed upstream the detector. Measuring the profile of the beamlet by scanning the laser across the beam allows to directly measure the transverse phase-space distribution and reconstruct the transverse beam emittance. In this report we will describe the analysis of the data collected during the 3 MeV and 12 MeV operation of the Linac 4. We will discuss the hardware status and future plans.

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MOPWI016

Development of a Versatile Bunch-length Monitor for Electron Beams at ASTA

laser, radiation, electron, optics

1181

A.H. Lumpkin, D.J. Crawford, D.R. Edstrom, J. Ruan, J.K. Santucci, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA

Funding: Work at Fermilab supported by Fermi Research Alliance, LLC under Contract No. DE-AC02- 07CH11359 with the United States Department of Energy.
The generation of bright electron beams at the ASTA/IOTA facility at Fermilab includes implementation of a versatile bunch-length monitor located after the 4-dipole chicane bunch compressor for electron beam energies of 20-50 MeV and integrated charges in excess of 10 nC. The station will include both a Hamamatsu C5680 synchroscan streak camera and a Martin-Puplett interferometer (MPI). An Al-coated Si screen will be used to generate both optical transition radiation (OTR) and coherent transition radiation (CTR) during the beam’s interaction with the screen. A chicane bypass beamline will allow the measurement of the initial bunch length at the same downstream beamline location using OTR and the streak camera. The UV component of the drive laser has previously been characterized with a Gaussian fit σ of 3.5 ps*, and the uncompressed electron beam is expected to be similar to this value at low charge per micropulse. In addition, OTR will be transported to the streak camera from the focal plane of the downstream spectrometer to provide an E-t distribution within the micropulse time scale. Commissioning of the system and initial results with beam will be presented as available.
*A.H. Lumpkin et al., Proceedings of FEL14, MOP021, Basel, Switzerland, www. JACoW.org.

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MOPWI021

The LCLS-II LLRF System

cavity, controls, LLRF, cryomodule

1195

C. Hovater, R. Bachimanchi
JLab, Newport News, Virginia, USA
S. Babel, B. Hong, D. Van Winkle
SLAC, Menlo Park, California, USA
B.E. Chase, E. Cullerton, P. Varghese
Fermilab, Batavia, Illinois, USA
L.R. Doolittle, G. Huang, A. Ratti, C. Serrano
LBNL, Berkeley, California, USA

Funding: This work was supported by the LCLS-II Project and the U.S. Department of Energy, Contract DE-AC02-76SF00515.
The SLAC National Accelerator Laboratory is planning an upgrade (LCLS-II) to the Linear Coherent Light Source with a 4 GeV CW superconducting (SCRF) linac. The SCRF linac consists of 35 ILC style cryomodules (eight cavities each) for a total of 280 cavities. Expected cavity gradients are 16 MV/m with a loaded QL of ~ 4x10⁷. The RF system will have 3.8 kW solid state amplifiers driving single cavities. To ensure optimum field stability a single source single cavity control system has been chosen. It consists of a precision four channel cavity receiver and RF stations (Forward, Reflected and Drive signals). In order to regulate the resonant frequency variations of the cavities due to He pressure, the tuning of each cavity is controlled by a Piezo actuator and a slow stepper motor. In addition the system (LLRF-amplifier-cavity) is being modeled and cavity microphonic testing has started. This paper describes the LLRF system under consideration, including recent modeling and cavity tests.

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MOPWI023

Development Plan for Physics Application Software for FRIB Driver Linac

software, ion, EPICS, operation

1201

M. Ikegami, G. Shen
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
FRIB is a heavy ion linac facility presently under construction at Michigan State University, USA, and its driver linac accelerates CW beams of all stable ions up to uranium to the energy of 200 MeV/u with the beam power of 400 kW. We plan to start beam commissioning of the driver linac from December 2017. An adequate software environment and infrastructure is critical for our commissioning and operation. Recently, a middle layer based architecture, EPICS V4 based services for example, for physics application has been rapidly developed at other facilities like NSLS II. It has been showing its flexibility, and portability. After reviewing those recent developments, we decided to adopt these services as software infrastructure for FRIB driver linac commissioning. It enables us to take advantage of their cutting edge technologies and maturity as a system sustained by the experience accumulated in the commissioning of NSLS-II. In this paper, we present a plan to develop physics application software for FRIB driver linac based on EPICS V4 services and related software. We also present a plan to adjust these EPICS V4 related software to meet the FRIB specific requirements.

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MOPWI025

Phase and Amplitude Tuning Algorithms for the FRIB Superconducting Cavities

cavity, acceleration, simulation, SRF

1207

Y. Zhang, P. Chu, Z.Q. He
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
FRIB driver linac will deliver all heavy ion beams up to uranium with energy above 200 MeV/u, and maximum beam power on target 400 kW for nuclear physics research. Phase and amplitude tuning of the FRIB superconducting cavities – totally about 330 of them, are important to the linac beam commissioning at low power and normal operation at high power. Because relatively low beam energy and high acceleration gradient, beam velocity changes significantly in the cavity RF gaps and the beam bunch cannot preserve perfectly in the further downstream beam diagnostics systems, beam longitudinal tuning algorithms are studied for different FRIB cavities and at different beam energy, which include the acceleration cavities as well as the re-buncher cavities.

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MOPWI026

Transverse Matching of Horizontal-Vertical Coupled Beams for the FRIB Linac

quadrupole, simulation, lattice, solenoid

1211

Y. Zhang, P. Chu, Z.Q. He, S.M. Lund, D.G. Maxwell
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
FRIB driver linac will deliver all heavy ion beams up to uranium with energy above 200 MeV/u, and maximum beam power on target 400 kW for nuclear physics research. Strong horizontal-vertical beam coupling exists in the FRIB linac since superconducting solenoids are applied to focus multi charge state beams. Further, the FRIB low beta SRF cavities have raised quadrupole field components. The combined effects make beam transverse matching challenging. In this paper, we study transverse matching of horizontal-vertical coupled beams based on beam profile measurements with multiple wire scanners. There are multiple solutions for the initial linac beams with coupling, and errors of the beam diagnostics and magnet power supplies introduce further complication. Nonetheless, simulation studies show that satisfactory transverse matching can be achieved with proper linac beam tuning.

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MOPWI033

Advantages to an Online Multi-particle Beam Dynamics Model for High-power Proton Linacs

operation, emittance, proton, beam-losses

1234

L. Rybarcyk, S.A. Baily, X. Pang
LANL, Los Alamos, New Mexico, USA

High-power proton linacs like the 800-MeV LANSCE accelerator typically use a physics-based approach and online single-particle and envelope beam dynamics models to establish nominal set points for operation. However, these models are not good enough to enable immediate transition to high-power operation. Instead, some amount of empirical adjustment is necessary to achieve stable, low beam-loss operation. At Los Alamos, we have been developing a new online model, which employs multiparticle beam dynamics, as a tool for providing more information and insight to the operations staff, especially during this transition to high-power operations. This presentation will discuss some of the advantages and benefits of using this type of tool in the tune-up and operation of a high-power proton linac.

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MOPWI046

eDT and Model-based Configuration of 12 GeV CEBAF

operation, controls, radiation, synchrotron

1259

D.L. Turner
JLab, Newport News, Virginia, USA

Funding: Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
This poster will discuss model-driven setup of CEBAF for the 12GeV era, focusing on the elegant Download Tool (eDT). eDT is a new operator tool that generates magnet design setpoints for various machine energies and pass configurations. eDT was developed in the effort towards a process for reducing machine configuration time and reproducibility by way of an accurate accelerator model.

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TUXB2

Upgrade of the Unilac for Fair

DTL, proton, ion, emittance

1281

L. Groening, A. Adonin, R. M. Brodhage, X. Du, R. Hollinger, O.K. Kester, S. Mickat, A. Orzhekhovskaya, B. Schlitt, G. Schreiber, H. Vormann, C. Xiao
GSI, Darmstadt, Germany
H. Hähnel, U. Ratzinger, A. Seibel, R. Tiede
IAP, Frankfurt am Main, Germany

The UNIversal Linear Accelerator (UNILAC) at GSI serves as injector for all ion species from protons to uranium since four decades. Its 10⁸ MHz Alvarez type DTL providing acceleration from 1.4 MeV/u to 11.4 MeV/u has suffered from material fatigue. The DTL will be replaced by a completely new section with almost same design parameters, i.e. pulsed current of up to 15 mA of 238U²⁸⁺ at 11.4 MeV/u. A dedicated terminal & LEBT for operation with 238U⁴⁺ is currently constructed. The uranium sources need to be upgraded in order to provide increased beam brilliances and for operation at 3 Hz. In parallel a 70 MeV / 70 mA proton linac based on H-mode cavities is under design and construction. This contribution will also give a brief summary of the overall status of the FAIR project.

Slides TUXB2 [4.634 MB]

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TUYB1

Progress of SuperKEKB

emittance, positron, electron, gun

1291

T. Miura, T. Abe, T. Adachi, K. Akai, M. Akemoto, A. Akiyama, D.A. Arakawa, Y. Arakida, Y. Arimoto, M. Arinaga, K. Ebihara, K. Egawa, A. Enomoto, J.W. Flanagan, S. Fukuda, H. Fukuma, Y. Funakoshi, K. Furukawa, T. Furuya, K. Hara, T. Higo, H. Hisamatsu, H. Honma, T. Honma, R. Ichimiya, N. Iida, H. Iinuma, H. Ikeda, M. Ikeda, T. Ishibashi, H. Ishii, M. Iwasaki, A. Kabe, T. Kageyama, H. Kaji, K. Kakihara, S. Kamada, T. Kamitani, S. Kanaeda, K. Kanazawa, H. Katagiri, S. Kato, S. Kazama, M. Kikuchi, T. Kobayashi, H. Koiso, Y. Kojima, M. Kurashina, K. Marutsuka, M. Masuzawa, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, F. Miyahara, K. Mori, T. Mori, A. Morita, Y. Morita, H. Nakai, H. Nakajima, T.T. Nakamura, K. Nakanishi, K. Nakao, H. Nakayama, T. Natsui, M. Nishiwaki, J.-I. Odagiri, Y. Ogawa, K. Ohmi, Y. Ohnishi, S. Ohsawa, Y. Ohsawa, N. Ohuchi, K. Oide, T. Oki, M. Ono, H. Sakai, Y. Sakamoto, S. Sasaki, M. Sato, M. Satoh, K. Shibata, T. Shidara, M. Shirai, A. Shirakawa, M. Suetake, Y. Suetsugu, R. Sugahara, H. Sugimoto, T. Suwada, S. Takasaki, T. Takatomi, T. Takenaka, Y. Takeuchi, M. Tanaka, M. Tawada, S. Terui, M. Tobiyama, N. Tokuda, K. Tsuchiya, X. Wang, K. Watanabe, H. Yamaoka, Y. Yano, K. Yokoyama, Ma. Yoshida, M. Yoshida, S.I. Yoshimoto, K. Yoshino, R. Zhang, D. Zhou, X. Zhou, Z.G. Zong
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

This presentation will cover the status of the installation and the injector commissioning status of SuperKEKB. The IR optics and design with very low β^* of less than 1 mm will be discussed.

Slides TUYB1 [6.588 MB]

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TUYB2

Accelerator Physics in ERL Based Polarized Electron Ion Collider

electron, ion, luminosity, radiation

1296

Y. Hao
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
This talk will present the current accelerator physics challenges and solutions in designing ERL-based polarized electron-hadron colliders, and illustrate them with examples from eRHIC and LHeC designs. These challenges include multi-pass ERL design, highly HOM-damped SRF linacs, cost effective FFAG arcs, suppression of kink instability due to beam-beam effect, and control of ion accumulation and fast ion instabilities.

Slides TUYB2 [14.101 MB]

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TUBB1

Charge Stripper Development for FRIB

ion, heavy-ion, proton, plasma

1339

F. Marti, P. Guetschow, J.A. Nolen
FRIB, East Lansing, Michigan, USA
A. Hershcovitch, P. Thieberger
BNL, Upton, Long Island, New York, USA
Y. Momozaki, J.A. Nolen, C.B. Reed
ANL, Argonne, Illinois, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 and NSF grant PHY-1102511
The Facility for Rare Isotope Beams (FRIB) at Michigan State University is building a heavy ion linac to produce rare isotopes by the fragmentation method. The linac will accelerate ions up to U to energies above 200 MeV/u with beam powers up to 400 kW. At energies between 16 and 20 MeV/u the ions will be stripped to higher charge states to increase the energy gain downstream in the linac. The main challenges in the stripper design are due to the high power deposited by the ions in the stripping media (~ 30 MW/cm³) and radiation damage if solids are used. For that reason self-recovering stripper media must be used. The baseline stripper choice is a high-velocity, thin film of liquid lithium with an alternative option of a helium gas stripper. We present in this paper the status of the R&D and construction of the final stripper. Extensive experimental work has been performed on both options.

Slides TUBB1 [3.534 MB]

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TUAD3

LLRF Commissioning of the European XFEL RF Gun and Its First Linac RF Station

LLRF, cryomodule, gun, electronics

1377

J. Branlard, G. Ayvazyan, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hoffmann, F. Ludwig, U. Mavrič, M. Omet, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, K. Oliwa, J. Piekarski, K.T. Pozniak, I. Rutkowski, R. Rybaniec, D. Sikora, W. Wierba, L.Z. Zembala, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
W. Cichalewski, D.R. Makowski, A. Mielczarek, P. Perek
TUL-DMCS, Łódź, Poland
A. Piotrowski
FastLogic Sp. z o.o., Łódź, Poland

The European X-ray free electron laser (XFEL) at the Deutsches Elektronen-Synchrotron (DESY), Hamburg Germany is in its construction phase. Approximately a third of the super-conductive cryomodules have been produced and tested. The RF gun is installed since 2013; periods of commissioning are regularly scheduled between installation phases of the rest of the injector. The first linac, L1, consisting of 4 cryomodules powered by one 10 MW klystron is installed and being commissioned. This contribution reports on the installation and preparation work of the low-level radio frequency system (LLRF) to perform the commissioning of the XFEL first components. The commissioning plans, schedule and first results are presented.

Slides TUAD3 [14.016 MB]

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TUBD2

Final Cooling For a High-luminosity High-energy Lepton Collider

emittance, collider, luminosity, solenoid

1384

D.V. Neuffer
Fermilab, Batavia, Illinois, USA
T.L. Hart, D.J. Summers
UMiss, University, Mississippi, USA
H. K. Sayed
BNL, Upton, Long Island, New York, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the U. S. Department of Energy.
The final cooling system for a high-energy high-luminosity muon collider requires reduction of the transverse emittance by an order of magnitude to ~0.00003 m (rms, N), while allowing longitudinal emittance increase to ~0.1m. In the present baseline approach, this is obtained by transverse cooling of low-energy muons within a sequence of high field solenoids with low-frequency rf systems. Recent studies of such systems are presented. Since the final cooling steps are actually emittance exchange a variant form of that final system can be obtained by a round to flat transform in x-y, with transverse slicing of the enlarged flat transverse dimension followed by longitudinal recombination of the sliced bunchlets. Development of final exchange following lowest-emittance cooling is discussed.

Slides TUBD2 [1.976 MB]

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TUBD3

Effects of Accelerating Structures on On-line DFS in the Main Linac of CLIC

wakefield, emittance, dipole, simulation

1387

J. Pfingstner, E. Adli
University of Oslo, Oslo, Norway
D. Schulte
CERN, Geneva, Switzerland

Long-term ground motion will create significant dispersion in the time-scale of hours in the main linac of CLIC. To preserve the emittance to an acceptable level, a dispersion correction with on-line dispersion-free steering (DFS) is inevitable. For this on-line technique, the dispersion has to be measured using beam energy variations of only about one per mil in order to not disturb the operation of the accelerator. For such small energy variations, the interaction of the particle beam and the accelerating structures creates large enough additional signals components in the measured dispersion to cause the dispersion correction to not work properly anymore. In this paper, the additional signals are described and their effect on the DFS algorithm is analysed. Finally, methods for the mitigation of the deteriorating signal components are presented and studied via simulations.

Slides TUBD3 [1.697 MB]

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TUPWA002

Layout Options for the AXXS Injector and XFEL

storage-ring, FEL, lattice, dipole

1394

M.J. Boland, Y.E. Tan, D. Zhu
SLSA, Clayton, Australia

A new injector is being planned for the Australian Synchrotron that is designed to feed both an upgraded storage ring and an XFEL. The desire to fit the AXXS project on the same site as the existing light source presents several layout difficulties. Several options are studied and simulations are performed to check the impact each choice has on the beam performance.

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TUPWA005

Comparison of Bunch Compression Schemes for the AXXS FEL

simulation, FEL, electron, synchrotron

1399

T.K. Charles, D.M. Paganin
Monash University, Faculty of Science, Clayton, Victoria, Australia
A.A. Aksoy
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
M.J. Boland, R.T. Dowd
SLSA, Clayton, Australia
A. Latina, D. Schulte
CERN, Geneva, Switzerland

Different types of electron bunch compression schemes are compared for the AXXS FEL design study. The main linac for the proposed machine is based on CLIC x-band structures. This choice leaves several options for the bunch compression schemes which impact the injection system RF band. Both harmonic linearization and phase modulation linearization are considered and their relative strengths and weaknesses compared. Simulations were performed to compare the performance of an s-band injector with a higher harmonic RF linearization and an x-band injector. One motivation for the study is to optimise the length of the AXXS machine, allowing the linac to fit onto the proposed and also act as the injector to the existing storage ring at the Australian Synchrotron.

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TUPWA009

50 MeV Electron Linac with a RF Gun and a Thermoionic Cathode

gun, cavity, focusing, cathode

1413

A.S. Setty, A.S. Chauchat, D. Fasse, D. Jousse, P. Sirot
Thales Communications & Security (TCS), Gennevilliers Cedex, France

The low energy part of our pre injectors is made up of a 90 kV DC themoionic trioode gun, followed by a 500 MHz sub harmonic prebuncher and a 3 GHz prebuncher. We propose a new design for a 50 MeV linac with a RF gun *. this study will compare the beam dynamics simulations for the new design and for our previous pre injectors.
* A. Setty et al. "Study of a RF gun with a Thermoionic Cathode", Proceeding IPAC 2014, Germany, Dresden, June 2014.

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TUPWA020

BNL ATF II Beamlines Design

experiment, electron, laser, cavity

1445

M.G. Fedurin, Y.C. Jing, D. Stratakis, C. Swinson
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Brookhaven National Lab. Accelerator Test Facility (BNL ATF) is currently undergoing a major upgrade (ATF-II). Together with a new location and much improved facilities, the ATF will see an upgrade in its major capabilities: electron beam energy and quality and CO2 laser power. The electron beam energy will be increased in stages, first to 100-150 MeV followed by a further increase to 500 MeV. Combined with the planned increase in CO2 laser power (from 1-100 TW), the ATF-II will be a powerful tool for Advanced Accelerator research. A high-brightness electron beam, produced by a photocathode gun, will be accelerated and optionally delivered to multiple beamlines. Besides the energy range (up to a possible 500 MeV in the final stage) the electron beam can be tailored to each experiment with options such as: small transverse beam size (<10 um), flat beam, short bunch length (<100 fs) and, combined short and small bunch options. This report gives a detailed overview of the ATF-II capabilities and beamlines configuration.

