HB2012 - List of Keywords (linac)

Paper	Title	Other Keywords	Page
MOI1A02	J-PARC Recovery Status	extraction, status, kicker, vacuum	6
	K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	J-PARC facilities were seriously damaged by the Great East Japan Earthquake in March 2011, but all facilities resumed a beam operation from December 2012. We report the operation status of J-PARC accelerators after the earthquake.
	Slides MOI1A02 [12.726 MB]

MOI1B02	Technological Challenges for High-Intensity Proton Rings	proton, injection, acceleration, space-charge	15
	Y. Yamazaki FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 High-intensity, pulsed proton accelerators have been and will be requested by a wide variety of scientific fields and industrial and medical applications, for example, pulsed spallation neutron sources and neutrino sources. We will focus our discussion on the proton rings with a pulse length of a few μsec and a beam power of MW. These accelerators may be used for boosting injectors to higher-energy accelerators, like a neutrino factories. At first, we will discuss on the space-charge force which limit the stored charges in a ring together with the negative-ion injection scheme. The pulsed spallation neutron sources are classified into two schemes. One is the combination of a full-energy linac and an accumulation ring (AR) exemplified by SNS and LANSCE. The other is that of a low-energy linac and a Rapid-Cycle Synchrotron (RCS) exemplified by J-PARC RCS and ISIS. In general, pros and cons of accelerator schemes are dependent upon the technological development results. Pros and cons of AR versus RCS will be discussed on the basis of recent technological developments and beam experiment data together with the future perspectives for MW-class machines.
	Slides MOI1B02 [3.850 MB]

MOI1B03	Technical Challenges in Multi-MW Proton Linacs	rfq, cryomodule, proton, acceleration	20
	V.A. Lebedev Fermilab, Batavia, USA
	The intensity frontier research is an important part of modern elementary particle physics. It uses proton beams to create secondary beams consisting of, but not necessary limited to, neutrinos, muons, kaons and neutrons. Deferent experiments require different time structure of proton beams but all of them require the beam power of about or exceeding 1 MW. In addition, powerful proton linacs can find an application in accelerator driven nuclear reactors and transmutation of radioactive waste. Recent advances in the superconducting RF technology make a multi-MW power level economically acceptable. This paper discusses main physics and technical limitations determining ultimate parameters of such accelerators, their structure and performance.
	Slides MOI1B03 [2.863 MB]

MOI1C01	Intense-beam Issues in CSNS and C-ADS Accelerators	cavity, emittance, lattice, simulation	25
	S. Fu, S.X. Fang, Z. Li, J. Peng, J.Y. Tang, S. Wang, F. Yan IHEP, Beijing, People's Republic of China
	In 2011 construction of two intense-beam accelerators were launched for China Spallation Neutron Source (CSNS) project and China Accelerator Driven System (C-ADS) project. CSNS uses a pulsed accelerator with an H⁻ linac and a rapid cycling synchrotron, and C-ADS has a CW proton linac with superconducting cavities. In both cases, the beam power is high and beam loss control is a key issue in beam dynamics. Beam emittance growth and beam halo formation must be carefully studied in beam dynamics and well controlled in machine design. This paper will present a brief introduction to the physics design of the two intense-beam accelerators, especially on the issue of beam instability. In their linac design equapartitioning focusing scheme is adopted to avoid coupling instability. Some beam halo formation experimental results due to mismatching will be compared with simulations. Beam halo generation due to the quench of superconducting cavity and magnet is investigated in detail and compensation scheme is also proposed. Beam loss study for the error effects and orbit correction will be presented.
	Slides MOI1C01 [3.747 MB]

MOI1C02	Challenges in Benchmarking of Simulation Codes against Real High Intensity Accelerators	simulation, space-charge, resonance, emittance	30
	I. Hofmann GSI, Darmstadt, Germany
	Benchmarking of simulation codes for linear or circular accelerators involves several levels of complexity, which will be revisited and discussed in this talk. As ultimate goal of benchmarking it is hoped that a predictive capacity and a practical control over emittance growth and/or beam loss can be obtained. We first give some examples of how simulation codes can be used to gain as much understanding of the underlying physics mechanisms as possible, which is an almost inevitable first step. With more and more experimental data from running high intensity accelerators having become available in recent years more questions need to be raised: Besides the proper physics, can we feed our codes with an accurate enough model of the real machine? What actually is the required accuracy, and does a specific accelerator have enough diagnostics to enable this accuracy? In the paper we explore these questions by discussing several examples of benchmarking efforts, their achievements as well as the limits and difficulties that have been encountered.
	Slides MOI1C02 [2.838 MB]

MOI1C03	Beam Loss Mechanisms in High Intensity Linacs	DTL, proton, ion, optics	36
	M.A. Plum 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. Beam loss is a critical issue in high intensity linacs, and much work is done during both the design and operation phases to keep the loss down to manageable levels. Linacs for H⁻ ion beams have many more loss mechanisms compared to H⁺ (proton) linacs. Interesting H⁻ beam loss mechanisms include residual gas stripping, H⁺ capture and acceleration, field stripping, and intra-beam stripping (IBSt). Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H⁺ and H⁻ accelerators. The IBSt mechanism has recently been characterized at the Oak Ridge Spallation Neutron Source, and we have found that it accounts for most of the loss in the superconducting linac. In this paper we will detail the IBSt measurements, and also discuss the other beam loss mechanisms that are important for high intensity linacs.
	Slides MOI1C03 [5.588 MB]

MOP212	Simulation of Longitudinal Beam Instability caused by HOMs	HOM, simulation, cavity, damping	73
	P. Cheng, Z. Li, J.Y. Tang, J.Q. Wang IHEP, Beijing, People's Republic of China
	Superconducting cavities are employed in C-ADS linac to accelerate 10mA CW proton beams from 3.2 MeV to 1.5 GeV. High order modes in superconducting cavities are found by using the simulation tools CST and HFSS, then power dissipation caused by HOMs have been investigated, it is indicated that the Qext should not go beyond 10⁷} in order to limit the additional heat load. Beam instabilities caused by high order modes in elliptical cavity sections are investigated using the code offered by Dr. Jean-Luc Biarrotte (CNRS, IPN Orsay, France). Beam errors, linac errors and high order modes frequency spread are investigated in detail. It shows that the monopole modes do not affect the proton beam critically and need no HOM couplers (Q_ext=10⁵}) if high order modes frequency spread is more than 100 kHz.

MOP217	MEBT2 Design for the C-ADS Linac	emittance, focusing, space-charge, proton	93
	Z. Guo, H. Geng, Z. Li, J.Y. Tang IHEP, Beijing, People's Republic of China
	The C-ADS linac is composed by two parallel injectors and a main linac, a section of Medium Energy Beam Line (MEBT2) is designed to guide and match beams from two injectors to the main linac. The two injectors are hot-spare for each other in order to satisfied the requirement of high availability and reliability. The beam in online operation mode will be directed to the main linac from one injector, while the beam in the offline mode with low repetition frequency from the other injector, will be directed to a beam dump through an auxiliary beam line. With a long drift distance and in the presence of space charge force for 10 mA 10 MeV proton beam, the debunching effect is very strong and it requires very strict control over beam losses and emittance growth. It is difficult to obtain satisfactory longitudinal matching without bunchers in the bending section. An analytical study using transfer matrix shows that with two bunchers of same voltage in the bending section the achromatism can be maintained if the effective voltage is inversely proportional to the distance between the two bunchers. It is also under consideration if and how a beam collimation can be implanted in MEBT2.

MOP218	Dynamics of Particles in a Tilted Solenoidal Focusing Channel	focusing, emittance, solenoid, alignment	97
	H. Jiang, S. Fu IHEP, Beijing, People's Republic of China
	We use the paraxial ray approximation equations to analysis the dynamics of particles in a tilted solenoidal focusing channel. In this case, the particles' initial canonical angular momentum is nonzero, so we need to add the term of centrifugal potential to the dynamics equation of particles. And in the dynamics equation this centrifugal potential term is nonlinear, which results in the emittance growth. In practice, we also need to consider the spherical aberration's effect on emittance growth and the linear part of the space-charge force of a Kapchinskij-Vladimirskij distribution beam in the dynamics equation of particles.

