IPAC2015 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOYGB3	Commissioning of NSLS-II	insertion, insertion-device, damping, lattice	11
	F.J. Willeke BNL, Upton, Long Island, New York, USA
	NSLS-II, the new 3rd generation light source at BNL was designed for a brightness of 10²² photons s^-1 mm^-2 mrad^-2 (0.1%BW)^-1. It was constructed between 2009 and 2014. The storage ring was commissioned in April 2014 which was followed by insertion device and beamline commissioning in the fall of 2014. All ambitious design parameters of the facility have already been achieved except for commissioning the full beam intensity of 500 mA which requires more RF installation. This paper reports on the results of commissioning.
	Slides MOYGB3 [3.884 MB]
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MOAB2	Overview of Beam Instrumentation for the CADS Injector I Proton Linac	linac, rfq, 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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MOPWA001	Instability Thresholds and Tune Shift Estimation for Sirius	impedance, feedback, damping, simulation	70
	F.H. de Sá, L. Liu, N. Milas, X.R. Resende LNLS, Campinas, Brazil
	In this work we present the evaluation of longitudinal and transverse instability thresholds as well as tune shifts for Sirius using time and frequency domain codes that are being developed in-house and take into account various effects on the beam instability, such as bunch by bunch feedback system, quadrupolar impedances from undulator chambers and tune spreads.
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MOPWA006	Core-Halo Limit as an Indicator of High Intensity Beam Internal Dynamics	space-charge, linac, 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	linac, rfq, 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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MOPWA010	Emittances of the Core and of the Halo	linac, 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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MOPWA012	Study of Optimal MBA Lattice Structures for the SOLEIL Upgrade	dipole, lattice, optics, quadrupole	106
	R. Nagaoka, P. Brunelle, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Within the context of a future upgrade of the SOLEIL ring, a series of lattice studies has been made with the aim of reducing the current 4 nm-rad horizontal emittance ex by more than an order of magnitude, with a dynamic aperture allowing off-axis injection. As in most upgrades, the important constraint imposed is to keep all the existing straight sections and photon source points. A particularity of SOLEIL are the short straight sections in half of the 16 double-bend cells, created in between the dipoles, which limits the number of dipoles in a MBA cell. In the previous studies, a combination of 5- and 4BA was followed, where with the use of longitudinal gradient bends (LGBs), ex ~440 pm-rad was obtained. The present paper reports on studies extended along the same strategy: In particular, the feasibility and the attainable ex are pursued with a combination of 7- and 6BA, by employing dipoles with transverse gradient and LGBs. In addition, the effectiveness of a few known nonlinear optimization methods, such as the resonance driving term cancellation, interleaved sextupoles with proper phases, and genetic algorithm-based numerical searches shall be explored.
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MOPWA014	New Functionality for Beam Dynamics in Accelerator Toolbox (AT)	lattice, radiation, dipole, simulation	113
	B. Nash, N. Carmignani, L. Farvacque, S.M. Liuzzo, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White ESRF, Grenoble, France
	Accelerator Toolbox is a widely used code for beam dynamic simulations based on Matlab. To continue the development of the code in a collaborative manner, a SourceForge project and SVN repository called atcollab has been established. Here we describe the contributions to atcollab from the ESRF beam dynamics group. Additional modules have been developed: general matching (atmatch), improved plotting (atplot), Touschek lifetime computation via the Piwinski formula, nonlinear dynamics computations such as resonance driving terms, improved reporting of lost particles and improvements and additions to the integration routines. One example of the latter includes diffusion due to quantum fluctuations. Modeling of collective effects may now be performed using pass methods representing a variety of impedance models. Finally, routines to replace the full ring with a compact representation have been developed, facilitating studies in which many turns and many particles are required.
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MOPWA017	Design Status of the ESSvSB Switchyard	proton, target, dipole, quadrupole	125
	E. Bouquerel IPHC, Strasbourg Cedex 2, France
	The feasibility of the distribution of 5 MW proton beam power pulsed at 70 Hz onto a 4-target station for the production of neutrino super beams is discussed. To deflect and focus the beam having a magnetic rigidity of 11.0 Tm onto the targets, different configurations of beam switchyard are proposed and compared. The number of dipoles and quadrupoles composing this system is defined for each scenario. The length, the aperture, the magnetic fields and the field gradients of these optical elements are determined. The code TraceWin is used to simulate and optimize the envelopes of the beam along the beam lines. The transverse emittances at the exit of the system are shown.
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MOPWA026	Demonstration of Flat Ion Beam Creation and Injection into a Synchrotron	solenoid, injection, synchrotron, ion	153
	L. Groening, S. Appel, L.H.J. Bozyk, Y. El Hayek, M.T. Maier, C. Xiao GSI, Darmstadt, Germany
	At GSI an ion beam with different horizontal and vertical emittances has been created from a beam with initially equal emittances. This round-to-flat adoption has been accomplished without any beam loss. In the set-up the beam passes through a stripping foil placed inside a solenoid followed by a skewed quadrupole triplet. The amount of beam flatness has been controlled by setting the solenoid field strength only. Increase of the product of the two transverse emittances is purely due to the stripping process that occurs anyway along an ion linac. Beams with different amounts of flatness were injected into a synchrotron applying horizontal multi-turn injection. The efficiency of injection increased as smaller as the horizontal emittance was set by the round-to-flat adaptor.
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MOPWA037	Mirror Symmetric Chicane-Type Emittance Exchange Beamline with Two Deflecting Cavities	quadrupole, focusing, cavity, dipole	190
	V. Balandin, W. Decking, N. Golubeva DESY, Hamburg, Germany
	Among optical systems for transverse-to-longitudinal emittance exchange (EEX) chicane-type beamlines are of keen interest, because they do not alter the beam propagation direction. Several designs of such beamlines involving a single dipole-mode cavity (TDC) are known. In this paper we present a chicane-type EEX beamline utilizing two TDCs instead of one. The advantages of this beamline are that it is mirror symmetric and does not require an additional accelerating mode cavity for compensation of the so-called thick-lens effect, and, in the compact design, it allows better control of the beam focusing in the non-bending plane than known beamlines with one TDC.
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MOPWA039	Emittance Reduction Possibilities in the PETRA III Magnet Lattice	optics, sextupole, lattice, synchrotron	197
	N. Golubeva, V. Balandin, W. Decking, R. Wanzenberg DESY, Hamburg, Germany
	PETRA III is a third generation light source that has been operated as a user facility since 2010 at DESY. An upgrade for additional beam lines has been carried out, and the recommissioning of the new beam lines is starting in spring 2015. In order to fully exploit the potential of the existing magnet lattice of the PETRA III ring, we present a study of beam optics modifications enabling the reduction of the horizontal emittance without changes of the lattice.
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MOPWA048	Transverse Emittance Measurement for Low Energy Ion Beams Using Quadrupole Scan Method	ion, plasma, ion-source, ECR	226
	S. Kumar, A. Mandal IUAC, New Delhi, India
	Low energy ion beam facility (LEIBF) * at IUAC consists of all permanent magnet 10 Ghz electron cyclotron resonance (ECR) ion source (NANOGUN) along with 400 kV high voltage accelerating platform, a switching cum analysing magnet and electrostatic quadrupoles. Higher beam currents of heavy charge states and low energy of ion beams puts tremendous challenge to transport the ion beam from source to target. The normalized emittance of analysed ion beam is measured for specific charge to mass ratio using electrostatic quadrupole scan method * for various source parameters like RF power and injection pressure of gas etc. For various m/q ratios, the normalized transverse emittance ranges from 0.1 to 0.6 mm-mrad. It is attributed to beam rotation induced by ECR axial magnetic field, effect of ion temperature in plasma, non linear electric fields and space charge etc which play a significant role in emittance growth. * A. Mandal et. al. Proceedings of IPAC2011, WEPC011, San Sebastián, Spain D Kanjilal et. al. Indian J. Pure Appl. Phys. 39 (2001) 25 * I. G. Brown:The physics and technology of ion sources
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MOPWA050	Beam Dynamics Studies to Develop a High-energy Luminosity Model for the LHC	simulation, luminosity, beam-beam-effects, collider	233
	G. Campogiani Rome University La Sapienza, Roma, Italy Y. Papaphilippou CERN, Geneva, Switzerland
	Funding: support provided by the EPS-AG through the EPS-AG student grant program Luminosity, the key figure of merit of a collider as the LHC, depends on the brightness of the colliding beams. This makes the intensity dependent beam-beam effect the dominant performance limiting factor at collision. The parasitic interactions due to the electromagnetic mutual influence of the beams in the interaction region of a collider induce a diffusive behaviour in the tails of the beam. The evolution of charge density distribution is studied to model the beam tails evolution in order to characterize beam lifetime and luminosity. To achieve this, tools are developed for tracking distributions of arbitrary number of single particles interacting with the opposing strong-beam, to analyse the halo formation processes due to the combined effect of beam-beam and machine non-linearities. This paper presents preliminary results of the simulations, both for the LHC Run I and nominal LHC parameters. The former will be used to benchmark simulations while the latter aims at supporting luminosity estimate for the Run II.
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MOPWA053	Emittance Preservation in SuperKEKB Injector	wakefield, simulation, linac, 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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MOPWA055	Study of Emittance Growth Caused by Space Charge and Lattice Induced Resonances	resonance, space-charge, lattice, synchrotron	245
	K. Ohmi KEK, Ibaraki, Japan
	Resonance strength and resonance width induced by space charge and lattice nonlinearity is discussed with integrals along a ring like the radiation integrals. Emittance growth is evaluated by model with the resonance width to understand the mechanism. The results are compared with fully PIC simulations.
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MOPWA057	Space Charge Simulation and Matching at Low Energy Section of J-PARC Linac	rfq, space-charge, simulation, solenoid	251
	S. Artikova, T. Morishita JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Kondo JAEA, Ibaraki-ken, Japan
	An intensity upgrade of Japan Proton Accelerator Research Complex (J-PARC) included the installation of a new ion source (IS) and a radio-frequency quadrupole (RFQ) which to be used at first stage of acceleration. The linac is divided into two sections on the basis of operating frequencies and three sections on the basis of family of RF cavities to be used for the acceleration of 50 mA beam of H⁻ ions from 50 keV to 400 MeV. Low energy part of linac consists of an IS, a two-solenoid low energy beam transport (LEBT) and the RFQ. The transition from one section to another can limit the acceptance of the linac if these are not matched properly in both longitudinal and transverse plane. We performed a study to calculate the acceptance of the RFQ at zero current in which space charge effects are not considered. In addition, a particle tracking technique is employed to study the space charge effects in LEBT of the J-PARC linac after the intensity upgrade in order to match the beam to the RFQ. Also, RFQ tank level and intervene voltage calibration factor is determined by comparing the simulation results of the beam transmission with the test measurement of tank level vs. transmission.
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MOPWA061	ADS Injector I Frequency Choice at IHEP	linac, rfq, 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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MOPWA067	Theory of Transverse Ionization Cooling in a Linear Channel	lattice, quadrupole, scattering, collider	279
	M. Xiao, J. Gao, Y. Yue IHEP, Beijing, People's Republic of China
	Ionization cooling is the most hopeful method to reduce the emittance of muon beams, which plays an important role in neutrino factory and muon collider. Within the moment-equation approach, I present a way to derive the formulae of emittance in transverse under linear channel. All heating and coupling terms are reserved in the deriving process. From my formulae, it is a way to achieve a small emittance by designing the cooling channel compact to make the beta function changing sharply.
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MOPWA072	Emittance Exchange Beam Line Design In THU Accelerator Lab	quadrupole, cavity, simulation, electron	285
	Q. Gao, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA
	Funding: National Natural Science Foundation of China Emittance exchange (EEX) provides a novel tool to enhance the phase space manipulation techniques. Based on Tsinghua Thomson scattering experimental platform, this study presented a beam line design for exchanging the transverse and longitudinal emittance of an electron bunch. This beam line consists of a 2.856 GHz half-one-half cell deflecting cavity with no axis offset and two doglegs. In this paper, by optimizing the beam envelope parameter for Tsinghua Thomson scattering source, we report the theoretical analysis and a good particle tracking simulation result about emittance exchange and longitudinal shaping.
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MOPJE009	Lattice Design of the SSRF-U Storage Ring	storage-ring, lattice, dynamic-aperture, injection	304
	S.Q. Tian, B.C. Jiang, M.Z. Zhang, Q.L. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Multi-Bend Achromatic (MBA) cell has been well known to significantly reduce the beam emittance of the synchrotron radiation light sources in the past two decades. With the great development of the high gradient magnets, the small-aperture vacuum chamber and the precise alignment, the ultimate-emittance ring based on MBA lattice became practical in recent years. We present a preliminary lattice design for the upgraded SSRF storage ring based on a 7BA lattice in this paper. The circumference and the number of the straight sections are preserved for the existing tunnel. The beam energy is reduced to 3 GeV, and the beam emittance is reduced to about 200 pm.rad. The optimized dynamic aperture is about 10 mm in the horizontal plane, and a sufficient beam injection based on the closed orbit bump can be implemented.
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MOPJE016	Start-to-End Simulation for RAON Superconducting Linac	linac, ion, cryomodule, lattice	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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MOPJE019	Categorization and Estimation of Possible Deformation in Emittance Exchange based Current Profile Shaping	cavity, wakefield, acceleration, collective-effects	317
	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
	Funding: This work is partly supported by POSTECH BK²¹⁺ program and Argonne National Laboratory Shaping the current profile is one of the important issues in collinear wakefield acceleration. In the emittance exchange based shaping technique, the shaped current profile seriously depends on the incoming beam and beam line parameters. To design the beam and beam line properly, it is important to estimate the deformation in the shaped current profile. There are several different deformation types whose level depend on deformation parameter. We categorize the possible deformation types and observe the deformation patterns of the current profile depending on its type and the deformation parameter.
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MOPJE020	High Resolution Longitudinal Property Measurement using Emittance Exchange Beam Line	quadrupole, cavity, space-charge, collective-effects	320
	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
	Most of longitudinal measurement techniques introduce the transverse-longitudinal correlation because it is very hard to measure the longitudinal properties directly. This correlation is necessary to observe the longitudinal property through the transverse screen, but initial transverse components of the beam restrict the measurement. It is possible to overcome this intrinsic limit using emittance exchange beam line which makes transverse properties at the downstream only depend on longitudinal properties at the upstream. We present the new idea to measure the longitudinal properties using the emittance exchange beam line and preliminary simulation results.
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MOPJE034	Low Emittance Tuning for the CLIC Damping Rings	quadrupole, lattice, sextupole, coupling	356
	J. Alabau-Gonzalvo, F. Antoniou, Y. Papaphilippou CERN, Geneva, Switzerland
	A study on the sensitivity of the CLIC Damping Ring lattice to different sources of misalignment is presented. Dipole and quadrupole rolls, quadrupole and sextupole vertical offsets are considered, as well as the impact of a finite BPM resolution. The result of this study defines a low emittance tuning procedure and establishes alignment tolerances to preserve the vertical emittance below the design value (1 pm·rad). Non-linear dynamics studies including dynamic aperture and frequency maps are shown and synchrotron radiation effects are discussed.
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MOPJE042	Longitudinal Injection Schemes For the CERN PS Booster at 160 MeV Including Space Charge Effects	space-charge, injection, linac, simulation	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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MOPJE051	Effect of Electron Cloud in Quadrupoles on Beam Instability	quadrupole, electron, dipole, simulation	409
	G. Iadarola, A.P. Axford, H. Bartosik, K.S.B. Li, G. Rumolo CERN, Geneva, Switzerland
	Both simulations and machine experience at the CERN-SPS and LHC have shown that the electron cloud has a lower build up threshold in quadrupoles than in dipoles and field free regions. As a consequence, while beam induced scrubbing can efficiently suppress the electron cloud in both dipoles and field free regions, a residual electron cloud can still survive in the quadrupoles and potentially degrade the beam quality. To study this effect, a PyECLOUD module for electron tracking in quadrupole fields including effects of secondary emission at the vacuum chamber has been implemented in PyHEADTAIL. With this module, the effect of the electron cloud in quadrupoles on beam stability and beam quality preservation can be assessed, as well as its impact on future LHC and HL-LHC operation.
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MOPJE053	NSLS-II Beam Lifetime Measurements and Modeling	scattering, cavity, coupling, lattice	416
	B. Podobedov, W.X. Cheng, Y. Hidaka, H.-C. Hseuh, G.M. Wang BNL, Upton, Long Island, New York, USA
	NSLS-II is a recently constructed 3 GeV synchrotron light source with design horizontal emittance values in sub-nm range. Achieving good beam lifetime is critically important for NSLS-II as it is closely tied in to such important operational aspects as top-off injection frequency, injector components wear, radiation protection and control, and others. In this paper we present lifetime-related commissioning results, describe our present understanding of beam lifetime at NSLS-II and extrapolate our models to the fully built-up machine operating at 500 mA design beam current.
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MOPJE059	Tests of Wakefield-Free Steering at ATF2	wakefield, cavity, extraction, alignment	438
	A. Latina, J. Pfingstner, D. Schulte CERN, Geneva, Switzerland E. Adli University of Oslo, Oslo, Norway N. Fuster-Martínez IFIC, Valencia, Spain J. Snuverink JAI, Egham, Surrey, United Kingdom
	Charge-dependent effects on the orbit and on the beam size affect the performance of the Accelerator Test Facility (ATF2) in a non-negligible way. Until now small beam sizes have only been achieved running with a beam charge significantly smaller than the nominal value. These detrimental effects on the beam have been attributed to wakefields, in the cavity BPMs, in the multi-Optical Transition Radiation (OTR) systems as well as in other components of the beamline. The successful tests of a Wakefield-free Steering (WFS) algorithm at FACET have encouraged performing tests of the same correction scheme at ATF2. The performance of the algorithm has been simulated in detail, including several realistic imperfection scenarios, including charge-dependent BPMs resolution, and incoming injection error and position jitters, which are described in this paper. Tests of WFS have been performed at ATF2 during December 2014. The results are discussed here.
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MOPJE060	BBA and Coupling Correction at CLIC RTML	coupling, quadrupole, dipole, alignment	442
	Y. Han, L. Ma SDU, Shandong, People's Republic of China A. Latina, D. Schulte CERN, Geneva, Switzerland
	The CLIC Ring To Main Linac (RTML) must transport the electron and the positron bunches through more than 20 km of beamlines with minimal emittance growth. The turnaround loops (TAL) are one of the most critical sections, featuring a lattice designed to minimize emittance growth due to synchrotron radiation emission and chromaticity, while being isochronous to avoid bunch lengthening. With such a design, the impact of static imperfections like element misalignment is particularly critical. In this paper a study of the Beam-Based Alignment (BBA) techniques in the TAL of the CLIC RTML is presented. In order to reduce the emittance growth, the one-to-one and dispersion-free corrections have been tested. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes. The impact of coupling errors due to magnets rolls on the emittance has also been studied and a coupling correction section has been designed and inserted in the lattice.
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MOPJE065	Contribution of Optical Aberrations to Spot-size Increase with Bunch Intensity at ATF2	damping, optics, extraction, simulation	455
	M. Patecki, R. Tomás, F. Zimmermann CERN, Geneva, Switzerland K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma KEK, Ibaraki, Japan M. Patecki Warsaw University of Technology, Warsaw, Poland G.R. White SLAC, Menlo Park, California, USA
	A primary goal of ATF2 (Accelerator Test Facility) is to demonstrate a low vertical beam size at the interaction point (IP) of about 37 nm. Measurements over the past years indicate that the ATF2 vertical beam size strongly rises with bunch intensity. Several different origins of this increase are considered, e.g. wakefields occurring between the ATF damping ring and the IP, and/or intrabeam scattering (IBS) causing the increase of transverse emittances and energy spread in the damping ring with the increase of the bunch intensity. In this paper we address the second possibility. Past measurements and simulations of the IBS effects in the ATF are used to model the intensity-dependent initial emittances and energy spread at the entrance of the final focus. Particle tracking simulations predict the IP vertical beam size growth expected from the known optical aberrations for initial beam parameters corresponding to varying bunch intensities. Comparing simulation results with emittance measurements at different locations allows us to draw some conclusions about the impact of IBS in the damping ring on the IP spot size, and about possible single-bunch wakefields in the ATF2.
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MOPJE076	Multi-objective Genetic Optimization with the General Particle Tracer (GPT) Code	solenoid, factory, cavity, target	492
	S.B. van der Geer, M.J. de Loos Pulsar Physics, Eindhoven, The Netherlands
	In a typical design process there are a large number of variables, external constraints, and multiple conflicting objectives. Examples of the latter are short pulse, high charge, low emittance and low price. The classical solution to handle such problems is to combine all objectives into one merit function. This however implicitly assumes that the tradeoffs between all objectives are a-priori known. Especially in the early design stages this is hardly ever the case. A popular solution to this problem is to switch to multi-objective genetic optimization algorithms. This class of algorithms solves the problem by genetically optimising an entire population of sample solutions. Selection and recombination operators are defined such that the output, the so-called Pareto front, only includes solutions that are fully optimized where no objective can be improved without degrading any other. Here we present numerical studies and practical test runs of the genetic optimizer built into the General Particle Tracer (GPT) code.
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MOPJE084	Particle-in-cell Simulations of a Plasma Lens at Daresbury Laboratory	plasma, focusing, simulation, experiment	518
	K. Hanahoe, O. Mete, G.X. Xia UMAN, Manchester, United Kingdom D. Angal-Kalinin, J.K. Jones STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom J.D.A. Smith TXUK, Warrington, United Kingdom
	Feasibility of a focusing element using the transverse fields provided by a plasma cell was studied numerically. In this paper, an experimental set up is proposed for various beam parameters available from the VELA and CLARA beam lines at Daresbury Laboratory. 2D simulation results from VSim, and expected results from planned measurement stations are presented. Field properties and the advantages and disadvantages of such an instrument compared to conventional focusing elements are discussed.
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MOPMA012	Intra-Beam and Touschek Scattering Computations for Beam with Non-Gaussian Longitudinal Distributions	scattering, distributed, simulation, lattice	559
	A. Xiao, M. Borland ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 Both intra-beam scattering (IBS) and the Touschek effect become prominent for multi-bend-achromat- (MBA-) based ultra-low-emittance storage rings. To mitigate the transverse emittance degradation and obtain a reasonably long beam lifetime, a higher harmonic rf cavity (HHC) is often proposed to lengthen the bunch. The use of such a cavity results in a non-gaussian longitudinal distribution. However, common methods for computing IBS and Touschek scattering assume Gaussian distributions. Modifications have been made to several simulation codes that are part of the {\tt elegant} toolkit to allow these computations for arbitrary longitudinal distributions. After describing these modifications, we review the results of detailed simulations for the proposed hybrid seven-bend-achromat (H7BA) upgrade lattice for the Advanced Photon Source.
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MOPMA013	Experience with Round Beam Operation at the Advanced Photon Source	coupling, operation, resonance, storage-ring	562
	A. Xiao, L. Emery, V. Sajaev, B.X. Yang ANL, Argonne, Ilinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357 Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beam lifetime, such a machine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a ‘‘round beam''. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement.
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MOPMA015	Applications of an MPI Enhanced Simulated Annealing Algorithm on nuSTORM and 6D Muon Cooling	sextupole, lattice, storage-ring, simulation	568
	A. Liu Fermilab, Batavia, Illinois, USA
	The nuSTORM decay ring is a compact racetrack storage ring with a circumference ∼ 480 m using large aperture (∅=60 cm) magnets. The design goal of the ring is to achieve a momentum acceptance of 3.8±10\% GeV/c and a phase space acceptance of 2000 μm·rad. The design has many challenges because the acceptance will be affected by many nonlinearity terms with large particle emittance and/or large momentum offset. In this paper, we present the application of a meta-heuristic optimization algorithm to the sextupole correction in the ring. The algorithm is capable of finding a balanced compromise among corrections of the nonlinearity terms, and finding the largest acceptance. This technique can be applied to the design of similar storage rings that store beams with wide transverse phase space and momentum spectra. We also present the recent study on the application of this algorithm to a part of the 6D muon cooling channel. The technique and the cooling concept will be applied to design a cooling channel for the extracted muon beam at nuSTORM in the future study.
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MOPMA016	Coupler RF Kick in the Input 1.3 GHz Accelerating Cavity of the LCLS-II Linac	cavity, focusing, HOM, accelerating-gradient	571
	A. Lunin, N. Solyak, A.I. Sukhanov, V.P. Yakovlev Fermilab, Batavia, Illinois, USA
	Main and HOM couplers break the cavity axial symmetry, distort RF field and, thus, create a transverse kick, even for a particle moving along the cavity axes. Dependence of a kick on the RF phase causes a beam emittance dilution and degrade the FEL radiation quality. The transverse kick is most dangerous for a beam passing through the first accelerating structure of a linac, where particles energy and their relativistic mass are low. In the paper we analyze the coupler RF kick in the first accelerating structure of the LCSL-II linac.
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MOPMA024	A Parallel Particle-Particle, Particle-Mesh Solver for Studying Coulomb Collisions in the Code IMPACT-T	electron, simulation, plasma, space-charge	593
	C.E. Mitchell, J. Qiang LBNL, Berkeley, California, USA
	Funding: This work is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231. In intense charged-particle beams, the presence of Coulomb collisions can result in growth of the beam slice energy spread and emittance that cannot be captured correctly using traditional particle-in-cell codes. Particle-particle, particle-mesh solvers take a hybrid approach, combining features of N-body and particle-in-cell solvers, to correctly capture the effect of short-range particle interactions with less computing time than direct N-body solvers. We describe the implementation and benchmarking of such a solver in the code IMPACT-T for beam dynamics applications.
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MOPMA026	Proposed Cavity for Reduced Slip-Stacking Loss	cavity, booster, injection, beam-loading	600
	J.S. Eldred Indiana University, Bloomington, Indiana, USA J.S. Eldred, R.M. Zwaska Fermilab, Batavia, Illinois, USA
	This paper employs a novel dynamical mechanism to improve the performance of slip-stacking. Slip-stacking in an accumulation technique used at Fermilab since 2004 which nearly double the proton intensity. During slip-stacking, the Recycler or the Main Injector stores two particles beams that spatially overlap but have different momenta. The two particle beams are longitudinally focused by two 53 MHz 100 kV RF cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV RF cavity, with a frequency at the double the average of the upper and lower main RF frequencies. In simulation, we find the proposed RF cavity significantly enhances the stable bucket area and reduces slip-stacking losses under reasonable injection scenarios. We quantify and map the stability of the parameter space for any accelerator implementing slip-stacking with the addition of a harmonic RF cavity.
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MOPMA029	Experiences Simulating Nonlinear Integrable Optics	lattice, simulation, optics, diagnostics	611
	S.D. Webb, D.L. Bruhwiler RadiaSoft LLC, Boulder, Colorado, USA V.V. Danilov ORNL, Oak Ridge, Tennessee, USA R.A. Kishek UMD, College Park, Maryland, USA S. Nagaitsev, A. Valishev Fermilab, Batavia, Illinois, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0011340. With increasing interest in the nonlinear integrable optics, it is important that early experiences with simulating the lattices be shared to save time and point out potential difficulties in the simulations. We present here some details of simulating the nonlinear integrable lattices. We discuss correctly implementing and testing the elliptic element kicks, and the limits of the thin lens approximation. We also discuss generating a properly matched bunch in the transverse phase space, and how to analyze the resulting computational data from simulations.
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MOPMA044	Barrier Shock Compression with Longitudinal Space Charge	space-charge, simulation, electron, plasma	646