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TUPWA028

Simulation Results of the Beam Transport of Ultra-Short Electron Bunches in Existing Beam Transfer Lines to Sinbad

optics, gun, electron, synchrotron

1466

U. Dorda, R.W. Aßmann, K. Flöttmann, B. Marchetti, Y.C. Nie, J. Zhu
DESY, Hamburg, Germany

SINBAD, the upcoming accelerator R&D facility at DESY, will host multiple independent experiments on the production and acceleration of ultra-short bunches including plasma wakefield experiments. As a possible later upgrade the option to transport higher energy electrons (up to 800 MeV) or positrons (up to 400 MeV) from the existing DESY Linac 2 to the facility is studied. Though existing a possible connection using e.g. a part of the DESY synchrotron as a transfer line and other currently unused transfer-line, these machines were not designed for the desired longitudinal bunch compression and high peak current required by e.g. beam driven plasma wake-field experiments. Simulation results illustrate the modifications to the current layout that would have to be implemented and the corresponding achievable beam parameters are given.

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TUPWA029

ARES: Accelerator Research Experiment at SINBAD

electron, cavity, bunching, experiment

1469

B. Marchetti, R.W. Aßmann, C. Behrens, R. Brinkmann, U. Dorda, K. Flöttmann, J. Grebenyuk, M. Hüning, Y.C. Nie, H. Schlarb, J. Zhu
DESY, Hamburg, Germany

ARES is a planned linear accelerator for R&D for production of ultra-short electron bunches. It will be hosted at the SINBAD facility, at DESY in Hamburg*. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with high arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration**. The baseline layout of the accelerator foresees an S-band photo-injector which compresses low charge electron bunches via velocity bunching and accelerates them to 100 MeV energy. In the second stage, it is planned to install a third S-band accelerating cavity to reach 200 MeV as well as two X-band cavities: One for the linearization of the longitudinal phase space (subsequently allowing an improved bunch compression) and another one as a transverse deflecting cavity for longitudinal beam diagnostics. Moreover a magnetic bunch compressor is envisaged allowing to cut out the central slice of the beam*** or hybrid bunch compression.
* R. Assmann et al., TUPME047, Proceedings of IPAC 2014.
** R. Assmann, J. Grebenyuk, TUOBB01, Proceedings of IPAC 2014.
*** P. Emma et al., PRL 92 7 (2004).

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TUPWA031

Compression of Train of Bunches with Ramped Intensity Profile at SPARC_LAB

laser, cathode, plasma, electron

1476

B. Marchetti
DESY, Hamburg, Germany
A. Bacci
Istituto Nazionale di Fisica Nucleare, Milano, Italy
E. Chiadroni, M. Ferrario, R. Pompili
INFN/LNF, Frascati (Roma), Italy
A. Cianchi
Università di Roma II Tor Vergata, Roma, Italy

The production and acceleration of train of bunches with variable spacing in the ps/sub-ps range having ramped intensity profile are interesting to drive a plasma wave in the so-called resonant Plasma Wake-Fields Acceleration (r-PWFA)*. At SPARC_LAB trains having a constant intensity profile have been produced for the first time by using a shaped photo-cathode laser combined with the use of the velocity bunching compression technique**,***,****. If the sub-bunches have ramped intensity, i.e. they have different charge density, the space charge force affects differently the development of the longitudinal phase space of each one of them during the compression. In this paper we present preliminary simulations for the compression of a ramped train of bunches. The differences between the beam dynamics for a train of bunches having constant intensity profile and the ramped train are underlined. We discuss also the possibility of properly tuning the shaping of the photocathode laser to balance the space charge effect.
* SLAC-PUB-3528
** M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010).
*** M. Ferrario et al. NIM A 637, S43-S46 (2011).
**** E. Chiadroni et al., Rev. Sci. Instrum. 84, 022703

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TUPWA032

Progress in the Injector Upgrade of the LINAC II at DESY

electron, gun, simulation, solenoid

1479

Y.C. Nie, M. Hüning, C. Liebig, M. Schmitz
DESY, Hamburg, Germany

A new injection system is under development for the LINAC II at DESY to improve the reliability of the machine and mitigate the radiological problem due to electron losses at energy of hundreds of MeV. It consists of a 100 kV triode DC gun, a 2.998 GHz pre-buncher, a novel 2.998 GHz hybrid buncher, and the dedicated beam transport and diagnostic elements. As the key components, the pre-buncher and the hybrid buncher realize a two-stage velocity bunching process including the ballistic bunching and the phase space rotation. Therefore, they produce a certain number of well-bunched 5 MeV micro-bunches from the input 2 ns-50 ns electron pulse for the downstream LINAC II. The overall upgrade plan, developments of the critical components, as well as the latest beam test results will be reported.

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TUPWA035

Progress in Optics Studies at FLASH

optics, quadrupole, FEL, free-electron-laser

1488

J. Zemella, T. Hellert, M. Scholz, M. Vogt
DESY, Hamburg, Germany

FLASH is the superconducting soft X-ray Free Electron Laser in Hamburg at DESY, Germany. Good control over the beam optics is a key aspect of the operation of a SASE FEL. In 2013 a second beam line, FLASH2, was assembled and the modifications necessary to feed the two beam lines were installed downstream of the FLASH linac. As reported before * we started a campaign of optics consolidation. We give an update on the progress of this effort and on results.
* J. Zemella, T. Hellert, M.Scholz, M.Vogt, "Measurements of the Optical Functions at FLASH", Proc. of IPAC'14, TUPRO050.

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TUPWA042

Status of the Accelerator Physics Test Facility FLUTE

electron, gun, diagnostics, laser

1506

M.J. Nasse, A. Bernhard, I. Birkel, A. Borysenko, A. Böhm, S. Hillenbrand, N. Hiller, S. Höninger, S. Marsching, A.-S. Müller, R. Rossmanith, R. Ruprecht, M. Schuh, M. Schwarz, B. Smit, S. Walther, M. Weber, P. Wesolowski
KIT, Karlsruhe, Germany
R.W. Aßmann, M. Felber, K. Flöttmann, C. Gerth, M. Hoffmann, P. Peier, H. Schlarb, B. Steffen
DESY, Hamburg, Germany
R. Ischebeck, B. Keil, V. Schlott, L. Stingelin
PSI, Villigen PSI, Switzerland

A new compact versatile linear accelerator named FLUTE (Ferninfrarot Linac Und Test Experiment) is currently under construction at the Karlsruhe Institute of Technology (KIT). It will serve as an accelerator test facility and allow conducting a variety of accelerator physics studies. In addition, it will be used to generate intense, ultra-short THz pulses for photon science experiments. FLUTE consists of a ~7 MeV photo-injector gun, a ~41 MeV S-band linac and a D-shaped chicane to compress bunches to a few femtoseconds. This contribution presents an overview of the project status and the accompanying simulation studies.

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TUPWA045

Further Investigations on the MESA injector

coupling, simulation, space-charge, experiment

1515

R.G. Heine, K. Aulenbacher, S. Friederich, C. Matejcek, F. Schlander
IKP, Mainz, Germany

Funding: work supported by the German Federal Ministery of Education and Research under the Cluster of Excellence "PRISMA"
The MESA ERL to be build at Mainz in the next years is a multi turn recirculating linac with beam currents of up to 10 mA. The dynamic range of the beam currents demanded by the experiments is of at least two orders of magnitude. This is a special challenge for the layout design of an injector. In this paper we present the current status of the design of the injector linac called MAMBO (MilliAMpereBOoster).

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TUPWA053

Influence of a Non-uniform Longitudinal Heating on High Brightness Electron Beams for FEL

electron, laser, FEL, undulator

1535

E. Roussel, E. Allaria, M.B. Danailov, G. De Ninno, S. Di Mitri, E. Ferrari, D. Gauthier, L. Giannessi, G. Penco
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Laser-heater systems are essential tools to control and optimize high-gain free electron lasers (FELs), working in the x-ray wavelength range. Indeed, these systems induce a controllable heating of the energy spread of the electron bunch. The heating allows in turn to suppress longitudinal microbunching instabilities limiting the FEL performance. In this communication, we show that a long-wavelength energy modulation of the electron beam induced by the laser heater can persist until the beam entrance in the undulators, affecting the FEL emission process. This non-uniform longitudinal heating can be exploited to investigate the electron-beam microbunching in the linac, as well as to control the FEL spectral properties. Here, we present experimental, analytical and numerical studies carried out at FERMI.

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TUPWA056

New Gun Implementation and Performance of the DAΦNE LINAC

gun, cathode, electron, operation

1546

B. Buonomo, L.G. Foggetta, G. Piermarini
INFN/LNF, Frascati (Roma), Italy

A new electron gun system has been developed for DAΦNE LINAC, and put into operation since January 2014. Several elements of the system were upgraded, including a new grid pulser, an improved bias voltage system and a renewed cathode socket. The new LINAC gun has now a wider range of parameters, i.e. the emission pulse length spans from 1.4ns up to 40ns, while the better control of the grid and bias voltage allows a maximum peak current of 5A with a pulse repetition rate of 50 Hz. This paper describes the details of the pulser, the power supply, the socket, all the service components of the upgraded gun and its integration in the main LINAC control system. A report on the performance of the LINAC with the new gun will follow.

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TUPWA057

DAΦNE LINAC: Beam Diagnostics and Outline of the Last Improvements

klystron, electron, positron, operation

1549

B. Buonomo, L.G. Foggetta
INFN/LNF, Frascati (Roma), Italy

The LINAC of the DAΦNE complex is in operation since 1996, both as injector of the e⁺ e⁻ phi-factory, and, since 2003, for the extraction of electron beam to the Beam Test Facility. In the last years, many improvements has been developed in different sub-systems of the LINAC, aiming at a wider, tunable range of beam parameters, in particular the pulse time width and the pulse charge. A long term measurement campaign has been recently started to characterize the LINAC performance after that many sub-systems has been overhauled and improved, starting from RF power (i.e. klystron substitution, modulator re-newing, RF driver layout, SLED tuning) as well as the timing system, magnets, cooling, vacuum, control system and energy/position diagnostics. This work reports the latest results on the optimization of the fully consolidated system.

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TUPWA058

Study of a C-band Harmonic RF System to Optimize the RF Bunch Compression Process of the SPARC Beam

cavity, gun, experiment, emittance

1552

A. Gallo, D. Alesini, M. Bellaveglia, M. Ferrario
INFN/LNF, Frascati (Roma), Italy
A. Bacci, V. Petrillo, A.R. Rossi, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
F. Cardelli, L. Piersanti
INFN-Roma1, Rome, Italy
B. Marchetti
DESY, Hamburg, Germany
M. Rossetti Conti
Universita' degli Studi di Milano & INFN, Milano, Italy

The SPARC linac at the INFN Frascati Labs is a high brilliance electron source with a wide scientific program including production of THz and Thomson backscattering radiation, FEL studies and plasma wave acceleration experiments. The linac is based on S-band RF and consists in an RF Gun followed by 3 accelerating structures, while an energy upgrade based on 2 C-band accelerating structures is ready to be implemented. Short bunches are ordinarily produced by using the linear RF bunch compression concept. A harmonic RF structure interposed between the Gun and the 1st accelerating structure can be used to optimize the RF compression by a longitudinal phase space pre-correction, allowing to reach shorter bunches, a much more uniform current distribution and in general to control better the whole compression process. Here we report the results of numerical studies on the SPARC bunch compression optimization through the use of a harmonic cavity, and the design of a C-band RF system to implement it. The proposed system consists in a multi-cell SW cavity powered by a moderate portion of the total RF power spilled from the C-band power plant already installed for the linac energy upgrade.

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TUPWA069

Simulation Study on Bunch Compression and Decompression for the Compact ERL

sextupole, simulation, optics, emittance

1591

N. Nakamura, K. Harada, T. Miyajima, S. Sakanaka, M. Shimada, O. Tanaka
KEK, Ibaraki, Japan

Generation of THz coherent radiation (THz-CSR) is planned for the near future at the Compact Energy Recovery Linac (cERL) in KEK where the beam recirculation and energy recovery were already achieved in February 2014 and an experiment for generation of laser-Compton scattering X-rays (LCS-X) is being prepared to start in February 2015. To achieve a ultra-short bunch less than 100 fs for generation of the THz-CSR up to 5 THz, we have studied bunch compression and decompression in the cERL mainly by using a simulation code ELEGANT. In this study, off-crest acceleration in the main superconducting linac and non-zero R56 optics in the two arc sections are used and sextupole magnets are introduced into the two arc sections for correcting T566 of the arc sections. In this paper, we will present the simulation results and the requirements for the sextupole magnets including their number and layout.

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TUPJE002

Demonstration of High-flux Photon Generation from an ERL-based Laser Compton Photon Source

laser, photon, electron, cavity

1607

R. Nagai, R. Hajima, M. Mori, T. Shizuma
JAEA, Ibaraki-ken, Japan
T. Akagi, S. Araki, Y. Honda, A. Kosuge, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

A high-flux photon source from the laser Compton scattering (LCS) by an electron beam in an energy-recovery linac (ERL) is a key technology for a nondestructive assay system to identify nuclear materials. In order to demonstrate accelerator and laser technologies required for a LCS photon generation, a LCS photon source is under construction at the Compact ERL (cERL). The LCS photon source consists of a mode-locked fiber laser and a laser enhancement cavity. Flux monitors and a data aqcuisition system are also under construction. The commissioning of the LCS photon source will be started in February 2015 and LCS photon generation is scheduled in March 2015. The demonstration result of the LCS photon source will be presented in detail.

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TUPJE007

Measurement of Temporal Electric Field of Electron Bunch using Photoconductive Antenna

electron, laser, polarization, radiation

1623

K. Kan, M. Gohdo, T. Kondoh, I. Nozawa, A. Ogata, T. Toigawa, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

A temporal electric field profile, which is a radially polarized terahertz (THz) pulse from an electron bunch, was measured by a large-aperture photoconductive antenna (PCA) with micro-structured concentric electrodes* for the detection of THz pulses. Photo-induced charge carriers were generated by irradiation of femtosecond laser pulses on semiconductor plane of the electrodes on the PCA. Time-domain measurement of coherent transition radiation (CTR) was conducted by the measurement of electric-field-induced current output from the PCA with sweeping the timing of the laser irradiation. The measurements on femtosecond electron bunches of 32 MeV and >80 pC will be reported.
* K. Kan et al., Appl. Phys. Lett. 102, 221118 (2013).

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TUPJE008

Relocation and Improvement Status of the SCSS Test Accelerator to Provide Dual FEL Drivers at SACLA

acceleration, undulator, electron, laser

1626

Y. Otake
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

To increase user experiment chances at SACLA, Equipping a new beamline and an additional linac as a further FEL driver is effective. For this reason, the SCSS test accelerator as the prototype of SACLA is reused and improved, because of terminating its role. SCSS with an electron beam energy of 250 MeV generated an extreme ultraviolet laser with 50-60 nm. We relocated SCSS into the SACLA undulator hall and improved its performance. Three newly designed C-band accelerator-units for the relocated SCSS accelerator with an acceleration gradient of 47 MeV/m at maximum boost an electron beam energy of up to 420 MeV. By FEL simulation, the EUV-FEL with 30-40 nm and 100 uJ are expected in conditions of the electron energy and 2 modified undulators with 5 m long each. As a further capability, the relocated SCSS accelerator has space to add 9 C-band accelerator units and 2 undulators and the units increase a beam energy of up to 1.4 GeV, as which can generate a soft X-ray FEL. The relocation of the accelerator was finished in the summer of 2014 and its RF conditioning was now started. This paper describes the relocation and improvement status of the modified SCSS accelerator.

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TUPJE011

Laser-Compton Scattering X-ray Source Based on Normal Conducting Linac and Optical Enhancement Cavity

laser, cavity, electron, photon

1635

K. Sakaue, M. Washio
Waseda University, Tokyo, Japan
S. Araki, M.K. Fukuda, Y. Honda, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

Funding: Work supported by Photon and Quantum Basic Research Coordinated Development Program from the Ministry of Education, Culture, Sports, Science and Technology, Japan.
We have been developing a compact X-ray source via laser-Compton scattering (LCS) at KEK-LUCX (Laser Undulator Compact X-ray source) facility. The LUCX system is based on S-band normal conducting linac with an energy of 30 MeV and optical enhancement cavity for photon target. As a photon target, we invented a burst mode laser pulse storage technique for a normal conducting linac, which enables to store the high power laser pulses at the timing of electron bunchs. The peak storage power exceeds to more than 250 kW with 357 MHz repetition. Electron linac is under operation with multi-bunch mode, 1000 bunches/train with 600 pC charge in each bunches. We have succeeded to produce 1000 pulse/train LCS X-ray train. Combining high repetition rate electron linac and burst mode optical enhancement cavity, more than 10⁹ ph./sec/10%b.w. flux would be possible. In this conference, the introduction of our test facility LUCX, recent expermental results, and future prospective including normal conducting LCS X-ray source will be presented.

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TUPJE014

An X-Band Linac with Tunable Beam Energy

electron, simulation, gun, software

1644

L. Zhang, H.B. Chen, Y.-C. Du, Q.X. Jin, J. Shi, C.-X. Tang, P. Wang, Z. Zhang
TUB, Beijing, People's Republic of China

The low-energy X-band linac has a wide application in medical imaging. In this paper, an X-band linac is designed to produce beam energy between 0.5MeV and 1.5MeV, and the output beam energy is continuously adjustable within this range. Two sections of linacs are combined and powered by a single microwave source. During the experiment, we can tune the RF phase and amplitude of the second section of the linac, the electron beam can see either acceleration or deceleration, which tunes the output energy. This paper presented the production of the whole linac system, as well as the measurement of the continuously-adjustable beam energy.

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TUPJE041

Progress on a Compact Accelerator Design for a Compton Light Source

gun, dipole, space-charge, solenoid

1706

K.E. Deitrick, J.R. Delayen, B.R.P. Gamage, G.A. Krafft, T. Satogata
ODU, Norfolk, Virginia, USA

A compact Compton light source using an electron linear accelerator is in design at the Center for Accelerator Science at Old Dominion University and Jefferson Lab. We report on the current design, including beam properties through the entire system based on a full end-to-end simulation, compare current specifications to design goals, and target areas for improvement.

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TUPJE049

TPS Linac Relocation and Beam Test of the LTB Transfer Line

optics, electron, quadrupole, injection

1731

H.-P. Chang, A.Y. Chen, C.L. Chen, Y.-S. Cheng, C.-S. Fann, K.T. Hsu, S.Y. Hsu, K.-K. Lin, Y.C. Lin, J. Liu, K.L. Tsai
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) 150 MeV linac has been relocated from its 2011 test site to the TPS linac tunnel in 2014. After functional test of the linac hardware modules, the beam parameters were carefully examined at a 31-degree bend diagnostic beam line LTD (linac to beam dump) and compared with previous results. Then, the 150 MeV electron beam was delivered to the linac to booster transfer line (LTB) for beam commissioning. The beam optics matching at both the LTB entrance (i.e. linac exit) and the LTB exit (i.e. injection point of booster) was performed for injection optimization purpose. The LTB lattice setting was verified in the beam steering through LTD and LTB with the help of diagnostics tools such as beam profile monitors (SM) and beam position monitors (BPM). The overall performance of the linac and LTB will be described in this report.
#peace@nsrrc.org.tw

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TUPJE052

Bunch Compression in the Driver Linac for the Proposed NSRRC VUV FEL

electron, optics, gun, FEL

1738

N.Y. Huang, W.K. Lau, A.P. Lee
NSRRC, Hsinchu, Taiwan
A. Chao, K. Fang, M.-H. Wang, J. Wu
SLAC, Menlo Park, California, USA

A bunch compressor is designed for the S-band driver linac system of the proposed NSRRC VUV free electron laser (FEL). Instead of using a more conventional rf harmonic linearizer, one main feature of this compressor is to use electron linearization optics to correct the nonlinearity in the energy-time correlation of the electron bunch longitudinal phase space. The strategy of compressor design will be discussed by an analytical calculation and particle tracking simulation. The beam dynamics which include the collective instabilities such as the space charge effects, the wake fields and the coherent synchrotron radiation (CSR) effects are discussed.