MOP219	Error Analysis and Correction Scheme in C-ADS Injector-I	emittance, cavity, simulation, solenoid	99
	C. Meng, Z. Li, J.Y. Tang IHEP, Beijing, People's Republic of China
	Funding: Supported by the China ADS Project (XDA03020000) C-ADS Injector-I is a 10 mA 10 MeV CW proton linac. It uses a 3.2MeV normal conducting 4-Vane RFQ and 12 superconducting single-Spoke cavities. According to the detailed sensitivity analysis of alignment and RF errors, the error tolerance of both static and dynamic ones for Injector-I are presented. The simulation results show that with the error tolerance there are beam losses, the residual orbit is too large which will produce significant emittance growth, so the correction is necessary for Injector-I. After detailed numerical studies, a correction scheme and monitor distributions are proposed. After correction the RMS residual orbit can be controlled within 0.4mm and RMS emittance growth can be controlled within 10%, but it still has 1.7×10^-6 beam loss, which comes from the RF errors and low longitudinal acceptance. According to detailed analysis and simulations with 10⁸ macro particles, as a consequence, longitudinal emittance control and longitudinal distribution control as well as large longitudinal acceptance are the key to minimizing beam losses in low energy section. To minimize beam loss, a short period Injector-I lattice with larger longitudinal acceptance have been designed and performance very good error tolerance.

MOP221	Physics Design of the C-ADS Main Linac Based on Two Different Injector Design Schemes	emittance, simulation, lattice, cavity	107
	F. Yan, Z. Li, C. Meng, J.Y. Tang IHEP, Beijing, People's Republic of China
	Funding: Supported by Advanced Research Project of the Chinese Academy of Science Two design schemes for the main linac of C-ADS (China Accelerator Driven Subcritical system) are presented in this paper. They are corresponding to two different injector schemes. Injector-II scheme makes use of room-temperature RFQ and superconducting HWR cavities with the RF frequency of 162.5 MHz; Injector-I scheme makes use of higher-energy RFQ and superconducting spoke cavities with the RF frequency of 325 MHz. At the first choice, a relatively smaller longitudinal emittance is adopted for the RFQ designs with both the injector schemes to obtain more efficient acceleration. However, compared with the injector-I scheme, with the injector-II scheme, bunch current will be doubled in the main linac due to the half RF frequency in the injector-II. This means stronger space charge effects. Alternate design for the main linac with the injector-II scheme is to increase the longitudinal emittance by 50% so that the space charge effects will be alleviated. However, totally 30 cavities more and 36 m longer in the main linac have to be paid for this design scheme. The design considerations, the lattice designs, the simulation results including halo information are presented.

MOP231	Study of Non-equi-partitioning Lattice Setting and IBS Effects for J-PARC Linac Upgrade	emittance, lattice, simulation, DTL	118
	Y. Liu IMP, Lanzhou, People's Republic of China M. Ikegami JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	For the coming upgrade of J-Parc, the peak power of linac will be greatly increased. This may open many interesting questions. For instance, for efficient acceleration from 19 0MeV to 400 MeV the annular coupled structure (ACS) was applied with frequency jump from 324 MHz to 972 MHz. Upstream part of J-PARC linac from the frequency jump is set with the equi-partitioning (EP) condition, which prevents from the coherent resonances. If EP condition is kept for the downstream part, due to the frequency jump, the transverse focusing should also ‘jump' 3 times with shrink of envelop. The increased beam-density affects the interactions between particles, including the intra-beam stripping (IBS) effect in the H⁻ beam. The temperature ratio between transverse and longitudinal planes is used as a knob for studying the beam behavior for the cases away from equi-partitioning. The IBS effects, as well as strategies for setting downstream non-equi-partitioning lattice due to frequency jump are studied. The matching and beam evolution in the transition section from EP to non-EP (MEBT2) are also studied. The results help to reach an optimum with least risks from resonances and IBS effects and so on.

MOP232	Optimization of the Superconducting Section of Injector Ⅱ for C-ADS	solenoid, emittance, simulation, lattice	122
	S.H. Liu, Y. He, Z.J. Wang IMP, Lanzhou, People's Republic of China
	Abstract: The China Accelerator driven System (C-ADS) project which includes a high current SC proton linac is being studied under Chinese Academy of Science. Injector II, one of parallel injectors, is undertaken by Institute of Modern Physics (IMP). The lattice design of Injector II has been done. While in most case, the elements, such as SC cavities and SC solenoids, have different weight to the final beam parameters. What is more, in the real operation process of the machine, the optimized mode is hard to find. In the paper, Latin sampling method specified in DAKOTA code combined with TRACK is adopted to build hundreds of virtual machines to analyse the sensitivity of the SC section and to find optimization operation mode.

MOP233	Error and Tolerance Studies for Injector II of C-ADS	simulation, solenoid, alignment, emittance	125
	W.S. Wang, Y. He, Z.J. Wang IMP, Lanzhou, People's Republic of China
	The proposed Chinese Accelerator Driven System (C-ADS) driver linac is being designed by Chinese Academic Science (CAS). Injector II is designed and fabricated in Institute of Modern Physics (IMP). Injector II will accelerate 10 mA proton beams to 10 MeV. Because of the high final beam power (100 kW) specified for the linac operation, beam loss must be limited to 10^-5 level to avoid radiation damage. Misalignment and RF error simulation for cavities and focusing elements after RFQ were performed and the correction schemes developed using the computing code TRACK. Error and tolerance studies for Injector II are presented.

MOP235	Medium Energy Beam Transport Design Update for ESS	cavity, quadrupole, DTL, rfq	128
	I. Bustinduy, F.J. Bermejo, A. Ghiglino, O. González, J.L. Muñoz, I. Rodríguez, A. Zugazaga ESS Bilbao, Bilbao, Spain B. Cheymol, M. Eshraqi, R. Miyamoto ESS, Lund, Sweden J. Stovall CERN, Geneva, Switzerland
	The major challenge of this part of the accelerator is to keep a high quality beam, with a pulse well defined in time, a low emittance and a minimized halo, so that the beam losses downstream the linac be limited and the overall ESS reliability be maximized. In order to minimize beam loss at high energy linac, and the consequent activation of components, a fast chopping scheme is presented for the medium energy beam transport section (MEBT). The considered versatile MEBT is being designed to achieve four main goals: First, to contain a fast chopper and its correspondent beam dump, that could serve in the commissioning as well as in the ramp up phases. Second, to serve as a halo scraping section by means of two adjustable blades. Third, to measure the beam phase and profile between the RFQ and the DTL, along with other beam monitors. And finally, to match the RFQ output beam characteristics to the DTL input both transversally and longitudinally. For this purpose a set of ten quadrupoles is used to match the beam characteristics transversally, combined with two 352.2 MHz buncher cavities, which are used to adjust the beam in order to fulfill the required longitudinal parameters.

MOP238	Beam Position Monitor System of the ESS Linac	LLRF, quadrupole, controls, target	133
	H. Hassanzadegan, A. Jansson ESS, Lund, Sweden A.J. Johansson Lund University, Lund, Sweden
	The pulsed ESS linac will include about 100 BPMs, mostly with a European XFEL style button design, 6 BPMs with a special design for the Medium Energy Beam Transport, as well as 8 stripline BPMs foreseen for the Drift Tubes. The required accuracy and resolution of the position measurement are 100 μm (rms) and 20 μm (rms) respectively with the 50 mA 2.86 ms nominal pulse. In addition to the position measurement, the BPM system needs to measure the beam phase in the nominal pulse as well as several diagnostics pulse modes with a minimum duration and intensity of 5 μs and 5 mA respectively. After a study of the possible electronics platforms, MTCA.4 is now considered as the main prototyping platform for the high performance sub-systems at ESS. It is foreseen to prototype a Rear Transition Module for IQ-based RF signal measurements intended for both the BPM and LLRF systems. The requirements and specifications of the BPM system are presented and the plan for the continuation of the project is described in this paper.

MOP244	CERN High-Power Proton Synchrotron Design Study for LAGUNA-LBNO Neutrino Production	proton, synchrotron, target, status	154
	R. Steerenberg, M. Benedikt, I. Efthymiopoulos, F. Gerigk, Y. Papaphilippou CERN, Geneva, Switzerland
	Within the framework of the LAGUNA-LBNO project, CERN has started design studies in view of producing neutrinos for future long base line neutrino experiments. These design studies foresee a staged approach in the increase of the primary proton beam power, used for the neutrino production. The first step consists of exploring the feasibility of a CERN SPS beam power upgrade from the existing 500 kW, presently available to CNGS, to 750 kW. This beam should then be transferred to a new to be built neutrino beam line that is dimensioned for a beam power of 2 MW. The 2 MW proton beam is to be provided at a subsequent stage by a 30 - 50 GeV High-Power Proton Synchrotron (HP-PS), which is a major part of the design studies. This paper will provide an overview of the project and then focus on the preliminary ideas for the HP-PS design study.