	B. Beaudoin, I. Haber, R.A. Kishek UMD, College Park, Maryland, USA
	Funding: This work is supported by the US Dept. of Energy, Office of High Energy Physics. Synchrotrons and storage rings routinely employ RF barrier buckets as a means of accumulating charge to increase the peak intensity and preserve longitudinal emittance while minimizing emittance growth [1-3]. This was shown in the main injector and recycler at Fermilab as well as the SIS-18 at GSI Helmholtz center for heavy ion research. The RF cavities typically used are ferrite loaded magnetic alloys with low Q to maximize bandwidth and generate single pulses, either as delta functions, triangular or half/full period sine waves. The University of Maryland Electron Ring (UMER) group is studying a novel scheme of bunch compression in the presence of longitudinal space charge. It has been analytically shown through 1-D computations that the presence of space-charge considerably improves the efficiency of the barrier compression by taking advantage of the shock-front that launches when the barrier moves into a space-charge dominated beam. In this paper, we summarize the initial results of the study.
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MOPMA045	Conceptual Difficulties of a Thermodynamics Description of Charged-Particle Beams	space-charge, simulation, focusing, beam-transport	649
	S. Bernal UMD, College Park, Maryland, USA
	Funding: This work is funded by the US Dept. of Energy We review the existing phenomenological theories of emittance growth with and without entropy terms and re-examine the condition for thermal equipartitioning in an unbunched charged-particle beam. The model incorporates linear space charge and a uniform-focusing lattice. Because of non-extensitivity of the transverse ("thermal") energy and the absence of a classical heat bath, we conclude that a rigorous classical thermodynamics treatment of charged-particle beams is not possible. In particular, the postulated relationships between the rms emittance and temperature and entropy must be qualified.
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MOPMA050	Smooth Fast Multipole Method for Space Charge Tracking: An Alternate to Particle-In-Cell	multipole, space-charge, simulation, framework	663
	A.J. Gee, B. Erdelyi Northern Illinois University, DeKalb, Illinois, USA B. Erdelyi ANL, Argonne, USA
	The fast multipole method (FMM) algorithm was developed by Greengard and Rokhlin in 1987 . As one of the top ten algorithms of the 20th century, it has been applied in a wide range of fields. The FMM complexity is O(N), where N is the number of articles, allowing for large-scale simulations. However, it includes all the two-body collisional forces, in contrast to other methods such as the popular particle in-cell (PIC) methods. While collisionality can be very important, many applications require only the mean field effects. PIC is frequently used in this regime. Due to recent concerns of unphysical effects of grids, interpolation and other approximations in PIC codes, an alternative based on different underlying assumptions would prove enlightening. For these cases, a smoothed or softened FMM using a Plummer-like smoothing parameter holds much promise. Unfortunately, the original FMM based on analytic expansions of the 1/r-like potentials does not allow for Plummer softening. We present our new soft-FMM employing differential algebras (DA) to obtain the modified expansions. We also compare the performance of the smoothed DA-FMM with examples from PIC simulations. L. Greengard and V. Rokhlin. “A fast algorithm for particle simulations".
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MOPMA051	Generation of Modulated Bunch Using a Masked Chicane for Beam-Driven Acceleration Experiments at ASTA	simulation, bunching, dipole, space-charge	666
	Y.-M. Shin, P. Piot Northern Illinois University, DeKalb, Illinois, USA D.R. Broemmelsiek, D.J. Crawford, A.H. Lumpkin Fermilab, Batavia, Illinois, USA A.T. Green Northern Illinois Univerity, Dekalb, Illinois, USA
	Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC. Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling . The sub-ps beam modulation has been studied with a masked chicane * *** by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the nominal 50 MeV chicane parameters and 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 um and aperture width 300 μm generates about 100-um modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 um of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 0.25, 1 , and 3.2 nC, by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments. * E. Kallos, Southern California 2008 D. C. Nguyen, B. E. Carlston, NIMA 375, 597 (1996) * P. Muggli, V. Yakimenko, M. Babzien, E. Kallos, and K. P. Kusche, PRL 101, 054801 (2008)
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MOPMA052	Implementation of Quadrupole-scan Emittance Measurement at Fermilab's Advanced Superconducting Test Accelerator (ASTA)	quadrupole, controls, monitoring, simulation	669
	A.T. Green Northern Illinois Univerity, Dekalb, Illinois, USA Y.-M. Shin Fermilab, Batavia, Illinois, USA Y.-M. Shin Northern Illinois University, DeKalb, Illinois, USA
	Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC. Transverse-emittance measurements based on the quadrupole-scan technique * , have been widely used to characterize the beam phase-space parameters in linear accelerators. This paper discusses the implementation of the technique at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. We plan on deploying a flexible implementation that permits an operator to select the quadrupole associated analysing screen to measure the beam emittance. Our implementation utilizes Python scripts combined with Fermilab’s control system ACNet and ELEGANT quadrupole-scan method at 50 MeV given the range of operating charge (20 pC to 3.2 nC) available at ASTA. Some preliminary measurements will also be presented. B.E. Carlsten, et al, Nucl. Instrum. Methods Phys. Res. Sect. A 331, 791 (1993) C. Eckman et al, IPAC 2012 * K. Poorrezaei, et al, Phys. Rev. ST-AB 16, 082801 (2013)
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MOPMA056	Measurement and Modeling of Single Bunch Wake Field Effects in CESR	simulation, impedance, wakefield, storage-ring	681
	J.R. Calvey, M.G. Billing, W. Hartung, J.D. Perrin, D. L. Rubin, D. Sagan, S. Wang Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by NSF PHY-1416318 and NSF DMR 1332208. This research used the National Energy Research Scientific Computing Center, which is supported by DOE Contract No. DE-AC02-05CH11231. Short-range wake fields have been incorporated into a Bmad-based particle tracking code in order to assess their contribution to current-dependent emittance growth, tune shift, and single bunch instabilities. The wakes are computed for CESR vacuum components using the T3P modeling software. Simulation results are compared with measurements of bunch length, vertical beam size, and coherent tune shift. Additionally, we use insertable scrapers to vary the transverse wake and measure the effect on the beam. We show that a vertical emittance increase at high current may be due to a transverse monopole wake, originating in the lump pump slots throughout CESR.
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MOPMA057	Space Charge Neutralization of 750 keV Proton Beam in LANSCE Injector Line	space-charge, simulation, proton, beam-transport	685
	Y.K. Batygin LANL, 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 750-keV low-energy beam transport of the Los Alamos Neutron Science Center (LANSCE) linac consists of two independent beam lines for simultaneous injection of H⁺ and H⁻ beams into the linear accelerator. Space charge effects play an important role in the beam transport therein. A series of experiments were performed to determine the level of proton beam space charge neutralization by residual gas ionization, and time required for neutralization. Study was performed as emittance scans between pair of emittance measurement stations. The value of compensated space charge was determined through comparison of results of measurements and simulations using macroparticle method and envelope code. Obtained results provide new setup for beam tuning in transport beamline.
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MOPMA058	Effect of Spherical Aberration on Beam Emittance Growth	focusing, space-charge, proton, simulation	688
	Y.K. Batygin LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396 Spherical aberration in axial-symmetric magnetic focusing lenses results in S-shape figure of beam emittance. Filamentation of beam emittance in phase space is a fundamental property of a beam affected by aberrations. Analytical expression for effective beam emittance growth due to spherical aberration as a function of lens aberraion coefficient, initial beam emittance, beam radius, and focal lens of the focusing lens is obtained. Analysis is extended for beam space charge aberrations. Analytical results are confirmed by numerical calculations.
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MOPMN008	Space Charge Studies in FFAG Using the Tracking Code Zgoubi	space-charge, simulation, betatron, damping	717
	M. Haj Tahar, F. Méot, 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. A method is implemented in Zgoubi that allows the computation of space charge effects in 2D distributions and with some restrictions in 3D distributions. It relies on decomposiing field maps or analytical elements into slices and applying a space charge kick to the particles. The aim of this study is to investigate the accuracy of this technique, its limitations/advantages by comparisons with other linear/nonlinear computation methods and codes, and to apply it to high power fixed field ring design studies.
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MOPMN018	A Generic Formulation for Emittance and Lattice Function Evolution for Non-Hamiltonian Systems with Stochastic Effects	lattice, radiation, synchrotron, scattering	740
	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. I describe a generic formulation for the evolution of emittances and lattice functions under arbitrary, possibly non-Hamiltonian, linear equations of motion. The average effect of stochastic processes, which would include ionization interactions and synchrotron radiation, is also included. I first compute the evolution of the covariance matrix, then the evolution of emittances and lattice functions from that. I examine the particular case of a cylindrically symmetric system, which is of particular interest for ionization cooling.
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MOPMN028	Design of Bunch Compressing System with Suppression of Coherent Synchrotron Radiation for ATF Upgrade	electron, dipole, simulation, linac	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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MOPMN029	Spin Resonance Strength Calculation Through Single Particle Tracking for Rhic	resonance, betatron, proton, lattice	763
	Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar 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 strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with code DEPOL, which numerically integrate through the whole ring based on analytical approximate formula. In this article, we calculate the spin resonance strength by performing Fourier transformation to the actual transverse magnetic field seen by a single particle travelling through the ring. Comparison is made between the results from this method and DEPOL and other approaches.
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MOPHA020	Automated Transverse Beam Emittance Measurement using a Slow Wire Scanner at the S-DALINAC	quadrupole, electron, EPICS, controls	817
	P. Dijkstal, M. Arnold, C. Burandt, F. Hug, N. Pietralla TU Darmstadt, Darmstadt, Germany
	Funding: This work has been supported by the DFG through CRC 63 and by the EPS-AG through the EPS-AG student grant program. The superconducting linear accelerator S-DALINAC of the TU Darmstadt provides electron beams of up to 130 MeV in cw mode. It consists of a 10 MeV injector and a 40 MeV main linac, both equipped with elliptical cavities operating in liquid helium at 2 K at a frequency of 3 GHz. The final energy is reached by using up to two recirculation paths. In order to improve beam simulations, it is planned to monitor the transverse beam emittance at different locations along the beam line. A system of slow wire scanners in combination with quadrupole variation is foreseen to accomplish this task. For a first test a wire scanner was installed in the 250 keV section behind the thermionic electron gun of the S-DALINAC. A procedure to automatize measurements was developed and integrated in the EPICS-based control system. We will show the status of the work on the automatized control and the results of first emittance measurements. A report on the future plans will be given.
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MOPHA024	A Novel Transverse Deflecting Cavity for Slice Diagnostics at BERLinPro	cavity, polarization, SRF, low-level-rf	827
	A. Ferrarotto, B. Riemann, T. Weis DELTA, Dortmund, Germany H.-W. Glock, T. Kamps, J. Völker HZB, Berlin, Germany
	Funding: Work supported by BMBF under contract no. 05K10PEA BERLinPro is an energy-recovery linac project to be realized at the Helmholtz-Zentrum Berlin (HZB) for an electron beam with 1mm mrad normalized emittance and 100 mA average current. The initial beam parameters are determined by the performance of the electron source, an SRF photo-electron injector. The development auf this SRF photon-electron injector is a main task of BERLinPro. Especially the beam emittance is basically defined by the SRF photogun. For beam diagnostics time dependent effects from the RF curvature and space charge must be taken into account and a sophisticated slice diagnostics is required. To perform this type of diagnostics a transverse deflecting cavity has been designed, characterized and is presently under construction.. This single cell cavity operates in a TM110-like mode at 1.3 GHz optimized for high transverse shuntimpedance of appr. 3.2 MOhm by a concentration of fields near the beam axis. The cavity has a novel geometry that allows for an operation with both polarizations of the TM110-Mode. The layout of the deflecting cavity will be presented together with the results of the low RF characterization.
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MOPHA027	Transverse Emittance Measurement at REGAE	electron, detector, background, solenoid	837
	M. Hachmann, K. Flöttmann DESY, Hamburg, Germany
	The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. A standard magnet scan is used for the emittance measurement which is in case of a low charged bunch most sensitive to the beam size determination (2nd central moment of a distribution). Therefore the diagnostic and a routine to calculate proper central moments of an arbitrary distribution will be introduced and discussed.
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MOPHA041	Laser Wire Based Transverse Emittance Measurement of H⁻ Beam at Spallation Neutron Source	laser, electron, neutron, dipole	879
	Y. Liu, A.V. Aleksandrov, C.D. Long, A.A. Menshov, A.P. Zhukov ORNL, Oak Ridge, Tennessee, USA
	Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725. A laser wire based transverse emittance measurement system has been developed at the Spallation Neutron Source (SNS). The system enables a nonintrusive measurement of the transverse emittance in both directions on a 925 MeV/1 MW hydrogen ion (H⁻) beam at the high energy beam transport (HEBT) beam line.
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MOPTY023	Beam Diagnostic of the LINAC for the Compact High-Performance THz-FEL	linac, gun, FEL, 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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MOPTY025	High-current RFQ Design Study on RAON	rfq, cavity, ion, acceleration	990
	J. Bahng, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea B.H. Choi IBS, Daejeon, Republic of Korea
	Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator has been designed as a facility for a rare isotepe accelerator of the Rare Isotope Science Project (RISP). RAON provides 400 kW CW heavy ion beams from proton to uranium to support researches in various science fields. The RAON system consists of a few ECR ion source, low energy beam transport systems (LEBTs), CW radio frequency quadrupole (RFQ) accelerators, a medium energy beam transport and superconducting linac. We present the design study of the RFQ accelerator from 30 keV/u to 1.5 MeV/u of deuteron beam with meeting a requirement of over 15 mA beam at the target. We optimized the normal conducting CW RFQ accelerator that has a high transmission and a low longitudinal emittance. In this paper, we will present the design result of RFQ beam dynamics studies and its 2D and 3D EM analysis.
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MOPTY082	Beam Instrumentation of the PXIE LEBT Beam Line	ion, solenoid, ion-source, diagnostics	1129
	R.T.P. D'Arcy UCL, London, United Kingdom B.M. Hanna, L.R. Prost, V.E. Scarpine, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	The PXIE accelerator is the front-end test stand of the proposed Proton Improvement Plan (PIP-II) initiative: a CW-compatible pulsed H⁻ superconducting RF linac upgrade to Fermilab’s injection system. The PXIE Ion Source and Low-Energy Beam Transport (LEBT) section are designed to create and transfer a 1–10 mA H⁻ beam, in either pulsed (0.001–16 ms) or DC mode, from the ion source through to the injection point of the RFQ. This paper discusses the range of diagnostic tools Allison-type Emittance Scanner, Faraday Cup, Toroid, DCCT, electrically isolated diaphragms – involved in the commissioning of the beamline and preparation of the beam for injection into the RFQ.
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MOPWI002	Bunch Length Measurements using Synchrotron Light Monitor	linac, 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, linac, detector, 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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MOPWI005	Emittance and Optics Measurements on the Versatile Electron Linear Accelerator at Daresbury Laboratory	space-charge, quadrupole, gun, coupling	1153
	C.P. Topping, D.J. Scott, A. Wolski Cockcroft Institute, Warrington, Cheshire, United Kingdom S.D. Barrett, C.P. Topping, A. Wolski The University of Liverpool, Liverpool, United Kingdom B.L. Militsyn, D.J. Scott STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide a high quality electron beam for accelerator systems development, as well as industrial and scientific applications. Currently, the RF gun can deliver short (of order a few ps) bunches with charge in excess of 250 pC at up to 5.0 MeV/c beam momentum. Measurement of the beam emittance and optics in the section immediately following the gun is a key step in tuning both the gun and the downstream beamlines for optimum beam quality. We report the results of measurements (taking account of coupling and space charge) indicating normalised emittances of order 0.5 μm at low bunch charge.
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MOPWI030	Low Emittance Tuning With a Witness Bunch	betatron, lattice, storage-ring, coupling	1223
	D. L. Rubin, R.E. Meller, J.P. Shanks Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by NSF PHY-1416318, PHY-0734867 and PHY-1002467, and DOE DE-FC02-08ER- 41538 and DE-SC0006505 Electron positron damping rings and colliders will require frequent tuning to maintain ultra-low vertical emittance. Emittance tuning begins with precision beam based measurement of lattice errors (orbit, transverse coupling, and dispersion) followed by compensation with corrector magnets. Traditional techniques for measuring lattice errors are incompatible with simultaneous operation of the storage ring as light source or damping ring. Dedicated machine time is required. The gated tune tracker (the device that drives the beam at the normal mode frequencies) and the bunch-by-bunch, turn-by-turn beam position monitor system developed at CESR are integrated to allow synchronous detection of phase. The system is capable of measuring lattice errors during routine operation. A single bunch at the end of a train of arbitrary length, is designated as the witness. The witness bunch alone is resonantly excited, and the phase and amplitude of the witness is mea- sured at each of the 100 beam position monitors. Lattice errors are extracted from the measurements. Corrections are then applied. The emittance of all of the bunches in the train is measured and the effectiveness of the correction procedure demonstrated.
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MOPWI033	Advantages to an Online Multi-particle Beam Dynamics Model for High-power Proton Linacs	linac, operation, 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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TUXB2	Upgrade of the Unilac for Fair	DTL, proton, linac, ion	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	positron, electron, gun, linac	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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TUXC2	Engineering Challenges of Future Light Sources	storage-ring, vacuum, feedback, synchrotron	1308
	R.T. Neuenschwander, L. Liu, S.R. Marques, A.R.D. Rodrigues, R.M. Seraphim LNLS, Campinas, Brazil
	We review some of the present engineering challenges associated with the design and construction of ultra-low emittance storage rings, the 4th generation storage rings (4GSR). The field is experiencing a growing interest since MAX-IV, followed by Sirius, started to build storage rings based on multi-bend-achromat (MBA) lattices. It was the recent progress in accelerator technology that allowed these facilities to base their designs on this kind of lattice. Although the challenges are starting to be overcome, many issues are still open and a lot of R&D is required until the 4GSR achieve optimal performance.
	Slides TUXC2 [7.022 MB]
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TUXC3	Commissioning of the Taiwan Photon Source	booster, storage-ring, quadrupole, synchrotron	1314
	C.-C. Kuo, C.-T. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, K.T. Hsu, Y.C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is a 3-GeV third-generation synchrotron light source located in Hsinchu, Taiwan. After ground breaking on February 7, 2010 and five years of construction and hardware developments, commissioning of the beam began on December 12, 2014. The booster ring reached the design energy of 3 GeV on December 16. Beam transferred to the storage ring and first accumulation at 3 GeV produced the first synchrotron light on December 31. This report presents results and experience of the TPS commissioning.
	Slides TUXC3 [5.425 MB]
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TUAB3	Chromaticity Effects for Space Charge Dominated Beams in the CERN PS Booster	space-charge, resonance, simulation, sextupole	1335
	V. Forte Université Blaise Pascal, Clermont-Ferrand, France E. Benedetto, F. Schmidt CERN, Geneva, Switzerland
	In view of the LHC Injectors Upgrade (LIU) project, an extensive campaign is on-going in the CERN PS Booster (PSB) to study collective effects for the future operation with the 160 MeV injection from Linac4. In operation, the machine is running with uncorrected natural chromaticity. This paper focuses on the study of the effects of chromaticity on losses and beam blow-up.
	Slides TUAB3 [4.887 MB]
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TUBD1	Optics Measurement and Correction during Acceleration with Beta-squeeze in RHIC	optics, acceleration, quadrupole, injection	1380
	C. Liu, A. Marusic, M.G. Minty 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 past, beam optics correction at RHIC has only taken place at injection and at final energy, with interpolation of corrections partially into the acceleration cycle. Recent measurements of the beam optics during acceleration and squeeze have evidenced significant beta-beats that, if corrected, could minimize undesirable emittance dilutions and maximize the spin polarization of polarized proton beams by avoiding the high-order multipole fields sampled by particles within the bunch. We recently demonstrated successfully beam optics corrections during acceleration at RHIC. We verified conclusively the superior control of the beam realized via these corrections. As a valuable by-product, these corrections have minimized the beta-beat at the profile monitors, so providing more precise measurements of the evolution of the beam emittances during acceleration.
	Slides TUBD1 [1.581 MB]
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TUBD2	Final Cooling For a High-luminosity High-energy Lepton Collider	collider, luminosity, solenoid, linac	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, linac, 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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TUPWA007	UPGRADED OPTICS FOR SIRIUS WITH IMPROVED MATCHING OF ELECTRON AND PHOTON BEAM EMITTANCES	photon, optics, quadrupole, brightness	1407
	L. Liu, N. Milas, A.H.C. Mukai, X.R. Resende, F. H. de Sá LNLS, Campinas, Brazil
	A new optics has been designed for Sirius with improved betatron function matching in the 6 meter-long low beta straight sections for insertion devices. Both horizontal and vertical betatron functions are set to 1.5 m in the center of the section, improving the matching of the electron and undulator photon beams. In addition, the horizontal beam stay clear has also been reduced allowing for small horizontal gap devices as well as the conventional small vertical gap ones. The new design optics has been optimized to the same previous performance regarding dynamic aperture and momentum acceptance.
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TUPWA030	Compression of an Electron-bunch by Means of Velocity Bunching at ARES	bunching, electron, simulation, plasma	1472
	B. Marchetti, R.W. Aßmann, U. Dorda, J. Grebenyuk, J. Zhu DESY, Hamburg, Germany
	ARES is a planned linear accelerator for research and development in the field of production of ultra-short electron bunches. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with improved arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The ARES layout will allow to perform and compare different kind of conventional e-bunch compression techniques, such as pure velocity bunching, hybrid velocity bunching (i.e. velocity bunching plus magnetic compression) and pure magnetic compression with the slit insertion. This flexibility will allow to directly compare the different methods in terms of arrival time stability and local peak current. In this paper we present simulation results for the compression of an electron bunch with 0.5 pC charge. We compare the case of pure velocity bunching compression to the one of a hybrid compression using velocity bunching plus a magnetic compressor. M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010). ** P. Emma et al., PRL 92 7 (2004).
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TUPWA034	Status of the Recommissioning of the Synchrotron Light Source PETRA III	synchrotron, lattice, operation, optics	1485
	R. Wanzenberg, M. Bieler, M. Ebert, L. Fröhlich, J. Keil, J. Klute, G. Kube, G.K. Sahoo DESY, Hamburg, Germany
	At DESY the Synchrotron Light Source PETRA III has been extended in the North and East section of the storage ring to accommodate ten additional beam lines. The PETRA ring was converted into a dedicated synchrotron light source from 2007 to 2009. Regular user operation started in summer 2010 with a very low emittance of 1 nm at a beam energy of 6 GeV and a total beam current of 100 mA. All photon beamlines were installed in one octant of the storage ring. Nine straight sections facilitated the installation of insertion devices for 14 beam lines. Due to the high demand for additional beamlines the lattice of the ring was redesigned to accommodate 10 additional beamlines in the future. In a one year long shut-down two new experimental halls were built. The recommissioning of PETRA III started in February 2015. We are reporting the current status of synchrotron light source including the performance of the subsystems.
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TUPWA036	Possibility of Longitudinal Bunch Compression in Petra III	optics, FEL, undulator, storage-ring	1492
	I.V. Agapov XFEL. EU, Hamburg, Germany S.I. Tomin NRC, Moscow, Russia R. Wanzenberg DESY, Hamburg, Germany
	A scheme of short bunch production in storage rings using a longitudinally focusing insertion was presented in . In this work we study the possibility of integrating such insertion into the PetraIII storage ring. In particular, we discuss possible optics solutions to integrate RF stations, chicane-type delay sections, and the undulators into existing ring geometry. I. Agapov and G. Geloni, proc. FEL 2014.
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TUPWA044	Test electron source for increased brightness emission by near band gap photoemission	cathode, electron, vacuum, simulation	1512
	S. Friederich, K. Aulenbacher IKP, Mainz, Germany
	Funding: Bundesministerium für Bildung und Forschung/Federal Ministry of Education and Research; Joint project HOPE A new photoemissive electron source is being built in order to make use of the reduction of ensemble temperature in near band gap photoemission. It will operate at up to 200 kV bias voltage with NEA GaAs photocathodes. High bunch charges will be investigated in pulsed mode with respect to the conservation of emittances at low energy excitations. High field gradients at the cathode surface will also allow further investigation of the field emission process of these photocathodes.
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TUPWA047	First Results Attained With the Quasi 3-D Ellipsoidal Photo Cathode Laser Pulse System at the High Brightness Photo Injector PITZ	laser, electron, cathode, simulation	1522
	T. Rublack, J.D. Good, M. Khojoyan, M. Krasilnikov, F. Stephan DESY Zeuthen, Zeuthen, Germany A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky IAP/RAS, Nizhny Novgorod, Russia I. Hartl, S. Schreiber DESY, Hamburg, Germany E. Syresin JINR, Dubna, Moscow Region, Russia
	Funding: Funded by the German Federal Ministry of Education and Research (BMBF) project 05K10CHE in the framework of the German-Russian collaboration "Development and Use of Accelerator-Based Photon Sources". 3-D ellipsoidal photo cathode laser pulses are considered as the next step in optimization of photo injectors required for a successful operation of linac based free electron lasers. Beam dynamics simulations using such laser pulses compared to conventional cylindrical pulses have shown a significant improvement in electron beam emittance. In collaboration with the Institute of Applied Physics (Nizhny Novgorod, Russia) and the Joint Institute of Nuclear Research (Dubna, Russia) such a 3-D ellipsoidal laser pulse system has been developed and afterwards installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). The pulse shaping is realized using the spatial light modulator technique. This allows very fine amplitude modulation within a laser pulse. The characterization of the shape of the laser pulses can be done by cross-correlation measurements. Using this method the ability to generate and measure quasi ellipsoidal laser pulses has been demonstrated. In this contribution the overall set-up, working principle and first results received with the new photo cathode laser system at PITZ will be reported.
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TUPWA051	Elettra Status and Future Prospects	operation, wiggler, insertion, insertion-device	1529
	E. Karantzoulis, A. Carniel, S. Krecic Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The operational status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with possible future upgrades and a vision to its future.
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TUPWA052	Elettra 2.0 - The Next Machine	dipole, lattice, quadrupole, dynamic-aperture	1532
	E. Karantzoulis Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	A next generation light source (ULS) to replace Elettra, the third generation Italian light source, is presented and discussed
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TUPWA055	DAΦNE Gamma-Ray Factory	electron, laser, photon, factory	1542
	D. Alesini, S. Guiducci, C. Milardi, A. Variola, M. Zobov INFN/LNF, Frascati (Roma), Italy I. Chaikovska, Z.F. Zomer LAL, Orsay, France
	Gamma sources with high flux and spectral densities are the main requirements for new nuclear physics experiments to be performed in several worldwide laboratories with dedicated facilities. The presentation is focalized on a proposal of experiment of gamma photons production using Compton collisions between the DAΦNE electron beam and a high average power laser pulse, amplified in a Fabry-Pérot optical resonator. The calculations show that the resulting gamma beam source has extremely interesting properties in terms of spectral density, energy spread and gamma flux comparable (and even better) with the last generation gamma sources. The energy of the gamma beam depends on the adopted laser wavelength and can be tuned changing the energy of the electron ring. In particular we have analyzed the case of a gamma factory tunable in the 2-9 MeV range. The main parameters of this new facility are presented and the perturbation on the transverse and longitudinal electron beam dynamics is discussed. A preliminary accelerator layout to allow experiments with the gamma beam is presented with a first design of the accelerator optics.
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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, linac, experiment	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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Paper