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TUPJE053

Hardware Improvements and Beam Commissioning of the Booster Ring in Taiwan Photon Source

booster, hardware, synchrotron, injection

1741

H.-J. Tsai, C.-T. Chen, J.Y. Chen, M.-S. Chiu, P.C. Chiu, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, Y.-C. Liu, G.-H. Luo, F.H. Tseng
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS), a low emittance 3-GeV third-generation synchrotron light source, began its hardware integration testing, safety checkout and beam commissioning on August 12, 2014 [1]. The booster ring and the storage ring share the same tunnel in a concentric fashion; the booster ring has circumference 496.8 m, the largest among light source facilities in operation. A combined-function FODO lattice is adopted for the booster ring with natural emittance 10 nm-rad. After hardware improvements were completed, the commissioning of the beam in the booster ring began on December 12 and attained the 3-GeV design energy on December 16.

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TUPJE054

Developments in CLARA Accelerator Design and Simulations

FEL, laser, simulation, undulator

1744

P.H. Williams, D. Angal-Kalinin, A.D. Brynes, F. Jackson, J.K. Jones, J.W. McKenzie, B.L. Militsyn, B.D. Muratori, N. Thompson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom

We present recent developments in the accelerator design of CLARA (Compact Linear Accelerator for Research and Applications), the proposed UK FEL test facility at Daresbury Laboratory. The layout changes include a dedicated collimator in CLARA front end to provide some control over the dark current, changes to low energy diagnostics section and modifications to FEL modules. The progress in the design simulations mainly focus on injector simulations incorporating wake fields in ASTRA, comparison of using ELEGANT and CSRTRACK for the Variable Bunch Compressor and first considerations of requirement of laser heater for CLARA.

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TUPJE059

Modeling of an Electron Injector for the AWAKE Project

emittance, space-charge, booster, quadrupole

1762

Ö. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
R. Apsimon, G. Burt
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
S. Döbert
CERN, Geneva, Switzerland
R.B. Fiorito
The University of Liverpool, Liverpool, United Kingdom
C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Cockcroft Institute Core Grant
Particle in cell simulations were performed to characterise an electron injector for AWAKE project in order to provide a tuneable electron beam within a range of specifications required by the plasma wakefield experiments. Tolerances and errors were investigated. These results are presented in this paper alongside with the investigation regarding the beam dynamics implications of the 3GHz travelling wave structure developed for the injector.

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TUPJE081

Model of Dark Current in SRF Linac

cavity, electron, radiation, quadrupole

1834

A.I. Sukhanov, A. Saini, N. Solyak, I.S. Tropin
Fermilab, Batavia, Illinois, USA

Currently, few linacs based on 9-cell TESLA-type SRF cavities are being designed or bult, including XEFL, LCLS-II and ILC. Dark current electron generated by field emission in SRF cavities can be captured and accelerated in the linac up to hundreds MeV before they removed by focusing magnets. Lost dark current electrons interact with the materials surrounding SRF cavities and magnets, produce electromagnetic showers and contribute to the radiation in the linac tunnel. In this paper we present a model of dark current in a linac based on TESLA cavities. We show preliminary results of the simulation applied to ILC main linac.

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TUPMA026

Status of the MaRIE X-FEL Accelerator Design

emittance, FEL, electron, undulator

1894

J.W. Lewellen, K. Bishofberger, B.E. Carlsten, L.D. Duffy, F.L. Krawczyk, Q.R. Marksteiner, D.C. Nguyen, S.J. Russell, R.L. Sheffield, N.A. Yampolsky
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the MaRIE program at Los Alamos National Laboratory, under contract DE-AC52-06NA25396
The Matter-Radiation Interactions in Extremes (MaRIE) facility is intended to probe and control the time-dependent properties of materials under extreme conditions. At its core, the “MaRIE 1.0” X-FEL is being designed to deliver pulse trains of ~10¹⁰ 42 keV photons, with a minimum bunch spacing of 2.4 ns, enabling time-dependent studies particularly of mesoscale phenomena. The X-FEL accelerator is also intended to deliver a series of 2 nC electron bunches to enable electron radiography concurrently with the X-ray pulse train, so as to provide multi-probe capability to MaRIE. In 2014, the reference design for the MaRIE X-FEL 12 GeV driver linac was changed from an S-band normal-conducting to an L-band superconducting linac to accommodate pulse trains up to 100 μs in duration. This paper does not present a complete solution for the MaRIE linac design; rather it describes our current reference design, achieved parameters, areas of concern and paths towards mitigation of identified issues.

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TUPMA042

THz Radiation Generation in a Multimode Wakefield Structure

radiation, wakefield, experiment, electron

1929

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, D. Wang, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571
A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.

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TUPMA050

NSLS-II Injector Commissioning and Initial Operation

booster, storage-ring, operation, injection

1944

E.B. Blum, B. Bacha, G. Bassi, J. Bengtsson, A. Blednykh, S. Buda, W.X. Cheng, J. Choi, J. Cupolo, R. D'Alsace, M.A. Davidsaver, J.H. De Long, L. Doom, D.J. Durfee, R.P. Fliller, M. Fulkerson, G. Ganetis, F. Gao, C. Gardner, W. Guo, R. Heese, Y. Hidaka, Y. Hu, M.P. Johanson, B.N. Kosciuk, S. Kowalski, S.L. Kramer, S. Krinsky, Y. Li, W. Louie, M.A. Maggipinto, P. Marino, J. Mead, J. Oliva, D. Padrazo, K. Pedersen, B. Podobedov, R.S. Rainer, J. Rose, M. Santana, S. Seletskiy, T.V. Shaftan, O. Singh, P. Singh, V.V. Smaluk, R.M. Smith, T. Summers, J. Tagger, Y. Tian, W.H. Wahl, G.M. Wang, G.J. Weiner, F.J. Willeke, L. Yang, X. Yang, E. Zeitler, E. Zitvogel, P. Zuhoski
BNL, Upton, Long Island, New York, USA
A. Akimov, P.B. Cheblakov, I.N. Churkin, A.A. Derbenev, S.M. Gurov, S.E. Karnaev, V.A. Kiselev, A.A. Korepanov, E.B. Levichev, S.V. Sinyatkin, A.N. Zhuravlev
BINP SB RAS, Novosibirsk, Russia

The injector for the National Synchrotron Light Source II storage ring consists of a 3 GeV booster synchrotron and a 200 MeV S-band linac. The linac was designed to produce either a single bunch with a charge of 0.5 nC of electrons or a train of bunches up to 300 ns long containing a total charge of 15 nC. The booster was designed to accelerate up to 15 nC each cycle. Linac commissioning was completed in April 2012. Booster commissioning was started in November 2013 and completed in March 2014. All of the significant design goals were satisfied including beam emittance, energy spread, and transport efficiency. While the maximum booster charge accelerated was only 10 nC this has proven to be more than sufficient for storage ring commissioning. The injector has operated reliably during storage ring operation since then. Results will be presented showing measurements of injector operating parameters achieved during commissioning and initial operation. Operating experience and reliability during the first year of NSLS-II operation will be discussed.

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TUPHA008

NSLS-II Injector High Level Application Tools

controls, operation, booster, emittance

1980

G.M. Wang, E.B. Blum, R.P. Fliller, Y. Hu, T.V. Shaftan, X. Yang
BNL, Upton, Long Island, New York, USA

The National Synchrotron Light Source II (NSLS-II) is a state of the art 3 GeV third generation light source at Brookhaven National Laboratory. The injection system consists of a 200 MeV linac, a 3 GeV booster synchrotron and transfer lines in connection of linac, booster and storage ring. The transfer lines, designed and built from BNL, are equipped with sufficient diagnostics to commission to characterize the beam parameters from linac and booster. In the paper, we summarized the high level applications tools, beam emittance, energy and energy spread measurement, developed during the injector commissioning.

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TUPTY008

Commissioning Status and Plan of SuperKEKB Injector Linac

emittance, electron, positron, operation

2013

M. Satoh, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, Y. Enomoto, S. Fukuda, Y. Funakoshi, K. Furukawa, T. Higo, H. Honma, N. Iida, M. Ikeda, H. Iwase, H. Kaji, K. Kakihara, T. Kamitani, H. Katagiri, S. Kazama, M. Kikuchi, H. Koiso, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Mimashi, T. Miura, F. Miyahara, T. Mori, A. Morita, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, Y. Ohnishi, S. Ohsawa, Y. Seimiya, T. Shidara, A. Shirakawa, M. Suetake, H. Sugimoto, T. Suwada, T. Takenaka, M. Tanaka, M. Tawada, Y. Yano, K. Yokoyama, M. Yoshida, R. Zhang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

Toward SuperKEKB project, the injector linac upgrade is ongoing at KEK in order to deliver the low emittance electron/positron beams with the high intensity and small emittance. In the September of 2013, the injector linac commissioning has started. In this presentation, we will describe the commissioning status and plan of SuperKEKB injector linac.

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TUPTY015

Study on the transverse painting during the injection process for CSNS/RCS

injection, neutron, proton, target

2025

M.Y. Huang, L. Huang, N. Huang, J. Qiu, S. Wang, S.Y. Xu
IHEP, Beijing, People's Republic of China

Funding: Work supported by National Natural Science Foundation of China (11205185, 11175020, 11175193 )
For the China Spallation Neutron Source (CSNS), a combination of the H⁻ stripping and phase space painting method is used to accumulate a high intensity beam in the Rapid Cycling Synchrotron (RCS). In this paper, firstly, the injection processes with different painting ranges and different painting methods were studied. With the codes ORBIT and MATLAB, the particle distribution and painting image were obtained. Then, the reasonable painting range which is suitable for the aperture size and magnet gap can be selected. Since the real field uniformity of BH3 and BV3 is not completely in conformity with the design requirement, the painting method and painting range also need to be selected to reduce the effects of bad field uniformity.

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TUPTY047

ERL with Non-Scaling Fixed Field Alternating Gradient Lattice for eRHIC

electron, hadron, collider, ion

2120

D. Trbojevic, J.S. Berg, S.J. Brooks, Y. Hao, V. Litvinenko, C. Liu, F. Méot, M.G. Minty, V. Ptitsyn, T. Roser, P. Thieberger, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work performed under Contract Number DE-AC02-98CH10886 with the auspices of the US Department of Energy.
The proposed eRHIC electron-hadron collider uses a "non-scaling FFAG" lattice to recirculate 16 turns of different energy through just two beamlines located in the RHIC tunnel. This paper presents lattices for these two FFAGs that are optimised for low magnet field and to minimise total synchrotron radiation across the energy range. The higher number of recirculations in the FFAG allows a shorter linac (1.322GeV) to be used, drastically reducing cost, while still achieving a 21.2GeV maximum energy to collide with one of the existing RHIC hadron rings at up to 250GeV. eRHIC uses many cost-saving measures in addition to the FFAG: the linac operates in energy recovery mode, so the beams also decelerate via the same FFAG loops and energy is recovered from the interacted beam. All magnets will constructed from NdFeB permanent magnet material, meaning chillers and large magnet power supplies are not needed. This paper also describes a smaller prototype ERL-FFAG accelerator that will test all of these technologies in combination to reduce technical risk for eRHIC.

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TUPTY054

RF Design of the CLIC Structure Prototype Optimized for Manufacturing from Two Halves

multipole, wakefield, simulation, collider

2147

H. Zha, A. Grudiev
CERN, Geneva, Switzerland
V.A. Dolgashev
SLAC, Menlo Park, California, USA

We present the RF design of a 12GHz Compact Linear Collider (CLIC) main linac accelerating structure prototype. The structure is made from two longitudinally symmetric halves. The main manufacturing process of each half is precision milling. The structure uses the same iris dimensions as the CLIC-G structure but the cell shape is optimized for milling. The geometry is optimized to reduce the surface electric and magnetic fields and the modified Poynting vector. This design can potentially reduce fabrication cost.

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TUPTY055

Optimization of the RF Design of the CLIC Main Linac Accelerating Structure

wakefield, simulation, collider, cavity

2150

H. Zha, A. Grudiev
CERN, Geneva, Switzerland

We present a new optimized design of the accelerating structure for the main linac of CLIC (Compact Linear Collider). The new structure has lower surface magnetic fields and a significantly smaller transverse size compared to the baseline design described in the CLIC Concept Design Report (CDR). This new design should reach higher accelerating gradients and have a reduced manufacturing cost. The details of the RF design procedure and the obtained results are presented in this paper.

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TUPTY056

Beam-Based Measurements of Long Range Transverse Wakefields in CLIC Main Linac Accelerating Structure

wakefield, positron, electron, experiment

2153

H. Zha, A. Grudiev, A. Latina, D. Schulte, A. Solodko, W. Wuensch
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway
G. De Michele
EPFL, Lausanne, Switzerland
G. De Michele
PSI, Villigen PSI, Switzerland
N. Lipkowitz, G. Yocky
SLAC, Menlo Park, California, USA

The baseline design of CLIC (Compact Linear Collider) uses X-band accelerating structures in the main linac. Every accelerating structure cell has four waveguides, terminated with individual RF loads, to damp the unwanted long-range transverse wakefields, in order to maintain beam stability in multi-bunch operation. In order to experimentally verify the calculated suppression of the wakefields, a prototype structure has been built and installed in FACET test facility at SLAC. The results of the measurements of the wakefields in the prototype structure by means of positron and electron bunches are presented.

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TUPTY083

Conceptual MEIC Electron Ring Injection Scheme using CEBAF as a Full Energy Injector

injection, electron, operation, gun

2232

J. Guo, F. Lin, R.A. Rimmer, H. Wang, S. Wang, Y. Zhang
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177
The Medium-energy Electron-Ion Collider (MEIC) proposed by Jefferson Lab is planning to use the newly upgraded 12 GeV CEBAF 1497 MHz SRF CW recirculating linac as a full-energy injector for the electron collider ring. The electron collider ring is proposed to reuse the 476MHz PEP-II RF system to achieve high installed voltage and high beam power. The MEIC electron injection requires 3-10 (or 12) GeV beam in 3-4μs long bunch trains with low duty factor and high peak current, resulting in strong transient beam loading for the CEBAF. In this paper, we propose an injection scheme that can match the two systems’ frequencies with acceptable injection time, and also address the transient beam loading issue in CEBAF. The scheme is compatible with future upgrade to 952.6 MHz SRF system in the electron ring.

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TUPWI003

Proton Beam Applications for Silicon Bulk Micromachining

proton, ion, experiment, quadrupole

2241

P. Nenzi, G. Bazzano, F. Marracino, L. Picardi, C. Ronsivalle, V. Surrenti, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
University of Rome La Sapienza, Rome, Italy
F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
M. Balucani, A. Klyshko
University of Rome "La Sapienza", Rome, Italy
C. Snels, M. Tucci
ENEA Casaccia, Roma, Italy

The irradiation of silicon with ion beams is an established technique to modify its properties. Protons are used for micromachining applications, in conjunction with porous silicon. Porous silicon does not form in areas irradiated with a given fluence of protons (>10¹⁴ cm^-2). Our work concentrated on the applicability of masked irradiation of silicon wafers with 1.8 MeV proton beams delivered by the TOP-IMPLART LINAC. In our experiments 1-10 Ω*cm n,p-type silicon wafers were masked and irradiated with protons at fluences between 10¹⁴ and 10¹⁵ protons/cm². Porous silicon did not form in the irradiated areas up to a distance from the surface corresponding to the stopping range (30um). The suppression of porous silicon formation is due to the to the neutralization of dopant impurities by implanted protons that increases the local resistivity. The interest in using RF LINAC for micromachining applications lies in the possibility of deep implantation, that allows the realization of 3D structures for MEMS applications. The use of metal masks with uniform beams, instead of scanned micro- and nano-metric ion probes, increases throughput achievable in industrial processing of wafers.

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TUPWI004

Status of the TOP-IMPLART Proton LINAC

proton, operation, controls, klystron

2245

P. Nenzi, A. Ampollini, G. Bazzano, F. Marracino, L. Picardi, C. Ronsivalle, V. Surrenti, M. Vadrucci
ENEA C.R. Frascati, Frascati (Roma), Italy
F. Ambrosini
University of Rome La Sapienza, Rome, Italy
F. Ambrosini
Università di Roma "La Sapienza", SAPIENZA-DIET, Roma, Italy
C. Snels
ENEA Casaccia, Roma, Italy

In this work we present the latest update on the TOP-IMPLART LINAC. It is a 150 MeV proton linear accelerator for protontherapy application under realization at ENEA-Frascati in the framework of a project developed by ENEA, the Italian National Institute of Health (ISS) and Regina Elena National Cancer Institute-IFO-Rome. The accelerator consists of a 7 MeV injector operating at 425 MHz followed by a LINAC booster working at 2997.92 MHz at a maximum repetition frequency of 100 Hz. The medium energy section up to 35 MeV is a sequence of four SCDTL modules (Side Coupled Drift Tube LINAC) powered by a single 10 MW klystron: the first module bringing beam energy from 7MeV to 11.6MeV with an input power of 1.3 MW in a 4usec pulse has been successfully commissioned with a 10 uA per pulse beam accelerated at the design energy demonstrating the functionality of low energy proton acceleration at high RF frequency. The effects on beam dynamics, caused by the absence of any harmonic relation between the two operating frequencies of the LINAC has been simulated and experimentally verified during the commissioning activity. The second and third module installation and testing is undergoing.

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TUPWI027

Radiography Capabilities for Matter-Radiation Interactions in Extremes

electron, proton, scattering, quadrupole

2295

P.L. Walstrom, R.L. Barber, C.A. Chapman, R.W. Garnett, T.S. Gomez, J.A. O'Toole, H.R. Salazar
LANL, Los Alamos, New Mexico, USA

Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
The Matter-Radiation Interactions in Extremes (MaRIE) experimental facility will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges. This new facility will provide the new tools scientists need to develop next-generation materials that will perform predictably and on-demand for currently unattainable lifetimes in extreme environments. The MaRIE facility is based on upgrades to the existing LANSCE 800-MeV proton linac and a new 12-GeV electron linac and associated X-ray FEL to provide simultaneous multiple probe beams, and new experimental areas. In addition to the high-energy photon probe beam, both electron and proton radiography capabilities will be available at the MaRIE facility. Recently, detailed radiography system studies have been performed to develop conceptual layouts of high-magnification electron and proton radiography systems that can meet the experimental requirements for the expected first experiments to be performed at the facility. A description of the radiography systems, their performance requirements, and a proposed facility layout will be presented.

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TUPWI035

MEIC Proton Beam Formation with a Low Energy Linac

booster, ion, collider, proton

2322

Y. Zhang
JLab, Newport News, Virginia, USA

The MIEC proton and ion beams are generated, accumulated, accelerated and cooled in a new green-field ion injector complex designed specifically to support its high luminosity goal. This injector consists of sources, a linac and a small booster ring. In this paper we explore feasibility of a short ion linac that injects low energy protons and ions into the booster ring.