MOP249	Tune Spread Studies at Injection Energies for the CERN Proton Synchrotron Booster	injection, emittance, space-charge, proton	175
	B. Mikulec, A. Findlay, V. Raginel, G. Rumolo, G. Sterbini CERN, Geneva, Switzerland
	In the near future, a new H⁻ injector, Linac4, will replace the current proton injector of the CERN Proton Synchrotron Booster (PSB), Linac2. The new charge-exchange injection at 160 MeV will yield higher brightness beams compared to the conventional 50 MeV multi-turn injection of Linac2. To make full use of the higher injection energy, space-charge effects will need to be understood and mitigated to optimize the intensity versus transverse emittance reach. This includes an optimization of longitudinal acceptance and distribution with a two-harmonic rf system, careful selection of the working point to accommodate the large Laslett tune-shift of approximately -0.5 and compensation of resonances within their stopbands. This paper will present calculations of the tune spread, based on measurements of longitudinal parameters and transverse emittances, for energies up to 160 MeV, different bunch densities and varying beam intensities. It should provide valuable information on the expected tune spread after the connection of Linac4 with the PSB and input for the study of resonance compensation techniques.

TUO1A01	The High Intensity/High Brightness Upgrade Program at CERN: Status and Challenges	injection, emittance, space-charge, extraction	226
	S.S. Gilardoni, G. Arduini, T. Argyropoulos, S. Aumon, H. Bartosik, E. Benedetto, N. Biancacci, T. Bohl, J. Borburgh, C. Carli, F. Caspers, H. Damerau, J. Esteban Müller, V. Forte, R. Garoby, M. Giovannozzi, B. Goddard, S. Hancock, K. Hanke, A. Huschauer, G. Iadarola, M. Meddahi, G. Métral, B. Mikulec, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, R. Steerenberg, G. Sterbini, M. Taborelli, H. Timko, M. Vretenar, R. Wasef, C. Yin Vallgren, C. Zannini CERN, Geneva, Switzerland G. Franchetti GSI, Darmstadt, Germany M. Migliorati University of Rome "La Sapienza", Rome, Italy A.Y. Molodozhentsev J-PARC, KEK & JAEA, Ibaraki-ken, Japan M.T.F. Pivi SLAC, Menlo Park, California, USA V.G. Vaccaro Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli, Italy
	The future beam brilliance and intensities required by the HL-LHC (High-Luminosity LHC) project and for possible new neutrino production beams triggered a deep revision of the LHC injector performances. The analysis, progressing in the framework of the LHC Injectors Upgrade (LIU) projects, outlined major limitations mainly related to collective effects - space charge in PSB and PS, electron cloud driven and TMCI instabilities in the SPS, longitudinal coupled bunch instabilities in the PS for example - but also to the existing hardware capability to cope with beam instabilities and losses. A summary of the observations and simulation studies carried out so far, as well as the future ones, will be presented. The solution proposed to overcome the different limitations and the plans for their implementation will be also briefly reviewed.
	Slides TUO1A01 [12.748 MB]

TUO3A01	Dynamical Aspects of Emittance Coupling in Intense Beams	emittance, resonance, coupling, simulation	240
	I. Hofmann GSI, Darmstadt, Germany I. Hofmann HIJ, Jena, Germany
	In this paper we study in an idealized lattice model the dynamical behavior of non-equipartitioned beams and of approach to equipartition. It is shown that emittance transfer depends on times scales of tune change, but also the direction of crossing the stopbands of space charge resonances. This provides additional information to support the stability charts suggested previously as design tool for high current linacs.
	Slides TUO3A01 [4.897 MB]

TUO3A03	Equipartition, Reality or Swindle?	resonance, coupling, emittance, space-charge	250
	J.-M. Lagniel GANIL, Caen, France
	By way of introduction to a general discussion on space-charge induced energy equipartition (EQP), the following questions will be tackled: Why the formula presently used to define EQP is wrong? Why energy exchanges can occur although the EQP rule is respected? Why safe tunings can be find although the EQP rule is not respected? Why EQP is a swindle for a large majority of our accelerated beams? Why LINAC designers nevertheless like to use the EQP rule?
	Slides TUO3A03 [1.537 MB]

TUO1B02	Injection Design for Fermilab Project X	injection, booster, dipole, proton	259
	D.E. Johnson, C.-Y. Tan, Z. Tang Fermilab, Batavia, USA
	Fermilab is proposing a staged approach for Project X, a high power proton accelerator system. The first stage of this project will be to construct a 1 GeV CW H⁻ superconducting linear accelerator to inject into the existing 8 GeV Booster synchrotron ultimately providing in excess of 1 MW beam power for the Neutrino program out of the Main Injector. We will discuss the current project plans for injection into the Booster and related issues.
	Slides TUO1B02 [1.380 MB]

TUO1B05	The Design and Commissioning of the Accelerator System of the Rare Isotope Reaccelerator - ReA3 at Michigan State University	cryomodule, rfq, target, ion	269
	X. Wu, B. Arend, C. Compton, A. Facco, M.J. Johnson, D. Lawton, D. Leitner, F. Montes, S. Nash, J. Ottarson, G. Perdikakis, J. Popielarski, J.A. Rodriguez, M.J. Syphers, W. Wittmer, Q. Zhao NSCL, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Sciences under Cooperative Agreement DE-SC0000661 The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is currently constructing its new rare isotope reaccelerator facility: ReA3, which will provide unique low-energy rare isotope beams by stopping fast rare isotopes in gas stopping systems, boosting the charge state in an Electron Beam Ion Trap (EBIT) and reaccelerating them in a superconducting linac. The rare isotope beams will be producted intially by Coupled Cyclotron Facility (CCF) at NSCL and later by Facility for Rare Isotope Beams (FRIB), currently being designed and constructed at MSU. The accelerator system consists of a Low Energy Beam Transport (LEBT), a room temperature RFQ and a linac utilizing superconducting QWRs. An achromatic High Energy Beam Transport (HEBT) will deliver the reaccelerated beams to the mutiple target stations. Beams from ReA3 will range from 3 MeV/u for heavy nuclei such as uranium to about 6 MeV/u for ions with A<50. The commissioning of the EBIT, RFQ and two cryomodules of the linac is currently underway. The ReA3 accelerator system design and status of commissioning will be presented.
	Slides TUO1B05 [6.046 MB]

TUO3B01	Beam Dynamics Design of ESS Warm Linac	rfq, DTL, emittance, proton	274
	M. Comunian, F. Grespan, A. Pisent INFN/LNL, Legnaro (PD), Italy I. Bustinduy ESS Bilbao, Bilbao, Spain L. Celona, S. Gammino, L. Neri INFN/LNS, Catania, Italy R. De Prisco Lund University, Lund, Sweden M. Eshraqi, R. Miyamoto, A. Ponton ESS, Lund, Sweden
	In the present design of the European Spallation Source (ESS) accelerator, the Warm Linac will accelerate a pulsed proton beam of 50 mA peak current from source at 0.075 MeV up to 80 MeV. Such Linac is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period).In this paper the main design choices and the beam dynamics studies for the source up to the end of DTL are shown.
	Slides TUO3B01 [17.664 MB]

TUO3B02	Beam Dynamics of the ESS Superconducting Linac	cavity, proton, quadrupole, emittance	278
	M. Eshraqi, H. Danared, R. Miyamoto ESS, Lund, Sweden
	The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal beam power is 5 MW at an energy of 2.5 GeV. The superconducting part covers more than 95\% of the energy gain and 90\% of the length. The beam dynamics criteria applied to the design of the superconducting part of the linac including the frequency jump at a medium energy of 200 MeV as well as the beam dynamics performance of this structure are described in this paper.
	Slides TUO3B02 [4.406 MB]