Title

Other Keywords

Page

MOYGB3

Commissioning of NSLS-II

insertion, insertion-device, damping, lattice

11

F.J. Willeke
BNL, Upton, Long Island, New York, USA

NSLS-II, the new 3rd generation light source at BNL was designed for a brightness of 10²² photons s^-1 mm^-2 mrad^-2 (0.1%BW)^-1. It was constructed between 2009 and 2014. The storage ring was commissioned in April 2014 which was followed by insertion device and beamline commissioning in the fall of 2014. All ambitious design parameters of the facility have already been achieved except for commissioning the full beam intensity of 500 mA which requires more RF installation. This paper reports on the results of commissioning.

Slides MOYGB3 [3.884 MB]

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MOAB2

Overview of Beam Instrumentation for the CADS Injector I Proton Linac

linac, rfq, 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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MOPWA001

Instability Thresholds and Tune Shift Estimation for Sirius

impedance, feedback, damping, simulation

70

F.H. de Sá, L. Liu, N. Milas, X.R. Resende
LNLS, Campinas, Brazil

In this work we present the evaluation of longitudinal and transverse instability thresholds as well as tune shifts for Sirius using time and frequency domain codes that are being developed in-house and take into account various effects on the beam instability, such as bunch by bunch feedback system, quadrupolar impedances from undulator chambers and tune spreads.

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MOPWA006

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

space-charge, linac, 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

linac, rfq, 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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MOPWA010

Emittances of the Core and of the Halo

linac, 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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MOPWA012

Study of Optimal MBA Lattice Structures for the SOLEIL Upgrade

dipole, lattice, optics, quadrupole

106

R. Nagaoka, P. Brunelle, F.J. Cullinan, X.N. Gavaldà, A. Loulergue, A. Nadji, L.S. Nadolski, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Within the context of a future upgrade of the SOLEIL ring, a series of lattice studies has been made with the aim of reducing the current 4 nm-rad horizontal emittance ex by more than an order of magnitude, with a dynamic aperture allowing off-axis injection. As in most upgrades, the important constraint imposed is to keep all the existing straight sections and photon source points. A particularity of SOLEIL are the short straight sections in half of the 16 double-bend cells, created in between the dipoles, which limits the number of dipoles in a MBA cell. In the previous studies, a combination of 5- and 4BA was followed, where with the use of longitudinal gradient bends (LGBs), ex ~440 pm-rad was obtained. The present paper reports on studies extended along the same strategy: In particular, the feasibility and the attainable ex are pursued with a combination of 7- and 6BA, by employing dipoles with transverse gradient and LGBs. In addition, the effectiveness of a few known nonlinear optimization methods, such as the resonance driving term cancellation, interleaved sextupoles with proper phases, and genetic algorithm-based numerical searches shall be explored.

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MOPWA014

New Functionality for Beam Dynamics in Accelerator Toolbox (AT)

lattice, radiation, dipole, simulation

113

B. Nash, N. Carmignani, L. Farvacque, S.M. Liuzzo, T.P. Perron, P. Raimondi, R. Versteegen, S.M. White
ESRF, Grenoble, France

Accelerator Toolbox is a widely used code for beam dynamic simulations based on Matlab. To continue the development of the code in a collaborative manner, a SourceForge project and SVN repository called atcollab has been established. Here we describe the contributions to atcollab from the ESRF beam dynamics group. Additional modules have been developed: general matching (atmatch), improved plotting (atplot), Touschek lifetime computation via the Piwinski formula, nonlinear dynamics computations such as resonance driving terms, improved reporting of lost particles and improvements and additions to the integration routines. One example of the latter includes diffusion due to quantum fluctuations. Modeling of collective effects may now be performed using pass methods representing a variety of impedance models. Finally, routines to replace the full ring with a compact representation have been developed, facilitating studies in which many turns and many particles are required.

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MOPWA017

Design Status of the ESSvSB Switchyard

proton, target, dipole, quadrupole

125

E. Bouquerel
IPHC, Strasbourg Cedex 2, France

The feasibility of the distribution of 5 MW proton beam power pulsed at 70 Hz onto a 4-target station for the production of neutrino super beams is discussed. To deflect and focus the beam having a magnetic rigidity of 11.0 Tm onto the targets, different configurations of beam switchyard are proposed and compared. The number of dipoles and quadrupoles composing this system is defined for each scenario. The length, the aperture, the magnetic fields and the field gradients of these optical elements are determined. The code TraceWin is used to simulate and optimize the envelopes of the beam along the beam lines. The transverse emittances at the exit of the system are shown.

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MOPWA026

Demonstration of Flat Ion Beam Creation and Injection into a Synchrotron

solenoid, injection, synchrotron, ion

153

L. Groening, S. Appel, L.H.J. Bozyk, Y. El Hayek, M.T. Maier, C. Xiao
GSI, Darmstadt, Germany

At GSI an ion beam with different horizontal and vertical emittances has been created from a beam with initially equal emittances. This round-to-flat adoption has been accomplished without any beam loss. In the set-up the beam passes through a stripping foil placed inside a solenoid followed by a skewed quadrupole triplet. The amount of beam flatness has been controlled by setting the solenoid field strength only. Increase of the product of the two transverse emittances is purely due to the stripping process that occurs anyway along an ion linac. Beams with different amounts of flatness were injected into a synchrotron applying horizontal multi-turn injection. The efficiency of injection increased as smaller as the horizontal emittance was set by the round-to-flat adaptor.

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MOPWA037

Mirror Symmetric Chicane-Type Emittance Exchange Beamline with Two Deflecting Cavities

quadrupole, focusing, cavity, dipole

190

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

Among optical systems for transverse-to-longitudinal emittance exchange (EEX) chicane-type beamlines are of keen interest, because they do not alter the beam propagation direction. Several designs of such beamlines involving a single dipole-mode cavity (TDC) are known. In this paper we present a chicane-type EEX beamline utilizing two TDCs instead of one. The advantages of this beamline are that it is mirror symmetric and does not require an additional accelerating mode cavity for compensation of the so-called thick-lens effect, and, in the compact design, it allows better control of the beam focusing in the non-bending plane than known beamlines with one TDC.

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MOPWA039

Emittance Reduction Possibilities in the PETRA III Magnet Lattice

optics, sextupole, lattice, synchrotron

197

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

PETRA III is a third generation light source that has been operated as a user facility since 2010 at DESY. An upgrade for additional beam lines has been carried out, and the recommissioning of the new beam lines is starting in spring 2015. In order to fully exploit the potential of the existing magnet lattice of the PETRA III ring, we present a study of beam optics modifications enabling the reduction of the horizontal emittance without changes of the lattice.

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MOPWA048

Transverse Emittance Measurement for Low Energy Ion Beams Using Quadrupole Scan Method

ion, plasma, ion-source, ECR

226

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

Low energy ion beam facility (LEIBF) * at IUAC consists of all permanent magnet 10 Ghz electron cyclotron resonance (ECR) ion source (NANOGUN) ** along with 400 kV high voltage accelerating platform, a switching cum analysing magnet and electrostatic quadrupoles. Higher beam currents of heavy charge states and low energy of ion beams puts tremendous challenge to transport the ion beam from source to target. The normalized emittance of analysed ion beam is measured for specific charge to mass ratio using electrostatic quadrupole scan method *** for various source parameters like RF power and injection pressure of gas etc. For various m/q ratios, the normalized transverse emittance ranges from 0.1 to 0.6 mm-mrad. It is attributed to beam rotation induced by ECR axial magnetic field, effect of ion temperature in plasma, non linear electric fields and space charge etc which play a significant role in emittance growth.
* A. Mandal et. al. Proceedings of IPAC2011, WEPC011, San Sebastián, Spain
** D Kanjilal et. al. Indian J. Pure Appl. Phys. 39 (2001) 25
*** I. G. Brown:The physics and technology of ion sources

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MOPWA050

Beam Dynamics Studies to Develop a High-energy Luminosity Model for the LHC

simulation, luminosity, beam-beam-effects, collider

233

G. Campogiani
Rome University La Sapienza, Roma, Italy
Y. Papaphilippou
CERN, Geneva, Switzerland

Funding: support provided by the EPS-AG through the EPS-AG student grant program
Luminosity, the key figure of merit of a collider as the LHC, depends on the brightness of the colliding beams. This makes the intensity dependent beam-beam effect the dominant performance limiting factor at collision. The parasitic interactions due to the electromagnetic mutual influence of the beams in the interaction region of a collider induce a diffusive behaviour in the tails of the beam. The evolution of charge density distribution is studied to model the beam tails evolution in order to characterize beam lifetime and luminosity. To achieve this, tools are developed for tracking distributions of arbitrary number of single particles interacting with the opposing strong-beam, to analyse the halo formation processes due to the combined effect of beam-beam and machine non-linearities. This paper presents preliminary results of the simulations, both for the LHC Run I and nominal LHC parameters. The former will be used to benchmark simulations while the latter aims at supporting luminosity estimate for the Run II.

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MOPWA053

Emittance Preservation in SuperKEKB Injector

wakefield, simulation, linac, 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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MOPWA055

Study of Emittance Growth Caused by Space Charge and Lattice Induced Resonances

resonance, space-charge, lattice, synchrotron

245

K. Ohmi
KEK, Ibaraki, Japan

Resonance strength and resonance width induced by space charge and lattice nonlinearity is discussed with integrals along a ring like the radiation integrals. Emittance growth is evaluated by model with the resonance width to understand the mechanism. The results are compared with fully PIC simulations.

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MOPWA057

Space Charge Simulation and Matching at Low Energy Section of J-PARC Linac

rfq, space-charge, simulation, solenoid

251

S. Artikova, T. Morishita
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Kondo
JAEA, Ibaraki-ken, Japan

An intensity upgrade of Japan Proton Accelerator Research Complex (J-PARC) included the installation of a new ion source (IS) and a radio-frequency quadrupole (RFQ) which to be used at first stage of acceleration. The linac is divided into two sections on the basis of operating frequencies and three sections on the basis of family of RF cavities to be used for the acceleration of 50 mA beam of H⁻ ions from 50 keV to 400 MeV. Low energy part of linac consists of an IS, a two-solenoid low energy beam transport (LEBT) and the RFQ. The transition from one section to another can limit the acceptance of the linac if these are not matched properly in both longitudinal and transverse plane. We performed a study to calculate the acceptance of the RFQ at zero current in which space charge effects are not considered. In addition, a particle tracking technique is employed to study the space charge effects in LEBT of the J-PARC linac after the intensity upgrade in order to match the beam to the RFQ. Also, RFQ tank level and intervene voltage calibration factor is determined by comparing the simulation results of the beam transmission with the test measurement of tank level vs. transmission.

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MOPWA061

ADS Injector I Frequency Choice at IHEP

linac, rfq, 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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MOPWA067

Theory of Transverse Ionization Cooling in a Linear Channel

lattice, quadrupole, scattering, collider

279

M. Xiao, J. Gao, Y. Yue
IHEP, Beijing, People's Republic of China

Ionization cooling is the most hopeful method to reduce the emittance of muon beams, which plays an important role in neutrino factory and muon collider. Within the moment-equation approach, I present a way to derive the formulae of emittance in transverse under linear channel. All heating and coupling terms are reserved in the deriving process. From my formulae, it is a way to achieve a small emittance by designing the cooling channel compact to make the beta function changing sharply.

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MOPWA072

Emittance Exchange Beam Line Design In THU Accelerator Lab

quadrupole, cavity, simulation, electron

285

Q. Gao, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

Funding: National Natural Science Foundation of China
Emittance exchange (EEX) provides a novel tool to enhance the phase space manipulation techniques. Based on Tsinghua Thomson scattering experimental platform, this study presented a beam line design for exchanging the transverse and longitudinal emittance of an electron bunch. This beam line consists of a 2.856 GHz half-one-half cell deflecting cavity with no axis offset and two doglegs. In this paper, by optimizing the beam envelope parameter for Tsinghua Thomson scattering source, we report the theoretical analysis and a good particle tracking simulation result about emittance exchange and longitudinal shaping.

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MOPJE009

Lattice Design of the SSRF-U Storage Ring

storage-ring, lattice, dynamic-aperture, injection

304

S.Q. Tian, B.C. Jiang, M.Z. Zhang, Q.L. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Multi-Bend Achromatic (MBA) cell has been well known to significantly reduce the beam emittance of the synchrotron radiation light sources in the past two decades. With the great development of the high gradient magnets, the small-aperture vacuum chamber and the precise alignment, the ultimate-emittance ring based on MBA lattice became practical in recent years. We present a preliminary lattice design for the upgraded SSRF storage ring based on a 7BA lattice in this paper. The circumference and the number of the straight sections are preserved for the existing tunnel. The beam energy is reduced to 3 GeV, and the beam emittance is reduced to about 200 pm.rad. The optimized dynamic aperture is about 10 mm in the horizontal plane, and a sufficient beam injection based on the closed orbit bump can be implemented.

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MOPJE016

Start-to-End Simulation for RAON Superconducting Linac

linac, ion, cryomodule, lattice

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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MOPJE019

Categorization and Estimation of Possible Deformation in Emittance Exchange based Current Profile Shaping

cavity, wakefield, acceleration, collective-effects

317

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

Funding: This work is partly supported by POSTECH BK²¹⁺ program and Argonne National Laboratory
Shaping the current profile is one of the important issues in collinear wakefield acceleration. In the emittance exchange based shaping technique, the shaped current profile seriously depends on the incoming beam and beam line parameters. To design the beam and beam line properly, it is important to estimate the deformation in the shaped current profile. There are several different deformation types whose level depend on deformation parameter. We categorize the possible deformation types and observe the deformation patterns of the current profile depending on its type and the deformation parameter.

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MOPJE020

High Resolution Longitudinal Property Measurement using Emittance Exchange Beam Line

quadrupole, cavity, space-charge, collective-effects

320

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

Most of longitudinal measurement techniques introduce the transverse-longitudinal correlation because it is very hard to measure the longitudinal properties directly. This correlation is necessary to observe the longitudinal property through the transverse screen, but initial transverse components of the beam restrict the measurement. It is possible to overcome this intrinsic limit using emittance exchange beam line which makes transverse properties at the downstream only depend on longitudinal properties at the upstream. We present the new idea to measure the longitudinal properties using the emittance exchange beam line and preliminary simulation results.

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MOPJE034

Low Emittance Tuning for the CLIC Damping Rings

quadrupole, lattice, sextupole, coupling

356

J. Alabau-Gonzalvo, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

A study on the sensitivity of the CLIC Damping Ring lattice to different sources of misalignment is presented. Dipole and quadrupole rolls, quadrupole and sextupole vertical offsets are considered, as well as the impact of a finite BPM resolution. The result of this study defines a low emittance tuning procedure and establishes alignment tolerances to preserve the vertical emittance below the design value (1 pm·rad). Non-linear dynamics studies including dynamic aperture and frequency maps are shown and synchrotron radiation effects are discussed.

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MOPJE042

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

space-charge, injection, linac, simulation

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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MOPJE051

Effect of Electron Cloud in Quadrupoles on Beam Instability

quadrupole, electron, dipole, simulation

409

G. Iadarola, A.P. Axford, H. Bartosik, K.S.B. Li, G. Rumolo
CERN, Geneva, Switzerland

Both simulations and machine experience at the CERN-SPS and LHC have shown that the electron cloud has a lower build up threshold in quadrupoles than in dipoles and field free regions. As a consequence, while beam induced scrubbing can efficiently suppress the electron cloud in both dipoles and field free regions, a residual electron cloud can still survive in the quadrupoles and potentially degrade the beam quality. To study this effect, a PyECLOUD module for electron tracking in quadrupole fields including effects of secondary emission at the vacuum chamber has been implemented in PyHEADTAIL. With this module, the effect of the electron cloud in quadrupoles on beam stability and beam quality preservation can be assessed, as well as its impact on future LHC and HL-LHC operation.

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MOPJE053

NSLS-II Beam Lifetime Measurements and Modeling

scattering, cavity, coupling, lattice

416

B. Podobedov, W.X. Cheng, Y. Hidaka, H.-C. Hseuh, G.M. Wang
BNL, Upton, Long Island, New York, USA

NSLS-II is a recently constructed 3 GeV synchrotron light source with design horizontal emittance values in sub-nm range. Achieving good beam lifetime is critically important for NSLS-II as it is closely tied in to such important operational aspects as top-off injection frequency, injector components wear, radiation protection and control, and others. In this paper we present lifetime-related commissioning results, describe our present understanding of beam lifetime at NSLS-II and extrapolate our models to the fully built-up machine operating at 500 mA design beam current.

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MOPJE059

Tests of Wakefield-Free Steering at ATF2

wakefield, cavity, extraction, alignment

438

A. Latina, J. Pfingstner, D. Schulte
CERN, Geneva, Switzerland
E. Adli
University of Oslo, Oslo, Norway
N. Fuster-Martínez
IFIC, Valencia, Spain
J. Snuverink
JAI, Egham, Surrey, United Kingdom

Charge-dependent effects on the orbit and on the beam size affect the performance of the Accelerator Test Facility (ATF2) in a non-negligible way. Until now small beam sizes have only been achieved running with a beam charge significantly smaller than the nominal value. These detrimental effects on the beam have been attributed to wakefields, in the cavity BPMs, in the multi-Optical Transition Radiation (OTR) systems as well as in other components of the beamline. The successful tests of a Wakefield-free Steering (WFS) algorithm at FACET have encouraged performing tests of the same correction scheme at ATF2. The performance of the algorithm has been simulated in detail, including several realistic imperfection scenarios, including charge-dependent BPMs resolution, and incoming injection error and position jitters, which are described in this paper. Tests of WFS have been performed at ATF2 during December 2014. The results are discussed here.

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MOPJE060

BBA and Coupling Correction at CLIC RTML

coupling, quadrupole, dipole, alignment

442

Y. Han, L. Ma
SDU, Shandong, People's Republic of China
A. Latina, D. Schulte
CERN, Geneva, Switzerland

The CLIC Ring To Main Linac (RTML) must transport the electron and the positron bunches through more than 20 km of beamlines with minimal emittance growth. The turnaround loops (TAL) are one of the most critical sections, featuring a lattice designed to minimize emittance growth due to synchrotron radiation emission and chromaticity, while being isochronous to avoid bunch lengthening. With such a design, the impact of static imperfections like element misalignment is particularly critical. In this paper a study of the Beam-Based Alignment (BBA) techniques in the TAL of the CLIC RTML is presented. In order to reduce the emittance growth, the one-to-one and dispersion-free corrections have been tested. The results showed that the emittance growth budgets can be met both in the horizontal and vertical planes. The impact of coupling errors due to magnets rolls on the emittance has also been studied and a coupling correction section has been designed and inserted in the lattice.

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MOPJE065

Contribution of Optical Aberrations to Spot-size Increase with Bunch Intensity at ATF2

damping, optics, extraction, simulation

455

M. Patecki, R. Tomás, F. Zimmermann
CERN, Geneva, Switzerland
K. Kubo, S. Kuroda, T. Naito, T. Okugi, T. Tauchi, N. Terunuma
KEK, Ibaraki, Japan
M. Patecki
Warsaw University of Technology, Warsaw, Poland
G.R. White
SLAC, Menlo Park, California, USA

A primary goal of ATF2 (Accelerator Test Facility) is to demonstrate a low vertical beam size at the interaction point (IP) of about 37 nm. Measurements over the past years indicate that the ATF2 vertical beam size strongly rises with bunch intensity. Several different origins of this increase are considered, e.g. wakefields occurring between the ATF damping ring and the IP, and/or intrabeam scattering (IBS) causing the increase of transverse emittances and energy spread in the damping ring with the increase of the bunch intensity. In this paper we address the second possibility. Past measurements and simulations of the IBS effects in the ATF are used to model the intensity-dependent initial emittances and energy spread at the entrance of the final focus. Particle tracking simulations predict the IP vertical beam size growth expected from the known optical aberrations for initial beam parameters corresponding to varying bunch intensities. Comparing simulation results with emittance measurements at different locations allows us to draw some conclusions about the impact of IBS in the damping ring on the IP spot size, and about possible single-bunch wakefields in the ATF2.

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MOPJE076

Multi-objective Genetic Optimization with the General Particle Tracer (GPT) Code

solenoid, factory, cavity, target

492

S.B. van der Geer, M.J. de Loos
Pulsar Physics, Eindhoven, The Netherlands

In a typical design process there are a large number of variables, external constraints, and multiple conflicting objectives. Examples of the latter are short pulse, high charge, low emittance and low price. The classical solution to handle such problems is to combine all objectives into one merit function. This however implicitly assumes that the tradeoffs between all objectives are a-priori known. Especially in the early design stages this is hardly ever the case. A popular solution to this problem is to switch to multi-objective genetic optimization algorithms. This class of algorithms solves the problem by genetically optimising an entire population of sample solutions. Selection and recombination operators are defined such that the output, the so-called Pareto front, only includes solutions that are fully optimized where no objective can be improved without degrading any other. Here we present numerical studies and practical test runs of the genetic optimizer built into the General Particle Tracer (GPT) code.

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MOPJE084

Particle-in-cell Simulations of a Plasma Lens at Daresbury Laboratory

plasma, focusing, simulation, experiment

518

K. Hanahoe, O. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
D. Angal-Kalinin, J.K. Jones
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
J.D.A. Smith
TXUK, Warrington, United Kingdom

Feasibility of a focusing element using the transverse fields provided by a plasma cell was studied numerically. In this paper, an experimental set up is proposed for various beam parameters available from the VELA and CLARA beam lines at Daresbury Laboratory. 2D simulation results from VSim, and expected results from planned measurement stations are presented. Field properties and the advantages and disadvantages of such an instrument compared to conventional focusing elements are discussed.