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TUPWI043

Chromatic Effects in Long Periodic Transport Channels

emittance, lattice, collider, linear-collider

2342

V. Litvinenko
Stony Brook University, Stony Brook, USA
Y. Hao, Y.C. Jing
BNL, Upton, Long Island, New York, USA

Long periodic transport channels are frequently used in accelerator complexes and suggested for using in high-energy ERLs for electron-hadron colliders. Without proper chromaticity compensation, such transport channels exhibit high sensitivity to the random orbit errors causing significant emittance growth. Such emittance growth can come from both the correlated and the uncorrelated energy spread. In this paper we present results of our theoretical and numerical studies of such effects and develop a criteria for acceptable chromaticity in such channels

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TUPWI045

Consequences of Bounds on Longitudinal Emittance Growth for the Design of Recirculating Linear Accelerators

emittance, quadrupole, dipole, collider

2350

J.S. Berg
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Recirculating linear accelerators (RLAs) are a cost-effective method for the acceleration of muons for a muon collider in energy ranges from a couple GeV to a few 10s of GeV. Muon beams generally have longitudinal emittances that are large for the RF frequency that is used, and it is important to limit the growth of that longitudinal emittance. This has particular consequences for the arc design of the RLAs. I estimate the longitudinal emittance growth in an RLA arising from the RF nonlinearity. Given an emittance growth limitation and other design parameters, one can then compute the maximum momentum compaction in the arcs. I describe how to obtain an approximate arc design satisfying these requirements based on the deisgn in Bogacz (2005)*. Longitudinal dynamics also determine the energy spread in the beam, and this has consequences on the transverse phase advance in the linac. This in turn has consequences for the arc design due to the need to match beta functions. I combine these considerations to discuss design parameters for the acceleration of muons for a collider in an RLA from 5 to 63 GeV.
*Bogacz, S. A. 2005. Low energy stages - 'dogbone' muon RLA. Nucl. Phys. B (Proc. Supp.) 149:309-312.

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TUPWI052

End-to-end 9-D⁺SR Polarized Bunch Transport in eRHIC Energy-recovery Recirculator, Some Aspects

emittance, polarization, electron, quadrupole

2369

F. Méot, S.J. Brooks, V. Ptitsyn, D. Trbojevic, N. Tsoupas
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The energy-recovery electron beam recirculator, part of the eRHIC electron-ion collider project complex at BNL, is subject to feasibility studies in an FFAG arc based version. We develop here on tracking simulations and their analysis, regarding end-to-end polarized e-bunch transport in presence of synchrotron radiation, magnet alignment and field errors. Simulations include the evolution of energy, orbits, emittances, polarization profiles.

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TUPWI055

Chromatic Effects and Orbit Correction in eRHIC Arcs

emittance, lattice, quadrupole, simulation

2378

F. Méot, C. Liu
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In the FFAG version of the electron energy recovery recirculator of the eRHIC electron-ion collider project, natural chromaticity is important and not corrected. Tracking simulations illustrate various aspects of its effects on 6-D bunch dynamics over the 16 turn recirculation from 1.3 to 21.2GeV collision energy, and back down to injection energy. These effects can be mitigated via orbit control, the methodology for that is described and its effectiveness illustrated via a series of ad hoc numerical simulations. Because polarization is paramount in the eRHIC NP program, its careful monitoring is part of the simulations.

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WEXB1

Coherent Synchrotron Radiation in Energy Recovery Linacs

FEL, electron, experiment, dipole

2387

C.C. Hall, S. Biedron, A.L. Edelen, S.V. Milton
CSU, Fort Collins, Colorado, USA
S.V. Benson, D. Douglas, R. Li, C. Tennant
JLab, Newport News, Virginia, USA
B.E. Carlsten
LANL, Los Alamos, New Mexico, USA

Collective beam effects, including coherent synchrotron radiation (CSR), have been studied on free-electron lasers (FELs). Here we will discuss a particular case of the CSR effects, that in energy-recovery linacs (ERLs). Special consideration is given to these machines because of their high average beam power and the architecture of the machine for energy recovery forces extreme bends. A recent study conducted on the JLab IR FEL looked at how CSR impacts both average energy and the energy spectrum of the beam. Such studies are important, both broadly, to the understanding of CSR and more specifically for a number of proposed ERL projects. A few proposed examples include the MEIC bunched beam cooler ERL design and ERL FELs for potential lithography purposes that would operate in the EUV range.

Slides WEXB1 [16.383 MB]

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WEYB2

Beam Dynamics in a High Frequency RFQ

rfq, alignment, emittance, proton

2408

A.M. Lombardi, V.A. Dimov, M. Garlaschè, A. Grudiev, S.J. Mathot, E. Montesinos, S. Myers, M.A. Timmins, M. Vretenar
CERN, Geneva, Switzerland

CERN is constructing a 750 MHz Radio Frequency Quadrupole (RFQ) which can accelerate a proton beam to 5 MeV in a length of 2 m. The beam dynamics strategic parameters have been chosen to make this RFQ a good candidate for the injector of a medical facility operating at frequency of 3 GHz. Minimising beam losses above 1 MeV, containing the RF power losses and opening the road to industrialisation have been the guidelines for an unconventional RFQ design. In this paper, the optimisation efforts, the structure design and the expected beam qualities will be detailed. The status of the construction as well as the potential for further developments will be presented.

Slides WEYB2 [2.166 MB]

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WEXC1

Machine and Personnel Protection for High Power Hadron Linacs

radiation, hadron, ion, controls

2418

M. Ikegami
FRIB, East Lansing, Michigan, USA

Machine and personnel safety are increasingly important for high power hadron linacs as involved beam power increases. Design requirements and characteristic features of machine protection system and personnel protection system for operating and proposed high power hadron linacs, such as J-PARC, SNS, FRIB, ESS, and IFMIF, are reviewed.

Slides WEXC1 [9.859 MB]

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WEXC2

Advances in Proton Linac Online Modeling

GPU, space-charge, simulation, operation

2423

X. Pang
LANL, Los Alamos, New Mexico, USA

This talk will review current online modeling tools used for proton linacs and then focus on a new approach that marries multi-particle beam dynamics with modern GPU technology to provide pseudo real-time beam information in a control room setting. Benefits to be discussed will include fast turnaround, accurate beam quality prediction, cost efficiency, test bed for new control and operation scheme development and operator training.

Slides WEXC2 [4.292 MB]

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WEYC1

Technical Challenges of the LCLS-II

undulator, gun, electron, cavity

2434

T.O. Raubenheimer
SLAC, Menlo Park, California, USA

The LCLS-II will be a CW X-ray FEL upgrade to the existing LCLS X-ray FEL at the SLAC National Accelerator Laboratory (SLAC). This paper describes the overall layout and the technical challenges that the upgrade project faces.

Slides WEYC1 [4.446 MB]

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WEYC2

Status of the PAL XFEL Construction

undulator, klystron, controls, FEL

2439

H.-S. Kang, K.W. Kim, I.S. Ko
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: This work has been supported by the Ministry of Science, ICT and Future Planning of Korea.
The PAL-XFEL, a 0.1-nm hard X-ray FEL facility consisting of a 10-GeV S-band linac, is being constructed in Pohang, South Korea. Its building construction was completed at the end of 2014. The major procurement contracts were complete for the critical components of S-band linac modules and undulators. The installation of linac, undulator, and beam line will be completed by 2015. The commissioning will get started in January 2016 aiming for the first lasing in 2016. We will report the current status, construction progress, and commissioning plans for the PAL XFEL project, including major subsystem preparations.

Slides WEYC2 [9.069 MB]

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WEYC3

Commissioning and Operation of the ARIEL Electron Linac at TRIUMF

cavity, cryomodule, electron, TRIUMF

2444

M. Marchetto, F. Ames, Z.T. Ang, R.A. Baartman, I.V. Bylinskii, Y.-C. Chao, D. Dale, K. Fong, R. Iranmanesh, F.W. Jones, D. Kaltchev, J. Kavarskas, P. Kolb, S.R. Koscielniak, A. Koveshnikov, M.P. Laverty, R.E. Laxdal, L. Merminga, N. Muller, R.R. Nagimov, R.B. Nussbaumer, T. Planche, M. Rowe, S. Saminathan, V.A. Verzilov, Z.Y. Yao, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

Funding: Funded under a contribution agreement with NRC (National Research Council Canada). Capital funding from CFI (Canada Foundation for Innovation).
ARIEL is the new TRIUMF facility for production of radioactive ion beams that will enable the delivery of three simultaneous RIB beams to the ISAC experimental stations. Two additional target stations will produce beams by using either a 50 kW proton or from 500 kW electrons via photo-fission. The electron beam driver is going to be a 50 MeV 10 mA CW superconducting electron linac. The first stage of the e-linac installation is completed and commissioning is underway. The paper will present the e-linac design characteristics, installation, commissioning strategy and current results.

Slides WEYC3 [13.765 MB]

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WEBD1

12 GeV CEBAF Transverse Emittance Evolution

emittance, optics, operation, synchrotron

640

T. Satogata, Y. Roblin, M.G. Tiefenback, D.L. Turner
JLab, Newport News, Virginia, USA

We present commissioning results of measurements of beam phase space evolution of the newly commissioned 12 GeV CEBAF accelerator. These measurements range over two orders of magnitude in energy for a non-equilibrium beam, from near the photocathode to the diamond bremsstrahlung target for the GlueX experiment. We also compare these measurements to modeled beam evolution, and emittance growth expectations driven by synchrotron radiation.

Slides WEBD1 [4.297 MB]

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WEPWA016

CsKSb Photocathode R&D with High Quantum Efficiency and Long Lifetime

laser, cathode, electron, vacuum

2526

Y. Seimiya, R. Kaku, M. Kuriki, A. Yokota
HU/AdSM, Higashi-Hiroshima, Japan
T. Konomi
UVSOR, Okazaki, Japan
T. Miyajima, M. Yamamoto
KEK, Ibaraki, Japan

Advanced electron linear accelerator such as Energy Recovery Linac and Free Electron Laser needs high brightness electron source. Photocathode is suitable for the high brightness requirement because some of them has low emittance and high quantum efficiency. In the photocathode, CsKSb multi-alkali photocathode has excellent features: high quantum efficiency, long lifetime, and driven by visible light, for example green laser. Therefore, the multi-alkali photocathode is considered to be one of the best candidates for the high brightness electron source of the advanced electron accelerator. We report developments of our evaporation system and results of quantum efficiency and lifetime measurement in Hiroshima University. Multi-alkali surface analyzation has being measured by ultra-violet photoemission spectroscopy to study conditions between the multi-alkali performances and the surface condition in Institute Molecular Science. We also report the status of the progress abort the study.

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WEPWA017

An Optimization of ILC Positron Source for Electron-Driven Scheme

positron, electron, target, beam-loading

2529

Y. Seimiya, M. Kuriki, M. Urano
HU/AdSM, Higashi-Hiroshima, Japan
S. Kashiwagi
Tohoku University, School of Science, Sendai, Japan
T. Okugi, T. Omori, M. Satoh, J. Urakawa
KEK, Ibaraki, Japan
T. Takahashi
Hiroshima University, Graduate School of Science, Higashi-Hiroshima, Japan

International Linear Collider is a future accelerator to find new physics behind the electroweak symmetry breaking by precise measurements of Higgs sector, Top quark, and so on. ILC has capacities to reveal new phenomena beyond Standard model, such as Supersymmetry particles and dark matters. In current design of positron source, undulator scheme is adapted as a baseline. In the scheme, positrons are generated from gamma rays through pair-creation process in Ti-alloy target. Generations of the gamma rays by the undulator radiation requires more than 130 GeV electrons. Therefore, a system demonstration of the scheme is practically difficult prior to the real construction. Consequently, it is desirable to prepare a technical backup of this undulator scheme. We study an optimization of positron source based on the conventional electron-driven scheme for ILC. In this scheme, positron beam is generated by several GeV electron beam impinging on W-Re target. Although heavy heat load and destruction of the target is a potential problem, it can be relaxed by stretching the effective pulse length to 60 ms instead of 1 ms, by a dedicated electron linac for the positron production. In this report, a start-to-end simulation of the electron-driven ILC positron source is performed. Beam-loading effect caused by multi-bunch acceleration in the standing wave RF cavity is also considered.

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WEPWA018

Re-acceleration of Ultra Cold Muon in J-PARC MLF

acceleration, rfq, proton, experiment

2532

M. Yoshida, F. Naito
KEK, Ibaraki, Japan
S. Artikova, Y. Kondo
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
N. Hayashizaki
RLNR, Tokyo, Japan
Y. Iwashita
Kyoto ICR, Uji, Kyoto, Japan
K. Torikai
Gunma University, Heavy-Ion Medical Research Center, Maebashi-Gunma, Japan

Funding: MEXT KAKENHI Grant Number 6108718
The ultra cold muon beam by two-photon laser resonant ionization of muonium atoms is unique way to obtain very low emittance muon beam. Its muon source is a surface muon from the muon target in MLF where one percent proton beam from J-PARC RCS is reacted. In close collaboration with the Muon Science Es- tablishment (MUSE) at Material and Life science experi- mental Facility (MLF) of the Japan Proton Accelerator Re- search Complex (J-PARC), we are developing the reacceleration system of the ultra cold muon beam. Its optimum accelerating structure is similar to a proton accelerator in low beta part and an electron accelerator in high beta part. Further the muon bunch is only two bunch corresponding to the bunch structure of the J-PARC RCS. Thus we are testing the dielectric transmission line accelerator based on the photoconductive switch as the altenative acceleration method.

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WEPWA034

High-charge-short-bunch Operation Possibility at Argonne Wakefield Accelerator Facility

emittance, wakefield, dipole, simulation

2572

G. Ha, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
W. Gai, G. Ha, K.-J. Kim, J.G. Power
ANL, Argonne, Illinois, USA

Originally the drive beam line at Argonne Wakefield Accelerator (AWA) Facility was designed to generate the high charge bunch train. However, we recently installed the double dog-leg type emittance exchange beam line which have two identical dog-leg structures. With this beam line, it is possible to compress the bunch by introducing the chicane or using single dog-leg. Simulation studies have been carried out to confirm the minimum bunch length for each charge and the emittance growth by the coherent synchrotron radiation. We present GPT simulation results to show high-charge-short-bunch operation possibility at AWA facility.

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WEPWA052

RF Conditioning of the Photo-Cathode RF Gun at the Advanced Photon Source - NWA RF Measurements

gun, detector, cathode, vacuum

2621

T.L. Smith, N.P. DiMonte, A. Nassiri, Y.-E. Sun, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
A new S-band photo-cathode (PC) gun was recently installed and RF conditioned at the Advanced Photon Source (APS) Injector Test-stand (ITS) at Argonne National Lab (ANL). The APS PC gun is a LCLS type gun fabricated at SLAC [1]. The PC gun was delivered to the APS in October 2013 and installed in the APS ITS in December 2013. At ANL, we developed a new method of fast detection and mitigation of the gun’s internal arcs during the RF conditioning process to protect the gun from arc damage and to RF condition more efficiently. Here, we report the results of RF measurements for the PC gun and an Auto-Restart method for high power RF conditioning.

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WEPJE002

Photoinjector Improvement and Control by Surface Acoustic Waves

electron, photon, experiment, controls

2678

R.P. Johnson
Muons, Inc, Illinois, USA
A. Afanasev, C.E. Korman
GWU, Washington, USA

A new technique is being developed to enhance the efficiency of photocathodes used for electron sources to improve emission capabilities of electron sources, such as bunch charge and average current. The proposed technique is based on the use of surface acoustical waves (SAW) generated on the piezoelectric surface of a GaAs photocathode. The generation of SAW on piezoelectric substrates is known to produce strong piezoelectric fields that propagate on the surface of the material. These fields can significantly suppress recombination effects and result in enhanced quantum efficiency of photoemission. Experimental measurements of photoemission quantum efficiency will be done on semiconductors used as photocathode materials (e.g., GaAs) in presence of SAW with varied parameters. The experimental results will be used as input for physics modeling that will provide a basis for design of operational SAW-enhanced photocathodes. While the improved quantum efficiency and parameter control expected from the use of SAW will be useful for many research devices and accelerators, the commercialization of such a widespread field as electron microscopy is compelling.

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WEPMA001

Proposed Linac Upgrade with a SLED Cavity at the Australian Synchrotron, SLSA

klystron, cavity, operation, injection

2738

K. Zingre, B. Mountford
ASCo, Clayton, Victoria, Australia
M.P. Atkinson, R.T. Dowd, G. LeBlanc
SLSA, Clayton, Australia
C.G. Hollwich
SPINNER GmbH, Westerham, Germany

The Australian Synchrotron Light Source has been operating successfully since 2007 and in top-up mode since 2012 while gradually being upgraded to reach an excellent beam availability exceeding 99 %. Considering the ageing of the equipment, effort is required in order to maintain the reliability at this level. The proposed upgrade of the linac with a SLED cavity has been chosen to mitigate the risks of single point of failure and lack of spare parts. The linac is normally fed from two independent 35 MW pulsed klystrons to reach 100 MeV beam energy and can be operated in single (SBM) or multi-bunch mode (MBM). The SLED cavity upgrade will allow remote selection of single klystron operation in SMB and possibly limited MBM without degradation of beam energy and reduce down time in case of a klystron failure. The proposal for the SLED cavity upgrade is shown and the linac designs are detailed.

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WEPMA005

Particularities of the ARIEL e-Linac Cryogenic System

cryomodule, cryogenics, radiation, TRIUMF

2750

I.V. Bylinskii, G.W. Hodgson, D. Kishi, S.R. Koscielniak, A. Koveshnikov, R.E. Laxdal, R.R. Nagimov, D. Yosifov
TRIUMF, Vancouver, Canada

Funding: Canada Foundation for Innovation, British Columbia Knowledge Development Fund, and National Research Council Canada.
The Advanced Rare IsotopE Laboratory (ARIEL) is a major expansion of the Isotope Separation and Acceleration (ISAC) facility at TRIUMF [1]. A key part of the ARIEL project is a 10 mA 50 MeV continuous-wave superconducting radiofrequency (SRF) electron linear accelerator (e-linac). The 1.3 GHz SRF cavities are cooled by liquid helium (LHe) at 2 K [2]. The 4 K 2 K LHe transition is achieved onboard of each cryomodule by the cryoinsert containing counterflow heat exchanger augmented with JT valve [3]. Air Liquide LHe cryoplant provides 4 K LHe to cryomodules. After successful commissioning of the cryoplant, 2 K sub-atmospheric (SA) system and cryomodules, the ultimate integration test confirmed stable operation of two cryomodules comprising two 9 cell SRF cavities. Particularities of this cryogenic system include conservative design of the oil removal system, original design heat exchanger in the SA pumping system, hermetic SA pumps, inline full SA flow purifier, multipurpose recovery/purification compressor, modular LHe distribution system, top-loaded design cryomodules, and overall radiation resistant design. The paper presents details of these features as well as integration tests results.

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WEPMA008

RF Design of a High Gradient S-Band Travelling Wave Accelerating Structure for Thomx Linac

accelerating-gradient, impedance, simulation, vacuum

2757

M. El Khaldi, L. Garolfi
LAL, Orsay, France

There is growing demand from the industrial and research communities for high gradient, compact RF accelerating structures. The Thomx high gradient structure (HGS) is travelling wave (TW), quasi constant gradient section and will operate at 2998.55 MHz (30°C in vacuum) in the 2π/3 mode. The optimization of the cell shape (Electromagnetic design) has been carried out with the codes HFSS and CST MWS, in order to improve the main RF characteristics of the cavity such as shunt impedance, accelerating gradient, group velocity, modified Poynting vector, surface fields, etc. Prototypes with a reduced number of cells have been designed. For an input power of about 20 MW, EM simulation results show that an average accelerating gradient of 28 MV/m is achieved which corresponds to a peak accelerating gradient of 35 MV/m, a peak surface gradient of 44 MV/m and peak modified Poynting vector S_cmax of 0.24 MW/mm².