TUO3B03	Linac4 Beam Commissioning Strategy	emittance, space-charge, DTL, diagnostics	283
	J.-B. Lallement, A.M. Lombardi, P.A. Posocco CERN, Geneva, Switzerland
	Linac4 is a 160 MeV H⁻ ion linear accelerator, presently under construction, which will replace the 50 MeV Linac2 as injector of the CERN proton complex. Linac4 is a 90 m long normal-conducting Linac made of a 3 MeV Radio Frequency Quadrupole (RFQ) followed by a 50 MeV Drift Tube Linac (DTL), a 100 MeV Cell-Coupled Drift Tube Linac (CCDTL) and a Pi-Mode Structure (PIMS). Starting in 2013, five commissioning stages, interlaced with installation periods, are foreseen at the energies of 3, 12, 50, 100 and 160 MeV. In addition to the diagnostics permanently installed in the Linac, temporary measurement benches will be located at the end of each structure and will be used for beam commissioning. Comprehensive beam dynamics simulations were carried out through the Linac and the diagnostic benches to define a commissioning procedure, which is summarised in this paper. In particular, we will present a method for emittance reconstruction from profile measurements which keeps into account the effects of space charge and finite diagnostics resolution.
	Slides TUO3B03 [2.951 MB]

TUO3B04	End to End Beam Dynamics and Design Optimization for CSNS Linac	DTL, lattice, quadrupole, rfq	286
	J. Peng, S. Fu, H.C. Liu, H.F. Ouyang, X. Yin IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) will use a linear accelerator delivering a 15mA beam up to 80MeV for injection into a rapid cycling synchrotron (RCS). Since each section of the linac was determined individually, a global optimization based on end-to-end simulation results has refined some design choices, including the drift-tube linac (DTL) and the medium energy beam transport (MEBT). The simulation results and reasons for adjustments are presented in this paper.
	Slides TUO3B04 [1.131 MB]

TUO1C02	Online Monitoring System for the Waste Beam in the 3-GeV RCS of J-PARC	injection, monitoring, proton, target	297
	P.K. Saha, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	We have established two independent methods for monitoring the waste beam of only about 0.4% in the 3 GeV Rapid Cycling Synchrotron of the Japan Proton Accelerator. Although using conventional monitor systems, the measurement technique made it possible for clearly measuring such a waste beam even with significantly low error. One of the method uses a current transformer to measure the waste beam as a whole, while the other one uses a multi-wire profile monitor for clearly measuring beam profiles of both un-stripped and partially stripped components of the waste beam. While the raw signal measured by a CT (current transformer) contains a large noise, an FFT (Fast Fourier Transformation) analysis made it possible to clearly identify the beam signal corresponding to the frequency of the intermediate pulse. The waste beam was measured to be (0.38±0.03)%. Being non destructive, the 1st method is efficiently operating for online monitoring of the waste beam during the RCS user operation so as to directly know the the stripper foil condition and would have great importance for higher power operation.
	Slides TUO1C02 [2.687 MB]

TUO1C03	The Beam Diagnostics of CSNS	diagnostics, emittance, injection, neutron	302
	T.G. Xu, J.N. Bai, C. Chen, L.X. Han, F. Li, P. Li, M. Meng, J.L. Sun, J.M. Tian, A.X. Wang, B. Wang, M.H. Xu, Zh.H. Xu, X.Y. Yang, L. Zeng IHEP, Beijing, People's Republic of China
	CSNS project is in the construction stage. The overview of CSNS beam diagnostics is presented which includes linac, RCS and both transport beam line. also some predevelopment of CSNS beam diagnostics is presented.
	Slides TUO1C03 [8.366 MB]

TUO1C06	Instrumentation Developments and Beam Studies for the Fermilab Proton Improvement Plan Linac Upgrade and New RFQ Front-End	rfq, proton, ion-source, instrumentation	315
	V.E. Scarpine, D.S. Bollinger, K.L. Duel, N. Eddy, P.R. Karns, N. Liu, W. Pellico, A. Semenov, C.-Y. Tan, R.E. Tomlin Fermilab, Batavia, USA
	Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359. Fermilab is developing a Proton Improvement Plan (PIP) to increase throughput of it's the proton source. The plan addresses hardware modifications to increase repetition rate and improve beam loss while ensuring viable operation of the proton source through 2025. The first phase of the PIP will enable the Fermilab proton source to deliver 1.8·10¹⁷ protons per hour by mid-2013. As part of this initial upgrade, Fermilab plans to install a new front-end consisting of dual H⁻ ion sources and a 201 MHz pulsed RFQ. This talk will present beam studies measurements of this new front-end as well as present new beam instrumentation upgrades for the Fermilab linac.
	Slides TUO1C06 [2.546 MB]

TUO3C03	Characterizing and Controlling Beam Losses at the LANSCE Facility	DTL, proton, beam-losses, neutron	324
	L. Rybarcyk LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by DOE under contract DE-AC52-06NA25396. The Los Alamos Neutron Science Center (LANSCE) currently provides 100-MeV H⁺ and 800-MeV H⁻ beams to several user facilities that have distinct beam requirements, e.g. intensity, micropulse pattern, duty factor, etc.. Minimizing beam loss is critical to achieving good performance and reliable operation, but can be challenging in the context of simultaneous multi-beam delivery. This presentation will discuss various aspects related to the observation, characterization and minimization of beam loss associated with normal production beam operations.
	Slides TUO3C03 [3.534 MB]

TUO3C04	Beam Loss Mitigation in the Oak Ridge Spallation Neutron Source	quadrupole, DTL, neutron, injection	329
	M.A. Plum 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. The Oak Ridge Spallation Neutron Source (SNS) accelerator complex routinely delivers 1 MW of beam power to the spallation target. Due to this high beam power, understanding and minimizing the beam loss is an ongoing focus area of the accelerator physics program. In some areas of the accelerator facility the equipment parameters corresponding to the minimum loss are very different from the design parameters. In this presentation we will summarize the SNS beam loss measurements, the methods used to minimize the beam loss, and a compare the design vs. the loss-minimized equipment parameters.
	Slides TUO3C04 [4.617 MB]

TUO3C05	Beam Commissioning Plan for CSNS Accelerators	DTL, injection, optics, target	334
	S. Wang, S. Fu, H.F. Ouyang, J. Peng IHEP, Beijing, People's Republic of China
	Funding: Supported by National Natural Science Foundation of China (11175193) The China Spallation Neutron Source (CSNS) is now under construction, and the beam commissioning of ion source will start from the end of 2013, and will last several years for whole accelerator. The commissioning plan for CSNS accelerators will be presented in the presentation, including the commissioning correlated parameters, the goal at different commissioning stages and some key commissioning procedures for each part of accelerators. The detailed schedule for commissioning will be also given.
	Slides TUO3C05 [3.574 MB]

WEO3A02	Beam Loss and Collimation in the ESS Linac	proton, simulation, DTL, collimation	368
	R. Miyamoto, B. Cheymol, H. Danared, M. Eshraqi, A. Ponton, J. Stovall, L. Tchelidze ESS, Lund, Sweden I. Bustinduy ESS Bilbao, Bilbao, Spain A.I.S. Holm, S.P. Møller, H.D. Thomsen ISA, Aarhus, Denmark
	The European Spallation Source (ESS), to be built in Lund, Sweden, is a spallation neutron source based on a 5 MW proton linac. A high power proton linac has a tight tolerance on beam losses to avoid activation of its components and it is ideal to study patterns of the beam loss and prepare beam loss mitigation schemes at the design stage. This paper presents simulations of the beam loss in the ESS linac as well as beam loss mitigation schemes using collimators in beam transport sections.
	Slides WEO3A02 [6.377 MB]

WEO3B01	FRIB Accelerator Beam Dynamics Design and Challenges	ion, target, solenoid, rfq	404
	Q. Zhao, A. Facco, F. Marti, E. Pozdeyev, M.J. Syphers, J. Wei, X. Wu, Y. Yamazaki, Y. Zhang FRIB, East Lansing, Michigan, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. The Facility for Rare Isotope Beams (FRIB) will be a new national user facility for nuclear science. This cw, high power, superconducting (SC), heavy ion driver linac consists of a frontend to provide various highly charged ions at 0.5 MeV/u, three SC acceleration segments connected by two 180° bending systems to achieve an output beam energy of ≥200 MeV/u for all varieties of stable ions, and a beam delivery system to transport multi-charge-state beams to a fragmentation target at beam power of up to 400 kW. The linac utilizes four types of low-beta resonators with one frequency transition from 80.5 to 322 MHz after Segment 1, where ion charge state(s) is boosted through a stripper at ≤20 MeV/u. The beam dynamics design challenges include simultaneous acceleration of multi-charge-state beams to meet beam-on-target requirements, efficient acceleration of high intensity, low energy heavy ion beams, limitation of uncontrolled beam loss to <1 W/m, accommodation of multiple charge stripping scenarios, etc. We present the recent optimizations on linac lattice, the results of end-to-end beam simulations with machine errors, and the simulation of beam tuning and fault conditions.
	Slides WEO3B01 [7.899 MB]