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MOPMA012

Intra-Beam and Touschek Scattering Computations for Beam with Non-Gaussian Longitudinal Distributions

scattering, distributed, simulation, lattice

559

A. Xiao, M. Borland
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
Both intra-beam scattering (IBS) and the Touschek effect become prominent for multi-bend-achromat- (MBA-) based ultra-low-emittance storage rings. To mitigate the transverse emittance degradation and obtain a reasonably long beam lifetime, a higher harmonic rf cavity (HHC) is often proposed to lengthen the bunch. The use of such a cavity results in a non-gaussian longitudinal distribution. However, common methods for computing IBS and Touschek scattering assume Gaussian distributions. Modifications have been made to several simulation codes that are part of the {\tt elegant} toolkit to allow these computations for arbitrary longitudinal distributions. After describing these modifications, we review the results of detailed simulations for the proposed hybrid seven-bend-achromat (H7BA) upgrade lattice for the Advanced Photon Source.

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MOPMA013

Experience with Round Beam Operation at the Advanced Photon Source

coupling, operation, resonance, storage-ring

562

A. Xiao, L. Emery, V. Sajaev, B.X. Yang
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
Very short Touschek lifetime becomes a common issue for next-generation ultra-low emittance storage ring light sources. In order to reach a longer beam lifetime, such a machine often requires operating with a vertical-to-horizontal emittance ratio close to an unity, i.e. a ‘‘round beam''. In tests at the APS storage ring, we determined how a round beam can be reached experimentally. Some general issues, such as beam injection, optics measurement and corrections, and orbit correction have been tested also. To demonstrate that a round beam was achieved, the beam size ratio is calibrated using beam lifetime measurement.

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MOPMA015

Applications of an MPI Enhanced Simulated Annealing Algorithm on nuSTORM and 6D Muon Cooling

sextupole, lattice, storage-ring, simulation

568

A. Liu
Fermilab, Batavia, Illinois, USA

The nuSTORM decay ring is a compact racetrack storage ring with a circumference ∼ 480 m using large aperture (∅=60 cm) magnets. The design goal of the ring is to achieve a momentum acceptance of 3.8±10\% GeV/c and a phase space acceptance of 2000 μm·rad. The design has many challenges because the acceptance will be affected by many nonlinearity terms with large particle emittance and/or large momentum offset. In this paper, we present the application of a meta-heuristic optimization algorithm to the sextupole correction in the ring. The algorithm is capable of finding a balanced compromise among corrections of the nonlinearity terms, and finding the largest acceptance. This technique can be applied to the design of similar storage rings that store beams with wide transverse phase space and momentum spectra. We also present the recent study on the application of this algorithm to a part of the 6D muon cooling channel. The technique and the cooling concept will be applied to design a cooling channel for the extracted muon beam at nuSTORM in the future study.

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MOPMA016

Coupler RF Kick in the Input 1.3 GHz Accelerating Cavity of the LCLS-II Linac

cavity, focusing, HOM, accelerating-gradient

571

A. Lunin, N. Solyak, A.I. Sukhanov, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA

Main and HOM couplers break the cavity axial symmetry, distort RF field and, thus, create a transverse kick, even for a particle moving along the cavity axes. Dependence of a kick on the RF phase causes a beam emittance dilution and degrade the FEL radiation quality. The transverse kick is most dangerous for a beam passing through the first accelerating structure of a linac, where particles energy and their relativistic mass are low. In the paper we analyze the coupler RF kick in the first accelerating structure of the LCSL-II linac.

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MOPMA024

A Parallel Particle-Particle, Particle-Mesh Solver for Studying Coulomb Collisions in the Code IMPACT-T

electron, simulation, plasma, space-charge

593

C.E. Mitchell, J. Qiang
LBNL, Berkeley, California, USA

Funding: This work is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
In intense charged-particle beams, the presence of Coulomb collisions can result in growth of the beam slice energy spread and emittance that cannot be captured correctly using traditional particle-in-cell codes. Particle-particle, particle-mesh solvers take a hybrid approach, combining features of N-body and particle-in-cell solvers, to correctly capture the effect of short-range particle interactions with less computing time than direct N-body solvers. We describe the implementation and benchmarking of such a solver in the code IMPACT-T for beam dynamics applications.

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MOPMA026

Proposed Cavity for Reduced Slip-Stacking Loss

cavity, booster, injection, beam-loading

600

J.S. Eldred
Indiana University, Bloomington, Indiana, USA
J.S. Eldred, R.M. Zwaska
Fermilab, Batavia, Illinois, USA

This paper employs a novel dynamical mechanism to improve the performance of slip-stacking. Slip-stacking in an accumulation technique used at Fermilab since 2004 which nearly double the proton intensity. During slip-stacking, the Recycler or the Main Injector stores two particles beams that spatially overlap but have different momenta. The two particle beams are longitudinally focused by two 53 MHz 100 kV RF cavities with a small frequency difference between them. We propose an additional 106 MHz 20 kV RF cavity, with a frequency at the double the average of the upper and lower main RF frequencies. In simulation, we find the proposed RF cavity significantly enhances the stable bucket area and reduces slip-stacking losses under reasonable injection scenarios. We quantify and map the stability of the parameter space for any accelerator implementing slip-stacking with the addition of a harmonic RF cavity.

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MOPMA029

Experiences Simulating Nonlinear Integrable Optics

lattice, simulation, optics, diagnostics

611

S.D. Webb, D.L. Bruhwiler
RadiaSoft LLC, Boulder, Colorado, USA
V.V. Danilov
ORNL, Oak Ridge, Tennessee, USA
R.A. Kishek
UMD, College Park, Maryland, USA
S. Nagaitsev, A. Valishev
Fermilab, Batavia, Illinois, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award Number DE-SC0011340.
With increasing interest in the nonlinear integrable optics, it is important that early experiences with simulating the lattices be shared to save time and point out potential difficulties in the simulations. We present here some details of simulating the nonlinear integrable lattices. We discuss correctly implementing and testing the elliptic element kicks, and the limits of the thin lens approximation. We also discuss generating a properly matched bunch in the transverse phase space, and how to analyze the resulting computational data from simulations.

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MOPMA044

Barrier Shock Compression with Longitudinal Space Charge

space-charge, simulation, electron, plasma

646

B. Beaudoin, I. Haber, R.A. Kishek
UMD, College Park, Maryland, USA

Funding: This work is supported by the US Dept. of Energy, Office of High Energy Physics.
Synchrotrons and storage rings routinely employ RF barrier buckets as a means of accumulating charge to increase the peak intensity and preserve longitudinal emittance while minimizing emittance growth [1-3]. This was shown in the main injector and recycler at Fermilab as well as the SIS-18 at GSI Helmholtz center for heavy ion research. The RF cavities typically used are ferrite loaded magnetic alloys with low Q to maximize bandwidth and generate single pulses, either as delta functions, triangular or half/full period sine waves. The University of Maryland Electron Ring (UMER) group is studying a novel scheme of bunch compression in the presence of longitudinal space charge. It has been analytically shown through 1-D computations that the presence of space-charge considerably improves the efficiency of the barrier compression by taking advantage of the shock-front that launches when the barrier moves into a space-charge dominated beam. In this paper, we summarize the initial results of the study.

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MOPMA045

Conceptual Difficulties of a Thermodynamics Description of Charged-Particle Beams

space-charge, simulation, focusing, beam-transport

649

S. Bernal
UMD, College Park, Maryland, USA

Funding: This work is funded by the US Dept. of Energy
We review the existing phenomenological theories of emittance growth with and without entropy terms and re-examine the condition for thermal equipartitioning in an unbunched charged-particle beam. The model incorporates linear space charge and a uniform-focusing lattice. Because of non-extensitivity of the transverse ("thermal") energy and the absence of a classical heat bath, we conclude that a rigorous classical thermodynamics treatment of charged-particle beams is not possible. In particular, the postulated relationships between the rms emittance and temperature and entropy must be qualified.

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MOPMA050

Smooth Fast Multipole Method for Space Charge Tracking: An Alternate to Particle-In-Cell

multipole, space-charge, simulation, framework

663

A.J. Gee, B. Erdelyi
Northern Illinois University, DeKalb, Illinois, USA
B. Erdelyi
ANL, Argonne, USA

The fast multipole method (FMM) algorithm was developed by Greengard and Rokhlin in 1987 *. As one of the top ten algorithms of the 20th century, it has been applied in a wide range of fields. The FMM complexity is O(N), where N is the number of articles, allowing for large-scale simulations. However, it includes all the two-body collisional forces, in contrast to other methods such as the popular particle in-cell (PIC) methods. While collisionality can be very important, many applications require only the mean field effects. PIC is frequently used in this regime. Due to recent concerns of unphysical effects of grids, interpolation and other approximations in PIC codes, an alternative based on different underlying assumptions would prove enlightening. For these cases, a smoothed or softened FMM using a Plummer-like smoothing parameter holds much promise. Unfortunately, the original FMM based on analytic expansions of the 1/r-like potentials does not allow for Plummer softening. We present our new soft-FMM employing differential algebras (DA) to obtain the modified expansions. We also compare the performance of the smoothed DA-FMM with examples from PIC simulations.
* L. Greengard and V. Rokhlin. “A fast algorithm for particle simulations".

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MOPMA051

Generation of Modulated Bunch Using a Masked Chicane for Beam-Driven Acceleration Experiments at ASTA

simulation, bunching, dipole, space-charge

666

Y.-M. Shin, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Broemmelsiek, D.J. Crawford, A.H. Lumpkin
Fermilab, Batavia, Illinois, USA
A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling *. The sub-ps beam modulation has been studied with a masked chicane ** *** by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the nominal 50 MeV chicane parameters and 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 um and aperture width 300 μm generates about 100-um modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 um of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 0.25, 1 , and 3.2 nC, by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments.
* E. Kallos, Southern California 2008
** D. C. Nguyen, B. E. Carlston, NIMA 375, 597 (1996)
*** P. Muggli, V. Yakimenko, M. Babzien, E. Kallos, and K. P. Kusche, PRL 101, 054801 (2008)

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MOPMA052

Implementation of Quadrupole-scan Emittance Measurement at Fermilab's Advanced Superconducting Test Accelerator (ASTA)

quadrupole, controls, monitoring, simulation

669

A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA
Y.-M. Shin
Fermilab, Batavia, Illinois, USA
Y.-M. Shin
Northern Illinois University, DeKalb, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Transverse-emittance measurements based on the quadrupole-scan technique * ** ***, have been widely used to characterize the beam phase-space parameters in linear accelerators. This paper discusses the implementation of the technique at the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. We plan on deploying a flexible implementation that permits an operator to select the quadrupole associated analysing screen to measure the beam emittance. Our implementation utilizes Python scripts combined with Fermilab’s control system ACNet and ELEGANT quadrupole-scan method at 50 MeV given the range of operating charge (20 pC to 3.2 nC) available at ASTA. Some preliminary measurements will also be presented.
* B.E. Carlsten, et al, Nucl. Instrum. Methods Phys. Res. Sect. A 331, 791 (1993)
** C. Eckman et al, IPAC 2012
*** K. Poorrezaei, et al, Phys. Rev. ST-AB 16, 082801 (2013)

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MOPMA056

Measurement and Modeling of Single Bunch Wake Field Effects in CESR

simulation, impedance, wakefield, storage-ring

681

J.R. Calvey, M.G. Billing, W. Hartung, J.D. Perrin, D. L. Rubin, D. Sagan, S. Wang
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF PHY-1416318 and NSF DMR 1332208. This research used the National Energy Research Scientific Computing Center, which is supported by DOE Contract No. DE-AC02-05CH11231.
Short-range wake fields have been incorporated into a Bmad-based particle tracking code in order to assess their contribution to current-dependent emittance growth, tune shift, and single bunch instabilities. The wakes are computed for CESR vacuum components using the T3P modeling software. Simulation results are compared with measurements of bunch length, vertical beam size, and coherent tune shift. Additionally, we use insertable scrapers to vary the transverse wake and measure the effect on the beam. We show that a vertical emittance increase at high current may be due to a transverse monopole wake, originating in the lump pump slots throughout CESR.

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MOPMA057

Space Charge Neutralization of 750 keV Proton Beam in LANSCE Injector Line

space-charge, simulation, proton, beam-transport

685

Y.K. Batygin
LANL, 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 750-keV low-energy beam transport of the Los Alamos Neutron Science Center (LANSCE) linac consists of two independent beam lines for simultaneous injection of H⁺ and H⁻ beams into the linear accelerator. Space charge effects play an important role in the beam transport therein. A series of experiments were performed to determine the level of proton beam space charge neutralization by residual gas ionization, and time required for neutralization. Study was performed as emittance scans between pair of emittance measurement stations. The value of compensated space charge was determined through comparison of results of measurements and simulations using macroparticle method and envelope code. Obtained results provide new setup for beam tuning in transport beamline.

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MOPMA058

Effect of Spherical Aberration on Beam Emittance Growth

focusing, space-charge, proton, simulation

688

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

Funding: Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396
Spherical aberration in axial-symmetric magnetic focusing lenses results in S-shape figure of beam emittance. Filamentation of beam emittance in phase space is a fundamental property of a beam affected by aberrations. Analytical expression for effective beam emittance growth due to spherical aberration as a function of lens aberraion coefficient, initial beam emittance, beam radius, and focal lens of the focusing lens is obtained. Analysis is extended for beam space charge aberrations. Analytical results are confirmed by numerical calculations.

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MOPMN008

Space Charge Studies in FFAG Using the Tracking Code Zgoubi

space-charge, simulation, betatron, damping

717

M. Haj Tahar, F. Méot, 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.
A method is implemented in Zgoubi that allows the computation of space charge effects in 2D distributions and with some restrictions in 3D distributions. It relies on decomposiing field maps or analytical elements into slices and applying a space charge kick to the particles. The aim of this study is to investigate the accuracy of this technique, its limitations/advantages by comparisons with other linear/nonlinear computation methods and codes, and to apply it to high power fixed field ring design studies.

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MOPMN018

A Generic Formulation for Emittance and Lattice Function Evolution for Non-Hamiltonian Systems with Stochastic Effects

lattice, radiation, synchrotron, scattering

740

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.
I describe a generic formulation for the evolution of emittances and lattice functions under arbitrary, possibly non-Hamiltonian, linear equations of motion. The average effect of stochastic processes, which would include ionization interactions and synchrotron radiation, is also included. I first compute the evolution of the covariance matrix, then the evolution of emittances and lattice functions from that. I examine the particular case of a cylindrically symmetric system, which is of particular interest for ionization cooling.

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MOPMN028

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

electron, dipole, simulation, linac

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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MOPMN029

Spin Resonance Strength Calculation Through Single Particle Tracking for Rhic

resonance, betatron, proton, lattice

763

Y. Luo, Y. Dutheil, H. Huang, F. Méot, V.H. Ranjbar
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 strengths of spin resonances for the polarized-proton operation in the Relativistic Heavy Ion Collider are currently calculated with code DEPOL, which numerically integrate through the whole ring based on analytical approximate formula. In this article, we calculate the spin resonance strength by performing Fourier transformation to the actual transverse magnetic field seen by a single particle travelling through the ring. Comparison is made between the results from this method and DEPOL and other approaches.

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MOPHA020

Automated Transverse Beam Emittance Measurement using a Slow Wire Scanner at the S-DALINAC

quadrupole, electron, EPICS, controls

817

P. Dijkstal, M. Arnold, C. Burandt, F. Hug, N. Pietralla
TU Darmstadt, Darmstadt, Germany

Funding: This work has been supported by the DFG through CRC 63 and by the EPS-AG through the EPS-AG student grant program.
The superconducting linear accelerator S-DALINAC of the TU Darmstadt provides electron beams of up to 130 MeV in cw mode. It consists of a 10 MeV injector and a 40 MeV main linac, both equipped with elliptical cavities operating in liquid helium at 2 K at a frequency of 3 GHz. The final energy is reached by using up to two recirculation paths. In order to improve beam simulations, it is planned to monitor the transverse beam emittance at different locations along the beam line. A system of slow wire scanners in combination with quadrupole variation is foreseen to accomplish this task. For a first test a wire scanner was installed in the 250 keV section behind the thermionic electron gun of the S-DALINAC. A procedure to automatize measurements was developed and integrated in the EPICS-based control system. We will show the status of the work on the automatized control and the results of first emittance measurements. A report on the future plans will be given.

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MOPHA024

A Novel Transverse Deflecting Cavity for Slice Diagnostics at BERLinPro

cavity, polarization, SRF, low-level-rf

827

A. Ferrarotto, B. Riemann, T. Weis
DELTA, Dortmund, Germany
H.-W. Glock, T. Kamps, J. Völker
HZB, Berlin, Germany

Funding: Work supported by BMBF under contract no. 05K10PEA
BERLinPro is an energy-recovery linac project to be realized at the Helmholtz-Zentrum Berlin (HZB) for an electron beam with 1mm mrad normalized emittance and 100 mA average current. The initial beam parameters are determined by the performance of the electron source, an SRF photo-electron injector. The development auf this SRF photon-electron injector is a main task of BERLinPro. Especially the beam emittance is basically defined by the SRF photogun. For beam diagnostics time dependent effects from the RF curvature and space charge must be taken into account and a sophisticated slice diagnostics is required. To perform this type of diagnostics a transverse deflecting cavity has been designed, characterized and is presently under construction.. This single cell cavity operates in a TM110-like mode at 1.3 GHz optimized for high transverse shuntimpedance of appr. 3.2 MOhm by a concentration of fields near the beam axis. The cavity has a novel geometry that allows for an operation with both polarizations of the TM110-Mode. The layout of the deflecting cavity will be presented together with the results of the low RF characterization.

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MOPHA027

Transverse Emittance Measurement at REGAE

electron, detector, background, solenoid

837

M. Hachmann, K. Flöttmann
DESY, Hamburg, Germany

The linear accelerator REGAE at DESY produces short and low charged electron bunches, on the one hand to resolve the excitation transitions of atoms temporally by pump probe electron diffraction experiments and on the other hand to investigate principal mechanisms of laser plasma acceleration. For both cases a high quality electron beam is required which can be identified with a small beam emittance. A standard magnet scan is used for the emittance measurement which is in case of a low charged bunch most sensitive to the beam size determination (2nd central moment of a distribution). Therefore the diagnostic and a routine to calculate proper central moments of an arbitrary distribution will be introduced and discussed.

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MOPHA041

Laser Wire Based Transverse Emittance Measurement of H⁻ Beam at Spallation Neutron Source

laser, electron, neutron, dipole

879

Y. Liu, A.V. Aleksandrov, C.D. Long, A.A. Menshov, A.P. Zhukov
ORNL, Oak Ridge, Tennessee, USA

Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
A laser wire based transverse emittance measurement system has been developed at the Spallation Neutron Source (SNS). The system enables a nonintrusive measurement of the transverse emittance in both directions on a 925 MeV/1 MW hydrogen ion (H⁻) beam at the high energy beam transport (HEBT) beam line.

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MOPTY023

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

linac, gun, FEL, 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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MOPTY025

High-current RFQ Design Study on RAON

rfq, cavity, ion, acceleration

990

J. Bahng, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
B.H. Choi
IBS, Daejeon, Republic of Korea

Rare isotope Accelerator Of Newness (RAON) heavy ion accelerator has been designed as a facility for a rare isotepe accelerator of the Rare Isotope Science Project (RISP). RAON provides 400 kW CW heavy ion beams from proton to uranium to support researches in various science fields. The RAON system consists of a few ECR ion source, low energy beam transport systems (LEBTs), CW radio frequency quadrupole (RFQ) accelerators, a medium energy beam transport and superconducting linac. We present the design study of the RFQ accelerator from 30 keV/u to 1.5 MeV/u of deuteron beam with meeting a requirement of over 15 mA beam at the target. We optimized the normal conducting CW RFQ accelerator that has a high transmission and a low longitudinal emittance. In this paper, we will present the design result of RFQ beam dynamics studies and its 2D and 3D EM analysis.

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MOPTY082

Beam Instrumentation of the PXIE LEBT Beam Line

ion, solenoid, ion-source, diagnostics

1129

R.T.P. D'Arcy
UCL, London, United Kingdom
B.M. Hanna, L.R. Prost, V.E. Scarpine, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

The PXIE accelerator is the front-end test stand of the proposed Proton Improvement Plan (PIP-II) initiative: a CW-compatible pulsed H⁻ superconducting RF linac upgrade to Fermilab’s injection system. The PXIE Ion Source and Low-Energy Beam Transport (LEBT) section are designed to create and transfer a 1–10 mA H⁻ beam, in either pulsed (0.001–16 ms) or DC mode, from the ion source through to the injection point of the RFQ. This paper discusses the range of diagnostic tools Allison-type Emittance Scanner, Faraday Cup, Toroid, DCCT, electrically isolated diaphragms – involved in the commissioning of the beamline and preparation of the beam for injection into the RFQ.

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MOPWI002

Bunch Length Measurements using Synchrotron Light Monitor

linac, 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, linac, detector, 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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MOPWI005

Emittance and Optics Measurements on the Versatile Electron Linear Accelerator at Daresbury Laboratory

space-charge, quadrupole, gun, coupling

1153

C.P. Topping, D.J. Scott, A. Wolski
Cockcroft Institute, Warrington, Cheshire, United Kingdom
S.D. Barrett, C.P. Topping, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
B.L. Militsyn, D.J. Scott
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The Versatile Electron Linear Accelerator (VELA) is a facility designed to provide a high quality electron beam for accelerator systems development, as well as industrial and scientific applications. Currently, the RF gun can deliver short (of order a few ps) bunches with charge in excess of 250 pC at up to 5.0 MeV/c beam momentum. Measurement of the beam emittance and optics in the section immediately following the gun is a key step in tuning both the gun and the downstream beamlines for optimum beam quality. We report the results of measurements (taking account of coupling and space charge) indicating normalised emittances of order 0.5 μm at low bunch charge.

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MOPWI030

Low Emittance Tuning With a Witness Bunch

betatron, lattice, storage-ring, coupling

1223

D. L. Rubin, R.E. Meller, J.P. Shanks
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by NSF PHY-1416318, PHY-0734867 and PHY-1002467, and DOE DE-FC02-08ER- 41538 and DE-SC0006505
Electron positron damping rings and colliders will require frequent tuning to maintain ultra-low vertical emittance. Emittance tuning begins with precision beam based measurement of lattice errors (orbit, transverse coupling, and dispersion) followed by compensation with corrector magnets. Traditional techniques for measuring lattice errors are incompatible with simultaneous operation of the storage ring as light source or damping ring. Dedicated machine time is required. The gated tune tracker (the device that drives the beam at the normal mode frequencies) and the bunch-by-bunch, turn-by-turn beam position monitor system developed at CESR are integrated to allow synchronous detection of phase. The system is capable of measuring lattice errors during routine operation. A single bunch at the end of a train of arbitrary length, is designated as the witness. The witness bunch alone is resonantly excited, and the phase and amplitude of the witness is mea- sured at each of the 100 beam position monitors. Lattice errors are extracted from the measurements. Corrections are then applied. The emittance of all of the bunches in the train is measured and the effectiveness of the correction procedure demonstrated.

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MOPWI033

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

linac, operation, 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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TUXB2

Upgrade of the Unilac for Fair

DTL, proton, linac, ion

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

positron, electron, gun, linac

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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TUXC2

Engineering Challenges of Future Light Sources

storage-ring, vacuum, feedback, synchrotron

1308

R.T. Neuenschwander, L. Liu, S.R. Marques, A.R.D. Rodrigues, R.M. Seraphim
LNLS, Campinas, Brazil

We review some of the present engineering challenges associated with the design and construction of ultra-low emittance storage rings, the 4th generation storage rings (4GSR). The field is experiencing a growing interest since MAX-IV, followed by Sirius, started to build storage rings based on multi-bend-achromat (MBA) lattices. It was the recent progress in accelerator technology that allowed these facilities to base their designs on this kind of lattice. Although the challenges are starting to be overcome, many issues are still open and a lot of R&D is required until the 4GSR achieve optimal performance.

Slides TUXC2 [7.022 MB]

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TUXC3

Commissioning of the Taiwan Photon Source

booster, storage-ring, quadrupole, synchrotron

1314

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

The Taiwan Photon Source (TPS) is a 3-GeV third-generation synchrotron light source located in Hsinchu, Taiwan. After ground breaking on February 7, 2010 and five years of construction and hardware developments, commissioning of the beam began on December 12, 2014. The booster ring reached the design energy of 3 GeV on December 16. Beam transferred to the storage ring and first accumulation at 3 GeV produced the first synchrotron light on December 31. This report presents results and experience of the TPS commissioning.

Slides TUXC3 [5.425 MB]

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TUAB3

Chromaticity Effects for Space Charge Dominated Beams in the CERN PS Booster

space-charge, resonance, simulation, sextupole

1335

V. Forte
Université Blaise Pascal, Clermont-Ferrand, France
E. Benedetto, F. Schmidt
CERN, Geneva, Switzerland

In view of the LHC Injectors Upgrade (LIU) project, an extensive campaign is on-going in the CERN PS Booster (PSB) to study collective effects for the future operation with the 160 MeV injection from Linac4. In operation, the machine is running with uncorrected natural chromaticity. This paper focuses on the study of the effects of chromaticity on losses and beam blow-up.