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WEPMA009

3 GHz Single Cell Cavity Optimization Design

accelerating-gradient, simulation, cavity, electron

2761

L. Garolfi, M. El Khaldi
LAL, Orsay, France
N. Faure
PMB-ALCEN, PEYNIER, France

In order to develop a high gradient S-band electron accelerating structure, an optimized travelling wave (TW) single-cell cavity operating at the frequency of 3 GHz with 2π/3 phase advance, is proposed. Starting from the well-known accelerating cells design developed by the Laboratoire de l'Accélérateur Linéaire (LAL) and the Stanford Linear Accelerator Centre (SLAC), for linear accelerators; it is possible to improve the main RF parameters, such as quality factor, shunt impedance, enhancement factor and group velocity, by choosing a suitable shape of the inner surface. Even though surface electric field is being considered as the only main quantity limiting the accelerating gradient; the importance of power flow and the modified Poynting vector*, has been highlighted from high-gradient experimental data. In this context, the new field quantity (Sc) is derived from a model describing the RF breakdown trigger phenomenon wherein field emission currents from potential breakdown sites produce local pulsed heating. In particular, the modified Poynting vector takes into account both active and reactive power flow travelling along the structure. The main results presented in this paper have been carried out with the 3D electromagnetic simulation codes: High Frequency Structural Simulator solver (HFSS) and CST MICROWAVE STUDIO (CST MWS).
* A. Grudiev et al., "New local field quantity describing the high gradient limit of accelerating structures", PRST:AB 12, 102001 (2009).

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WEPMA010

First Test Results of the BERLinPro 2-cell Booster Cavities

cavity, booster, cryomodule, SRF

2765

A. Burrill, W. Anders, A. Frahm, J. Knobloch, A. Neumann
HZB, Berlin, Germany
G. Ciovati, W.A. Clemens, P. Kneisel, L. Turlington
JLab, Newport News, Virginia, USA

The BERLinPro Energy Recovery Linac (ERL) is currently being built at Helmholtz-Zentrum Berlin in order to study the physics of operating a high current, a 100 mA, 50 MeV ERL utilizing all SRF cavity technology. This machine will utilize three unique SRF cryomodules for the photoinjector, booster and linac cryomodules respectively. The focus of this paper will be on the cavities contained within the booster cryomodule. Here there will be three 2-cell SRF cavities, based on the original design by Cornell University, but optimized to meet the needs of the project. All of the cavity fabrication, processing and testing was carried out at Jefferson Laboratory where 4 cavities were produced and the 3 cavities with the best RF performance were fitted with helium vessels for installation in the cryomodule. This paper will report on the test results of the cavities as measured in the vertical testing dewar at JLab after fabrication and again after outfitting with the helium vessels.

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WEPMA022

Progress of the Klystron and Cavity Test Stand for the FAIR Proton Linac

klystron, cavity, proton, operation

2802

A. Schnase, E. Plechov, J. Salvatore, G. Schreiber, W. Vinzenz
GSI, Darmstadt, Germany
C. Joly, J. Lesrel
IPN, Orsay, France

In collaboration between the FAIR project, GSI, and CNRS, the IPNO lab provided the high power RF components for a cavity and klystron test stand. For initial operation of the 3 MW Thales TH2181 klystron at 325.224 MHz we received a high voltage modulator from CERN Linac 4 as a loan. Here we report, how we integrated the combination of klystron, high voltage modulator, and auxiliaries to accumulate operating experience. RF operation of the klystron started on a water cooled load, soon the circulator will be included and then the prototype CH cavity in the radiation shielded area will be powered. The 45 kW amplifiers for the 3 buncher structures of the FAIR proton Linac were checked at the test stand, and the results are presented here.

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WEPMA040

Magnet Studies for the Accelerator FLUTE at KIT

dipole, experiment, multipole, simulation

2849

S. Hillenbrand, A. Bernhard, A.-S. Müller, M.J. Nasse, R. Rossmanith, R. Ruprecht, M. Sauter, S. Schott, M. Schuh, S. Schulz, M. Weber, P. Wesolowski, C. Widmann
KIT, Karlsruhe, Germany

At KIT we are currently constructing the compact linear accelerator FLUTE (Ferninfrarot Linac Und Test Experiment). This 41 MeV machine is aimed at accelerator physics and synchrotron radiation research, using ultra-short electron bunches. The electrons are generated at a photo-cathode using picosecond long UV laser pulses. A magnetic chicane is used to compress the bunches longitudinally to a few femtoseconds. This contribution describes both the magnet design, in particular the optimization of the chicane dipoles based on finite element method (FEM) simulations, as well as the implementation of a magnet measurement system.

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WEPMA041

1.3 GHz SRF Cryomodules for the Mainz Energy-recovering Superconducting Accelerator MESA

cryomodule, SRF, lattice, controls

2853

F. Schlander, K. Aulenbacher, R.G. Heine, D. Simon, T. Stengler
IKP, Mainz, Germany

Funding: Work supported by the German Federal Ministery of Education and Research (BMBF) and German Research Foundation (DFG) under the Cluster of Excellence "PRISMA"
The Mainz Energy-recovering Superconducting Accelerator MESA requires superconducting RF systems that provide sufficient energy of 50 MeV per turn to an electron beam. The ordering process of two Rossendorf-type cryomodules, containing two 9-cell 1.3 GHz XFEL-like cavities each, is in progress. Besides an overview of the adaptations required for the multipass and high current beam operation of the cryomodules, details about challenges regarding the installation of the cryomodules on the premises of the Institut für Kernphysik at Universität Mainz are given.

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WEPMA042

Experience and Developments on the S-band RF Power System of the FERMI Linac

klystron, operation, FEL, high-voltage

2856

A. Fabris, P. Delgiusto, F. Pribaz, N. Sodomaco, R. Umer, L. Veljak
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The S-band linac of FERMI, the seeded Free Electron Laser (FEL) located at the Elettra laboratory in Trieste, operates on a 24/7 basis accumulating more than 6000 hours of operation per year. The performance and operability requirements of a users facility pose stringent specifications on reliability and availability on all the systems of the machine and in particular on the RF power plants. This paper provides a review and discusses the operational experience with the S-band power plants, klystrons and modulators, operating at S-band in FERMI. Based on the satisfactorily results and following return of experience, upgrades of the existing power plants are being implemented in the continuous effort of extending the operability and availability of the systems. A description of these activities and an overview of the other developments under consideration on the RF power plants are also provided.

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WEPMA043

Five Years of Operations for the Magnet Power Supplies of FERMI

operation, FEL, controls, interface

2859

R. Visintini
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

FERMI, the FEL light source in Trieste, Italy, started its regular operation with external users in 2012. The construction of the facility began in 2008 and the commissioning of the complete system – LINAC, Undulators’ chains (FEL-1 and FEL-2), photon front-end – started in 2010. On December 13, 2010 the first lasing occurred. From the Photo-injector to the electron Main Beam Dump (MBD), there are more than 400 magnets and coils, including those mounted on the accelerating sections of the LINAC and on the Undulators. With few exceptions, each magnet power supply energizes a single magnet/coil: there are about 400 magnet power supplies spanning from few tens of watt up to 42 kW. The power supplies types range from custom-made ones, to COTS (Commercial Off The Shelf), to in-house design (these accounting to 88% of the total). Almost all magnet power supplies are in use since mid-2010. During 5 years of operations, the reliability of the magnet power supplies proved to be extremely high: the downtime of FERMI operations due to magnet power supplies is very low.

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WEPMA048

Development for Mass Production of Superconducting Cavity by MHI

cavity, cryomodule, niobium, superconducting-RF

2876

T. Yanagisawa, H. Hara, K. Kanaoka, K. Okihira, K. Sennyu
MHI, Hiroshima, Japan

Mitsubishi Heavy Industries (MHI) have developed manufacturing process of superconducting cavitis for a long time. In this presentation, recent progress will be reported.

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WEPMA051

Superconducting Solenoid Package Prototyping for FRIB SRF Linac

solenoid, dipole, operation, SRF

2886

K. Hosoyama, K. Akai, S. Yamaguchi
KEK, Ibaraki, Japan
E.E. Burkhardt, K. Saito, Y. Yamazaki
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Coopertive Agreement DESC000661.
FRIB is an under constructing machine in USA for nuclear physics, which has intensity front SRF linacs to accelerate ion beam from proton to uranium up to 200 MeV/u. FRIB has large users community, so the machine has to be operated very reliably and stably. Superconducting solenoid and steering dipoles as a package is mounted in the cryomodule nearby SRF cavities to focus beam strongly and space effectively. This produces an issue interacting between the fringe field from the solenoid and the SRF cavity, which makes potential performance degradation on SRF cavity. NbTi superconducting wire is utilized for the solenoid package. The high field design like 9T is very critical operation due to the SC characteristics of the wire. The solenoid package has to be designed very carefully. In this paper will report the prototyping of 25 cm 8T solenoid package for FRIB cryomodule, which includes design, fabrication, and cold test.
* This work has been done under the collaboration between KEK and MSU.

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WEPMA052

Low Level RF Systems for J-PARC Linac 50-mA Operation

rfq, cavity, operation, controls

2889

Z. Fang, Y. Fukui, K. Futatsukawa, T. Kobayashi, S. Michizono
KEK, Ibaraki, Japan
E. Chishiro, F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In the summer of 2014, lots of improvements were carried out in the J-PARC proton linac, including the ion source, the Radio Frequency Quadrupole linac (RFQ), and the medium-energy beam-transport line from the RFQ to the Drift Tube Linac (DTL) called as MEBT1. The output beam current of the ion source was upgraded from 20 to 50 mA. The previous RFQ with two RF power input ports was replaced by a newly developed RFQ with one input port. The RF power of the solid state amplifier for the rf cavities used in the MEBT1 section were upgraded; from 10 to 30 kW for both of the Buncher-1 and Buncher-2, and from 30 to 120 kW for the Chopper cavity. The old scraper used as dump of chopped beam after the Chopper cavity was also replaced by a new dump system using two scrapers; A new function of separating the chopped beam automatically to the two scrapers was developed by modifying the FPAG control program in the low level control systems. After those improvements, in the September 2014 the J-PARC linac was successfully upgraded for 50-mA beam operation. The details of the improvments, especially for the low level RF systems, will be reported in this paper.

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WEPMA056

Development of Superconducting Spoke Cavities for Laser Compton Scattered X-ray Sources

cavity, electron, operation, brightness

2902

R. Hajima, M. Sawamura
JAEA, Ibaraki-ken, Japan
E. Cenni, Y. Iwashita, H. Tongu
Kyoto ICR, Uji, Kyoto, Japan
T. Kubo, T. Saeki
KEK, Ibaraki, Japan

Funding: This study is supported by Photon and Quantum Basic Research Coordinated Development Program of MEXT, Japan.
A 5-year research program on the development of superconducting spoke cavities for electron accelerators has been funded by MEXT, Japan since 2013. The purpose of our program is establishing design and fabrication processes of superconducting spoke cavity optimized for compact X-ray sources based on laser Compton scattering. The spoke cavity is expected to realize a compact industrial-use X-ray source with a reasonable cost and easy operation. We have chosen a cavity frequency at 325 MHz due to possible operation at 4 K and carried out cavity shape optimization in terms of electromagnetic and mechanical properties. Production of press-forming dies is also in progress. In this paper, we present overview and up-to-date status of the research program.

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WEPMN009

Design and Thermal Analysis of ADS Beam Stop

vacuum, target, rfq, interface

2931

M.X. Li, J.L. Wang, L. Wu
IHEP, Beijing, People's Republic of China

ADS beam stop is an important device which required for the commissioning and accelerator tests of Accelerator Driven Sub-critical System (ADS), it is used to stop the beam which power is about 100kW and consume energy of the beam. This paper will present a triangular prism structure of the ADS beam stop, its mechanical design is described in detail, and there are numerous grooves and ribs in the cooling plates which is the core component of the beam stop. The thermal analysis is performed and its result proves that the triangular prism structure meet the design requirement. Key words：Beam stop, ADS, thermal analysis, triangular prism structure.

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WEPMN019

Calorimetric Power Measurements in X-band High Power RF

simulation, klystron, experiment, operation

2967

X.W. Wu, H.B. Chen, L. Zhang
TUB, Beijing, People's Republic of China
N. Catalán Lasheras, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland

With the aim to test prototype accelerating structures for CLIC at high-gradient, new klystron-based, X-band high power test stands are being built at CERN. These tests stands are referred to as Xboxes with Xbox1 and Xbox2 being already operational. Stainless steel loads are placed in the end of the Xbox-1 system to absorb the remaining power which comes out of the accelerating structure. Power information is important and needs to be measured precisely. A new power measuring method based on calorimetry is proposed independent from RF measurements subject to frequent calibration. The principles of the method and simulations are presented and the results of actual experimentation are used to validate the method. The results show calorimetric measurement is feasible method and have a good precision at this power level.

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WEPMN032

Microphonic Disturbances Prediction and Compensation in Pulsed Superconducting Accelerators

cavity, controls, operation, flattop

2997

R. Rybaniec, L.J. Opalski
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
V. Ayvazyan, L. Butkowski, S. Pfeiffer, K.P. Przygoda, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

Accelerators are affected by the cavities detuning variation caused by external mechanical disturbances (microphonics). The paper presents microphonics estimation and prediction methods applicable for superconducting accelerators operating in pulsed mode. A mathematical model is built using the estimates of detuning during previous RF pulses. The model can be used for predictions of disturbances for the future time step and setup of the fast tuners accordingly. The proposed method was successfully verified with measurements conducted at the FLASH linac.

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WEPMN033

The Fabrication of Prototype Normal Conducting Rebuncher for the MEBT in RISP

cavity, resonance, controls, operation

3000

H.J. Kim, M.O. Hyun, B.-S. Park
IBS, Daejeon, Republic of Korea

The Medium Energy Beam Transport (MEBT) system of RAON consists of several quadrupole magnets for controlling the transverse beam parameter at the entrance of the low energy linac, three normal-conducting (NC) re-bunchers to match the longitudinal beam ellipse into the acceptance of the low energy linac and several diagnostic devices. The NC QWR re-buncher, which has a frequency of 81.25 MHz, a geometric beta factor of 0.032, and an effective length of 24 cm, has been fabricated and tested to demonstrate the frequency tuning by using slug tuner, power transmission and reflection with low input power, and pulsed high power transmission with cooling channels. In this presentation, we show the design and fabrication criteria for the high power, ~ 10 kW, re-buncher and its test results.

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WEPMN065

Progress at the FREIA Laboratory

cavity, controls, cryogenics, EPICS

3072

M. Olvegård, A.K. Bhattacharyya, T.J.C. Ekelöf, J. Eriksson, K. Fransson, K.J. Gajewski, V.A. Goryashko, L. Hermansson, M. Holz, M. Jacewicz, M. Jobs, Å. Jönsson, H. Li, T. Lofnes, H. Nicander, R.J.M.Y. Ruber, R. Santiago Kern, R. Wedberg, V.G. Ziemann
Uppsala University, Uppsala, Sweden
D.S. Dancila, A. Rydberg
Uppsala University, Department of Engineering Sciences, Uppsala, Sweden
R.A. Yogi
ESS, Lund, Sweden

The FREIA Facility for Research Instrumentation and Accelerator Development at Uppsala University, Sweden, has reached the stage where the testing of superconducting cavities for the European Spallation Source (ESS) is starting. The new helium liquefaction plant has been commissioned and now supplies a custom-made, versatile horizontal cryostat, HNOSS, with liquid helium at up to 140 l/h. The cryostat has been designed and built to house up to two accelerating cavities, or, later on, other superconducting equipment such as magnets or crab cavities. A prototype cavity for the spoke section of the ESS linac will arrive mid 2015 for high-power testing in the horizontal cryostat. Two tetrode-based commercial RF power stations will deliver 400 kW peak power each, at 352 MHz, to the cavity through an RF distribution line developed at FREIA. In addition, significant progress has been made with in-house development of solid state amplifier modules and power combiners for future use in particle accelerators. We report here on these and other ongoing activities at the FREIA laboratory.

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WEPHA013

The Assembly Experience of the First Cryo-module for HIE-ISOLDE at CERN

cavity, vacuum, solenoid, instrumentation

3131

Y. Leclercq, G. Barlow, J.A. Bousquet, A. Chrul, P. Demarest, J-B. Deschamps, J.A. Ferreira Somoza, J. Gayde, M. Gourragne, A. Harrison, G. Kautzmann, D. Mergelkuhl, V. Parma, M. Struik, M. Therasse, L.R. Williams
CERN, Geneva, Switzerland
J. Dequaire
Intitek, Lyon, France

The HIE ISOLDE project aims at increasing the energy of the radioactive ion beams of the existing REX ISOLDE facility from the present 3 MeV/u up to 10 MeV/u for A/q to 4.5. The upgrade includes the installation of a superconducting linac in successive phases, for a final layout containing two low-β and four high-β cryo-modules. The first phase involves the installation of two high-B cryo-modules, each housing five high- β superconducting cavities and one superconducting solenoid, aligned within tight tolerances. After having designed and procured the cryo-module components, the first units is now being assembled at CERN, in a dedicated facility including class100 (ISO5) clean rooms equipped with specific tooling. The assembly is foreseen to be ultimate and the cryo-module cold tested by May 2015. In this paper, after a brief description of the main design features of the cryo-module , we present the assembly of the first unit, including the methodology, special tools, assembly procedures and quality assurance aspects. We report on the experience from this first assembly, including tests results, and present prospects for the next-coming cryo-module assemblies.

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WEPHA021

Status of HIE-ISOLDE SC Linac Upgrade

cavity, cryomodule, vacuum, niobium

3151

A. Sublet, L. Alberty, K. Artoos, S. Calatroni, O. Capatina, M.A. Fraser, N.M. Jecklin, Y. Kadi, P. Maesen, G.J. Rosaz, K.M. Schirm, M. Taborelli, M. Therasse, W. Venturini Delsolaro, P. Zhang
CERN, Geneva, Switzerland

The HIE-ISOLDE upgrade project at CERN aims at increasing the energy of radioactive beams from 3MeV/u up to 10 MeV/u with mass-to-charge ratio in the range 2.5-4.5. The objective is obtained by replacing part of the existing normal conducting linac with superconducting Nb/Cu cavities. The new accelerator requires the production of 32 superconducting cavities in three phases: 10 high-beta cavities for phase 1 (2016), 10 high-beta cavities for phase 2 (2017) and possibly 12 low-beta cavities for phase 3 (2020). Half of the phase 1 production is completed with 5 quarter-wave superconducting cavities ready to be installed in the first cryomodule. The status of the cavity production and the RF performance are presented. The optimal linac working configuration to minimize cryogenic load and maximize accelerating gradient is discussed.