WEO3B02	Acceleration and Transportation of Multiple Ion Species at Ebis-based Preinjector	ion, rfq, booster, emittance	409
	D. Raparia BNL, Upton, Long Island, New York, USA
	A new heavy ion pre-injector at Brookhaven National Laboratory consist of an electron Beam Ion Source (EBIS), RFQ and IH Linac and a short transport line. This pre-injector provide any ion Helium to Uranium at energy of 2 MeV/u for Relativistic Heavy Ion Collider (RHIC) and the NASA Space Radiation Laboratory (NSRL). EBIS produces multiple charge states of an ion of interested. These charge states are accelerated through RFQ (300 keV/u) and IH Linac (2 MeV/u) and transported to booster. Charge desecration occurs just before the injection into the booster. This paper discusses implication of acceleration and transports of multiple charge state ions.
	Slides WEO3B02 [5.825 MB]

WEO3B04	RFQ Beam Dynamics Design for Large Science Facilities and Accelerator-Driven Systems	rfq, proton, bunching, ion	419
	C. Zhang IAP, Frankfurt am Main, Germany
	Serving as the front-end of large science facilities and Accelerator-Driven Systems (ADS), the Radio-Frequency Quadrupole (RFQ) accelerator usually needs to reach low beam losses, good beam quality, high reliability, and cost savings such design goals at high beam intensities. To address the challenges for modern RFQs, a special beam dynamics design technique characterized by a reasonable and efficient bunching process with balanced space-charge forces has been developed as an alternative to the classic Four-Section Procedure proposed by Los Alamos National Laboratory (LANL). In this paper, the design studies of some recent RFQ projects will be presented as examples.
	Slides WEO3B04 [3.698 MB]

THO3A01	High Intensity Aspects of J-PARC Linac Including Re-commissioning after Earthquake	simulation, multipactoring, DTL, rfq	497
	M. Ikegami, K. Futatsukawa, T. Miyao KEK, Ibaraki, Japan Y. Liu KEK/JAEA, Ibaraki-Ken, Japan T. Maruta, A. Miura, J. Tamura JAEA/J-PARC, Tokai-mura, Japan
	We had a massive earthquake in March 2011, which forced us to shutdown J-PARC accelerators for nearly nine months due to its resultant damages. After significant restoration effort, we resumed the beam operation of J-PARC linac in December 2011 and user operation in January 2012. Subsequently, we restored the same beam power as just before the earthquake in March 2012. In the course of the beam commissioning after the earthquake, we have experienced beam losses which were not observed before the earthquake. We discuss the experimentally observed beam losses and its comparison with particle simulations.
	Slides THO3A01 [5.249 MB]

THO3A02	Beam Dynamics of China ADS Linac	cavity, rfq, lattice, emittance	502
	Z. Li Private Address, Beijing, People's Republic of China P. Cheng, H. Geng, Z. Guo, C. Meng, B. Sun, J.Y. Tang, F. Yan IHEP, Beijing, People's Republic of China
	Funding: Supported by China ADS Program(XDA03020000), National Natural Science Fundation of China (10875099) and IHEP Special Fundings(Y0515550U1) An ADS study program is approved by Chinese Academy of Sciences at 2011, which aims to design and built an ADS demonstration facility with the capability of more than 1000 MW thermal power within the following 25 years. The 15 MW driver accelerator will be designed and constructed by the Institute of High Energy Physics (IHEP) and Institute of Modern Physics (IMP) of China Academy of Sciences. This linac is characterized by the 1.5 GeV energy, 10 mA current and CW operation. It is composed by two parallel 10 MeV injectors and a main linac integrated with fault tolerance design. The superconducting acceleration structures are employed except the RFQ. The general considerations and the beam dynamics design of the driver accelerator will be presented.
	Slides THO3A02 [5.822 MB]

THO3A04	Beam Halo Definitions and its Consequences	emittance, beam-losses, injection, space-charge	511
	P.A.P. Nghiem, N. Chauvin, D. Uriot CEA/DSM/IRFU, France W. Simeoni CEA/IRFU, Gif-sur-Yvette, France
	In high-intensity accelerators, much attention is paid to the beam halo: formation, growth interaction with the beam core, etc. Indeed, beam losses, a critical issue for those high-power accelerators, directly depend on the beam halo behaviour. But in the presence of very strong space-charge forces, the beam distribution takes very different shapes along the accelerator, often very far from any regular distributions, with very varied halo extensions. The difficulty is then to find a general definition of the halo capable of describing any distribution type. This paper proposes a definition of the beam halo, studies its consequences and compares it to the most usual ones.
	Slides THO3A04 [9.030 MB]

THO3B02	SRF Technology Challenge and Development	cavity, SRF, HOM, ion	536
	A. Facco INFN/LNL, Legnaro (PD), Italy A. Facco FRIB, East Lansing, USA
	SRF technology in particle accelerators is in continuous evolution, providing a large variety of high gradient- low loss resonators with large apertures, suitable for many different beam current and energy regimes. Recent development was aiming not only at highest gradient and Q but also at improving field quality, reliability and cost reduction for large production. The SRF R&D effort, once concentrated mostly in the high energy electron machines, is increasingly focused to heavy ion linacs, energy recovery linacs and also to cavities for special applications. A concise overview of the present state of the art will be given.
	Slides THO3B02 [1.712 MB]

THO3B03	SRF Cavity Research for Project X	cavity, SRF, cryomodule, proton	541
	R.D. Kephart Fermilab, Batavia, USA
	Project X is a new SRF linac based multi-MW class proton source proposed for construction at Fermilab. It consists of a 3 MW, 1 mA CW H⁻ SRF linac that feeds an intensity frontier Physics program and a 3-8 GeV pulsed linac that accelerates ~5% of the output of the CW linac to 8 GeV for injection into the Fermilab Main Injector synchrotron resulting in an additional 2 MW of beam power at 60-120 GeV in support of a world class long baseline neutrino program. The project has chosen operating frequencies that are sub-harmonics of 1.3 GHz and is developing 6 separate cavity designs for acceleration of H⁻ particles with various velocities. An R&D program is in progress to develop these cavities; the associated cryomodules; and the required fabrication and test infrastructure. A status and progress report on this R&D program will be presented.
	Slides THO3B03 [4.034 MB]

THO1C05	Status and Beam Commissioning Plan of PEFP 100 MeV Proton Linac	proton, DTL, target, site	570
	J.-H. Jang, S. Cha, Y.-S. Cho, D.I. Kim, H.S. Kim, H.-J. Kwon, Y.M. Li, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun KAERI, Daejon, Republic of Korea
	Funding: This work was supported by Ministry of Education, Science and Technology of the Korean government. The proton engineering frontier project (PEFP) is developing a 100 MeV proton linac which consists of a 50 keV injector, a 3 MeV RFQ (radio frequency quadrupole), and a 100 MeV DTL (drift tube linac). The installation of the linac was finished on March this year. The other elements including the high power RF components will be installed after completing the other part of the accelerator building. The beam commissioning is scheduled at the end of this year. This work summarized the status of the PEFP linac development and the beam commissioning plan.
	Slides THO1C05 [5.104 MB]

THO3C02	Momentum Spread Determination of Linac Beams Using Incoherent Components of the Bunch Signals	cavity, synchrotron, pick-up, bunching	583
	P. Kowina, P. Forck, M. Schwickert GSI, Darmstadt, Germany F. Caspers CERN, Geneva, Switzerland
	Measurements of the momentum spread of the beam particles are of great importance when optimizing linac settings for high current operation with controlled longitudinal phase space occupation. A new method of momentum spread determination was tested at the GSI heavy ion linear accelerator UNILAC. The method is based on an analysis of incoherent components of the bunch signal. A significant enhancement of the signal-to-noise ratio was achieved by means of a resonant pick-up of pill-box shape. Spectra were analyzed on the 36th harmonics of the linac rf-frequency, i.e. at 1.3 GHz. Thus, the contribution of coherent components in the frequency spectrum of the bunched beam, e.g. due to common mode, was significantly damped. Fast digital processing and gating synchronized to the bunch train allowed for a drastic reduction of the measurement time and, additionally, suppressed noise signals in the frequency spectrum. This contribution describes the measurement setup and discusses first results obtained with heavy ion beams.
	Slides THO3C02 [2.131 MB]