Slides TUAB3 [4.887 MB]

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TUBD1

Optics Measurement and Correction during Acceleration with Beta-squeeze in RHIC

optics, acceleration, quadrupole, injection

1380

C. Liu, A. Marusic, M.G. Minty
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 past, beam optics correction at RHIC has only taken place at injection and at final energy, with interpolation of corrections partially into the acceleration cycle. Recent measurements of the beam optics during acceleration and squeeze have evidenced significant beta-beats that, if corrected, could minimize undesirable emittance dilutions and maximize the spin polarization of polarized proton beams by avoiding the high-order multipole fields sampled by particles within the bunch. We recently demonstrated successfully beam optics corrections during acceleration at RHIC. We verified conclusively the superior control of the beam realized via these corrections. As a valuable by-product, these corrections have minimized the beta-beat at the profile monitors, so providing more precise measurements of the evolution of the beam emittances during acceleration.

Slides TUBD1 [1.581 MB]

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TUBD2

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

collider, luminosity, solenoid, linac

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, linac, 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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TUPWA007

UPGRADED OPTICS FOR SIRIUS WITH IMPROVED MATCHING OF ELECTRON AND PHOTON BEAM EMITTANCES

photon, optics, quadrupole, brightness

1407

L. Liu, N. Milas, A.H.C. Mukai, X.R. Resende, F. H. de Sá
LNLS, Campinas, Brazil

A new optics has been designed for Sirius with improved betatron function matching in the 6 meter-long low beta straight sections for insertion devices. Both horizontal and vertical betatron functions are set to 1.5 m in the center of the section, improving the matching of the electron and undulator photon beams. In addition, the horizontal beam stay clear has also been reduced allowing for small horizontal gap devices as well as the conventional small vertical gap ones. The new design optics has been optimized to the same previous performance regarding dynamic aperture and momentum acceptance.

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TUPWA030

Compression of an Electron-bunch by Means of Velocity Bunching at ARES

bunching, electron, simulation, plasma

1472

B. Marchetti, R.W. Aßmann, U. Dorda, J. Grebenyuk, J. Zhu
DESY, Hamburg, Germany

ARES is a planned linear accelerator for research and development in the field of production of ultra-short electron bunches. The goal of ARES is to produce low charge (0.2-50pC), ultra-short (from few fs to sub-fs) bunches, with improved arrival time stability (less than 10fs) for various applications, such as external injection for Laser Plasma Wake-Field acceleration. The ARES layout will allow to perform and compare different kind of conventional e-bunch compression techniques, such as pure velocity bunching*, hybrid velocity bunching (i.e. velocity bunching plus magnetic compression) and pure magnetic compression with the slit insertion**. This flexibility will allow to directly compare the different methods in terms of arrival time stability and local peak current. In this paper we present simulation results for the compression of an electron bunch with 0.5 pC charge. We compare the case of pure velocity bunching compression to the one of a hybrid compression using velocity bunching plus a magnetic compressor.
* M. Ferrario et al., Phys. Rev. Lett. 104, 054801 (2010).
** P. Emma et al., PRL 92 7 (2004).

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TUPWA034

Status of the Recommissioning of the Synchrotron Light Source PETRA III

synchrotron, lattice, operation, optics

1485

R. Wanzenberg, M. Bieler, M. Ebert, L. Fröhlich, J. Keil, J. Klute, G. Kube, G.K. Sahoo
DESY, Hamburg, Germany

At DESY the Synchrotron Light Source PETRA III has been extended in the North and East section of the storage ring to accommodate ten additional beam lines. The PETRA ring was converted into a dedicated synchrotron light source from 2007 to 2009. Regular user operation started in summer 2010 with a very low emittance of 1 nm at a beam energy of 6 GeV and a total beam current of 100 mA. All photon beamlines were installed in one octant of the storage ring. Nine straight sections facilitated the installation of insertion devices for 14 beam lines. Due to the high demand for additional beamlines the lattice of the ring was redesigned to accommodate 10 additional beamlines in the future. In a one year long shut-down two new experimental halls were built. The recommissioning of PETRA III started in February 2015. We are reporting the current status of synchrotron light source including the performance of the subsystems.

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TUPWA036

Possibility of Longitudinal Bunch Compression in Petra III

optics, FEL, undulator, storage-ring

1492

I.V. Agapov
XFEL. EU, Hamburg, Germany
S.I. Tomin
NRC, Moscow, Russia
R. Wanzenberg
DESY, Hamburg, Germany

A scheme of short bunch production in storage rings using a longitudinally focusing insertion was presented in *. In this work we study the possibility of integrating such insertion into the PetraIII storage ring. In particular, we discuss possible optics solutions to integrate RF stations, chicane-type delay sections, and the undulators into existing ring geometry.
* I. Agapov and G. Geloni, proc. FEL 2014.

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TUPWA044

Test electron source for increased brightness emission by near band gap photoemission

cathode, electron, vacuum, simulation

1512

S. Friederich, K. Aulenbacher
IKP, Mainz, Germany

Funding: Bundesministerium für Bildung und Forschung/Federal Ministry of Education and Research; Joint project HOPE
A new photoemissive electron source is being built in order to make use of the reduction of ensemble temperature in near band gap photoemission. It will operate at up to 200 kV bias voltage with NEA GaAs photocathodes. High bunch charges will be investigated in pulsed mode with respect to the conservation of emittances at low energy excitations. High field gradients at the cathode surface will also allow further investigation of the field emission process of these photocathodes.

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TUPWA047

First Results Attained With the Quasi 3-D Ellipsoidal Photo Cathode Laser Pulse System at the High Brightness Photo Injector PITZ

laser, electron, cathode, simulation

1522

T. Rublack, J.D. Good, M. Khojoyan, M. Krasilnikov, F. Stephan
DESY Zeuthen, Zeuthen, Germany
A.V. Andrianov, E. Gacheva, E. Khazanov, S. Mironov, A. Poteomkin, V. Zelenogorsky
IAP/RAS, Nizhny Novgorod, Russia
I. Hartl, S. Schreiber
DESY, Hamburg, Germany
E. Syresin
JINR, Dubna, Moscow Region, Russia

Funding: Funded by the German Federal Ministry of Education and Research (BMBF) project 05K10CHE in the framework of the German-Russian collaboration "Development and Use of Accelerator-Based Photon Sources".
3-D ellipsoidal photo cathode laser pulses are considered as the next step in optimization of photo injectors required for a successful operation of linac based free electron lasers. Beam dynamics simulations using such laser pulses compared to conventional cylindrical pulses have shown a significant improvement in electron beam emittance. In collaboration with the Institute of Applied Physics (Nizhny Novgorod, Russia) and the Joint Institute of Nuclear Research (Dubna, Russia) such a 3-D ellipsoidal laser pulse system has been developed and afterwards installed at the Photo Injector Test facility at DESY, Zeuthen site (PITZ). The pulse shaping is realized using the spatial light modulator technique. This allows very fine amplitude modulation within a laser pulse. The characterization of the shape of the laser pulses can be done by cross-correlation measurements. Using this method the ability to generate and measure quasi ellipsoidal laser pulses has been demonstrated. In this contribution the overall set-up, working principle and first results received with the new photo cathode laser system at PITZ will be reported.

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TUPWA051

Elettra Status and Future Prospects

operation, wiggler, insertion, insertion-device

1529

E. Karantzoulis, A. Carniel, S. Krecic
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The operational status of the Italian 2.4/2.0 GeV third generation light source Elettra is presented together with possible future upgrades and a vision to its future.

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TUPWA052

Elettra 2.0 - The Next Machine

dipole, lattice, quadrupole, dynamic-aperture

1532

E. Karantzoulis
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

A next generation light source (ULS) to replace Elettra, the third generation Italian light source, is presented and discussed

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TUPWA055

DAΦNE Gamma-Ray Factory

electron, laser, photon, factory

1542

D. Alesini, S. Guiducci, C. Milardi, A. Variola, M. Zobov
INFN/LNF, Frascati (Roma), Italy
I. Chaikovska, Z.F. Zomer
LAL, Orsay, France

Gamma sources with high flux and spectral densities are the main requirements for new nuclear physics experiments to be performed in several worldwide laboratories with dedicated facilities. The presentation is focalized on a proposal of experiment of gamma photons production using Compton collisions between the DAΦNE electron beam and a high average power laser pulse, amplified in a Fabry-Pérot optical resonator. The calculations show that the resulting gamma beam source has extremely interesting properties in terms of spectral density, energy spread and gamma flux comparable (and even better) with the last generation gamma sources. The energy of the gamma beam depends on the adopted laser wavelength and can be tuned changing the energy of the electron ring. In particular we have analyzed the case of a gamma factory tunable in the 2-9 MeV range. The main parameters of this new facility are presented and the perturbation on the transverse and longitudinal electron beam dynamics is discussed. A preliminary accelerator layout to allow experiments with the gamma beam is presented with a first design of the accelerator optics.

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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, linac, experiment

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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TUPWA060

Design of Diffraction Limited Light Source Ring with Multi-bend Lattice on a Torus-knot

lattice, quadrupole, dynamic-aperture, alignment

1560

A. Miyamoto, S. Sasaki
HSRC, Higashi-Hiroshima, Japan

We proposed a torus knot type synchrotron radiation ring in that the beam orbit does not close in one turn but closes after multiple turns around the ring. Currently, we are designing a new ring based on the shape of a (11, 3) torus knot for our future plan ‘HiSOR-II.’ This ring is mid-low energy light source ring with beam energy of 700 MeV. Recently some light source rings are achieving very low emittance that reaches a diffraction limited light by adopting a multi-bend scheme to the arc section of the ring. It is not difficult for low-mid energy VUV-SX light source ring because the electron beam less than 10 nmrad can provide the diffraction limited light in the energy less than 10eV. On the other hand, the multi-bend lattice demands many families of the magnets and spaces to place them, therefore it is difficult to achieve diffraction limited emittance for compact SR ring. However, for the torus-knot type accumulation ring, it is not difficult to realize such a low emittance. We present the details of the designing procedure and the specifications of the ultra-low emittance light source ring having innovatively odd shape.

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TUPWA061

Analyses of Light's Orbital Angular Momentum from Helical Undulator Harmonics

radiation, undulator, polarization, photon

1563

S. Sasaki, A. Miyamoto
HSRC, Higashi-Hiroshima, Japan
M. Hosaka, N. Yamamoto
Nagoya University, Nagoya, Japan
M. Katoh, T. Konomi
UVSOR, Okazaki, Japan

Funding: Partially supported by the Grant-in-Aid for Scientific Research, Japan Society for the Promotion of Science, and supported by the Joint Studies Program of the Institute for Molecular Science.
The phenomenon of higher harmonic radiation from a helical undulator carrying orbital angular momentum (OAM)* attracts a great deal of attention because this novel property may be used as a new probe for synchrotron radiation science** that would be performed in a diffraction limited light source facility such as the APS-II. Although a diffraction limited x-ray source does not yet exist, the 750 MeV UVSOR-III is already a diffraction limited light source in the UV region. In this ring, a tandem-aligned double-APPLE undulator system similar to that in BESSY-II*** is installed for FEL and coherent light source experiments. Using this set-up, we observed spiral interference patterns between two different harmonic radiations with a scanning fiber multi-channel spectrometer and a CCD camera placed at the end of BL1U Beamline. By these measurements, various interference patterns such as single, double, and triple spirals were observed which concur with the theoretical prediction for every mode in the right or left circular polarization. The rotation of an interference pattern by rotating a polarizer was also observed.
* S. Sasaki and I. McNulty, Phys. Rev. Lett. 100, 124801, 2008.
** M. VanVeenendaal and I. McNulty, Phys. Rev. Lett. 98, 157401 (2007).
*** J. Bahrdt, et al., Phys. Rev. Lett. 111, 034801, 2013.

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TUPWA064

Study of Inherent Potential for Emittance Reduction at the SPring-8 Storage Ring

optics, brilliance, storage-ring, photon

1573

Y. Shimosaki
JASRI/SPring-8, Hyogo-ken, Japan

A design study for an upgrade project of the SPring-8, the SPring-8-II, is in progress, which is a full-scale major lattice modification. Besides the design study for the SPring-8-II, an inherent potential of achieving much higher brilliance than that of the present SPring-8 has been explored for the general evaluation. In this paper, the evaluation of the inherent potential for the SPring-8, not for the SPring-8-II, in terms of increasing the brilliance is discussed.

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TUPWA067

Status of Higher Bunch Charge Operation in Compact ERL

operation, optics, space-charge, recirculation

1583

T. Miyajima, K. Harada, Y. Honda, T. Miura, N. Nakamura, T. Obina, F. Qiu, H. Sakai, S. Sakanaka, M. Shimada, R. Takai, K. Umemori, M. Yamamoto
KEK, Ibaraki, Japan
R. Hajima, R. Nagai, N. Nishimori
JAEA, Ibaraki-ken, Japan
D. Lee
KNU, Deagu, Republic of Korea

In the KEK compact ERL (cERL), machine studies toward higher bunch charge operation is one of the most important issues. From January 2015 to April 2015, we carried out a higher bunch charge operation with an bunch charge of 0.5 pC for the experiment of laser compton scattering. After the study of space charge effect and optics tuning, we succeeded in the recirculation operation with the emittance, which was close to the design value. Moreover, a test operation in the injector section with the bunch charge of 7.7 pC was carried out as a preparation toward the recirculation operation with the average current of 10 mA.

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TUPWA069

Simulation Study on Bunch Compression and Decompression for the Compact ERL

sextupole, simulation, linac, optics

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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TUPJE001

Design of Wavelength Tunable Coherent X-Ray Source

electron, radiation, target, optics

1604

J. Hyun
Sokendai, Ibaraki, Japan
K. Endo
TOYAMA Co., Ltd., Zama-shi, Kanagawa, Japan
K. Hayakawa, Y. Hayakawa, T. Sakai, T. Tanaka
LEBRA, Funabashi, Japan
I. Sato
Nihon University, Advanced Research Institute for the Sciences and Humanities, Funabashi, Japan
M. Satoh, M. Yoshida
KEK, Ibaraki, Japan

KEK, Nihon University and TOYAMA CO., Ltd. have been developing the compact shieldless coherent X-ray source that can change the X-ray energy (3-25keV). This X-ray is the Parametric X-ray radiation (PXR) generated by relativistic charged particles passed through a single crystal. It has features that are monochromaticity, coherence and diffraction large angle for the incident beam. These indicate to the possibility for the application to the medical treatment and diagnosis. Furthermore, we try to reduce the radiation which is mainly generated when the high energy beam is damped. This system consists of an accelerating, a decelerating structure and four bending magnets (theta: 90 degree). These structures are operated under low temperature to get the high Q-value for long beam pulse. PXR is generated by colliding with a single crystal after electron beam is accelerated up to 75 MeV. The bunch passed through the crystal is transported into a decelerator structure and then is decelerated to 3 MeV there. Q-magnets are arranged that dispersion function is zero except arc sections. We calculated the beam transport, PXR intensity and emittance blow up. We'll report these details.

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TUPJE003

Quasi-Traveling Wave RF Gun and Beam Commissioning for SuperKEKB

gun, laser, cathode, cavity

1610

T. Natsui
The University of Tokyo, Nuclear Professional School, Ibaraki-ken, Japan
Y. Ogawa, M. Yoshida, X. Zhou
KEK, Ibaraki, Japan

We are developing a new RF gun for SuperKEKB. High charge low emittance electron and positron beams are required for SuperKEKB. We will generate 7.0 GeV electron beam at 5 nC 20 mm-mrad by J-linac. In this linac, a photo cathode S-band RF gun will be used as the electron beam source. For this reason, we are developing an advanced RF gun which has two side coupled standing wave field. We call it quasi-traveling wave side couple RF gun. This gun has a strong focusing field at the cathode and the acceleration field distribution also has a focusing effect. This RF gun has been installed in the KEK J-linac. Beam commissioning with the RF gun is in progress.

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TUPJE018

On-axis Injection Scheme for Ultimate Storage Ring with Double RF Systems

injection, synchrotron, storage-ring, radiation

1657

B.C. Jiang, S.Q. Tian, M.Z. Zhang, Q.L. Zhang, Z.T. Zhentang
SINAP, Shanghai, People's Republic of China

An on-axis injection scheme using double RF systems for an ultimate storage ring which holds very small dynamic aperture is proposed. By altering RF voltages, empty RF buckets can be created which will be used for on-axis injection. After bunches are injected, a reverse voltage altering process is performed and the injected bunches can be longitudinally dumped to the main buckets.

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TUPJE023

Consideration on the Future Major Upgrades of the SSRF Storage Ring

storage-ring, injection, cavity, optics

1672

Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, M.Z. Zhang
SINAP, Shanghai, People's Republic of China

The SSRF storage ring was in operation from 2008, currently it is operating at the energy of 3.5GeV, the natural emittance of 3.9 nm-rad and the beam current of 240 mA, serving for 13 beamlines with 9 IDs. There will be around 40 operated beamlines around 2020, which need some upgrade of the storage ring existing performance, such as the new lattice with superbends. And looking for the future beyond, the major upgrade towards a diffraction limited storage ring is under consideration. This paper presents the initial investigation and the proposal on the ultimate storage ring upgrade for SSRF.

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TUPJE045

Round Beam Operation in Electron Storage Rings and generalisation of Mobius accelerator

quadrupole, insertion, injection, lattice

1716

M. Aiba, M.P. Ehrlichman, A. Streun
PSI, Villigen PSI, Switzerland

A better performing photon beam can be obtained from light sources when the eletron beam is formed into a "round beam" rather than a flat beam. It is realised by equally distributing the natural emittance into the horizontal and vertical planes. There are a few approaches for the emittance distribution, and we explored the so-called Mobius accelerator scheme, where a transverse (horizontal-vertical) emittance exchange results at each turn of beam revolution. The original proposal of Mobius accelerator was based on a set of five succesive skew quadruples, requiring a dedicated long straight section. We generalise the Mobius accelerator section to find more convenient configurations. Applications to a light source storage ring lattice and some tracking results are also presented.

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TUPJE047

Design Studies for an Upgrade of the SLS Storage Ring

lattice, storage-ring, radiation, operation

1724

A. Streun, M. Aiba, M. Böge, M.P. Ehrlichman, A. Saá Hernández
PSI, Villigen PSI, Switzerland

An upgrade of the Swiss Light Source (SLS) would replace the existing storage ring by a low aperture multibend achromat lattice providing an emittance of about 100–200 pm at 2.4 GeV, while maintaining the hall, the beam lines and the injector. Since emittance scales inversely cubically with the number of lattice cells, an SLS upgrade is challenged by the comparatively small ring circumference of only 288 m. A new concept for a compact low emittance lattice is based on longitudinal gradient bending magnets for emittance minimization and on anti-bends (i.e bends of opposite field polarity) to disentangle dispersion and horizontal beta function in order to provide the optimum matching to the longitudinal gradient bends while minimizing the contribution to chromaticity.

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TUPJE048

Orbit Correction and Stability Studies for Ultra-Low Emittance Storage Rings

photon, simulation, dipole, storage-ring

1728

M. Böge, M. Aiba, A. Streun
PSI, Villigen PSI, Switzerland

Ultra-low emittance storage rings exhibit extremely strong focusing and sextupolar chromaticity corrections. The therefore mandatory excellent centering of the closed orbit in the small aperture magnets is a challenging task and necessitates a proper beam diagnostics and correction layout. Correction and stability studies for a possible ultra-low emittance upgrade of the Swiss Light Source are presented.

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TUPJE059

Modeling of an Electron Injector for the AWAKE Project

space-charge, booster, quadrupole, linac

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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TUPJE062

First Transparent Realignment Tests at the Diamond Storage Ring

controls, alignment, survey, storage-ring

1772

M. Apollonio, R. Bartolini, P. Dudin, M. Hoesch, W.J. Hoffman, E.C. Longhi, A.J. Rose, A. Thomson
DLS, Oxfordshire, United Kingdom
R. Bartolini
JAI, Oxford, United Kingdom

The Transparent Realignment of the Diamond Storage Ring is a program of work to improve the mechanical alignment of the machine by carefully moving the magnet girders with a virtually zero impact on the associated beamlines. The girders can be moved by means of a 5-axis motion system under remote control via the EPICS toolkit from the Diamond Control Room. Currently three cells (three girders in each) have been equipped with a permanent protection system to prevent excessive deflection across each of the inter-girder vacuum bellows. The protection and motion systems are installed in the associated Control and Instrumentation Area (CIA). Full commissioning of the motion and protection systems have been completed. Results from the alignment test sessions are hereby reported.

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TUPJE063

Hybrid Seven-Bend-Achromat Lattice for the Advanced Photon Source Upgrade

lattice, multipole, injection, sextupole

1776

M. Borland, V. Sajaev, Y. Sun
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A hybrid seven-bend-achromat lattice has been designed for the APS upgrade. We describe the design goals, constraints, and methodology, including the choice of beam energy. Magnet strength and spacing is compatible with engineering designs for the magnets, diagnostics, and vacuum system. Dynamic acceptance and local momentum acceptance were simulated using realistic errors, then used to assess workable injection methods and predict beam lifetime. Predicted brightness is two to three orders of magnitude higher than the existing APS storage ring. Pointers are provided to other papers in this conference that cover subjects in more detail.

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TUPJE067

Status of the APS Upgrade Project

brightness, photon, lattice, dipole

1791

S. Henderson
ANL, Argonne, Ilinois, USA

Funding: Work supported by U.S. Dept. of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
A concept for an upgrade to the Advanced Photon Source based on a multi-bend achromat lattice is being developed at Argonne National Laboratory. An MBA upgrade to the APS will reduce the horizontal emittance by a factor of ~50. Coupled with superconducting undulators, the APS-U brightness will be two to three orders of magnitude beyond that which is available today at the APS.

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TUPJE070

Preliminary Experimental Investigation of Quasi Achromat Scheme at Advanced Photon Source

lattice, resonance, operation, optics

1800

Y. Sun, H. Shang
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357.
Next generation storage rings require weaker dipole magnets and stronger quadrupole focusing to achieve very low emittance. To suppress the geometric and chromatic optics aberrations introduced by the strong sextupoles, achromat and quasi achromat schemes are applied in the lattice design to improve the beam dynamics performance. In this paper, some preliminary experimental investigation of the quasi achromat scheme at the Advanced Photon Source (APS) are presented. Three different operation lattices are compared on their beam dynamics performance. Although none of these operation lattices achieve ideal quasi achromat condition, they have certain relevant features. It is observed that fewer resonances are present in the nominal operation lattice which is most close to quasi achromat required conditions.

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TUPJE074

LCLS Injector Laser Modulation to Improve FEL Operation Efficiency and Performance

laser, electron, optics, FEL

1813

S. Li, D.K. Bohler, W.J. Corbett, A.S. Fisher, S. Gilevich, Z. Huang, A. Li, D.F. Ratner, J. Robinson, F. Zhou
SLAC, Menlo Park, California, USA
R.B. Fiorito, E.J. Montgomery
UMD, College Park, Maryland, USA
H.D. Zhang
Cockcroft Institute, Warrington, Cheshire, United Kingdom
H.D. Zhang
The University of Liverpool, Liverpool, United Kingdom

In the Linear Coherent Light Source (LCLS) at SLAC, the injector laser plays an important role as the source of the electron beam for the Free Electron Laser (FEL). The injector laser strikes a copper photocathode which emits photo-electrons due to photo-electric effect. The emittance of the electron beam is highly related to the transverse shape of the injector laser. Currently the LCLS injector laser has hot spots that degrade the FEL performance. The goal of this project is to use adaptive optics to modulate the transverse shape of the injector laser, in order to produce a desired shape of electron beam. With a more controllable electron transverse profile, we can achieve lower emittance for the FEL, improve the FEL performance and operation reliability. We first present various options for adaptive optics and damage test results. Then we will discuss the shaping process with an iterative algorithm to achieve the desired shape, characterized by Zernike polynomial deconstruction.

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TUPJE075

Simulation Study of Injection Performance for the Advanced Photon Source Upgrade

injection, simulation, storage-ring, kicker

1816

A. Xiao, V. Sajaev
ANL, Argonne, Ilinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
A vertical on-axis injection scheme has been proposed for the hybrid seven-bend-achromat (H7BA) Advanced Photon Source upgrade (APSU) lattice. In order to evaluate the injection performance, various errors, such as injection beam jitter, optical mismatch and errors, and injection element errors have been investigated and their significance has been discovered. Injection efficiency is then simulated under different error levels. Based on these simulation results, specifications and an error-budget for individual systems have been defined.

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TUPMA004

Synthesis of Ultra-Thin Single Crystal MgO/Ag/MgO Multilayer for Controlled Photocathode Emissive Properties

electron, cathode, laser, simulation

1846

D.G. Velázquez, R.L. Seibert, L.K. Spentzouris, J. Terry, Z.M. Yusof
Illinois Institute of Technology, Chicago, Illinois, USA

Photocathode emission properties are critical for electron beam applications such as photoinjectors for free electron lasers (FEL) and energy recovery Linacs (ERL). We investigate whether emission properties of photocathodes can be manipulated through the engineering of the surface electronic structure. The multilayers described here have been predicted to have emission properties in correlation with the film thickness. This paper describes how ultra-thin multilayered MgO/Ag/MgO films in the crystallographic orientations (001) and (111) multilayers were synthesized and characterized. Preliminary results of work function measurements are provided. Films were grown by pulsed laser deposition at 130 °C for the (001) orientation and 210 °C for the (111) orientation at a background pressure of ~ 5×10^-9 Torr. Epitaxial growth was monitored in-situ using reflection high-energy electron diffraction, which showed single crystal island growth for each stage of the multilayer formation. Photoelectron spectroscopy was used to track the chemical state transition from Ag to MgO during the deposition of successive layers. The Kelvin probe technique was used to measure the change in contact potential difference, and thus work function, for various MgO layer thicknesses in comparison with bare single crystal Ag(001)and Ag(111) thin films. The work function was observed to reduce with increasing thickness of MgO from 0 to 4 monolayers as much as 0.89 eV and 0.72 eV for the (001) and (111) orientations, respectively. Photoelectron spectra near the Fermi level revealed electron density shifts toward zero binding energy for the multilayered surfaces with respect to the clean Ag surfaces.