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WEPHA051

Development of a Hybrid Power Supply and RF Transmission Line for SANAEM RFQ Accelerator

rfq, power-supply, proton, operation

3228

S. Ogur
Bogazici University, Bebek / Istanbul, Turkey
F. Ahiska
EPROM Electronic Project & Microwave Ind. and Trade Ltd. Co., Ankara, Turkey
A. Alacakir
SNRTC, Ankara, Turkey
G. Turemen
Ankara University, Faculty of Sciences, Ankara, Turkey
G. Unel
UCI, Irvine, California, USA

SANAEM Project Prometheus (SPP) has been building a proton beamline at MeV range. Its proton source, two solenoids, and a low energy diagnostic box have been already manufactured and installed. These are going to be followed by a 4-vane RFQ to be powered by two stage PSU. The first stage is a custom-built solid state amplifier providing 6 kW at 352.2 MHz operating frequency. The second stage, employing TH 595 tetrodes from Thales, will amplify this input to 160 kW in a short pulsed mode. The power transfer to the RFQ will be achieved by the means of a number of WR2300 full and half height waveguides, 3 1/8" rigid coaxial cables, joined by appropriate adapters and converters and by a custom design circulator. This paper summarizes the experience acquired during the design and the production of these components.

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WEPTY016

RF Modeling of a Helical Kicker for Fast Chopping

kicker, impedance, simulation, experiment

3293

M.H. Awida, A.Z. Chen, T.N. Khabiboulline, G.W. Saewert, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

High intensity proton particle accelerators that supports several simultaneous physics experiments requires sharing the beam. A bunch by bunch beam chopper system located after the Radio Frequency Quadrupole (RFQ) is required in this case to structure the beam in the proper bunch format required by the several experiments. The unused beam will need to be kicked out of the beam path and is disposed in a beam dumb. In this paper, we report on the RF modeling results of a proposed helical kicker. Two beam kickers constitutes the proposed chopper. The beam sequence is formed by kicking in or out the beam bunches from the streamline. The chopper was developed for Project X Injection Experiment (PXIE).

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WEPTY017

Development of 650 MHz β=0.9 5-cell Elliptical Cavities for PIP-II

cavity, resonance, proton, controls

3296

M.H. Awida, M.H. Foley, I.V. Gonin, C.J. Grimm, T.N. Khabiboulline, A. Lunin, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

5-cell 650 MHz elliptical cavities are being developed for the Proton Improvement Plan II (PIP-II) of Fermilab. The cavities are designed to accelerate protons of relative group velocity β=0.9 at the high energy part of the linear particle accelerator. In this paper, we report the status of these cavities and summarize the results of the quality control measurements performed on four initial prototypes.

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WEPTY019

Transverse Field Perturbation For PIP-II SRF Cavities

quadrupole, cavity, multipole, dipole

3302

P. Berrutti, T.N. Khabiboulline, V.A. Lebedev, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by D.O.E. Contract No. DE-AC02-07CH11359
Proton Improvement Plan II (PIP-II) consists in a plan for upgrading the Fermilab proton accelerator complex to a beam power capability of at least 1 MW delivered to the neutrino production target. A room temperature section accelerates H⁻ ions to 2.1 MeV and creates the desired bunch structure for injection into the superconducting (SC) linac. Five cavity types, operating at three different frequencies 162.5, 325 and 650 MHz, provide acceleration to 800 MeV. This paper presents the studies on transverse field perturbation on particle dynamic for all the superconducting cavities in the linac. The effects studied include quadrupole defocusing for coaxial resonators, and dipole kick due to couplers for elliptical cavities. A multipole expansion has been performed for each of the cavity designs including effects up to octupole.

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WEPTY020

Design of a Marx-Topology Modulator for FNAL Linac

feedback, cavity, proton, flattop

3306

T.A. Butler, F.G. Garcia, M.R. Kufer, H. Pfeffer, D. Wolff
Fermilab, Batavia, Illinois, USA

The Fermilab Proton Improvement Plan (PIP) was formed in 2011 to address important and necessary upgrades to the Proton Source machines (Injector line, Linac and Booster). The goal is to increase the proton flux by doubling the Booster beam cycle rate while maintaining the same intensity per cycle, the same uptime, and the same residual activation on the accelerating structures. For Linac, the main focus within PIP is to address reliability. One of the main tasks is to replace the present hard-tube modulator used on the main 200MHz RF system. Plans to replace this high power system with a Marx-topology modulator, capable of providing the required waveform shaping to stable the accelerating gradient and compensate for beam loading, will be presented along with development data from the prototype unit.

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WEPTY028

Fermilab Linac Laser Notcher

laser, booster, cavity, ion

3328

D.E. Johnson, K.L. Duel, M.H. Gardner, T.R. Johnson, V.E. Scarpine, R. Tesarek
Fermilab, Batavia, Illinois, USA

Synchrotrons or storage rings require a small section of their circumference devoid of any beam (i.e. a “notch”) to allow for the rise time of an extraction kicker device. In multi-turn injection schemes, this notch in the beam may be generated either in the linac pulse prior to injection or in the accelerator itself after injection. In the case of the Fermilab Booster, the notch is created in the ring near injection energy by the use of fast kickers, thus depositing the beam in a shielded collimation region within the accelerator tunnel. With increasing beam powers, it is desirable to create this notch at the lowest possible energy to minimize activation. Fermilab has undertaken an R&D project to build a laser system to create the notch within a linac beam pulse, immediately after the RFQ at 750 keV, where activation issues are negligible. We will describe the concept for the laser notcher and discuss our current status and future plans for installation of the device.

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WEPTY063

Co-Linear X-Band Energy Booster (XCEB) Cavity and RF System Details

cavity, electron, impedance, extraction

3421

T. Sipahi, S. Biedron, S.V. Milton
CSU, Fort Collins, Colorado, USA

Due to their higher intrinsic shunt impedance X-band accelerating structures offer significant gradients with relatively modest input powers. At the Colorado State University Accelerator Laboratory (CSUAL) we would like to adapt this technology to our 1.3-GHz, L-band accelerator system in order to increase our overall beam energy in a manner that does not require investment in an expensive, custom, high-power X-band klystron system. Here we provide the design details of the X-band structures that will allow us to achieve our goal of reaching the maximum practical net potential across the X-band accelerating structure while driven solely by the beam from the L-band system.

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WEPTY069

Complection of the Cornell High Q CW Full Linac Cryo-module

HOM, cavity, cryomodule, alignment

3440

R.G. Eichhorn, B. Bullock, B. Clasby, J.V. Conway, B. Elmore, F. Furuta, G.M. Ge, G.H. Hoffstaetter, M. Liepe, T.I. O'Connel, P. Quigley, D.M. Sabol, J. Sears, E.N. Smith, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
Y. He
Fermilab, Batavia, Illinois, USA

Cornell University has finished building a 10 m long superconducting accelerator module as a prototype of the main linac of a proposed ERL facility. This module houses 6 superconducting cavities- operated at 1.8 K in continuous wave (CW) mode - with individual HOM absorbers and one magnet/ BPM section. In pushing the limits, a high quality factor of the cavities (2x10¹⁰) and high beam currents (100 mA accelerated plus 100 mA decelerated) were targeted. We will review the design shortly and present the results of the components tested before the assembly. This includes data of the quality-factors of all 6 cavities that we produced and treated in-house, the HOM absorber performance measured with beam on a test set-up as well as testing of the couplers and the tuners.

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WEPTY072

Update on Nitrogen-doped 9-cell Cavity Performance in the Cornell Horizontal Test Cryomodule

cavity, cryomodule, SRF, operation

3446

D. Gonnella, R.G. Eichhorn, F. Furuta, G.M. Ge, D.L. Hall, Y. He, K.M.V. Ho, G.H. Hoffstaetter, M. Liepe, J.T. Maniscalco, T.I. O'Connel, S. Posen, P. Quigley, J. Sears, V. Veshcherevich
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
A. Grassellino, C.J. Grimm, O.S. Melnychuk, A. Romanenko
Fermilab, Batavia, Illinois, USA

Funding: U.S. Department of Energy
The Linac Coherent Light Source-II (LCLS-II) is a new x-ray source that is planned to be constructed in the existing SLAC tunnel. To meet the quality factor specifications (2.7x 10¹⁰ at 2.0 K and 16 MV/m), nitrogen-doping has been proposed as a preparation method for the SRF cavities. In order to demonstrate the feasibility of these goals, four 9-cell cavity tests have been completed in the Cornell Horizontal Test Cryomodule (HTC), which serves as a test bench for the full LCLS-II cryomodule. Here we report on the most recent two cavity tests in the HTC: one cavity nitrogen-doped at Cornell and tested with high Q input coupler and then again tested with high power LCLS-II input coupler. Transition to test in horizontal cryomodule resulted in no degradation in Q0 from vertical test. Additionally, increased dissipated power due to the high power input coupler was small and in good agreement with simulations. These results represent a crucial step on the way to demonstrating technical readiness for LCLS-II.

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WEPTY082

High Gradient Testing of the Five-cell Superconducting RF Module with a PBG Coupler Cell

cavity, HOM, SRF, coupling

3471

S. Arsenyev, W.B. Haynes, D.Y. Shchegolkov, E.I. Simakov, T. Tajima
LANL, Los Alamos, New Mexico, USA
C.H. Boulware, T.L. Grimm, A. Rogacki
Niowave, Inc., Lansing, Michigan, USA

We report results of high-gradient testing of the first 5- cell superconducting radio frequency (SRF) module with a photonic band gap cell (PBG). Higher order mode (HOM) damping is vital for preserving the quality of high-current electron beams in novel SRF accelerators. Because HOMs are not confined by the PBG array, they can be effectively damped in order to raise the current threshold for beam instabilities. The PBG design increases the real-estate gradient of the linac because both HOM damping and the fundamental power coupling can be done through the PBG cell instead of via the beam pipe at the ends of the cavity. A superconducting multi-cell cavity with a PBG damping cell is therefore an attractive option for high-current linacs. The first-ever SRF multi-cell cavity incorporating a PBG cell was designed a LANL and built at Niowave Inc. The cavity was tuned to a desired gradient profile and underwent surface treatment at Niowave. A vertical test (VTS) was then performed at LANL, demonstrating an abnormally low cavity quality factor in the accelerating mode of 1.6*10⁶. Future tests are proposed to determine the source of the losses and resolve the problem.

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WEPWI001

An Overview of the MaRIE X-FEL and Electron Radiography Linac RF Systems

klystron, cavity, electron, FEL

3482

J.T. Bradley III, D. Rees, A. Scheinker, R.L. Sheffield
LANL, Los Alamos, New Mexico, USA

The purpose of the Matter-Radiation Interactions in Extremes (MaRIE) facility at Los Alamos National Laboratory is to investigate the performance limits of materials in extreme environments. The MaRIE facility will utilize a 12 GeV linac to drive an X-ray FEL. Most of the same linac will also be used to perform electron radiography. The main linac is driven by two shorter linacs; one short linac optimized for X-FEL pulses and one for electron radiography. The RF systems have historically been the one of the largest single component costs of a linac. We will describe the details of the different types of RF systems required by each part of the linacs. Starting with the High Power RF system, we will present our methodology for the choice of RF system peak power and pulselength with respect to klystrons parameters, modulator parameters, performance requirements and relative costs. We will also present an overview of the low level RF systems that are proposed for MaRIE and briefly describe their use with some proposed control schemes. *
* A. Scheinker, "Adaptive Accelerator Tuning", Proc. of IPAC'15.

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WEPWI002

Installation and Operation of Replacement 201 MHz High Power RF System at LANSCE

DTL, cavity, controls, electronics

3485

J.T.M. Lyles, W.C. Barkley, J. Davis, D. Rees, G. M. Sandoval, Jr.
LANL, Los Alamos, New Mexico, USA
R.E. Bratton, R.D. Summers
Compa Industries, Inc., Los Alamos, New Mexico, USA

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE--AC52--06NA25396.
The LANSCE RM project has restored the linac to high power capability after the power tube manufacturer could no longer provide triodes that consistently met our high average power requirement. Diacrodes® now supply RF power to two of the four DTL tanks. These tetrodes reuse the existing infrastructure including water-cooling systems, coaxial transmission lines, high voltage power supplies and capacitor banks. The power amplifier system uses a combined pair of LANL-designed cavity amplifiers using the TH628L Diacrode® to produce up to 3.5 MW peak and 420 kW of mean power. Design and prototype testing was completed in 2012, with commercialization following in 2013. The first installation was completed in 2014 and a second installed system is ready to test. The remaining replacement will follow in 2016. Meanwhile, there is a hybrid of old/new amplifiers until the changeover is complete. Operating results of the replacement system are summarized, along with observations from the rapid--paced installation project.

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WEPWI013

New Results of Development on High Efficiency High Gradient Superconducting RF Cavities

cavity, SRF, niobium, photon

3518

R.L. Geng
JLab, Newport News, Virginia, USA
C. Adolphsen, Z. Li
SLAC, Menlo Park, California, USA
J.K. Hao, K.X. Liu
PKU, Beijing, People's Republic of China
H.Y. Zhao
Ningxia Orient Tantalum Industry Co., Ltd., Dawukou District, Shizuishan city, People's Republic of China

We report on the latest results of development on high efficiency high gradient superconducting radio frequency (SRF) cavities. Several 1-cell cavities made of large-grain niobium (Nb) were built, processed and tested. Two of these cavities are of the Low Surface Field (LSF) shape. Series of tests were carried out following controlled thermal cycling. Experiments toward zero-field cooling were carried out. The best experimentally achieved results are Eacc = 41 MV/m at Q0 = 6.5×10¹⁰ at 1.4 K by a 1-cell 1.3 GHz large-grain Nb TTF shape cavity and Eacc = 49 MV/m at Q0 = 1.5×1010 at 1.8 K by a 1-cell 1.5 GHz large-grain Nb CEBAF upgrade low-loss shape cavity.

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WEPWI051

Update on the CeC POP 704 MHz 5-Cell Cavity Cryomodule Design and Fabrication

cavity, SRF, cryomodule, electron

3603

J.C. Brutus, S.A. Belomestnykh, I. Ben-Zvi, V. Litvinenko, I. Pinayev, J. Skaritka, L. Snydstrup, R. Than, J.E. Tuozzolo, W. Xu
BNL, Upton, Long Island, New York, USA
S.M. Gerbick, M.P. Kelly, T. Reid
ANL, Argonne, USA
T.L. Grimm, R. Jecks, J.A. Yancey
Niowave, Inc., Lansing, Michigan, USA
Y. Huang
Fermilab, Batavia, Illinois, USA

Funding: Work is supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the US DOE.
A 5-cell SRF cavity operating at 704 MHz will be used for the Coherent Electron Cooling Proof of Principle (CeC PoP) system currently under development for the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The CeC PoP experiment will demonstrate the ability of relativistic electrons to cool a single bunch of heavy ions in RHIC. The cavity will accelerate 2 MeV electrons from a 112 MHz SRF gun up to 22 MeV. Novel mechanical designs, including the helium vessel, vacuum vessel, tuner mechanism, and FPC are presented. This paper provides an overview of the design, the project status and schedule of the 704 MHz 5-cell SRF for the CeC PoP experiment.
.

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THSMS2

50th Anniversary: Accelerator Conferences in the U.S.

operation, plasma, site, FEL

3668

S.O. Schriber
SOS, Eagle, Idaho, USA

50th Anniversary: Accelerator Conferences in the U.S.

Slides THSMS2 [1.063 MB]

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THPF005

The SARAF-LINAC Project for SARAF-Phase 2

rfq, solenoid, cryomodule, proton

3683

N. Pichoff
CEA/DSM/IRFU, France
D. Berkovits, J. Luner, J. Rodnizki
Soreq NRC, Yavne, Israel
P. Bertrand, M. Di Giacomo, R. Ferdinand
GANIL, Caen, France
P. Brédy, G. Ferrand, P. Girardot, F. Gougnaud, M. Jacquemet, A. Mosnier
CEA/IRFU, Gif-sur-Yvette, France

SNRC and CEA collaborate to the upgrade of the SARAF Accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). This paper presents the reference design of the SARAF-LINAC Project including a four-vane 176 MHz RFQ, a MEBT and a superconducting linac made of four five-meter cryomodules housing 26 superconducting HWR cavities and 20 superconducting solenoids. The first two identical cryomodules house low-beta (βopt = 0.091), 280 mm long (flange to flange), 176 MHz HWR cavities, the two identical last cryomodules house high-beta (βopt = 0.181), 410 mm long, 176 MHz, HWR cavities. The beam is focused with superconducting solenoids located between cavities housing steering coils. A BPM is placed upstream each solenoid.

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THPF006

Design and Manufacturing Status of the IFMIF-LIPAC SRF LINAC

cryomodule, vacuum, cavity, solenoid

3686

H. Dzitko
CEA, Pontfaverger-Moronvilliers, France
N. Bazin, A. Bruniquel, P. Charon, P. Gastinel, P. Hardy, H. Jenhani, J. Neyret, O. Piquet, J. Relland, N. Sellami
CEA/IRFU, Gif-sur-Yvette, France
S. Chel, G. Devanz, G. Disset, V.M. Hennion, B. Renard
CEA/DSM/IRFU, France
D. Gex, G. Phillips
F4E, Germany
D. Regidor, F. Toral
CIEMAT, Madrid, Spain

The IFMIF accelerator aims to provide an accelerator-based D-Li neutron source to produce high intensity high energy neutron flux for testing of candidate materials for use in fusion energy reactors. The first phase of the project, called EVEDA (Engineering Validation and Engineering Design Activities) aims at validating the technical options by constructing an accelerator prototype, called LIPAc (Linear IFMIF Prototype Accelerator) whose construction has begun. It is a full scale of one of the IFMIF accelerator from the injector to the first cryomodule. The cryomodule contains all the necessary equipment to transport and accelerate a 125 mA deuteron beam from an input energy of 5 MeV up to output energy of 9 MeV. It consists of a horizontal vacuum tank approximately 6 m long, 3 m high and 2.0 m wide, and includes 8 superconducting HWRs working at 175 MHz and at 4.45 K for beam acceleration. 8 Power Couplers provide RF power to the cavities up to 70 kW CW in the LIPAc case and 200 kW CW in the IFMIF case, with 8 Solenoid Packages acting as focusing elements. This paper gives an overview of the progress, achievements and status of the IFMIF SRF LINAC.

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THPF007

Optimization of Multi-turn Injection into a Heavy-Ion Synchrotron using Genetic Algorithms

injection, space-charge, emittance, ion

3689

S. Appel, O. Boine-Frankenheim
GSI, Darmstadt, Germany
O. Boine-Frankenheim
TEMF, TU Darmstadt, Darmstadt, Germany

For heavy-ion synchrotrons an efficient multi-turn injection (MTI) from the injector linac is crucial in order to reach the specified currents using the available machine acceptance. The beam loss during the MTI must not exceed the limits determined by machine protection and vacuum requirements. Especially for low energy and intermediate charge state ions, the beam loss can cause a degradation of the vacuum and a corresponding reduction of the beam lifetime. In order to optimize the MTI a genetic algorithm based optimization is used to simultaneously minimize the loss and maximize the multiplication factor (e.g. stored currents in the synchrotron). The effect of transverse space charge force on the MTI has also been taken into account. The optimization resulted in injection parameters, which promise a significant improvement of the MTI performance for intense beams in the SIS18 synchrotron at GSI.

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THPF011

Status of the FAIR Proton Linac

cavity, rfq, proton, diagnostics

3702

R. M. Brodhage, M. Kaiser, W. Vinzenz, M. Vossberg
GSI, Darmstadt, Germany
U. Ratzinger
IAP, Frankfurt am Main, Germany

For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. The main acceleration of this room temperature linac will be provided by six CH cavities operated at 325 MHz. Within the last years, the assembly and tuning of the first power prototype was finished. The cavity was tested with a preliminary aluminum drift tube structure, which was used for precise frequency and field tuning. Afterwards, the final drift tube structure has been welded inside the main tanks and the galvanic copper plating has taken place at GSI workshops. This paper will report on the recent advances with the prototype as well as on the current status of the overall p-Linac project.