THO3C04	Longitudinal Beam Diagnosis with RF Chopper System	cavity, neutron, acceleration, DTL	591
	T. Maruta JAEA/J-PARC, Tokai-mura, Japan M. Ikegami KEK, Ibaraki, Japan
	J-PARC linac has a chopper system between RFQ and DTL, which utilizes an RF deflector cavity instead of a usual slow wave kicker. Taking advantage of this unique feature of the chopper system, we have experimentally measured the longitudinal full width of phase direction at the chopper cavity. In this presentation, I would like to discuss the measurement technique and measurement results.
	Slides THO3C04 [2.495 MB]

FRO1A02	WG-B: Beam Dynamics In High Intensity Linacs	rfq, emittance, DTL, resonance	612
	D. Raparia BNL, Upton, Long Island, New York, USA Z. Li IHEP, Beijing, People's Republic of China P.A.P. Nghiem CEA/DSM/IRFU, France
	Emittance coupling, equipartioning and losses were a few topics, which were discussed thoroughly during parallel session for beam dynamics in high intensity linacs (Group B). Linac designs for the future, under construction, upgrade and the existing linacs from around the world were presented in three working sessions. A total of 18 talks were presented. Five presentations are general beam dynamics in nature and twelve talks were project specific. The detail of each contribution can be found in these proceedings. Here we report the summary of the discussions and some concluding remarks of the general interest to all the projects presented in the working group.
	Slides FRO1A02 [14.464 MB]

FRO1B01	Summary of the Working Group on Commissioning and Operation	beam-losses, injection, proton, simulation	620
	R. Schmidt CERN, Geneva, Switzerland M.A. Plum ORNL, Oak Ridge, Tennessee, USA Y. Sato J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The Working Group D summary report focussed on answering the following issues: observation of beam losses (e.g. time structure, other parameters,…), reducing beam losses with operational parameters away from the design set points, reducing beam losses (or concentrating beam losses at a few locations) using collimators, minimizing beam losses due to beam transfer from one accelerator to the following accelerator - what parameters are important? The issue of reducing beam losses with operational parameters away from the design set points is especially valuable as it is rarely discussed.
	Slides FRO1B01 [0.426 MB]

FRO1B02	Qinclosing Plenary Summary of Working Group E:Diagnostics and Instrumentation for High-Intensity Beams	diagnostics, beam-losses, instrumentation, proton	625
	R. Dölling PSI, Villigen PSI, Switzerland N. Hayashi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan V.E. Scarpine Fermilab, Batavia, USA
	Working Group E Summary: Working group E was charged with presentations and discussions on diagnostics and instrumentation of high intensity beams. We had 2 sessions, consisting of a total of 12 talks, each of 20 minutes for presentation followed by some discussion. One session was followed by a discussion session of two hours. All sessions took place in parallel with the sessions of WG-D (Commissioning, operations and performance), inevitably preventing some possibly useful overlap. In addition, seven posters, regarding beam diagnostics, were presented in the single poster session.
	Slides FRO1B02 [18.507 MB]

Paper

Title

Other Keywords

Page

MOI1A02

J-PARC Recovery Status

extraction, status, kicker, vacuum

6

K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

J-PARC facilities were seriously damaged by the Great East Japan Earthquake in March 2011, but all facilities resumed a beam operation from December 2012. We report the operation status of J-PARC accelerators after the earthquake.

Slides MOI1A02 [12.726 MB]

MOI1B02

Technological Challenges for High-Intensity Proton Rings

proton, injection, acceleration, space-charge

15

Y. Yamazaki
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
High-intensity, pulsed proton accelerators have been and will be requested by a wide variety of scientific fields and industrial and medical applications, for example, pulsed spallation neutron sources and neutrino sources. We will focus our discussion on the proton rings with a pulse length of a few μsec and a beam power of MW. These accelerators may be used for boosting injectors to higher-energy accelerators, like a neutrino factories. At first, we will discuss on the space-charge force which limit the stored charges in a ring together with the negative-ion injection scheme. The pulsed spallation neutron sources are classified into two schemes. One is the combination of a full-energy linac and an accumulation ring (AR) exemplified by SNS and LANSCE. The other is that of a low-energy linac and a Rapid-Cycle Synchrotron (RCS) exemplified by J-PARC RCS and ISIS. In general, pros and cons of accelerator schemes are dependent upon the technological development results. Pros and cons of AR versus RCS will be discussed on the basis of recent technological developments and beam experiment data together with the future perspectives for MW-class machines.

Slides MOI1B02 [3.850 MB]

MOI1B03

Technical Challenges in Multi-MW Proton Linacs

rfq, cryomodule, proton, acceleration

20

V.A. Lebedev
Fermilab, Batavia, USA

The intensity frontier research is an important part of modern elementary particle physics. It uses proton beams to create secondary beams consisting of, but not necessary limited to, neutrinos, muons, kaons and neutrons. Deferent experiments require different time structure of proton beams but all of them require the beam power of about or exceeding 1 MW. In addition, powerful proton linacs can find an application in accelerator driven nuclear reactors and transmutation of radioactive waste. Recent advances in the superconducting RF technology make a multi-MW power level economically acceptable. This paper discusses main physics and technical limitations determining ultimate parameters of such accelerators, their structure and performance.

Slides MOI1B03 [2.863 MB]

MOI1C01

Intense-beam Issues in CSNS and C-ADS Accelerators

cavity, emittance, lattice, simulation

25

S. Fu, S.X. Fang, Z. Li, J. Peng, J.Y. Tang, S. Wang, F. Yan
IHEP, Beijing, People's Republic of China

In 2011 construction of two intense-beam accelerators were launched for China Spallation Neutron Source (CSNS) project and China Accelerator Driven System (C-ADS) project. CSNS uses a pulsed accelerator with an H⁻ linac and a rapid cycling synchrotron, and C-ADS has a CW proton linac with superconducting cavities. In both cases, the beam power is high and beam loss control is a key issue in beam dynamics. Beam emittance growth and beam halo formation must be carefully studied in beam dynamics and well controlled in machine design. This paper will present a brief introduction to the physics design of the two intense-beam accelerators, especially on the issue of beam instability. In their linac design equapartitioning focusing scheme is adopted to avoid coupling instability. Some beam halo formation experimental results due to mismatching will be compared with simulations. Beam halo generation due to the quench of superconducting cavity and magnet is investigated in detail and compensation scheme is also proposed. Beam loss study for the error effects and orbit correction will be presented.

Slides MOI1C01 [3.747 MB]

MOI1C02

Challenges in Benchmarking of Simulation Codes against Real High Intensity Accelerators

simulation, space-charge, resonance, emittance

30

I. Hofmann
GSI, Darmstadt, Germany

Benchmarking of simulation codes for linear or circular accelerators involves several levels of complexity, which will be revisited and discussed in this talk. As ultimate goal of benchmarking it is hoped that a predictive capacity and a practical control over emittance growth and/or beam loss can be obtained. We first give some examples of how simulation codes can be used to gain as much understanding of the underlying physics mechanisms as possible, which is an almost inevitable first step. With more and more experimental data from running high intensity accelerators having become available in recent years more questions need to be raised: Besides the proper physics, can we feed our codes with an accurate enough model of the real machine? What actually is the required accuracy, and does a specific accelerator have enough diagnostics to enable this accuracy? In the paper we explore these questions by discussing several examples of benchmarking efforts, their achievements as well as the limits and difficulties that have been encountered.

Slides MOI1C02 [2.838 MB]

MOI1C03

Beam Loss Mechanisms in High Intensity Linacs

DTL, proton, ion, optics

36

M.A. Plum
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.
Beam loss is a critical issue in high intensity linacs, and much work is done during both the design and operation phases to keep the loss down to manageable levels. Linacs for H⁻ ion beams have many more loss mechanisms compared to H⁺ (proton) linacs. Interesting H⁻ beam loss mechanisms include residual gas stripping, H⁺ capture and acceleration, field stripping, and intra-beam stripping (IBSt). Beam halo formation, and ion source or RF turn on/off transients, are examples of beam loss mechanisms that are common for both H⁺ and H⁻ accelerators. The IBSt mechanism has recently been characterized at the Oak Ridge Spallation Neutron Source, and we have found that it accounts for most of the loss in the superconducting linac. In this paper we will detail the IBSt measurements, and also discuss the other beam loss mechanisms that are important for high intensity linacs.