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TUPMA010

Development of a Field-Emission Type S-band RF-Gun System for High Brightness Electron Source Applications

cathode, gun, electron, vacuum

1856

Y.-M. Shin
Northern Illinois University, DeKalb, Illinois, USA
N. Barov
Far-Tech, Inc., San Diego, California, USA
A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA

Electron beams emitted from a cold cathode are thermally stable and mono-energetic with a small phase-space volume*. We have been developing a field-emission type RF-gun system for high brightness electron source applications, including electron scattering/diffraction and tunable coherent X-ray/THz generation. The system consists of a single-gap gun-cavity and an S-band klystron/modulator capable of powering the gun with up to 5.5 MW peak (PRR = 1 Hz, duration = 2.5 μs). The designed gun built with the symmetrised side-couplers has surface field on the cathode ranging 50 – 100 MV/m with 1.3 – 1.7 MW klystron-power and 1.2 field ratio (HFSS). ASTRA simulations also indicate that the gun produces the beam with transverse emittances of less than 1 mm-mrad with 10 – 20 pC bunch charge at 500 keV beam energy. Under the gun operating condition, particle tracking/PIC simulations (CST) show that a single-tip CNT field-emitter** produces short pulsed bunches (~ 1/10 RF-cycle) with small emittance ( 0.01 mm-mrad) and high peak current density ( 10,000 kA/cm²). After the gun is fully installed and commissioned, a CNT-tip cathode will be tested with RF-field emission.
* N. De Jonge, J.-M. Bonard, Phil. Trans. R. Soc. Lond. A 362, 2239 (2004)
** G. S. Bocharov, and A. V. Eletskii, Nanomaterials 3, 393 (2013)

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TUPMA022

CESR Upgrade as a High-Energy, High-Brightness X-Ray Light Source

positron, electron, lattice, storage-ring

1884

J.P. Shanks, D. L. Rubin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Research supported by NSF grant DMR-1332208.
The Cornell Electron Storage Ring (CESR) operates most of the year as the Cornell High Energy Synchrotron Source (CHESS). CESR was originally designed and operated as an electron/positron collider, circulating high-emittance beams in order to maximize luminosity. Beam lines were developed to extract x-rays from both electron and positron beams. The two beams share a common vacuum chamber, and are electrostatically separated to avoid collisions. The requirement to store counter-rotating beams significantly constrains the storage ring optics, limiting emittance and, beam current, and bunch distributions. The proposed upgrade eliminates two-beam operation in favor of a single optimized on-axis beam. Several new undulator-based beam lines are planned. The horizontal emittance is reduced in steps, first from 90nm to 20nm at 5.3 GeV, and then in a ring-wide upgrade to as low as 300 pm-rad at 6GeV. The low-emittance optics are based on multi-bend achromats with combined function bends. The details of the optics, apertures, and magnet parameters are presented.

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TUPMA025

X-Band RF Photoinjector for Laser Compton X-Ray and Gamma-Ray Sources

laser, electron, dipole, gun

1891

R.A. Marsh, G.G. Anderson, S.G. Anderson, C.P.J. Barty, D.J. Gibson
LLNL, Livermore, California, USA

Funding: This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
Extremely bright narrow bandwidth gamma-ray sources are expanding the application of accelerator technology and light sources in new directions. An X-band test station has been commissioned at LLNL to develop multi-bunch electron beams. This multi-bunch mode will have stringent requirements for the electron bunch properties including low emittance and energy spread, but across multiple bunches. The test station is a unique facility featuring a 200 MV/m 5.59 cell X-band photogun powered by a SLAC XL4 klystron driven by a Scandinova solid-state modulator. This paper focuses on its current status including the generation and initial characterization of first electron beam. Design and installation of the inverse-Compton scattering interaction region and upgrade paths will be discussed along with future applications.

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TUPMA026

Status of the MaRIE X-FEL Accelerator Design

linac, 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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TUPMA034

Control of Synchrotron Radiation Effects During Recirculation with Bunch Compression

controls, recirculation, lattice, simulation

1910

D. Douglas, S.V. Benson, R. Li, C. Tennant
JLab, Newport News, Virginia, USA
G.A. Krafft, B. Terzić
ODU, Norfolk, Virginia, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Studies of beam quality preservation during recirculation * have been extended to generate a design of a compact arc providing bunch compression with positive momentum compaction ** and control of both incoherent and coherent synchrotron radiation (ISR and CSR) effects using the optics balance methods of diMitri et al.***. In addition, the arc/compressor generates very little micro-bunching gain. We detail the beam dynamical basis for the design, discuss the design process, give an example solution, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of micro-bunching effects ****.
* D. Douglas et al., these proceedings
** S. Benson et al., these proceedings
*** S. diMitri et al., Phys. Rev. Lett. 110, 014801, 2 January 2013
**** C.Y. Tsai et al., these proceedings

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TUPMA035

Control of Synchrotron Radiation Effects during Recirculation

controls, recirculation, lattice, synchrotron

1913

D. Douglas, S.V. Benson, A.S. Hofler, R. Kazimi, R. Li, Y. Roblin, C. Tennant
JLab, Newport News, Virginia, USA
G.A. Krafft, B. Terzić
ODU, Norfolk, Virginia, USA
C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
Numerous proposals invoke recirculation and/or energy recovery for cost-performance optimization. These often encounter challenges with the beam-quality-degrading effects of incoherent and coherent synchrotron radiation (ISR and CSR). We describe a means of controlling of this degradation. The approach utilizes results by diMitri et al. *, and invokes behavior observed during simulations of the recirculation process. The method is based on the use of periodically isochronous 2nd-order achromats; this not only insures that the conditions for the suppression of CSR-driven emittance growth are met*, it also suppresses micro-bunching gain over a broad range of parameter space **. Details of specific designs will be presented, and a reference to an analysis of micro-bunching effects ** provided. A planned test of the CSR suppression mechanism in CEBAF will be described.
*S. diMitri et al., Phys. Rev. Lett. 110, 014801, 2 January 2013.
**C.Y. Tsai et al., these proceedings.

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TUPMA041

On the Characterization of a CCR Source

brightness, radiation, FEL, impedance

1926

A.V. Smirnov
RadiaBeam, Santa Monica, California, USA

Funding: US Department of Energy, contract # DE- SC-FOA-0000760
Peak and spectral brightness of a resonant long-range wakefield extractor are evaluated. It is shown that the brightness is dominated by beam density within the slow wave structure and antenna gain of the outcoupling. Far field radiation patterns and brightness of circular and high-aspect-ratio planar radiators are compared. A possibility to approach the diffraction limited brightness is demonstrated. Role of group velocity in designing of the Cherenkov source is emphasized. The approach can be applied for design and characterization of various structure-dominated sources (e.g., wakefield extractors with gratings or dielectrics, or FEL-Cherenkov combined sources) radiating into a free space using an antenna (from microwave to far infra-red regions). The high group velocity structures can be also effective as energy dechirpers and for diagnostics of microbunched relativistic electron beams.

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TUPMA043

Experimental Test of Semiconductor Dechirper

electron, wakefield, FEL, experiment

1932

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia
M.G. Fedurin, K. Kusche, C. Swinson
BNL, Upton, Long Island, New York, USA
W. Gai, S. Stoupin, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0006299
We report the observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 4 inch long rectangular waveguide loaded with two silicon bars 0.25 inch thick and 0.5 inch wide. Silicon being a semiconductor has a conductivity that allows it to drain the charge fast in case if some electrons get intercepted by the dechirper. At the same time the conductivity is low enough for the skin depth to be large (on the order of 1 cm) making the silicon loaded waveguide a slow wave structure supporting wakefields that dechirp the beam.

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TUPHA003

Sputter Growth of Alkali Antimonide Photocathodes: An in Operando Materials Analysis

cathode, target, gun, radiation

1965

J. Smedley, K. Attenkofer, M. Gaowei, J. Sinsheimer, J. Walsh
BNL, Upton, Long Island, New York, USA
H. Bhandari
Radiation Monitoring Devices, Watertown, USA
Z. Ding, E.M. Muller
SBU, Stony Brook, New York, USA
H.J. Frisch
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
H.A. Padmore, S.G. Schubert, J.J. Wong
LBNL, Berkeley, California, USA

Funding: Work supported by U.S. DoE, under KC0407-ALSJNT-I0013 and SBIR grant # DE-SC0009540. NSLS was supported by DOE DE-AC02-98CH10886, CHESS is supported by NSF & NIH/NIGMS via NSF DMR-1332208
Alkali antimonide photocathodes are a strong contender for the cathode of choice for next-generation photon sources such as LCLS II or the XFEL. These materials have already found extensive use in photodetectors and image intensifiers. However, only recently have modern synchrotron techniques enabled a systematic study of the formation chemistry of these materials. Such analysis has led to the understanding that these materials are inherently rough when grown through traditional sequential deposition; this roughness has a detrimental impact on the intrinsic emittance of the emitted beam. Sputter deposition may provide a path to achieving a far smoother photocathode, while maintaining adequate quantum efficiency. We report on the creation and vacuum transport of a K2CsSb sputter target, and its use to create an ultra-smooth (sub nm roughness) cathode with a 2% quantum efficiency at 532 nm.

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TUPHA006

NSLS-II Storage Ring Insertion Device and Front-End Commissioning

injection, storage-ring, insertion, SRF

1974

G.M. Wang, C. Amundsen, G. Bassi, J. Bengtsson, A. Blednykh, E.B. Blum, W.X. Cheng, J. Choi, O.V. Chubar, T.M. Corwin, M.A. Davidsaver, L. Doom, W. Guo, D.A. Harder, P. He, Y. Hidaka, Y. Hu, P. Ilinski, C.A. Kitegi, S.L. Kramer, Y. Li, M. Musardo, D. Padrazo, B. Podobedov, K. Qian, R.S. Rainer, J. Rank, S. Seletskiy, T.V. Shaftan, S.K. Sharma, O. Singh, V. Smalyuk, R.M. Smith, T. Summers, T. Tanabe, F.J. Willeke, L. Yang, X. Yang, L.-H. Yu
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. In the spring 2014, the storage ring was commissioning up to 50 mA without insertion device. In the fall, the project beamlines, includes seven insertion devices on six ID ports were commissioned within two and a half months. These beamlines consist of IXS, HXN, CSX-1, CSX-2, CHX, SRX, and XPD-1, from the radiation sources elliptically polarizing undulator (EPU), damping wiggler (DW) and in vacuum undulator (IVU) to cover the VUV through the very hard x-ray range. In this paper, a number of commissioning and operation experiences are discussed here, such as injection, lifetime, ID residual field and compensation, source point stability, beam alignment and tools for control, monitor and beam protection.

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TUPHA008

NSLS-II Injector High Level Application Tools

controls, operation, booster, linac

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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TUPHA013

Skew-Quad Parametric-Resonance Ionization Cooling: Theory and Modeling

coupling, resonance, betatron, focusing

1993

A. Afanasev
GWU, Washington, USA
Y.S. Derbenev, V.S. Morozov, A.V. Sy
JLab, Newport News, Virginia, USA
R.P. Johnson
Muons, Inc, Illinois, USA

Funding: This work was supported in part by U.S. DOE STTR Grants DE-SC0005589 and DE-SC0007634.
Muon beam ionization cooling is a key component for the next generation of high-luminosity muon colliders. To reach adequately high luminosity without excessively large muon intensities, it was proposed previously to combine ionization cooling with techniques using a parametric resonance (PIC). Practical implementation of PIC proposal is a subject of this report. We show that an addition of skew quadrupoles to a planar PIC channel gives enough flexibility in the design to avoid unwanted resonances, while meeting the requirements of radially-periodic beam focusing at ionization-cooling plates, large dynamic aperture and an oscillating dispersion needed for aberration corrections. Theoretical arguments are corroborated with models and a detailed numerical analysis, providing step-by-step guidance for the design of Skew-quad PIC (SPIC) beamline.

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TUPTY006

Study of Electron Cloud Instabilities in FCC-hh

electron, proton, photon, simulation

2007

K. Ohmi
KEK, Ibaraki, Japan
L. Mether, D. Schulte, F. Zimmermann
CERN, Geneva, Switzerland

Electron cloud effects are serious issue for LHC and future hadron colliders, FCC-hh. Electron cloud causes coherent instabilities due to collective motion between beam and electrons. Electron cloud also causes incoherent emittance growth due to nonlinear force of beam-cloud electron force. We discuss the fast head-tail instability and the emittance growth in FCC-hh.

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TUPTY007

Study of Beam-beam Effects in FCC-he

luminosity, electron, proton, simulation

2010

K. Ohmi
KEK, Ibaraki, Japan
F. Zimmermann
CERN, Geneva, Switzerland

Beam-beam effects of the ring-ring scheme of FCC-he and LHeC are being studied using weak-strong simulations. The beam-beam tune shift of the electron beam is one order larger than that of proton beam. The study of the electron motion under the beam-beam interaction is the main subject. Luminosity and equilibrium beam size and beam lifetime are analysed.

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TUPTY008

Commissioning Status and Plan of SuperKEKB Injector Linac

linac, 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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TUPTY020

Building a Luminosity Model for the LHC and HL-LHC

luminosity, brightness, injection, proton

2042

F. Antoniou, G. Arduini, Y. Papaphilippou, G. Papotti
CERN, Geneva, Switzerland

One key objective of the High Luminosity LHC Upgrade is to determine a set of beam parameters and the hardware configuration that will enable the LHC to reach a peak luminosity of 5×10³⁴ cm^-2 s^-1 and ultimately 7.5x10³⁴ cm^-2 s^-1 with levelling, allowing an integrated luminosity of 250-300 fb^-1 per year. In order to determine the integrated performance it is important to develop a realistic model of the luminosity evolution during a physics fill. In this paper, the different mechanisms affecting luminosity lifetime in the LHC are discussed and a luminosity model is presented. The model is benchmarked with data from LHC Run I.

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TUPTY022

Alternative Optics Design of the CLIC Damping Rings with Variable Dipole Bends and High-field Wigglers

wiggler, dipole, damping, optics

2046

P.S. Papadopoulou, F. Antoniou, Y. Papaphilippou
CERN, Geneva, Switzerland

The CLIC Damping Rings baseline design aims to reach an ultra-low horizontal normalised emittance of 500nm-rad at 2.86GeV, based on the combined effect of TME arc cells and high-field super-conducting damping wigglers, while keeping the ring as compact as possible. In this paper, an alternative design is described, based on TME cells with longitudinally variable bends and an optimized Nb3Sn high-field wiggler. The impact of these changes on ring optics parameters and the associated optimisation steps are detailed taking account the dominant effect of intrabeam scattering.

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TUPTY038

BPM Tolerances for HL-LHC Orbit Correction in the Inner Triplet Area

luminosity, optics, impedance, simulation

2094

M. Fitterer, R. De Maria
CERN, Geneva, Switzerland

Funding: The HiLumi LHC Design Study is partly funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.
For the HL-LHC beam spot sizes as small as 7 mum are considered for the high luminosity insertions IR1 and IR5. In addition, the luminosity has to be levelled over several hours by changing β^* resulting in constant changes of the optics and thus orbit changes. The small beam size and the continuous optics changes in general make the alignment of the beams at the IP challenging. In order to avoid continuous luminosity scans for the alignment of the beams at the IP, the orbit correction has to rely on the readings of the BPMs in the IT region. In this paper we review the requirements on resolution and accuracy of the BPMs and compare different options for the placement of the BPMs in the IT region.

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TUPTY059

First Considerations on Beam Optics and Lattice Design for the Future Electron-Positron Collider FCC-ee

optics, collider, lattice, operation

2162

B. Härer, B.J. Holzer, F. Zimmermann
CERN, Geneva, Switzerland
A.V. Bogomyagkov
BINP SB RAS, Novosibirsk, Russia

The Future Circular Collider (FCC) study includes the design of a 100-km electron positron collider (FCC-ee) with collision energies between 90 GeV and 350 GeV. This paper describes first aspects of the design and the optics of the FCC-ee collider, optimised for four different beam energies. Special emphasis is put on the need for a highly flexible magnet lattice in order to achieve the required beam emittances in each case and on the layout of the interaction region that will have to combine an advanced mini-beta concept, an effective beam separation scheme and a local chromaticity control to optimise the momentum acceptance and dynamic aperture of the ring.

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TUPTY061

Combined Operation and Staging Scenarios for the FCC-ee Lepton Collider

luminosity, collider, optics, operation

2169

M. Benedikt, B.J. Holzer, E. Jensen, R. Tomás, J. Wenninger, F. Zimmermann
CERN, Geneva, Switzerland
A.V. Bogomyagkov, E.B. Levichev, D.N. Shatilov
BINP SB RAS, Novosibirsk, Russia
K. Ohmi, K. Oide
KEK, Ibaraki, Japan
U. Wienands
SLAC, Menlo Park, California, USA

FCC-ee is a proposed high-energy electron positron circular collider that would initially occupy the 100-km FCC tunnel that will eventually house the 100 TeV FCC-hh hadron collider. The parameter range for the e⁺/e⁻ collider is large, operating at a cm energy from 90 GeV (Z-pole) to 350 GeV (t-tbar production) with the maximum beam current ranging from 1.5 A to 6 mA for each beam, corresponding to a synchrotron radiation power of 50 MW and a radiative energy loss varying from ~30 MeV/turn to ~7500 MeV/turn. This presents challenges for the rf system due to the varying rf voltage requirements and beam loading conditions. In this paper we present a possible gradual evolution of the FCC-ee complex by step-wise expansion, and possibly reconfiguration, of the superconducting RF system. The performance attainable at each step is discussed, along with the possible advantages and drawbacks.

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TUPTY070

Strong-Strong Simulations of Beta star Levelling for Flat and Round Beams

luminosity, simulation, resonance, detector

2192

M.P. Crouch, R.B. Appleby
UMAN, Manchester, United Kingdom
B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: STFC HL-LHC
The HL-LHC project aims to reach larger peak luminosities, however this can lead to a high pile up in the detectors. To control the pile up, luminosity levelling has been suggested. One proposed method is β*-luminosity levelling, in which beams collide at a larger than nominal β*. The β* is then reduced in steps as the beam intensity decays. This allows the luminosity to be kept constant over part of a physics fill. The use of round or flat optics will change the beam-beam effect of the head on collisions as well as the long range interactions. Here simulations of β* levelling are presented for the case of flat and round beam optics and the difference in terms of the beam-beam effect is highlighted.

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TUPTY074

Muon Beam Emittance Evolution in the Helical Ionization Cooling Channel for Bright Muon Sources

plasma, collider, space-charge, simulation

2203

K. Yonehara, C.Y. Yoshikawa
Fermilab, Batavia, Illinois, USA
C.M. Ankenbrandt, R.P. Johnson, S.A. Kahn
Muons, Inc, Illinois, USA
M. Chung
UNIST, Ulsan, Republic of Korea
Y.S. Derbenev, A.V. Sy
JLab, Newport News, Virginia, USA
B.T. Freemire
IIT, Chicago, Illinois, USA

The six-dimensional ionization cooling is essential to design a bright muon source. A geometry constraint is a challenge issue in a compact helical cooling channel (HCC). Especially, the HCC requires a large bore helical magnet and a compact helical RF system to incorporate the RF into the magnet chamber. A new emittance evolution has been designed to mitigate the geometry constraint. The HCC was functionally separated into three parts sections. The lattice at the initial section provides a large transverse acceptance by using a strong helical focus magnet. Once the transverse beam size is small enough to get into the compact RF the HCC lattice in the middle section generates a large longitudinal beta tune to dominate the longitudinal cooling. Consequently, the longitudinal emittance becomes smaller than the transverse one at the end of middle section. In the final section, the magnetic field strength is gradually reduced to match out the helical channel to the straight solenoid. As a result, the emittance exchange takes place and the final transverse emittance becomes smaller than the longitudinal one. The new emittance evolution scenario will be discussed in this presentation.

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TUPTY076

Beam-Beam Simulation of Crab Cavity White Noise for LHC Upgrade

luminosity, cavity, simulation, beam-beam-effects

2206

J. Qiang
LBNL, Berkeley, California, USA
J. Barranco García
EPFL, Lausanne, Switzerland
K. Ohmi
KEK, Ibaraki, Japan
T. Pieloni
CERN, Geneva, Switzerland

High luminosity LHC upgrade will improve the luminosity of the current LHC operation by an order of magnitude. Crab cavity as a critical component for compensating luminosity loss from large crossing angle collision and also providing luminosity leveling for the LHC upgrade is being actively pursued. In this paper, we will report on the study of potential effects of the crab cavity noise on the beam luminosity lifetime based on strong-strong beam-beam simulations.

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TUPTY077

Strong-Strong Beam-Beam Simulation of Bunch Length Splitting at the LHC

simulation, synchrotron, resonance, beam-beam-effects

2210

J. Qiang, S. Paret
LBNL, Berkeley, California, USA
K. Ohmi
KEK, Ibaraki, Japan
T. Pieloni
CERN, Geneva, Switzerland

Longitudinal bunch length splitting was observed for some LHC beams. In this paper, we will report on the study of the observation using strong-strong beam-beam simulations. We explore a variety of factors including initial momentum deviation, collision crossing angle, synchroton tune, chromaticity, working points and bunch intensity that contribute to the beam particle loss and the bunch length splitting, and try to understand the underlying mechanism of the observed phenomena.

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TUPWI007

Algorithm of Reconstructing Particle Distribution in N-dimensional Phase Space from Profile in Beam Transport

simulation, beam-transport, quadrupole, induction

2256

T. Aoki
Hitachi Ltd., Ibaraki-ken, Japan

In particle beam therapy, it is demanded to improve measurement of beam extracted from accelerator in order to realize more conformal irradiation. We developed a method of reconstructing particle distribution from measured profile in beam transport. In this method, particle distribution is obtained by solving a following equation: I=Dρ, where I is a counted number of particles at a single channel of the profile monitor, D is a matrix representing relation between I and ρ, and ρ is number of particles included in a single n-dimensional voxel of phase space at start point of the beam transport. D is a n×m matrix, where n is number of data which obtained under multiple conditions of beam transport, and m is number of voxels of phase space to be reconstructed. We succeeded formulation of D matrix from transportation matrix of the beam transport R, and discovered that D is formulated as piecewise-polynomials of elements of R. By this method, it is enable to reconstruct the particle distribution in arbitrary dimensional phase space. We show details of the formulation of D and results of simulations of reconstruction of particle distribution in phase space by this method.

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TUPWI008

RF Gun Based Ultrafast Electron Microscopy

electron, gun, cavity, cathode

2259

J. Yang, K. Tanimura, Y. Yoshida
ISIR, Osaka, Japan
J. Urakawa
KEK, Ibaraki, Japan

Ultrafast electron microscopy (UEM) would be a powerful tool for the direct visualization of structural dynamic processes in matter. The resolutions of the observation on femtosecond time scales over sub-nanometer (even atomic) spatial dimensions have long been a goal in science. To achieve such resolutions, we have designed and constructed a femtosecond time-resolved relativistic-energy electron microscopy using a photocathode radio-frequency (RF) electron gun (RF based UEM). The RF gun has successfully generated a high-brightness electron beam with bunch length of 100 fs and emittance of 0.2 mm-mrad, which are essential beam parameters for the achievement of nm-fs space-time resolution in the microscopy. Both the static measurements of both relativistic-energy electron diffraction and image have been succeeded. In this presentation, the activities on RF based UEM are introduced. The requirements and limitations of the beam parameters are reviewed. The concept and design of RF based UEM are reported. Finally, some demonstrations of the relativistic-energy UEM images are reported.

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TUPWI033

Matching into the Helical Bunch Coalescing Channel for a High Luminosity Muon Collider

acceleration, simulation, luminosity, collider

2315

A.V. Sy, Y.S. Derbenev, V.S. Morozov
JLab, Newport News, Virginia, USA
C.M. Ankenbrandt, R.P. Johnson
Muons, Inc, Illinois, USA
D.V. Neuffer, K. Yonehara, C.Y. Yoshikawa
Fermilab, Batavia, Illinois, USA

Funding: This work was supported in part by U.S. DOE STTR Grant DE-SC0007634. This manuscript has been authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
For high luminosity in a muon collider, muon bunches that have been cooled in the six-dimensional helical cooling channel (HCC) must be merged into a single bunch and further cooled in preparation for acceleration and transport to the collider ring. The helical bunch coalescing channel has been previously simulated [*, **] and provides the most natural match from helical upstream and downstream subsystems. This work focuses on the matching from the exit of the multiple bunch HCC into the start of the helical bunch coalescing channel. The simulated helical matching section simultaneously matches the helical spatial period λ in addition to providing the necessary acceleration for efficient bunch coalescing. Previous studies assumed that the acceleration of muon bunches from p=209.15 MeV/c to 286.816 MeV/c and matching of λ from 0.5 m to 1.0 m could be accomplished with zero particle losses and zero emittance growth in the individual bunches. This study demonstrates nonzero values for both particle loss and emittance growth, and provides considerations for reducing these adverse effects to best preserve high luminosity.
*C. Yoshikawa, et al., “Bunch Coalescing in a Helical Channel,” MAP-doc-4302-v2.
**C. Yoshikawa, et al., “Bunch Coalescing in a Helical Channel,” IPAC12 TUPPD013, New Orleans, Louisiana, USA.