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THPF013

UNILAC Proton Injector Operation for FAIR

proton, cavity, ion, operation

3709

M. Heilmann, A. Adonin, S. Appel, W.A. Barth, P. Gerhard, F. Heymach, R. Hollinger, W. Vinzenz, H. Vormann, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth
HIM, Mainz, Germany

The pbar physics program at the Facility for Antiproton and Ion Research (FAIR) requires a high number of cooled pbars per hour. The FAIR proton injector with coupled CH-cavities will provide for a high intensity (35 mA) pulsed 70 MeV proton beam at a repetition rate of 4 Hz. The recent heavy ion UNIversal Linear Accelerator (UNILAC) at GSI is able to deliver proton as well as heavy ion beams for injection into the FAIR-synchrotrons. Recently GSI UNILAC could provide for a two orders of magnitude higher proton beam current in routine operation. A hydrocarbon beam (CH3) from the MUCIS ion source was accelerated inside High Current Injector and cracked in a supersonic nitrogen gas jet into stripped protons and carbon ions. A new proton beam intensities record (3 mA) could be achieved during machine experiments in October 2014. Potentially up to 25% of the FAIR proton beam performance is achievable at a maximum UNILAC beam energy of 20 MeV and a repetition rate of 4 Hz. The UNILAC can be used as a high performance proton injector for initial FAIR-commissioning and as a redundant option for the first FAIR-experiments.

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THPF014

325 MHz High Power RF Coupler for the CH-Cavities of the FAIR p-LINAC

coupling, cavity, proton, simulation

3712

F. Maimone, R. M. Brodhage, M. Kaiser, W. Vinzenz, M. Vossberg
GSI, Darmstadt, Germany

In order to supply the input RF power to the Cross-bar H-mode (CH) cavities of the p-LINAC for FAIR an inductive RF coupler has been studied. The designed RF coupler, and its water cooled inductive loop, has to withstand up to a 3 MW pulsed power (at 325 MHz). At GSI a prototype has been manufactured and tests were performed. The prototype of the designed high power RF coupler is presented together with the results of the coupling measurements at the CH-prototype cavity.

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THPF017

Design Studies for the Proton-Linac RFQ for FAIR

rfq, proton, acceleration, simulation

3718

M. Vossberg, R. M. Brodhage, M. Kaiser, F. Maimone, W. Vinzenz, S. Yaramyshev
GSI, Darmstadt, Germany

The planned 27 m long Proton-Linac (P-LINAC) for FAIR (Facility for Antiproton and Ion Research) comprises a RFQ (Radio-Frequency Quadrupole) and 6 CH-cavities to accelerate a 70 mA proton beam up to 70 MeV. The FAIR Proton-Linac starts with a 325.2 MHz, from 95keV to 3 MeV RFQ accelerator. The main RFQ for this Proton-Linac will be a 4-Vane RFQ. RF analytics with varying and constant transverse focusing strengt for the electrode parameters will be used. CST simulations will help to find cavity parameters for the working frequency. This paper presents the main cavity designs concepts and CST simulation results.

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THPF019

Status and First Measurement Results for a High Gradient CH-Cavity

cavity, ion, resonance, operation

3724

A. Almomani, U. Ratzinger
IAP, Frankfurt am Main, Germany

Funding: BMBF, contract no. 05P12RFRB9
This pulsed linac activity aims on compact designs and on a considerable increase of the voltage gain per meter. A high gradient CH-cavity operated at 325 MHz was developed at IAP-Frankfurt. The mean effective accelerating field for this cavity is expected well above 10 MV/m at β = 0.164. This cavity is developed within a funded project. The results might influence the rebuilt of the UNILAC-Alvarez section, aiming to achieve the beam intensities specified for the GSI - FAIR project (15 mA U²⁸⁺). Another motivation is the development of an efficient pulsed ion accelerator for significantly higher energies like 60 AMeV. The new GSI 3 MW Thales klystron test stand will be used for the cavity RF power tests. Detailed studies on two different types of copper plating will be performed with this cavity.

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THPF020

Upgrade of the HSI-RFQ at GSI to Fulfill the FAIR Requirements

rfq, simulation, multipole, brilliance

3727

M. Baschke, H. Podlech
IAP, Frankfurt am Main, Germany
W.A. Barth
GSI, Darmstadt, Germany

In Darmstadt/Germany the existing accelerator facility GSI is expanding to one of the biggest joint research projects worldwide: FAIR, a new antiproton and ion research facility with so far unmatched intensities and quality. The existing accelerators will be used as pre-accelerators and therefor need to be upgraded. In a first step the 36 MHz-HSI-RFQ for high current beams will get new electrodes to fulfill the FAIR requirements. First simulation results for capacity and multipole momentums will be presented.

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THPF025

Beam Dynamics for the SC CW Heavy Ion LINAC at GSI

cavity, ion, heavy-ion, emittance

3742

M. Schwarz, M. Amberg, M. Basten, F.D. Dziuba, H. Podlech, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany
M. Amberg, K. Aulenbacher, M. Miski-Oglu
HIM, Mainz, Germany
W.A. Barth, V. Gettmann, M. Heilmann, S. Mickat, A. Orzhekhovskaya, S. Yaramyshev
GSI, Darmstadt, Germany

Funding: Work supported by BMBF contr. No. 05P12RFRBL
For future experiments with heavy ions near the coulomb barrier within the SHE (super-heavy elements) research project a multi-stage R&D program of GSI, HIM and IAP is currently in progress*. It aims at developing a superconducting (sc) continuous wave (cw) LINAC with multiple CH cavities as key components downstream the High Charge Injector (HLI) at GSI. The beam dynamics concept is based on EQUUS (equidistant multigap structure) constant-beta cavities. Advantages of its periodicity are a high simulation accuracy, easy manufacturing and tuning with minimized costs as well as a straightforward energy variation. The next milestone will be a full performance beam test of the first LINAC section, comprising two solenoids and a 15-gap CH cavity inside a cryostat (Demonstrator).
*W. Barth et al., ‘‘Further R&D for a new Superconducting cw Heavy Ion LINAC@GSI'', THPME004, IPAC'14, Dresden, Germany (2014)

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THPF026

Development of a 325 MHz Ladder-RFQ of the 4-Rod Type

rfq, simulation, proton, cavity

3745

M. Schütt, U. Ratzinger
IAP, Frankfurt am Main, Germany
R. M. Brodhage
GSI, Darmstadt, Germany

For the research program with cooled antiprotons at FAIR a dedicated 70 MeV, 70 mA proton injector is required. In the low energy section, between the Ion Source and the main linac an RFQ will be used. The 325 MHz RFQ will accelerate protons from 95 keV to 3.0 MeV. This particular high frequency for an RFQ creates difficulties, which are challenging in developing this cavity. In order to define a satisfactory geometrical configuration for this resonator, both from the RF and the mechanical point of view, different designs have been examined and compared. Very promising results have been reached with a ladder type RFQ, which has been investigated since 2013. We present recent 3D simulations of the general layout and of a complete cavity demonstrating the power of a ladder type RFQ as well as measurements of a 0,8 m prototype RFQ, which was manufactured in late 2014 and designed for RF power and vacuum tests. We will outline a possible RF layout for the RFQ within the new FAIR proton injector and highlight the mechanical advantages.

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THPF039

Stability Studies for J-PARC Linac Upgrade to 50 mA/400 MeV

lattice, emittance, simulation, operation

3785

Y. Liu, T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

J-PARC linac applies the Equi-partitioning (EP) setting as the base-line design. And it is the first machine to adopt this approach at the design stage. EP condition is a natural solution for avoiding emittance exchange between transverse and longitudinal planes. At J-PARC linac it is also possible to explore off-EP settings. One of the motivations could be a lattice with relaxed envelope for mitigating the intra-beam stripping (IBSt) effects in high current H⁻ beam. During and after the energy upgrade in Jan., 2014 and beam current upgrade in Oct., 2014, experiments were carried out to study the stability and emittance evolution for the EP and off-EP settings with high current H⁻ beam at J-PARC linac for better choices of lattice and better understanding.

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THPF040

Recent Progress of the Beam Commissioning in J-PARC Linac

DTL, rfq, emittance, simulation

3789

T. Maruta, Y. Liu
KEK/JAEA, Ibaraki-Ken, Japan
K. Futatsukawa, T. Miyao
KEK, Ibaraki, Japan
M. Ikegami
FRIB, East Lansing, Michigan, USA
A. Miura
JAEA/J-PARC, Tokai-mura, Japan

J-PARC linac iis replaced the front-end in the summer shutdown in year 2014 to extend the maximum peak current to 50 mA from 30 mA. By the combination with the energy upgrade conducted in year 2013, it becomes possible to achieve the design beam energy of 133 kW, which is corresponding to 1 MW at the extraction of 3 GeV Rapid Cycling Sychrotron (RCS). The beam commissioning after the replacement started at Sep./27, and we can successfully accelerate the beam at peak current of 30 mA and 50 mA. In this presentation, we introduce the resent progress of the beam commissioning of the J-PARC linac.

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THPF044

Status of the J-PARC 3 GeV RCS

operation, injection, vacuum, radiation

3798

M. Kinsho
JAEA/J-PARC, Tokai-mura, Japan

Beam injection energy of the RCS in J-PARC was increased from 181 MeV to 400 MeV, and user operation with beam energy of 300 kW for both the MLF and the MR was performed with high availability from February to Jun in 2014. Beam losses during beam injection period was decreased by reduction of space charge effect due to increase of beam injection energy. Since an ion source and an RFQ of the LINAC are replaced to realize 1 MW beam power at the RCS in summer maintenance period, injection beam peak current was increased from 30 mA to 50 mA. User operation was restarted from November with beam power of 300 kW. The beam power for user operation will be gradually increased after getting radiation safety permission from government. High intensity beam study was also performed and it was successfully to accelerate beam of 770 kW equivalent without beam loss except foil scattering loss. In this beam study it was cleared issues to realize 1MW operation in the RCS. Status of user operation and issues to realize high power operation in the RCS are presented.

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THPF050

Applications of Beam Parameter Measurements in Transport Lines at CSNS

optics, beam-transport, DTL, factory

3815

Z.P. Li, L. Huang, Y. Li, J. Peng, S. Wang
IHEP, Beijing, People's Republic of China

Several XAL-based applications for parameter measurements in Medium Energy Beam Transport line (MEBT) and Linac to Ring Beam Transport line (LRBT) at China Spallation Neutron Source (CSNS) have been developed. Algorithms and functions of these applications are introduced in this paper. Real Machine tests are carried out in the MEBT commissioning.

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THPF055

Status of the Superconducting Cavity Development at IHEP for the CADS Linac

cavity, SRF, operation, proton

3824

F.S. He, J.P. Dai, J. Dai, X. Huang, L.H. Li, Z.Q. Li, Q. Ma, Z.H. Mi, B. Ni, W.M. Pan, X.H. Peng, T. Qi, P. Sha, G.W. Wang, Q.Y. Wang, Z. Xue, X.Y. Zhang, G.Y. Zhao
IHEP, Beijing, People's Republic of China
H. Huang, H.Y. Lin
Institute of High Energy Physics (IHEP), Chinese Academy of Sciences, Beijing, People's Republic of China

IHEP (Institute of High Energy Physics) is developing a CW 10MeV proton injector and part of the 25MeV main linac for the CADS project. 14 SRF (superconducting radio frequency) spoke-012 cavities for the injector, as well as 6 SRF spoke-021 cavities for the main linac are to be beam commissioned before middle of 2016; meanwhile, VT (vertical test) of two more types of prototype cavities are to be finished with 2015, for the future phases of the project. In this paper, the VT statistics of 10 spoke012 cavities, 4 spoke021 cavities, and a 5-cell β0.82 elliptical cavity are reported; the cavity performance during beam commissioning of the TCM (test cryomodule) is reported as well.

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THPF057

Beam Commissioning of C-ADS Injector-I RFQ Accelerator

rfq, emittance, proton, simulation

3827

C. Meng, J.S. Cao, Y.Y. Du, H. Geng, T.M. Huang, R.L. Liu, H.F. Ouyang, W.M. Pan, S. Pei, H. Shi, Y.F. Sui, J.L. Wang, S.C. Wang, F. Yan, Q. Ye, L. Yu, Y. Zhao
IHEP, Beijing, People's Republic of China

The C-ADS accelerator is a CW (Continuous-Wave) proton linac with 1.5 GeV in beam energy, 10 mA in beam current, and 15 MW in beam power. C-ADS Injector-I accelerator is a 10-mA 10-MeV CW proton linac, which uses a 3.2-MeV normal conducting 4-Vane RFQ and superconducting single-spoke cavities for accelerating. The frequency of RFQ accelerator is 325 MHz. The test stand composed of an ECR ion source, LEBT, RFQ, MEBT and beam dump have been installed and the first stage of beam commissioning have been finished at IHEP in 2014 mid-year. At 90% duty factor, we got 11 mA proton beam at RFQ exit with 90% beam transmission efficiency, while 95% beam transmission efficiency at 70% duty factor. The energy after RFQ was measured by TOF method with FCTs. The transverse emittance measured by double-slits emittance meter was 0.135 π mm-mrad, which of detailed data analysis will be presented in this paper.

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THPF062

CADS 650 MHz β=0.63 Elliptical Cavity Study

cavity, HOM, proton, resonance

3836

L.J. Wen, Y. He, Y.M. Li, S.H. Zhang
IMP/CAS, Lanzhou, People's Republic of China

The China Accelerator Driven Sub-critical System (CADS) is a high intensity proton facility to dispose of nuclear waste and generate electric power. CADS is based on 1.5 GeV, 10mA CW superconducting (SC) linac as a driver. The high-energy section of the linac is composed of two families of SC elliptical cavities which are designed for the geometrical beta 0.63 and 0.82. In this paper, the 650 MHz β=0.63 SC elliptical cavity was studied, including cavity optimization, multipacting, high order modes (HOM) and generator RF power calculation.

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THPF072

Beam Optics of RISP Linac using Dynac Code

simulation, rfq, cavity, target

3845

J.-H. Jang, I.S. Hong, H. Jang, D. Jeon, H. Jin, H.J. Kim
IBS, Daejeon, Republic of Korea

Funding: This work was supported by the Rare Isotope Science Project of Institute for Basic Science funded by Ministry of Science, ICT and Future Planning.
The RISP (Rare Isotope Science Project) is developing a superconducting linac which accelerates uranium beams up to 200MeV/u with the beam power of 400kW. The linac consists of an injector which includes an ECR ion source and an RFQ, and superconducting cavities which include QWR (Quarter Wave Resonator), HWR (Half Wave Resonator), and SSR (Single Spoke Resonator). Up to HWR, two charge state beams will be accelerated to achieve the required beam current and then five charge state beams will be used to obtain the higher acceleration efficiency. In this work, we performed the beam optics calculation by using a beam dynamics code DYNAC in order to study a possibility of the code as an online model. We compared the results with the calculation in the baseline design by TRACK code.

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THPF074

Progress on Superconducting Linac for the RAON Heavy Ion Accelerator

cavity, cryomodule, ion, electron

3851

H.J. Kim, H.C. Jung, W.K. Kim
IBS, Daejeon, Republic of Korea

The RISP (Rare Isotope Science Project) has been proposed as a multi-purpose accelerator facility for providing beams of exotic rare isotopes of various energies. It can deliver ions from proton to Uranium. Proton and Uranium beams are accelerated upto 600 MeV and 200 MeV/u respectively. The facility consists of three superconducting linacs of which superconducting cavities are independently phased. Requirement of the linac design is especially high for acceleration of multiple charge beams. In this paper, we present the RISP linac design, the prototyping of superconducting cavity and cryomodule.

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THPF078

Effect of the Field Maps on the Beam Dynamics of the ESS Drift Tube Linac

emittance, DTL, klystron, focusing

3864

R. De Prisco, M. Eshraqi, Y.I. Levinsen, R. Miyamoto, E. Sargsyan
ESS, Lund, Sweden
A.R. Karlsson
Lund University, Lund, Sweden

In the beam dynamic design and modelling of the European Spallation Source (ESS) Drift Tube Linac (DTL) simplified models have been used for the focusing and accelerating structures. Since the high current requires precise control of the beam to minimise the losses it is useful to analyse the beam dynamics by using accurate field maps of the focusing and accelerating structures. In this paper the effects of the 3D-field maps on the beam dynamics of the ESS DTL are presented.

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THPF079

A Planning and Scheduling System for the ESS Accelerator Project

controls, neutron, project-management, cryomodule

3867

L. Lari, M.J. Conlon, H. Danared, L. Gunnarsson, G. Jacobsson, M. Jakobsson, M. Lindroos, E. Tanke, J.G. Weisend
ESS, Lund, Sweden
P. Bonnal, L. Lari
CERN, Geneva, Switzerland

Constructing a large, international research infrastructure is a complex task, especially when a large fraction of the equipment is delivered as in-kind contributions. A mature project management approach is essential to lead the planning and construction to deliver scientifically and technically. The purpose of this paper is to present how the ESS accelerator project is managed in terms of planning and scheduling from the design phase until commissioning, keeping time, budgets and resources constraints, as well as creating and maintaining a strong and trust-based partnership with the external contributors.

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THPF080

Status of the ESS Accelerator Construction Project

target, klystron, proton, beam-transport

3870

M. Lindroos, H. Danared, R. Garoby, D.P. McGinnis, E. Tanke
ESS, Lund, Sweden

The European spallation source is now under construction just outside in Lund in Sweden. The driver is a 5 MW linac operating at a duty factor of 4% and at 2 GeV. The detailed design of the buildings is just being completed, and the casting of the accelerator tunnel has started. The accelerator design is getting mature with the major parts under prototyping. A challenging aspect of the project is the large percentage of in-kind contributions. For the accelerator this is now reaching 47% percent in pre commitments by institutes and universities in the ESS member states. We will in this paper give an overview of the ESS accelerator design, the status of prototyping and the organization of the in-kind accelerator construction project.

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THPF081

On the Suitability of a Solenoid Horn for the ESS Neutrino Superbeam

solenoid, target, focusing, detector

3873

M. Olvegård, T.J.C. Ekelöf, R.J.M.Y. Ruber, V.G. Ziemann
Uppsala University, Uppsala, Sweden
J.-P. Koutchouk
CERN, Geneva, Switzerland

The European Spallation Source (ESS), now under construction in Lund, Sweden, offers unique opportunities for experimental physics, not only in neutron science but potentially in particle physics. The ESS neutrino superbeam project plans to use a 5 MW proton beam from the ESS linac to generate a high intensity neutrino superbeam, with the final goal of detecting leptonic CP-violation in an underground megaton Cherenkov water detector. The neutrino production requires a second target station and a complex focusing system for the pions emerging from the target. The normal-conducting magnetic horns that are normally used for these applications cannot accept the 2.86 ms long proton pulses of the ESS linac, which means that pulse shortening in an accumulator ring would be required. That, in turn, requires H⁻ operation in the linac to accommodate the high intensity. As an attractive alternative, we investigate the possibility of using superconducting solenoids for the pion focusing. This solenoid horn system needs to also separate positive and negative pion charge as completely as possible, in order to generate separately neutrino and anti-neutrino beams. We present here progress in the study of such a solenoid horn.