Slides MOI1C03 [5.588 MB]

MOP212

Simulation of Longitudinal Beam Instability caused by HOMs

HOM, simulation, cavity, damping

73

P. Cheng, Z. Li, J.Y. Tang, J.Q. Wang
IHEP, Beijing, People's Republic of China

Superconducting cavities are employed in C-ADS linac to accelerate 10mA CW proton beams from 3.2 MeV to 1.5 GeV. High order modes in superconducting cavities are found by using the simulation tools CST and HFSS, then power dissipation caused by HOMs have been investigated, it is indicated that the Qext should not go beyond 10⁷} in order to limit the additional heat load. Beam instabilities caused by high order modes in elliptical cavity sections are investigated using the code offered by Dr. Jean-Luc Biarrotte (CNRS, IPN Orsay, France). Beam errors, linac errors and high order modes frequency spread are investigated in detail. It shows that the monopole modes do not affect the proton beam critically and need no HOM couplers (Q_ext=10⁵}) if high order modes frequency spread is more than 100 kHz.

MOP217

MEBT2 Design for the C-ADS Linac

emittance, focusing, space-charge, proton

93

Z. Guo, H. Geng, Z. Li, J.Y. Tang
IHEP, Beijing, People's Republic of China

The C-ADS linac is composed by two parallel injectors and a main linac, a section of Medium Energy Beam Line (MEBT2) is designed to guide and match beams from two injectors to the main linac. The two injectors are hot-spare for each other in order to satisfied the requirement of high availability and reliability. The beam in online operation mode will be directed to the main linac from one injector, while the beam in the offline mode with low repetition frequency from the other injector, will be directed to a beam dump through an auxiliary beam line. With a long drift distance and in the presence of space charge force for 10 mA 10 MeV proton beam, the debunching effect is very strong and it requires very strict control over beam losses and emittance growth. It is difficult to obtain satisfactory longitudinal matching without bunchers in the bending section. An analytical study using transfer matrix shows that with two bunchers of same voltage in the bending section the achromatism can be maintained if the effective voltage is inversely proportional to the distance between the two bunchers. It is also under consideration if and how a beam collimation can be implanted in MEBT2.

MOP218

Dynamics of Particles in a Tilted Solenoidal Focusing Channel

focusing, emittance, solenoid, alignment

97

H. Jiang, S. Fu
IHEP, Beijing, People's Republic of China

We use the paraxial ray approximation equations to analysis the dynamics of particles in a tilted solenoidal focusing channel. In this case, the particles' initial canonical angular momentum is nonzero, so we need to add the term of centrifugal potential to the dynamics equation of particles. And in the dynamics equation this centrifugal potential term is nonlinear, which results in the emittance growth. In practice, we also need to consider the spherical aberration's effect on emittance growth and the linear part of the space-charge force of a Kapchinskij-Vladimirskij distribution beam in the dynamics equation of particles.

MOP219

Error Analysis and Correction Scheme in C-ADS Injector-I

emittance, cavity, simulation, solenoid

99

C. Meng, Z. Li, J.Y. Tang
IHEP, Beijing, People's Republic of China

Funding: Supported by the China ADS Project (XDA03020000)
C-ADS Injector-I is a 10 mA 10 MeV CW proton linac. It uses a 3.2MeV normal conducting 4-Vane RFQ and 12 superconducting single-Spoke cavities. According to the detailed sensitivity analysis of alignment and RF errors, the error tolerance of both static and dynamic ones for Injector-I are presented. The simulation results show that with the error tolerance there are beam losses, the residual orbit is too large which will produce significant emittance growth, so the correction is necessary for Injector-I. After detailed numerical studies, a correction scheme and monitor distributions are proposed. After correction the RMS residual orbit can be controlled within 0.4mm and RMS emittance growth can be controlled within 10%, but it still has 1.7×10^-6 beam loss, which comes from the RF errors and low longitudinal acceptance. According to detailed analysis and simulations with 10⁸ macro particles, as a consequence, longitudinal emittance control and longitudinal distribution control as well as large longitudinal acceptance are the key to minimizing beam losses in low energy section. To minimize beam loss, a short period Injector-I lattice with larger longitudinal acceptance have been designed and performance very good error tolerance.

MOP221

Physics Design of the C-ADS Main Linac Based on Two Different Injector Design Schemes

emittance, simulation, lattice, cavity

107

F. Yan, Z. Li, C. Meng, J.Y. Tang
IHEP, Beijing, People's Republic of China

Funding: Supported by Advanced Research Project of the Chinese Academy of Science
Two design schemes for the main linac of C-ADS (China Accelerator Driven Subcritical system) are presented in this paper. They are corresponding to two different injector schemes. Injector-II scheme makes use of room-temperature RFQ and superconducting HWR cavities with the RF frequency of 162.5 MHz; Injector-I scheme makes use of higher-energy RFQ and superconducting spoke cavities with the RF frequency of 325 MHz. At the first choice, a relatively smaller longitudinal emittance is adopted for the RFQ designs with both the injector schemes to obtain more efficient acceleration. However, compared with the injector-I scheme, with the injector-II scheme, bunch current will be doubled in the main linac due to the half RF frequency in the injector-II. This means stronger space charge effects. Alternate design for the main linac with the injector-II scheme is to increase the longitudinal emittance by 50% so that the space charge effects will be alleviated. However, totally 30 cavities more and 36 m longer in the main linac have to be paid for this design scheme. The design considerations, the lattice designs, the simulation results including halo information are presented.

MOP231

Study of Non-equi-partitioning Lattice Setting and IBS Effects for J-PARC Linac Upgrade

emittance, lattice, simulation, DTL

118

Y. Liu
IMP, Lanzhou, People's Republic of China
M. Ikegami
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

For the coming upgrade of J-Parc, the peak power of linac will be greatly increased. This may open many interesting questions. For instance, for efficient acceleration from 19 0MeV to 400 MeV the annular coupled structure (ACS) was applied with frequency jump from 324 MHz to 972 MHz. Upstream part of J-PARC linac from the frequency jump is set with the equi-partitioning (EP) condition, which prevents from the coherent resonances. If EP condition is kept for the downstream part, due to the frequency jump, the transverse focusing should also ‘jump' 3 times with shrink of envelop. The increased beam-density affects the interactions between particles, including the intra-beam stripping (IBS) effect in the H⁻ beam. The temperature ratio between transverse and longitudinal planes is used as a knob for studying the beam behavior for the cases away from equi-partitioning. The IBS effects, as well as strategies for setting downstream non-equi-partitioning lattice due to frequency jump are studied. The matching and beam evolution in the transition section from EP to non-EP (MEBT2) are also studied. The results help to reach an optimum with least risks from resonances and IBS effects and so on.

MOP232

Optimization of the Superconducting Section of Injector Ⅱ for C-ADS

solenoid, emittance, simulation, lattice

122

S.H. Liu, Y. He, Z.J. Wang
IMP, Lanzhou, People's Republic of China

Abstract: The China Accelerator driven System (C-ADS) project which includes a high current SC proton linac is being studied under Chinese Academy of Science. Injector II, one of parallel injectors, is undertaken by Institute of Modern Physics (IMP). The lattice design of Injector II has been done. While in most case, the elements, such as SC cavities and SC solenoids, have different weight to the final beam parameters. What is more, in the real operation process of the machine, the optimized mode is hard to find. In the paper, Latin sampling method specified in DAKOTA code combined with TRACK is adopted to build hundreds of virtual machines to analyse the sensitivity of the SC section and to find optimization operation mode.

MOP233

Error and Tolerance Studies for Injector II of C-ADS

simulation, solenoid, alignment, emittance

125

W.S. Wang, Y. He, Z.J. Wang
IMP, Lanzhou, People's Republic of China

The proposed Chinese Accelerator Driven System (C-ADS) driver linac is being designed by Chinese Academic Science (CAS). Injector II is designed and fabricated in Institute of Modern Physics (IMP). Injector II will accelerate 10 mA proton beams to 10 MeV. Because of the high final beam power (100 kW) specified for the linac operation, beam loss must be limited to 10^-5 level to avoid radiation damage. Misalignment and RF error simulation for cavities and focusing elements after RFQ were performed and the correction schemes developed using the computing code TRACK. Error and tolerance studies for Injector II are presented.