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TUPWI037

Electron Cooling Study for MEIC

electron, proton, solenoid, ion

2326

H. Zhang, Y.S. Derbenev, D. Douglas, 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.
Electron cooling of the ion beams is one critical R&D to achieve high luminosities in JLab’s MEIC proposal. In the present MEIC design, a multi-staged cooling scheme is adapted, which includes DC electron cooling in the booster ring and bunched beam electron cooling in the collider ring at both the injection energy and the collision energy. We explored the feasibility of using both magnetized and non-magnetized electron beam for cooling, and concluded that a magnetized electron beam is necessary. Electron cooling simulation results for the newly updated MEIC design is also presented.

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TUPWI040

End-to-End Simulation of Bunch Merging for a Muon Collider

solenoid, kicker, collider, simulation

2336

Y. Bao, G.G. Hanson
UCR, Riverside, California, USA
R.B. Palmer, D. Stratakis
BNL, Upton, Long Island, New York, USA

Muon accelerator beams are commonly produced indirectly through pion decay by interaction of a charged particle beam with a target. Efficient muon capture requires the muons to be first phase-rotated by rf cavities into a train of 21 bunches with much reduced energy spread. Since luminosity is proportional to the square of the number of muons per bunch, it is crucial for a Muon Collider to use relatively few bunches with many muons per bunch. In this paper we will describe a bunch merging scheme that should achieve this goal. We present for the first time a complete end-to-end simulation of a 6D bunch merger for a Muon Collider. The 21 bunches arising from the phase-rotator, after some initial cooling, are merged in longitudinal phase space into 7 bunches, which then go through 7 paths with different lengths and reach at the final collecting ”funnel” at the same time. The final single bunch has a transverse and a longitudinal emittance that matches well with the subsequent 6D rectilinear cooling scheme.

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TUPWI043

Chromatic Effects in Long Periodic Transport Channels

lattice, collider, linac, 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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TUPWI044

Final Muon Emittance Exchange in Vacuum for a Collider

quadrupole, collider, betatron, focusing

2346

D.J. Summers, J.G. Acosta, L.M. Cremaldi, T.L. Hart, S.J. Oliveros, L.P. Perera, W. Wu
UMiss, University, Mississippi, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA

Funding: Work supported by NSF Award 0969770
We outline a plan for final muon ionization cooling with quadrupole doublets focusing onto short absorbers followed by emittance exchange in vacuum to achieve the small transverse beam sizes needed by a muon collider. A flat muon beam with a series of quadrupole doublet half cells appears to provide the strong focusing required for final cooling. Each quadrupole doublet has a low beta region occupied by a dense, low Z absorber. After final cooling, normalized xyz emittances of (0.071, 0.141, 2.4) mm-rad are exchanged into (0.025, 0.025, 70) mm-rad. Thin electrostatic septa efficiently slice the bunch into 17 parts. The 17 bunches are interleaved into a 3.7 meter long train with RF deflector cavities. Snap bunch coalescence combines the muon bunch train longitudinally in a 21 GeV ring in 55 microseconds, one quarter of a synchrotron oscillation period. A linear long wavelength RF bucket gives each bunch a different energy causing the bunches to drift until they merge into one bunch and can be captured in a short wavelength RF bucket with a 13% muon decay loss and a packing fraction as high as 87%.

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TUPWI045

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

linac, 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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TUPWI049

Polarized Proton Beam for eRHIC

polarization, resonance, proton, booster

2360

H. Huang, F. Méot, V. Ptitsyn, T. Roser
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.
RHIC has provided polarized proton collisions from 31 GeV to 255 GeV in past decade. To preserve polarization through numerous depolarizing resonances through the whole accelerator chain, harmonic orbit correction, partial snakes, horizontal tune jump system and full snakes have been used. In addition, close attentions have been paid to betatron tune control, orbit control and beam line alignment. The polarization of 60% at 255 GeV has been delivered to experiments with 1.8×10¹¹ bunch intensity. For the eRHIC era, the beam brightness has to be maintained to reach the desired luminosity. Since we only have one hadron ring in the eRHIC era, existing spin rotator and snakes can be converted to six snake configuration for one hadron ring. With properly arranged six snakes, the polarization can be maintained at 70% at 250 GeV. This paper summarizes the effort and plan to reach high polarization with small emittance for eRHIC.

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TUPWI052

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

polarization, electron, quadrupole, linac

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

linac, 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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TUPWI059

Influence of Plasma Loading in a Hybrid Muon Cooling Channel

plasma, ion, electron, cavity

2381

D. Stratakis
BNL, Upton, Long Island, New York, USA
B.T. Freemire
IIT, Chicago, Illinois, USA
K. Yonehara
Fermilab, Batavia, Illinois, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In a hybrid 6D cooling channel, cooling is accomplished by reducing the beam momentum through ionization energy loss in wedge absorbers and replenishing the momentum loss in the longitudinal direction with gas-filled rf cavities. While the gas acts as a buffer to prevent rf breakdown, gas ionization may also occur as the beam passes through a HPRF cavity. The resulting plasma, may gain substantial energy from the rf electric field which it can transfer via collisions to the gas, an effect known as plasma loading. In this paper, we investigate the influence of plasma loading on the cooling performance of a rectilinear hybrid channel. With the aid of numerical simulations we examine the sensitivity in cooling performance and plasma loading to key parameters such as the rf gradient and gas pressure.

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TUPWI060

RHIC Polarized Proton-Proton Operation at 100 GeV in Run 15

proton, electron, polarization, operation

2384

V. Schoefer, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, Y. Dutheil, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, S.M. White, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
BNL, Upton, Long Island, New York, USA

The first part of RHIC Run 15 consisted of nine weeks of polarized proton on proton collisions at a beam energy of 100 GeV at two interaction points. In this paper we discuss several of the upgrades to the collider complex that allowed for improved performance this run. The largest effort consisted of commissioning of the electron lenses, one in each ring, which are designed to compensate one of the two beam-beam interactions experienced by the proton bunches. The e-lenses therefore raise the per bunch intensity at which luminosity becomes beam-beam limited. A new lattice was designed to create the phase advances necessary for a functioning e-lens which also has an improved off-momentum dynamic aperture relative to previous runs. In order to take advantage of the new, higher intensity limit without suffering intensity driven emittance deterioration, other features were commissioned including a continuous transverse bunch-by-bunch damper in RHIC and a double harmonic capture scheme in the Booster. Other high intensity protections include improvements to the abort system and the installation of masks to intercept beam lost due to abort kicker pre-fires.

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WEXB2

Measurement and Analysis of Electron Cloud Induced Emittance Growth at CesrTA

electron, simulation, feedback, positron

2390

K.G. Sonnad, L.Y. Bartnik, M.G. Billing, G. Dugan, M.J. Forster
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.W. Flanagan, K. Ohmi
KEK, Ibaraki, Japan
R. Holtzapple, K.E. McArdle, M.I. Miller
CalPoly, San Luis Obispo, California, USA
L. Pentecost
Colgate University, Hamilton, New York, USA
M.T.F. Pivi
EBG MedAustron, Wr. Neustadt, Austria
S. Tucker
Cal Poly, San Luis Obispo, California, USA

CesrTA is a test accelerator facility at Cornell University that has been configured to study physics associated with electron and positron damping rings. Electron cloud effects is a concern for positron beams for such damping rings. The presentation will give an overview of recent measurements and simulation results for CesrTA. The measurement conditions were set up in order to study single bunch phenomena by observing a "Witness bunch" behind a train of positron bunches. The beam size and the turn by turn spectra were obeserved for the witness bunch under different conditions. Simulations were performed under similar conditions using the program CMAD.

Slides WEXB2 [2.263 MB]

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WEYB2

Beam Dynamics in a High Frequency RFQ

rfq, alignment, proton, linac

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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WEAB3

Intra-beam Scattering Effects in ELENA

antiproton, electron, scattering, simulation

2458

J. Resta-López, J.R. Hunt, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
J.R. Hunt, J. Resta-López, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: Work supported by the EU under Grant Agreement 624854 and the STFC Cockcroft Institute core Grant No. ST/G008248/1.
Intra-Beam Scattering (IBS) is one of the main limiting processes for the performance of low energy ion storage rings, such as the Extra Low ENergy Antiproton ring (ELENA) that is being constructed at CERN. IBS effects limit the achievable equilibrium 6D beam phase space volume during the cooling process, as well as the stored beam intensity. In this contribution we analyze the IBS effects on the beam dynamics of the ELENA ring in detail. Numerical simulations using the codes BETACOOL and MAD-X have been performed to compute the beam life time and the equilibrium phase space parameters with electron cooling in the presence of IBS.

Slides WEAB3 [6.222 MB]

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WEAD2

Experimental Results of Carbon NanoTube Cathodes inside RF Environment

cathode, gun, electron, laser

2475

L. Faillace, S. Boucher, J.J. Hartzell, A.Y. Murokh
RadiaBeam, Santa Monica, California, USA
D. Mihalcea, P. Piot, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA
H. Panuganti
Northern Illinois University, DeKalb, Illinois, USA

Funding: Work supported by US DOE SBIR grant # DE-SC0004459
Carbon Nano Tubes (CNT’s) as field-emitters have been investigated for more than two decades and can produce relatively low emittance electron beams for a given cathode size. Unlike thermionic cathodes, CNT cathodes are able to produce electrons at room temperature and relatively low electric field (a few MV/m). In collaboration with FermiLab, we have recently tested CNT cathodes both with DC and RF fields. We observed a beam current close to 1A with a ~1cm² CNT cathode inside an L-band RF gun. Steady operation was obtained up to 650 mA and the measured current vs. surface field plot showed perfect agreement with the Fowler-Nordheim distribution.

Slides WEAD2 [10.445 MB]

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WEBD1

12 GeV CEBAF Transverse Emittance Evolution

optics, operation, linac, 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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WEPWA001

Electron Beam Transfer Line for Demonstration of Laser Plasma Based Free Electron Laser Amplification

FEL, electron, undulator, quadrupole

2489

A. Loulergue, M.-E. Couprie, M. Khojoyan, M. Labat, W. Wang
SOLEIL, Gif-sur-Yvette, France
C. Evain
PhLAM/CERCLA, Villeneuve d'Ascq Cedex, France

One direction towards compact Free Electron Lasers is to replace the conventional linac by a laser plasma driven beam, provided proper electron beam manipulation to handle the value of the energy spread and of the divergence is done. Applying seeding techniques enables also to reduce the required undulator length. The rapidly developing LWFA are already able to generate synchrotron radiation. With an electron divergence of typically 1 mrad and an energy spread of the order of 1 %, an adequate beam manipulation through the transport to the undulator is needed for FEL amplification. A test experiment for the demonstration of FEL amplification with a LWFA is under preparation in the frame of the COXINEL ERC contract. A specific design of electron beam transfer line following different steps with strong focusing variable strength permanent magnet quadrupoles, an energy de-mixing chicane with conventional dipoles and second set of quadrupoles for further dedicated focusing in the undulator has been investigated. Beam transfer simulations and expected FEL power in the XUV will be presented.

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WEPWA010

A High Intensity Proton Source for the European Spallation Source Facility

plasma, proton, extraction, site

2509

L. Celona, L. Allegra, L. Andò, A.C. Caruso, G. Castro, F. Chines, G. Gallo, S. Gammino, A. Longhitano, S. Marletta, D. Mascali, L. Neri, S. Passarello, G. Torrisi
INFN/LNS, Catania, Italy
A. Longhitano
ALTEK, San Gregorio (CATANIA), Italy
G. Torrisi
Universitá Mediterranea di Reggio Calabria, Reggio Calabria, Italy

Along the last twentyfive years, INFN-LNS has gained a relevant role in R&D of plasma-based ion sources. The laboratory is currently involved in the Proton Source and Low Energy Beam Transport (LEBT) line prototype construction for the European Spallation Source. ESS – based on a 2.0 GeV, 62.5 mA proton accelerator for neutron production – will be a fundamental instrument for research and application. The proton source is required to produce at least 90 mA beam (as total drain current) at 0.25 π.mm.mrad emittance, 2.86 ms pulse duration, 14 Hz repetition rate. We will illustrate the advanced design of the machine, including the innovations in plasma heating schemes, the final layout of the LEBT – based on detailed beam transport studies, a new vacuum scheme and the final chopper strategy – and the first steps of the devices installation at the INFN-LNS test-bench site.

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WEPWA028

Numerical Simulation on Emittance Growth Caused by Roughness of a Metallic Photocathode

simulation, electron, cathode, laser

2559

Z. Zhang, C.-X. Tang
TUB, Beijing, People's Republic of China

The roughness of a photocathode could lead to an additional uncorrelated divergence of the emitted electrons and therefore to an increased thermal emittance. The randomness of the real-life photocathode surface makes it unrealistic to perform typical beam dynamics simulation to study the roughness emittance growth. We developed a numerical simulation code based on the point spread function (PSF) and an estimated form of electric field distribution on an arbitrary gently undulating surface to deal with the problem. The simulation result surprisingly shows that the emittance growth factor is much smaller than expected (1.5 ~ 2).

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WEPWA032

CsK2Sb Growth Studies: Towards High Quantum Efficiency and Smooth Surfaces

cathode, simulation, detector, experiment

2566

S.G. Schubert, M. Gaowei, J. Sinsheimer, J. Smedley
BNL, Upton, Long Island, New York, USA
Z. Ding, E.M. Muller
SBU, Stony Brook, New York, USA
J. Kühn
HZB, Berlin, Germany
H.A. Padmore, J.J. Wong
LBNL, Berkeley, California, USA
J. Xie
ANL, Argonne, Illinois, USA

Funding: This work was supported by the US DOE, under Contracts DE-AC02-05CH11231, DE-AC02-98CH10886, KC0407-ALSJNT-I0013, DE-FG02-12ER41837 and the German BMBF, Helmholtz-Association and Land Berlin.
The properties of CsK2Sb, make this material an ideal candidate as photocathode for electron injector use. Producing photocathodes with quantum efficiencies with 7% and greater at 532 nm poses no challenge, nevertheless the traditional growth mechanisms, which are based on a sequential deposition of Antimony, Potassium and Cesium at a temperature gradient yield a rough surface with a rms roughness in the range of 25 nm. Surface roughness’s in this region impacts the emittance. At an accelerating field of 3 MV/m an rms surface roughness of 25 nm is the dominant effect on emittance and will limit injector performance. Studies are performed to optimize roughness. Various growth procedures are exploited and the surface roughness compared.

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WEPWA034

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

linac, 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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WEPWA035

Initial EEX-based Bunch Shaping Experiment Results at the Argonne Wakefield Accelerator Facility

experiment, dipole, simulation, cavity

2575

G. Ha, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: This work is partly supported by POSTECH BK²¹⁺ and Argonne National Laboratory
A program is under development at Argonne National Laboratory to use an emittance exchange (EEX) beamline to perform longitudinal bunch shaping (LBS). The double dog-leg EEX beamline was recently installed at the Argonne Wakefield Accelerator (AWA) and the goals of the proof-of-principle experiment are to demonstrate LBS and characterize its deformations from the ideal shape due to higher-order and collective effects. The LBS beamline at the AWA consists of insert-able transverse masks mounted on an actuator and four quadrupoles (to manipulate the transverse phase space) before the EEX beamline, which consists of two identical dog-legs and a deflecting cavity. The mask and input beam parameters are varied during the experiment to explore the shaping capability and clarify the deformation sources and their mitigation. Progress on the commissioning of the LBS beamline, initial experimental data and benchmarks to GPT simulations will be presented.

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WEPWA044

The Alignment of the MICE Tracker Detectors

alignment, experiment, detector, scattering

2597

M.A. Uchida
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

The Muon Ionization Cooling experiment (MICE) has been designed to demonstrate the reduction of the phase-space volume (cooling) occupied by a muon beam using the ionization-cooling technique. This demonstration will be an important step in establishing the feasibility of muon accelerators for particle physics. The emittance of the beam will be measured before and after the cooling cell using a solenoidal spectrometer. Each spectrometer will be instrumented with a high-precision scintillating-fibre tracking detector (Tracker). The Trackers will be immersed in a uniform magnetic field of 4T and will measure the normalised emittance reduction with a precision of 0.1%. A thorough knowledge of the alignment of the Trackers is essential for this accuracy to be achieved. The Trackers are aligned: mechanically inside the spectrometer solenoids, with respect to the MICE experimental hall, to one another, and to the magnetic and beam axes. These methods are described here.

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WEPWA047

Emittance Growth in a Plasma Wakefield Accelerator

plasma, electron, scattering, wakefield

2609

Ö. Mete, K. Hanahoe, G.X. Xia
UMAN, Manchester, United Kingdom
M. Labiche
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom

The interaction of the witness beam with the surrounding plasma particles and wakefields was studied. The implications of the elastic scattering process on beam emittance and, emittance evolution under the focusing and acceleration provided by plasma wakefields were discussed. Simulations results from GEANT4 are presented in this paper.

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WEPWA049

Low Energy Beam Tracking Under Scattering for a Cold Electron Source in Manchester

electron, scattering, extraction, experiment

2615

R.B. Appleby, W. Bertsche, O. Mete, G.X. Xia
UMAN, Manchester, United Kingdom
M.A. Harvey, M. Jones, A.J. Murray
The University of Manchester, The Photon Science Institute, Manchester, United Kingdom
B. Kyle
University of Manchester, Manchester, United Kingdom

High quality electron beams, with high spatial and temporal resolution, have an important use in electron diffraction experiments to probe and study the constituents of matter. A cold electron source is being developed based on electron ionisation from an atom cloud trapped by using AC magneto-optical methods in the University of Manchester. The technique will produce bunches of electrons well suited for high precision and single shot electron diffraction. In this paper issues of modelling at low energies for this state of art electron source with very low energy spread are presented, with a focus on newly developed tools to model the scattering in the meshes used to support the extraction electric fields. The dependence on emittance growth on mesh wire thickness is studied.

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WEPWA064

Ionization Cooling Channels in COSY Infinity

space-charge, simulation, multipole, solenoid

2652

B.T. Loseth, M. Berz
MSU, East Lansing, Michigan, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Ionization cooling is a method to reduce the emittance of a beam through the use of absorbers, rf cavities, and strong solenoids for focusing, arranged into a condensed lattice. By tuning lattice parameters, it is possible to construct a staged cooling channel in which the beam emittance is always considerably greater than the minimum value. In the late stages of the cooling channel, space charge effects can become a significant obstacle to further emittance reduction once the beam becomes sufficiently condensed. A method has been implemented in COSY Infinity, a beam dynamics simulation and analysis code, which efficiently and accurately calculates the self-fields of all particles on each other based on a variant of the Fast Multipole Method (FMM). In this paper, we present simulations of a muon ionization cooling channel performed in COSY, utilizing the FMM, benchmarked against G4beamline, a standard code for muon beam analysis, in order to investigate the significance of space charge effects.

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WEPJE010

Particle Production of a Graphite Target System for the Intensity Frontier

target, proton, factory, collider

2692

X.P. Ding
UCLA, Los Angeles, California, USA
H.G. Kirk
BNL, Upton, Long Island, New York, USA
K.T. McDonald
PU, Princeton, New Jersey, USA

A solid graphite target system is considered for an intense muon and/or neutrino source in support of physics at the intensity frontier. We previously optimized the geometric parameters of the beam and target to maximize particle production at low energies by incoming protons with kinetic energy of 6.75 GeV and an rms geometric emittance of 5 mm-mrad using the MARS15(2014) code. In this study, we ran MARS15 with ROOT-based geometry and also considered a mercury-jet target as an upgrade operation. The optimization was extended to focused proton beams with transverse emittances from 5 to 50 mm-mrad, showing that the particle production decreases slowly with increasing emittance. We also studied the beam dump configuration to suppress the rate of undesirable higher-energy secondary particles in the beam.

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WEPJE019

Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors

cathode, electron, simulation, gun

2711

D. Mihalcea, H. Panuganti, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
L. Faillace
RadiaBeam, Santa Monica, California, USA
P. Piot, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with the time-dependent Particle In Cell (PIC) code WARP.

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WEPJE025

Phase Space Density as a Measure of Cooling Performance for the International Muon Ionization Cooling Experiment

simulation, luminosity, experiment, scattering

2726

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.
The International Muon Ionization Cooling Experiment (MICE)* is an experiment to demonstrate ionization cooling of a muon beam in a beamline that shares characteristics with one that might be used for a muon collider or neutrino factory. I describe a way to quantify cooling performance by examining the phase space density of muons, and determining how much that density increases. This contrasts with the more common methods that rely on the covariance matrix and compute emittances from that. I discuss why a direct measure of phase space density might be preferable to a covariance matrix method. I apply this technique to an early proposal for the MICE final step beamline. I discuss how matching impacts the measured performance.
* http://mice.iit.edu/ I am not a MICE collaboration member, and nothing herein should be construed as representing the work or views of the collaboration.

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WEPMA030

Design and Characterization of Permanent Magnetic Solenoids for REGAE

solenoid, electron, experiment, simulation

2822

M. Hachmann, K. Flöttmann, T. Gehrke, F. Mayet
DESY, Hamburg, Germany

REGAE is a small electron linear accelerator at DESY. In order to focus short and low charged electron bunches down to a few micrometre permanent magnetic solenoids were designed, assembled and field measurements were done. Due to a shortage of space close to the operation area an in-vacuum solution has been chosen. Furthermore a tworing design made of wedges has been preferred in terms of beam dynamic issues. To keep the field quality of a piecewise built magnet still high a sorting algorithm for the wedge arrangement has been developed and used for the construction of the magnets. The magnetic field of these solenoids has been measured with high precision and has been compared to the simulated magnetic field.

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WEPMA033

Utilizing Gas Filled Cavities for the Generation of an Intense Muon Source

target, proton, cyclotron, cavity

2829

D. Stratakis
BNL, Upton, Long Island, New York, USA
D.V. Neuffer
Fermilab, Batavia, Illinois, USA

Funding: This manuscript has been authored by employees of Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
A key requirement for designing intense muon sources is operating rf cavities in multi-tesla magnetic fields. Recently, a proof-of-principle experiment demonstrated that an rf cavity filed with high pressure hydrogen gas could meet this goal. In this study, rigorous simulation is used to design and evaluate the performance of an intense muon source with gas filled cavities. We present a new lattice design and compare our results with conventional schemes. We detail the influence of gas pressure on the muon production rate.

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WEPMN010

Analysis of the Electromagnetic Field in the Coupler of Normal Temperature Travelling-Wave Accelerating Tube

coupling, cavity, electromagnetic-fields, simulation

2934

X. He, M. Hou
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

With the developed requirement of the beam quality in modern accelerators, rapid development of all kinds of accelerating structures with different frequencies and materials have been achieved. However, the normal temperature travelling-wave (TW) accelerating structures which are widely used in Free Electron Laser (FEL) are still indispensable. For reducing the beam emittance, it is very important to optimize the symmetry of the high-order electromagnetic field in the coupler of such accelerating structures. In this paper, the symmetry of the electromagnetic field in TW accelerator couplers using different coupling mechanisms was analysed. A lot of design optimization as well as the result analysis work has been done for the three kinds of commonly used waveguide-coupled TW accelerating structures: single-feed electrical-coupling, dual-feed electrical-coupling using magic tee in feeding waveguide and dual-feed magnetic-coupling using J-type feeding waveguide. Finally, basing on lots of simulation results and the performances during the fabrication, measurement and RF conditioning of these three kinds of structures, the J-type racetrack coupler type is regarded as the best choice.

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WEPTY012

Multiple Scattering Effects of a Thin Beryllium Window on a Short, 2 nC, 60 MeV Bunched Electron Beam

scattering, simulation, vacuum, experiment

3280

E.E. Wisniewski, M.E. Conde, W. Gai, G. Ha, J.G. Power
ANL, Argonne, Illinois, USA
G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea

Funding: U.S. Dept of Energy Office of Science under contract number DE-AC02-06CH11357.
The Argonne Wakefield Accelerator 75 MeV drive beamline at Argonne National Laboratory has as its electron source a Cesium telluride photocathode gun with a vacuum requirement on the order of 10^-10 torr. In conflict with this, the experimental program at AWA sometimes requires beamline installation of experimental structures which due to materials and/or construction cannot meet the stringent vacuum requirement. One solution is to sequester these types of structures inside a separate vacuum chamber and inject the beam through a thin Beryllium window. The downside is that multiple scattering effects degrade the beam quality to some degree which is not well-known. This study was done in an effort to better understand and predict the multiple scattering effects of the Be thin window, particularly on the beam transverse size. The results of measurements are compared with GEANT4 Monte Carlo simulations via G4beamline and analytical calculations via GPT.

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WEPTY047

Thermal and Lorentz Force Analysis of Beryllium Windows for the Rectilinear Muon Cooling Channel

cavity, Windows, simulation, collider

3381

T.H. Luo, D. Li, S.P. Virostek
LBNL, Berkeley, California, USA
D.L. Bowring
Fermilab, Batavia, Illinois, USA
R.B. Palmer, D. Stratakis
BNL, Upton, Long Island, New York, USA

Reduction of the 6-dimensional phase-space of a muon beam by several orders of magnitude is a key requirement for a Muon Collider. Recently, a 12-stage rectilinear ionization cooling channel has been proposed to achieve that goal. The channel consists of a series of low frequency (325 MHz-650 MHz) normal conducting pillbox cavities, which are enclosed within thin beryllium windows (foils) to increase shunt impedance and give a higher field on-axis for a given amount of power. These windows are subject to ohmic heating from RF currents and Lorentz force from the EM field in the cavity, both of which will produce out of plane displacements that can detune the cavity frequency. In this study, using the TEM3P code, we report on a detailed thermal and mechanical analysis for the actual Be windows used on a 325 MHz cavity in a vacuum ionization cooling rectilinear channel for a Muon Collider.