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THPF083

Painting Schemes for CERN PS Booster H⁻ Injection

injection, emittance, simulation, booster

3879

J.L. Abelleira, W. Bartmann, E. Benedetto, C. Bracco, G.P. Di Giovanni, V. Forte, M. Kowalska, M. Meddahi, B. Mikulec, G. Rumolo
CERN, Geneva, Switzerland
V. Forte
Université Blaise Pascal, Clermont-Ferrand, France
M. Kowalska
EPFL, Lausanne, Switzerland

The present 50-MeV proton injection into the PS Booster will be replaced by a H⁻ charge exchange injection at 160 MeV to be provided by Linac 4. The higher energy will allow producing beams at higher brightness. A set of kicker magnets (KSW) will move the beam across the stripping foil to perform phase space painting in the horizontal plane to reduce space charge effects. The PSB must satisfy the different users with very different beams in terms of emittance and intensity. Therefore, the KSW waveforms must be adapted for each case to meet the beam characteristics while minimizing beam losses. Here we present the results of the simulations performed to optimise the injection system. A detailed analysis of the different painting schemes is discussed, including the effect of the working point on the painted beam, and variations in the offset of the injected beam.

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THPF084

ProTec - A Normal-conducting Cyclinac for Proton Therapy Research and Radioisotope Production

cyclotron, proton, cavity, accelerating-gradient

3883

R. Apsimon, G. Burt, S. Pitman
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
A. Degiovanni
CERN, Geneva, Switzerland
J.A. Mitchell
Lancaster University, Lancaster, United Kingdom
H.L. Owen
UMAN, Manchester, United Kingdom

The ProTec cyclinac proposes the use of a 24 MeV high-current cyclotron to inject protons into a normal-conducting linac pulsed at up to 1 kHz to give energies up to 150 MeV. As well as being able to produce radioisotopes such as 99mTc, the cyclinac can also provide protons at higher energy with beam properties relevant for proton therapy research. In this paper we present a comparison of linac designs in which S-band structures are used at lower energies, prior to injection into a high-gradient X-band structure; issues such as beam capture and transmission are evaluated.

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THPF085

Beam Commissioning of Linac4 up to 12 MeV

DTL, emittance, diagnostics, quadrupole

3886

V.A. Dimov, E. Belli, G. Bellodi, J.-B. Lallement, A.M. Lombardi
CERN, Geneva, Switzerland
M. Yarmohammadi Satri
IPM, Tehran, Iran

CERN Linac4 is made of a 3 MeV front end including a 45 keV source , a 3 MeV Radio Frequency Quadrupole (RFQ) and a fast chopper, followed by a 50 MeV Drift Tube Linac (DTL), a 100 MeV Cell-Coupled Drift Tube Linac (CCDTL) and a 160 MeV Pi-Mode Structure (PIMS). The Linac4 beam commissioning is performed in 6 stages of increasing energy. Movable beam diagnostics benches, with various instruments, are used at each step to allow the detailed characterisation of operational parameters that will play a key role in the overall future performance. The first three stages of the commissioning, up to 12 MeV beam energy, have been completed at the end of 2014. The RFQ and the chopper line at 3 MeV, as well as the first tank of the DTL at 12 MeV were fully characterised, using permanent diagnostic instruments and a movable diagnostic bench equipped with a spectrometer, a slit-grid emittance meter, a Bunch Shape Monitor, Beam Position Monitors and a laser-emittance device. This paper reports on the strategy and the results of the commissioning up to 12 MeV. It also presents the validation of the set-up strategy, which is essential for the next stages of commissioning.

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THPF086

A New Hardware Design for PSB Kicker Magnets (KSW) for the 35 mm Transverse Painting in the Horizontal Plane

injection, kicker, vacuum, emittance

3890

L.M.C. Feliciano, C. Bracco, L. Ducimetière, T. Fowler, G. Gräwer, R. Noulibos, L. Sermeus, W.J.M. Weterings, C. Zannini
CERN, Geneva, Switzerland

The changeover from Linac2 to Linac4 in CERN’s injector chain will allow increasing the injection energy into the PS Booster from 50 MeV to 160 MeV. Transverse phase space painting will be performed in the horizontal plane, by means of four stacks of four KSW kicker magnets. The KSW magnets are located outside the injection region and will produce a 35 mm closed orbit bump, with falling amplitude during the injection to accomplish transverse phase space painting to the required emittance. New magnets with two different types of coils are being built using the existing design. The magnets are made of two halves, which are assembled together around a vacuum ceramic chamber. In order to reduce the beam impedance, the ceramic chamber is internally coated by a thin titanium layer. A new multiple-linear waveform generator has been developed to provide the high flexibility in the KSW kicker magnets current decay to fulfil the requirements of all the different users (LHC, nTOF, ISOLDE, CNGS, etc.).

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THPF092

European Spallation Source Lattice Design Status

lattice, target, DTL, quadrupole

3911

Y.I. Levinsen
CERN, Geneva, Switzerland
H. Danared, R. De Prisco, M. Eshraqi, R. Miyamoto, M. Muñoz, A. Ponton, E. Sargsyan
ESS, Lund, Sweden
S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark

The European Spallation Source will offer an unprecedented beam power for spallation sources of 5 MW. The accelerator will deliver a proton beam of 62.5 mA peak current and 2.0 GeV onto the spallation target. Since the technical design report (TDR) was published in 2013, work has continued to further optimize the accelerator design. We report on the advancements in lattice design optimizations after the TDR to improve performance and flexibility, and reduce cost of the ESS accelerator.

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THPF093

Status of the LHC Injectors Upgrade (LIU) Project at CERN

ion, brightness, proton, injection

3915

M. Meddahi, J. Coupard, H. Damerau, A. Funken, S.S. Gilardoni, B. Goddard, K. Hanke, L. Kobzeva, A.M. Lombardi, D. Manglunki, S. Mataguez, B. Mikulec, G. Rumolo, E.N. Shaposhnikova, M. Vretenar
CERN, Geneva, Switzerland

CERN is currently carrying out an ambitious improvement programme of the full LHC Injectors chain in order to enable the delivery of beams with the challenging HL-LHC parameters. The LHC Injectors Upgrade project coordinates this massive upgrade program, and covers a new linac (Linac4 project) as well as upgrades to the Proton Synchrotron Booster, the Proton Synchrotron and Super Proton Synchrotron. The heavy ion injector chain is also included, adding the Linac3 and Low Energy Ion Ring to the list of accelerators concerned. The performance objectives and roadmap of the main upgrades will be presented, including the work status and outlook. The machine studies and milestones during LHC Run 2 will be discussed and a preliminary Long Shutdown 2 installation planning given. Finally, for the LHC Run 3, the beam performance across the full injector chain after all the upgrades will be estimated and the required commissioning stages outlined.

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THPF100

Status of the ESSnuSB Accumulator

target, injection, lattice, proton

3942

E.H.M. Wildner, B.J. Holzer, M. Martini, Y. Papaphilippou, H.O. Schönauer
CERN, Geneva, Switzerland
T.J.C. Ekelöf, M. Olvegård, R.J.M.Y. Ruber
Uppsala University, Uppsala, Sweden
M. Eshraqi
ESS, Lund, Sweden

The European Spallation Source (ESS) is a research center based on the world's most powerful neutron source currently under construction in Lund, Sweden. 2.0 GeV, 2.86 ms long proton pulses at 14 Hz are produced for the spallation facility (5MW on target). The possibility to pulse the linac at higher frequency to deliver, in parallel with the spallation neutron production, a very intense, cost effective, high performance neutrino beam. Short pulses on the target require an accumulator ring. The optimization of the accumulator lattice to store these high intensity beams from the linac (1.1x10¹⁵ protons per pulse) has to take into account the space available on the ESS site, transport of H⁻ beams (charge exchange injection), radiation and shielding needs. Space must be available in the ring for collimation and an RF system for the extraction gap and loss control. We present the status of the accumulator for ESS neutrino facility.

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THPF101

Design of a Proton Travelling Wave Linac with a Novel Tracking Code

proton, quadrupole, lattice, simulation

3945

S. Benedetti
EPFL, Lausanne, Switzerland
U. Amaldi
TERA, Novara, Italy
A. Grudiev, A. Latina
CERN, Geneva, Switzerland

A non-relativistic proton linac based on high gradient backward travelling wave accelerating structures was designed using a novel dedicated 3D particle tracking code. Together with the specific RF design approach adopted, the choice of a 2.9985 GHz backward travelling wave (BTW) structure with 150° RF phase advance per cell was driven by the goal of reaching an accelerating gradient of 50 MV/m, which is more than twice that achieved so far. This choice dictated the need to develop a new code for tracking charged particles through travelling wave structures which were never used before in proton linacs. Nevertheless, the new code has the capability of tracking particles through any kind of accelerating structure, given its real and imaginary electromagnetic field map. This project opens a completely new field in the design of compact linacs for proton therapy, possibly leading to cost-effective and widespread single room facilities for cancer treatment.

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THPF106

Review of Linac Upgrade Options for the ISIS Spallation Neutron Source

DTL, neutron, proton, cavity

3962

D.C. Plostinar, C.R. Prior, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

The ISIS Spallation Neutron Source at Rutherford Appleton Laboratory has recently celebrated 30 years of neutron production. However, with increasing demand for improved reliability and higher beam power it has become clear that a machine upgrade is necessary in the medium to long term. One of the upgrade options is to replace the existing 70 MeV H⁻ injector. In this paper we review the ongoing upgrade programme and highlight three linac upgrade scenarios now under study. The first option is to keep the existing infrastructure and replace the current linac with a higher frequency, more efficient machine. This would allow energies in excess of 100 MeV to be achieved in the same tunnel length. A second option is to replace the current linac with a new 180 MeV linac, requiring a new tunnel. A third option is part of a larger upgrade scenario and involves the construction of an 800 MeV superconducting linac.

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THPF116

PIP-II Status and Strategy

proton, booster, operation, injection

3982

S.D. Holmes, P. Derwent, V.A. Lebedev, C.S. Mishra, D.V. Mitchell, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Funding: Work supported by the Fermi Research Alliance under U.S. Department of Energy contract number DE-AC02-07CH11359
Proton Improvement Plan-II (PIP-II) is the centerpiece of Fermilab’s plan for upgrading the accelerator complex to establish the leading facility in the world for particle physics research based on intense proton beams. PIP-II has been developed to provide 1.2 MW of proton beam power at the start of operations of the Long Baseline Neutrino Experiment (LBNE), while simultaneously providing a platform for eventual extension of LBNE beam power to >2 MW and enabling future initiatives in rare processes research based on high duty factor/higher beam power operations. PIP-II is based on the construction of a new, 800 MeV, superconducting linac, augmented by improvements to the existing Booster, Recycler, and Main Injector complex. PIP-II is currently in the development stage with an R&D program underway targeting the front end and superconducting rf acceleration technologies. This paper will describe the status of the PIP-II conceptual development, the associated technology R&D programs, and the strategy for project implementation.

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THPF118

Fermilab Booster Injection Upgrade to 800 MeV for PIP-II

injection, booster, dipole, closed-orbit

3986

D.E. Johnson, V.A. Lebedev, I.L. Rakhno
Fermilab, Batavia, Illinois, USA

Fermilab is proposing to build an 800 MeV superconducting linac which will be used to inject H⁻ ions into the existing Booster synchrotron as part of the proposed PIP-II project. The injection energy of the Booster will be raised from the current 400 MeV to 800 MeV. Transverse phase space painting will be required due to the small linac transverse emittance (emit_ring/emit_linac ~ 10) and low average linac current of 2 mA. The painting is also helpful with reduction of beam distributions resulting in a reduction of space charge effects. The injection will require approximately 300 turns corresponding to a ~ 0.5 ms injection time. A factor of seven increase in injected beam power (relative to present operation) requires an injection waste beam absorber. The paper describes the requirements for the injection insert, itsdesign, and plans for transverse painting.

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THPF119

Transfer Line Design for PIP-II Project

booster, injection, target, quadrupole

3989

A. Vivoli, J. Hunt, D.E. Johnson, V.A. Lebedev
Fermilab, Batavia, Illinois, USA

The recent U.S. Particle Physics Community P5 report encouraged the realization of the Proton Improvement Plan II (PIP-II) project to support future neutrino programs in the United States. PIP-II includes the construction of a new 800 MeV H⁻ Superconducting (SC) Linac at Fermilab and an upgrade of its current accelerator complex mostly focused on upgrades of the Booster and Main Injector synchrotrons. The SC Linac will initially operate in pulsed mode at 20 Hz. The design should be compatible with upgrades to CW mode and higher energy. A new transport line will connect the Linac to the Booster. This line has to provide adequate collimation and be instrumented for beam parameter measurements. In addition, to support beam based Linac energy stabilization, the line should provide a mechanism to redirect the beam from the dump to the Booster within one pulse. In this paper we present the design of the transport line developed to meet the above requirements. Tracking simulations results are reported to confirm the validity of the design.

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THPF137

Beam Dynamics Effects of High Order Multipoles in Non-Axisymmetric Superconducting RF Cavities

multipole, sextupole, octupole, lattice

4045

Z.Q. He, J. Wei, Y. Zhang
FRIB, East Lansing, Michigan, USA

Funding: The work is supported by the U.S. National Science Foundation under Grant No. PHY-11-02511, and the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
Non-axisymmetric superconducting RF cavities have been widely used in accelerator facilities. Because of the geometry, electric and magnetic multipole components, including steering terms, quadrupole terms, and higher order terms, would arise and have potential effects on beam dynamics. In this paper, we start with a simple linac periodic structure to study the effects of higher order terms. The action is defined as a figure of merit to quantify the effects. After that, we move to a more realistic situation of FRIB linac segment 1 (LS1). Multipole terms of quarter wave resonators (QWRs) are firstly calculated using multipole expansion scheme. Then, the scheme is tested using the FRIB linac lattice with QWRs, and the effects of higher order terms on FRIB LS1 are estimated.

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THPF140

Unique Accelerator Integration Features of the Heavy Ion CW Driver Linac at FRIB

proton, beam-loading, solenoid, focusing

4051

Y. Yamazaki, N.K. Bultman, A. Facco, M. Ikegami, F. Marti, G. Pozdeyev, J. Wei, Y. Zhang, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The FRIB driver linac is a front runner for the future high power hadron linacs, making a full use of CW, superconducting acceleration from very low β. Accelerator Driven Nuclear Waste Transmutation System (ADS), International Fusion Material Irradiation Facility (IFMIF), Project-X type proton accelerators for high energy physics and others may utilize the technologies developed for the design, construction, commissioning and power ramp up of the FRIB linac. Although each technology has been already well developed individually (except for charge stripper), their integration is another challenge. In addition, extremely high Bragg peak of uranium beams (several thousand times as high as that of proton beams) gives rise to one of the biggest challenges in many aspects. This report summarizes these challenges and their mitigations, emphasizing the commonly overlooked features.

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THPF148

LANSCE H⁺ RFQ Status

rfq, beam-transport, ion, ion-source

4073

R.W. Garnett, Y.K. Batygin, C.A. Chapman, I.N. Draganic, C.M. Fortgang, S.S. Kurennoy, R.C. McCrady, J.F. O'Hara, E.R. Olivas, L. Rybarcyk, H.R. Salazar
LANL, Los Alamos, New Mexico, USA
J. Haeuser
Kress GmbH, Biebergemuend, Germany
B. Koubek, A. Schempp
IAP, Frankfurt am Main, Germany

Funding: This work is supported by the U. S. Department of Energy Contract DE-AC52-06NA25396.
The LANSCE linear accelerator at Los Alamos National Laboratory provides H⁻ and H⁺ beams to several user facilities that support Isotope Production, NNSA Stockpile Stewardship, and Basic Energy Science programs. These beams are initially accelerated to 750 keV using Cockcroft-Walton (CW) based injectors that have been in operation for over 37 years. To reduce long-term operational risks and to realize future beam performance goals for LANSCE we are completing fabrication of a 4-rod Radio-Frequency Quadrupole (RFQ) and design of an associated beam transport line that together will eventually become the modern injector replacement for the existing obsolete H⁺ injector system. A similar H⁻ system is also planned for future implementation. An update on the status and progress of the project will be presented.

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THPF149

Electromagnetic Modeling of 4-Rod RFQ Tuning

rfq, simulation, vacuum, quadrupole

4076

S.S. Kurennoy, L. Rybarcyk
LANL, Los Alamos, New Mexico, USA

Modern codes make possible detailed 3D electromagnetic modeling of RFQ accelerators. We have recently analyzed two 201.25-MHz 4-rod RFQs – one commissioned at FNAL and a new design for LANL – with CST Studio using imported manufacturer CAD files*. The RFQ electromagnetic analysis with MicroWave Studio (MWS) was followed by beam dynamics modeling with Particle Studio as well as other multi-particle codes. Here we apply a similar approach to study the process of RFQ tuning in 3D CST models. In particular, the results will be used to better understand tuning the voltage flatness along the new LANL 4-rod RFQ.
* S.S. Kurennoy, LINAC14, Geneva, Switzerland, 2014, THPP097.

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THPF150

3D Electromagnetic and Beam Dynamics Modeling of the LANSCE Drift-Tube Linac

DTL, simulation, beam-losses, rfq

4079

S.S. Kurennoy, Y.K. Batygin
LANL, Los Alamos, New Mexico, USA

The LANSCE drift-tube linac (DTL) accelerates the proton or H⁻ beam to 100 MeV. It consists of four tanks containing tens of drift tubes and post-couplers; for example, tank 2 is almost 20 m long and has 66 cells. We have developed 3D models of full tanks [1] in the DTL with CST Studio to accurately calculate the tank modes, their sensitivity to post-coupler positions and tilts, tuner effects, and RF-coupler influence. Electromagnetic analysis of the DTL tank models is performed using MicroWave Studio (MWS). The full-tank analysis allows tuning the field profile of the operating mode and adjusting the frequencies of the neighboring modes within a realistic CST model. Beam dynamics is modeled with Particle Studio for bunch trains with realistic initial beam distributions using the MWS-calculated and tuned RF fields and quadrupole magnetic fields to determine the output beam parameters and locations of particle losses.
* S.S. Kurennoy, LINAC14, Geneva, Switzerland, 2014, MOPP106.

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FRXB3

Advances in CW Ion Linacs

rfq, cavity, cryomodule, ion

4085

P.N. Ostroumov
ANL, Argonne, Illinois, USA

Funding: This work was supported by the U.S. Department of Energy, Office of High Energy Physics and Nuclear Physics, under Contracts DE-AC02-76CH03000 and DE-AC02-06CH11357.
Substantial research and development related to CW proton and ion accelerators are being performed at ANL. A normal conducting CW RFQ and a 4K cryomodule with seven quarter-wave resonators (QWR) and SC solenoids have been developed, built, commissioned and operated as an upgrade of the CW ion linac, ATLAS, to achieve higher efficiency and beam intensities. The new CW RFQ and cryomodule were fully integrated into ATLAS and have been in routine operation for more than a year. Currently we are engaged in development of the first cryomodule for a CW H linac being built at FNAL. This work is well aligned with the development of a 1 GeV 25 MW linac as the driver of a sub-critical assembly for near-term spent nuclear fuel disposal. A 2K cryomodule with eight 162.5-MHz SC half wave resonators (HWR) and eight SC solenoids is being developed for FNAL and scheduled for commissioning in 2017. The testing of the first 2 HWRs demonstrated remarkable performance. Experience with the development and reliable operation of new copper and superconducting accelerating structures is an essential precursor for advanced, reliable future large scale high power CW accelerators.

Slides FRXB3 [4.963 MB]

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