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WEPTY059

Alternative Methods for Field Corrections in Helical Solenoids

dipole, solenoid, beam-cooling, simulation

3409

K.E. Melconian
Texas A&M University, College Station, Texas, USA
G. Flanagan, S.A. Kahn
Muons, Inc, Illinois, USA
S. Krave, M.L. Lopes, J.C. Tompkins, K. Yonehara
Fermilab, Batavia, Illinois, USA

Funding: Fermi Research Alliance under DOE Contract DE-AC02-07CH11359
Helical cooling channels have been proposed for highly efficient 6D muon cooling. Helical solenoids produce solenoidal, helical dipole, and helical gradient field components. Previous studies explored the geometric tunability limits on these main field components. In this paper we present two alternative correction schemes, tilting the solenoids and the addition of helical lines, to reduce the required strength of the anti-solenoid and add an additional tuning knob.

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WEPWI035

Beam Dynamics Studies of 499 MHz Superconducting RF-Dipole Deflecting Cavity System

cavity, dipole, multipole, superconducting-RF

3564

S.U. De Silva, K.E. Deitrick, J.R. Delayen, H. Park
ODU, Norfolk, Virginia, USA

A 499 MHz deflecting cavity has been designed as a three-way beam spreader to separate an electron beam into 3 beams. The rf tests carried out on the superconducting rf-dipole cavity have demonstrated that a transverse voltage of 4.2 MV can be achieved with a single cavity. This paper discusses the beam dynamics on a deflecting structure operating in continuous-wave mode with a relativistic beam. The study includes the analysis on emittance growth, energy spread, and change in bunch size including effects due to field non-uniformities.

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THYC1

Comparison of Beam Diagnostics for 3rd and 4th Generation Ring-based Light Sources

photon, diagnostics, feedback, electronics

3657

H. Maesaka
RIKEN SPring-8 Center, Sayo-cho, Sayo-gun, Hyogo, Japan

This talk will present the challenges and progress required in beam instrumentation for next generation storage-ring light sources. These light sources aim at small natural emittance of approximately 100 pm rad in order to achieve much higher brightness than the present 3rd generation light sources. This small emittance is realized by a multi-bend lattice, which has a small dynamic aperture of only several mm, a small beam size of approximately 10 microns, etc. Therefore, the beam orbit must be precisely measured by beam position monitors (BPM) for the orbit correction and the beam size should be monitored with less than 10-micron resolution in order to estimate the beam emittance. A bunch-by-bunch feedback system is also required for the suppression of various instabilities coming from narrow beam chamber. In addition, since the stable tune region is small, a real-time tune monitor is demanded for the tune correction. We introduce leading-edge instrumentation techniques to overcome these difficulties, comparing with of 3rd generation light sources.

Slides THYC1 [3.690 MB]

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THPF003

BEST 70P Cyclotron Factory Test

ion, ion-source, cyclotron, injection

3680

V. Sabaiduc, T. Boiesan, M. Carlson, D. Du, F.S. Grillet, R.R. Johnson, F.S. Labrecque, B.F. Milton, L. AC. Piazza, R. Ruegg, V. Ryjkov, W. Stazyk, K. Suthanthiran, S. Talmor, B.A. Versteeg, J. Zhu
BCSI, Vancouver, BC, Canada
T. Evans, J. Harris, N. Matte, J. Panama, P. Zanetti
Best Theratronics Ltd., Ottawa, Ontario, Canada

Best Cyclotron Systems Inc (BCSI) designed and manufactured a 70MeV compact cyclotron for radioisotope production and research applications. The cyclotron undergone exhaustive factory testing that has been successfully completed at Best Theratronics facility in Ottawa, Canada. The first 70MeV cyclotron has been build for the INFN-LNL laboratory in Legnaro, Italy. The cyclotron has external negative hydrogen ion source, four radial sectors with two dees in opposite valleys, cryogenic vacuum system and simultaneous beam extraction on opposite lines. The beam intensity is 700μA with variable extraction energy between 35 and 70MeV. We are reporting the factory acceptance testing results confirming the individual cyclotron systems performance and beam acceleration to 1MeV probe. Detail measurements of each system stability and performance have been taken as well as full characterisation of beam acceleration through the injection line and on to the 1MeV probe. The BEST70p cyclotron may also be used as injector to a post-accelerator or for the production of the radioactive beams.

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THPF007

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

injection, space-charge, linac, 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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THPF025

Beam Dynamics for the SC CW Heavy Ion LINAC at GSI

linac, cavity, ion, heavy-ion

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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THPF035

Stripping of High Intensity Heavy-Ion Beams in a Pulsed Gas Stripper Device at 1.4 MeV/u

ion, brilliance, dipole, acceleration

3773

P. Scharrer, W.A. Barth, Ch.E. Düllmann, J. Khuyagbaatar
HIM, Mainz, Germany
W.A. Barth, M. Bevcic, Ch.E. Düllmann, L. Groening, K.P. Horn, E. Jäger, J. Khuyagbaatar, J. Krier, A. Yakushev
GSI, Darmstadt, Germany
Ch.E. Düllmann
Mainz University, Mainz, Germany

As part of an injector system for FAIR, the GSI UNILAC has to meet high demands in terms of beam brilliance at a low duty factor. To accomplish this goal an extensive upgrade program has started. To increase the beam intensity behind the UNILAC, it is aimed to increase the efficiency of the 1.4 MeV/u gas stripper. A modification of the stripper setup was developed to replace the N2-jet with a pulsed gas injection, synchronized with the transit of the beam pulse. The pulsed gas injection lowers the gas load for the differential pumping system, rendering possible the use of other promising gas targets. In recent measurements the performance of the modified setup was tested using an 238U-beam with various stripper media, including H2, He, and N2. The data provide a systematic basis for an improved understanding of slow heavy ions passing through gaseous media. The stripping performance of the current N2-jet was excelled by using H2 at increased gas densities, enabled by the new pulsed gas cell.

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THPF038

RIB Transport and Selection for the SPES Project

rfq, simulation, ion, target

3782

M. Comunian, L. Bellan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
A.D. Russo
INFN/LNS, Catania, Italy

The SPES project, at Legnaro National Laboratories (LNL) in Italy, is a RIB ISOL facility for the production and acceleration of “neutron-rich” radioactive ion beams. The beam dynamics of the re-accelerator part is presented with the focus on the preselection and transfer to the charge breeder device and from this device to the CW RFQ used as injector to the LNL linac ALPI.

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THPF039

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

linac, lattice, 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, linac, rfq, 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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THPF042

Rectlinear Cooling Scheme for Bright Muon Sources

simulation, space-charge, lattice, cavity

3792

D. Stratakis
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Contract No, DE-AC02-07CH11359 with the US Department of Energy.
A fast cooling technique is described that simultaneously reduces all six phase-space dimensions of a charged particle beam. In this process, cooling is accomplished by reducing the beam momentum through ionization energy loss in absorbers and replenishing the momentum loss only in the longitudinal direction rf cavities. In this work we describe its main features and describe the main results.

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THPF045

Simulation Study of Muon Acceleration using RFQ for a New Muon g-2 Experiment at J-PARC

rfq, simulation, acceleration, experiment

3801

Y. Kondo, K. Hasegawa
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
R. Kitamura
University of Tokyo, Tokyo, Japan
T. Mibe, M. Otani, N. Saito
KEK, Tsukuba, Japan

A new muon g-2 experiment is planning at J-PARC. In this experiment, ultra cold muons will be generated and accelerated using a linear accelerator. As the first accelerating structure, an RFQ will be used. We are planning to use a spare RFQ of the J-PARC linac for the first acceleration test. We present simulation studies of this acceleration test. A design study of a muon dedicated RFQ is also shown.

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THPF046

Operation of the RHIC Injector Chain with Ions from EBIS

ion, booster, injection, extraction

3804

C.J. Gardner, J.G. Alessi, E.N. Beebe, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, J.J. Butler, C. Carlson, W. Fischer, D.M. Gassner, D. Goldberg, T. Hayes, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, J.S. Laster, D. Maffei, M. Mapes, I. Marneris, G.J. Marr, A. Marusic, D.R. McCafferty, K. Mernick, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, S. Perez, A.I. Pikin, D. Raparia, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, P. Thieberger, J.E. Tuozzolo, B. Van Kuik, A. Zaltsman, K. Zeno, W. Zhang
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.
Since 2012 gold and all other ions for the RHIC injector chain have been provided by an Electron Beam Ion Source (EBIS). The source is followed by an RFQ, a short Linac, and a 30 m transport line. These components replace the Tandem van de Graaff and associated 840 m transfer line. They provide ions at 2 MeV per nucleon (kinetic energy) for injection into the AGS Booster. The setup and operation of Booster and AGS with various ions from the new source are reviewed.

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THPF057

Beam Commissioning of C-ADS Injector-I RFQ Accelerator

rfq, proton, linac, 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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THPF060

The Simulation Study of Space Charge Effects for CSNS Linac

space-charge, DTL, focusing, simulation

3833

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

China Spallation Neutron Source (CSNS) is a high intensity accelerator based facility. Its accelerator consists of an H⁻ injector and a proton Rapid Cycling Synchrotron. The injector includes the front end and linac. The RFQ accelerates the beam to 3MeV, and then DTL accelerates it to 80MeV. The space charge effect is the most important cause of emittance growth and beam loss due to the low beam energy and the high peak current. The paper performed simulation studies on the space charge effects at the LINAC by using three-dimensional code IMPACT-Z. The emittance evolution is studied in the point of view of the singe-particle dynamics and multi-particle dynamics with different peak beam current. The effect of mismatch is studied by simulation, and the emittance growth with different mismatch factor are given.

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THPF078

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

DTL, klystron, focusing, linac

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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THPF083

Painting Schemes for CERN PS Booster H⁻ Injection

injection, simulation, linac, 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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THPF085

Beam Commissioning of Linac4 up to 12 MeV

linac, DTL, 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, linac, vacuum

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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THPF087

New Shaving Scheme for Low-Intensity Beams in the CERN PS Booster and Feasibility at 160 MeV

booster, closed-orbit, simulation, operation

3893

M. Kowalska, E. Benedetto, V. Forte, B. Mikulec, G. Rumolo
CERN, Geneva, Switzerland
V. Forte
Université Blaise Pascal, Clermont-Ferrand, France
M. Kowalska
EPFL, Lausanne, Switzerland

The PS Booster is the first synchrotron in the CERN proton accelerator chain, serving all downstream machines. As part of the LHC Injector Upgrade Project, the PSB injection energy will increase from 50 MeV to 160 MeV and a new H⁻ charge-exchange injection scheme will be implemented. Beam losses are a concern due to the increased injection energy, and mitigation scenarios are under investigation. On the other hand it is desirable for low-intensity beams to have the possibility to precisely tailor sub-micron beam emittances through controlled scraping (transverse shaving process) towards a suitable aperture restriction. Challenges are the higher activation potential of the beam and the smaller transverse beam sizes around 160 MeV as compared to 63 MeV, at which the shaving is presently done. This paper describes the proposal of a new shaving scheme, more robust with respect to the steering errors and the choice of the working point, which localizes the scraping losses on the main PS Booster aperture restriction. The robustness of the new method, together with the results of simulations and measurements are discussed for the current (50 MeV) and future (160 MeV) situation.

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THPF088

CERN PS Booster Upgrade and LHC Beams Emittance

injection, simulation, space-charge, booster

3897

E. Benedetto, J.L. Abelleira, C. Bracco, V. Forte, B. Mikulec, G. Rumolo
CERN, Geneva, Switzerland
V. Forte
Université Blaise Pascal, Clermont-Ferrand, France

By increasing the CERN PS Booster injection energy from 50 MeV to 160 MeV, the LHC Injector Upgrade Project aims at producing twice as brighter beams for the LHC. Previous measurements showed a linear dependence of the transverse emittance with the beam intensity and space-charge simulations confirmed the linear scaling. This paper is discussing in detail the dependence on the longitudinal emittance and on the choice of the working point, with a special attention to the H⁻ injection process and to the beam dynamics in the first 5 ms, during the fall of the injection chicane bump.

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THPF091

Detailed Studies of Beam Induced Scrubbing in the CERN-SPS

electron, injection, proton, operation

3908

G. Iadarola, H. Bartosik, T. Bohl, B. Goddard, G. Kotzian, K.S.B. Li, L. Mether, G. Rumolo, M. Schenk, E.N. Shaposhnikova, M. Taborelli
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade (LIU) program, it is foreseen to take all the necessary measures to avoid electron cloud effects in the CERN-SPS. This can be achieved by either relying on beam induced scrubbing or by coating the vacuum chambers with intrinsically low Secondary Electron Yield (SEY) material over a large fraction of the ring. To clearly establish the potential of beam induced scrubbing, and to eventually decide between the two above options, an extensive scrubbing campaign is taking place at the SPS. Ten days in 2014 and two full weeks in 2015 are devoted to machine scrubbing and scrubbing qualification studies. This paper summarizes the main findings in terms of scrubbing efficiency and reach so far, addressing also the option of using a special doublet beam and its implication for LHC.

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THPF099

Upgrade of the SPS Ion Injection System

ion, injection, kicker, simulation

3938

J.A. Uythoven, J. Borburgh, E. Bravin, S. Burger, E. Carlier, J.-M. Cravero, L. Ducimetière, S.S. Gilardoni, B. Goddard, J. Hansen, E.B. Holzer, M. Hourican, T. Kramer, F.L. Maciariello, D. Manglunki, F.-X. Nuiry, A. Perillo Marcone, G.E. Steele, F.M. Velotti, H. Vincke
CERN, Geneva, Switzerland

As part of the LHC Injectors Upgrade Project (LIU) the injection system into the SPS will be upgraded for the use with ions. The changes will include the addition of a Pulse Forming Line parallel to the existing PFN to power the kicker magnets MKP-S. With the PFL a reduced magnetic field rise time of 100 ns should be reached. The missing deflection strength will be given by two new septum magnets MSI-V, to be installed between the existing septum MSI and the kickers MKP-S. A dedicated ion dump will be installed downstream of the injection elements. The parameter lists of the elements and studies concerning emittance blow-up coming from the injection system are presented. The feasibility of the 100 ns kicker rise time and the small ripple of the septum power converter are presented. Material studies of the ion dump are presented together with the radiation impact.

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THPF105

Status of the RAL Front End Test Stand

rfq, proton, quadrupole, ion

3959

A.P. Letchford, M.A. Clarke-Gayther, M. Dudman, D.C. Faircloth, S.R. Lawrie
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
S.M.H. Alsari, M. Aslaninejad, J.K. Pozimski, P. Savage
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
J.J. Back
University of Warwick, Coventry, United Kingdom
G.E. Boorman, A. Bosco, S.M. Gibson
Royal Holloway, University of London, Surrey, United Kingdom
R.T.P. D'Arcy, S. Jolly
UCL, London, United Kingdom
J.K. Pozimski
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom

The Front End Test Stand (FETS) under construction at RAL is a demonstrator of front end systems for future high power proton linacs. Possible applications include a linac upgrade for the ISIS spallation neutron source, new future neutron sources, accelerator driven sub-critical systems, high energy physics proton drivers etc. Designed to deliver a 60mA H-minus beam at 3MeV with a 10% duty factor, FETS consists of a high brightness surface plasma ion source, magnetic solenoid low energy beam transport (LEBT), 4-vane 324MHz radio frequency quadrupole and medium energy beam transport (MEBT) containing a high speed beam chopper and non-destructive laser diagnostics. This paper describes the current status of the project and future plans.

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THPF112

A New Beam Injection Scheme for the Fermilab Booster

injection, booster, simulation, acceleration

3976

C.M. Bhat
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy
Here we present an improved beam injection scheme for the Fermilab Booster. The beam is injected on the deceleration part of the standard sinusoidal magnetic ramp and beam capture takes place almost immediately after the injection process, before the beam is fully de-bunched. During the entire capture process we impose in a changing field with changing from negative to zero to positive values. Our simulations clearly showed that this method of beam capture is more efficient to preserve longitudinal beam emittance at the early part of the acceleration cycle and helps to keep the required rf voltage to an optimal value of 15% lower than the current operational values. As a result of the reduced emittance growth at the early part of the Booster cycle we observe reduced required rf power on a typical Booster cycle by ~30%, which is quite important from the point of rf power requirements during the Booster operation. Further, we investigate snap bunch rotation at extraction to provide beam with lower to the MI/RR to improve the proton beam slip-stacking efficiency.

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THPF122

The Status of MICE Step IV

solenoid, experiment, detector, collider

4000

D. Rajaram
Fermilab, Batavia, Illinois, USA
V.C. Palladino
INFN-Napoli, Napoli, Italy

Funding: SFTC, DOE, NSF, INFN, CHIPP and more
Muon (μ) beams of low emittance provide the basis for the intense, well-characterised neutrino beams of the Neutrino Factory and for lepton-antilepton collisions at energies of up to several TeV at the Muon Collider. The International Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling; the technique by which it is proposed to reduce the μ phase-space volume. In a cooling channel, the μ beam traverses a material (the absorber) in which it looses energy, then replaced longitudinally by RF cavities. The net effect is to reduce transverse emittance(transverse cooling). MICE is being constructed in a series of Steps. At Step IV, MICE will study the properties of liquid hydrogen and lithium hydride that affect cooling. A solenoidal spectrometer will measure emittance up and downstream of the absorber vessel, where a focusing coil will focus muons. The construction of Step IV at RAL is well advanced towards scheduled completion early in 2015. Its status will be described together with a summary of the performance of the principal components. Plans for the commissioning and operation and the Step IV measurement programme will be described.

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THPF126

PXIE Low Energy Beam Transport Commissioning

solenoid, ion, ion-source, simulation

4013

L.R. Prost, M.L. Alvarez, R. Andrews, J.-P. Carneiro, R.T.P. D'Arcy, B.M. Hanna, V.E. Scarpine, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA
R.T.P. D'Arcy
UCL, London, United Kingdom
C. Wiesner
IAP, Frankfurt am Main, Germany

Funding: Operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
The Proton Improvement Plan II at Fermilab is a program of upgrades to the injection complex [1]. At its core is the design and construction of a CW-compatible, pulsed H⁻ superconducting RF linac. To validate the concept of the front-end of such machine, a test accelerator (a.k.a. PXIE) is under construction [2]. It includes a 10 mA DC, 30 keV H⁻ ion source, a 2m-long LEBT, a 2.1 MeV CW RFQ, followed by a MEBT that feeds the first of 2 cryomodules taking the beam energy to ~25 MeV, and a High Energy Beam Transport section (HEBT) that takes the beam to a dump. The ion source and LEBT, which includes 3 solenoids, several clearing electrodes/collimators and a chopping system, have been built, installed, and commissioned to full specification parameters. This report presents the outcome of our commissioning activities, including phase-space measurements at the end of the beam line under various neutralization schemes obtained by changing the electrodes’ biases and chopper parameters.

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THPF127

Scheme for a Low Energy Beam Transport with a Non-neutralized Section

ion, space-charge, ion-source, rfq

4016

A.V. Shemyakin, L.R. Prost
Fermilab, Batavia, Illinois, USA

Funding: Fermilab is operated by Fermi Research Alliance, LLC, under Contract DE-AC02-07CH11359 with the United States Department of Energy
A Low Energy Beam Transport (LEBT) line is the part of a modern ion accelerator between an ion source (IS) and a Radio-Frequency Quadrupole (RFQ). Typically, it includes 1-3 solenoidal lenses for focusing and relies on transport dynamics with nearly complete beam space charge neutralization over the entire length of the LEBT. In this paper, we discuss the possibility and rationality of imposing un-neutralized transport in the portion of the LEBT adjacent to the RFQ. For estimations, we will use the parameters from PXIE, a test accelerator presently being constructed at Fermilab.

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THPF129

The MICE Demonstration of Lonization Cooling

lattice, acceleration, radiation, cavity

4023

J. Pasternak, C. Hunt, J.-B. Lagrange, K.R. Long
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
V. Blackmore
Imperial College of Science and Technology, London, United Kingdom
N.A. Collomb
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
V.C. Palladino
INFN-Napoli, Napoli, Italy
R. Preece, J.S. Tarrant
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
C.T. Rogers
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
P. Snopok
Fermilab, Batavia, Illinois, USA

Funding: SFTC, DOE, NSF, INFN, CHIPP and more
Muon beams of low emittance provide the basis for the intense, well-characterised neutrino beams necessary to elucidate the physics of flavour at the Neutrino Factory and to provide lepton-antilepton collisions at energies of up to several TeV at the Muon Collider. The International Muon Ionization Cooling Experiment (MICE) will demonstrate ionization cooling, the technique by which it is proposed to reduce the phase-space volume occupied by the muon beam at such facilities. In an ionization-cooling channel, the muon beam passes through a material (the absorber) in which it loses energy. The energy lost is then replaced using RF cavities. The combined effect of energy loss and re-acceleration is to reduce the transverse emittance of the beam (transverse cooling). A major revision of the scope of the project was carried out over the summer of 2014. The revised project plan, which has received the formal endorsement of the international MICE Project Board and the international MICE Funding Agency Committee, will deliver a demonstration of ionization cooling by September 2017. In the revised configuration a central lithium-hydride absorber provides the cooling effect. The magnetic lattice is provided by the two superconducting focus coils and acceleration is provided by two 201 MHz single-cavity modules. The phase space of the muons entering and leaving the cooling cell will be measured by two solenoidal spectrometers. All the superconducting magnets for the ionization cooling demonstration are available at the Rutherford Appleton Laboratory and the first single-cavity prototype is under test in the MuCool Test Area at Fermilab. The design of the cooling demonstration experiment will be described together with a summary of the performance of each of its components. The cooling performance of the revised configuration will also be presented.

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THPF136

Beam Dynamics Optimization of FRIB Folding Segment 1 with Single-type Re-buncher Cryomodule

lattice, cavity, cryomodule, quadrupole

4042

Z.Q. He, M. Ikegami, F. Marti, T. Xu, Y. Zhang, Q. Zhao
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.
FRIB is using a charge stripper in folding segment 1 to increase the number of charge states of particles to enhance the acceleration efficiency. To control possible emittance growth after the charge stripper, the 3-dimensional on-stripper beam size should be as small as possible. The original 2-cavity-HWR (HWR stands for half wave resonator) rebuncher cryomodule is responsible for the longitudinal focusing before stripper. In order to accept and transport the beam downstream to linac segment 2, another kind of 3-cavity-QWR (QWR stands for quarter wave resonator) rebuncher cryomodule is baselined after the stripper. However, two kinds of cryomodules would increase the cost in design, therefore would be quite inefficient. In this paper, the FRIB lattice with only single-type 4-cavity-QWR rebuncher cryomodule in folding segment 1 is discussed. Positions of lattice elements are adjusted to accommodate the new type of cryomodule. Beam dynamics is optimized to meet the on-stripper beam requirement. The lattice is then adjusted and rematches.

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THPF146

Spin Coherence Time Lengthening of a Polarized Deuteron Beam Using Sextupole FieldsFields

polarization, sextupole, storage-ring, electron

4066

G. Guidoboni
UNIFE, Ferrara, Italy

Funding: Forschungszentrum Jülich is a member of the Helmholtz Association
The measurement of a non-zero electric dipole moment (EDM) aligned along the spin of sub-atomic particles would probe new physics beyond the standard model. It has been proposed to search for the EDM of charged particles using a storage ring and a longitudinally polarized beam. The EDM signal would be a rotation of the polarization from the horizontal plane toward the vertical direction as a consequence of the radial electric field always present in the particle frame. This experiment requires ring conditions that can ensure a lifetime of the in-plane polarization (spin coherence time, SCT) up to 1000 s. At the COoler SYnchrotron (COSY) located at the Forschungszentrum Jülich, the JEDI collaboration has begun to examine the effects of emittance and momentum spread on the SCT of a polarized deuteron beam at 0.97 GeV/c. The set of data presented here shows how second-order effects from emittance and momentum spread of the beam affect the lifetime of the horizontal polarization of a bunched beam. It has been observed that sextupole fields can correct for depolarizing sources and increase the spin coherence time up to hundreds of seconds while setting the chromaticities equal to zero.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF146

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THPF147

Increasing the Beam Brightness of a Duoplasmatron Proton Ion Source

extraction, brightness, ion, ion-source

4070

Y.K. Batygin, I.N. Draganic, C.M. Fortgang
LANL, 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 accelerator facility operates with two independent ion injectors for H⁺ and H⁻ particle beams. The H⁺ ion beam is formed using a duoplasmatron source followed by a 750 keV Cockroft-Walton accelerating column. Formation of an optimal plasma meniscus is an important feature for minimizing beam emittance and maximizing beam brightness. An experimental study was performed to determine optimal conditions of extracted H⁺ beam for maximizing beam brightness. Study was based on measurements of beam emittance versus variable beam current and extraction voltage. Measurements yielded 0.52 as the best ratio of beam perveance to Child - Langmuir perveance for maximizing beam brightness. As a result of optimization, beam brightness was increased by a factor of 2.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF147

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)