MOP235

Medium Energy Beam Transport Design Update for ESS

cavity, quadrupole, DTL, rfq

128

I. Bustinduy, F.J. Bermejo, A. Ghiglino, O. González, J.L. Muñoz, I. Rodríguez, A. Zugazaga
ESS Bilbao, Bilbao, Spain
B. Cheymol, M. Eshraqi, R. Miyamoto
ESS, Lund, Sweden
J. Stovall
CERN, Geneva, Switzerland

The major challenge of this part of the accelerator is to keep a high quality beam, with a pulse well defined in time, a low emittance and a minimized halo, so that the beam losses downstream the linac be limited and the overall ESS reliability be maximized. In order to minimize beam loss at high energy linac, and the consequent activation of components, a fast chopping scheme is presented for the medium energy beam transport section (MEBT). The considered versatile MEBT is being designed to achieve four main goals: First, to contain a fast chopper and its correspondent beam dump, that could serve in the commissioning as well as in the ramp up phases. Second, to serve as a halo scraping section by means of two adjustable blades. Third, to measure the beam phase and profile between the RFQ and the DTL, along with other beam monitors. And finally, to match the RFQ output beam characteristics to the DTL input both transversally and longitudinally. For this purpose a set of ten quadrupoles is used to match the beam characteristics transversally, combined with two 352.2 MHz buncher cavities, which are used to adjust the beam in order to fulfill the required longitudinal parameters.

MOP238

Beam Position Monitor System of the ESS Linac

LLRF, quadrupole, controls, target

133

H. Hassanzadegan, A. Jansson
ESS, Lund, Sweden
A.J. Johansson
Lund University, Lund, Sweden

The pulsed ESS linac will include about 100 BPMs, mostly with a European XFEL style button design, 6 BPMs with a special design for the Medium Energy Beam Transport, as well as 8 stripline BPMs foreseen for the Drift Tubes. The required accuracy and resolution of the position measurement are 100 μm (rms) and 20 μm (rms) respectively with the 50 mA 2.86 ms nominal pulse. In addition to the position measurement, the BPM system needs to measure the beam phase in the nominal pulse as well as several diagnostics pulse modes with a minimum duration and intensity of 5 μs and 5 mA respectively. After a study of the possible electronics platforms, MTCA.4 is now considered as the main prototyping platform for the high performance sub-systems at ESS. It is foreseen to prototype a Rear Transition Module for IQ-based RF signal measurements intended for both the BPM and LLRF systems. The requirements and specifications of the BPM system are presented and the plan for the continuation of the project is described in this paper.

MOP244

CERN High-Power Proton Synchrotron Design Study for LAGUNA-LBNO Neutrino Production

proton, synchrotron, target, status

154

R. Steerenberg, M. Benedikt, I. Efthymiopoulos, F. Gerigk, Y. Papaphilippou
CERN, Geneva, Switzerland

Within the framework of the LAGUNA-LBNO project, CERN has started design studies in view of producing neutrinos for future long base line neutrino experiments. These design studies foresee a staged approach in the increase of the primary proton beam power, used for the neutrino production. The first step consists of exploring the feasibility of a CERN SPS beam power upgrade from the existing 500 kW, presently available to CNGS, to 750 kW. This beam should then be transferred to a new to be built neutrino beam line that is dimensioned for a beam power of 2 MW. The 2 MW proton beam is to be provided at a subsequent stage by a 30 - 50 GeV High-Power Proton Synchrotron (HP-PS), which is a major part of the design studies. This paper will provide an overview of the project and then focus on the preliminary ideas for the HP-PS design study.

MOP249

Tune Spread Studies at Injection Energies for the CERN Proton Synchrotron Booster

injection, emittance, space-charge, proton

175

B. Mikulec, A. Findlay, V. Raginel, G. Rumolo, G. Sterbini
CERN, Geneva, Switzerland

In the near future, a new H⁻ injector, Linac4, will replace the current proton injector of the CERN Proton Synchrotron Booster (PSB), Linac2. The new charge-exchange injection at 160 MeV will yield higher brightness beams compared to the conventional 50 MeV multi-turn injection of Linac2. To make full use of the higher injection energy, space-charge effects will need to be understood and mitigated to optimize the intensity versus transverse emittance reach. This includes an optimization of longitudinal acceptance and distribution with a two-harmonic rf system, careful selection of the working point to accommodate the large Laslett tune-shift of approximately -0.5 and compensation of resonances within their stopbands. This paper will present calculations of the tune spread, based on measurements of longitudinal parameters and transverse emittances, for energies up to 160 MeV, different bunch densities and varying beam intensities. It should provide valuable information on the expected tune spread after the connection of Linac4 with the PSB and input for the study of resonance compensation techniques.

TUO1A01

The High Intensity/High Brightness Upgrade Program at CERN: Status and Challenges

injection, emittance, space-charge, extraction

226

S.S. Gilardoni, G. Arduini, T. Argyropoulos, S. Aumon, H. Bartosik, E. Benedetto, N. Biancacci, T. Bohl, J. Borburgh, C. Carli, F. Caspers, H. Damerau, J. Esteban Müller, V. Forte, R. Garoby, M. Giovannozzi, B. Goddard, S. Hancock, K. Hanke, A. Huschauer, G. Iadarola, M. Meddahi, G. Métral, B. Mikulec, E. Métral, Y. Papaphilippou, S. Persichelli, G. Rumolo, B. Salvant, F. Schmidt, E.N. Shaposhnikova, R. Steerenberg, G. Sterbini, M. Taborelli, H. Timko, M. Vretenar, R. Wasef, C. Yin Vallgren, C. Zannini
CERN, Geneva, Switzerland
G. Franchetti
GSI, Darmstadt, Germany
M. Migliorati
University of Rome "La Sapienza", Rome, Italy
A.Y. Molodozhentsev
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
M.T.F. Pivi
SLAC, Menlo Park, California, USA
V.G. Vaccaro
Naples University Federico II, Mathematical, Physical and Natural Sciences Faculty, Napoli, Italy

The future beam brilliance and intensities required by the HL-LHC (High-Luminosity LHC) project and for possible new neutrino production beams triggered a deep revision of the LHC injector performances. The analysis, progressing in the framework of the LHC Injectors Upgrade (LIU) projects, outlined major limitations mainly related to collective effects - space charge in PSB and PS, electron cloud driven and TMCI instabilities in the SPS, longitudinal coupled bunch instabilities in the PS for example - but also to the existing hardware capability to cope with beam instabilities and losses. A summary of the observations and simulation studies carried out so far, as well as the future ones, will be presented. The solution proposed to overcome the different limitations and the plans for their implementation will be also briefly reviewed.

Slides TUO1A01 [12.748 MB]

TUO3A01

Dynamical Aspects of Emittance Coupling in Intense Beams

emittance, resonance, coupling, simulation

240

I. Hofmann
GSI, Darmstadt, Germany
I. Hofmann
HIJ, Jena, Germany

In this paper we study in an idealized lattice model the dynamical behavior of non-equipartitioned beams and of approach to equipartition. It is shown that emittance transfer depends on times scales of tune change, but also the direction of crossing the stopbands of space charge resonances. This provides additional information to support the stability charts suggested previously as design tool for high current linacs.

Slides TUO3A01 [4.897 MB]

TUO3A03

Equipartition, Reality or Swindle?

resonance, coupling, emittance, space-charge

250

J.-M. Lagniel
GANIL, Caen, France

By way of introduction to a general discussion on space-charge induced energy equipartition (EQP), the following questions will be tackled: Why the formula presently used to define EQP is wrong? Why energy exchanges can occur although the EQP rule is respected? Why safe tunings can be find although the EQP rule is not respected? Why EQP is a swindle for a large majority of our accelerated beams? Why LINAC designers nevertheless like to use the EQP rule?

Slides TUO3A03 [1.537 MB]

TUO1B02

Injection Design for Fermilab Project X

injection, booster, dipole, proton

259

D.E. Johnson, C.-Y. Tan, Z. Tang
Fermilab, Batavia, USA

Fermilab is proposing a staged approach for Project X, a high power proton accelerator system. The first stage of this project will be to construct a 1 GeV CW H⁻ superconducting linear accelerator to inject into the existing 8 GeV Booster synchrotron ultimately providing in excess of 1 MW beam power for the Neutrino program out of the Main Injector. We will discuss the current project plans for injection into the Booster and related issues.

Slides TUO1B02 [1.380 MB]

TUO1B05

The Design and Commissioning of the Accelerator System of the Rare Isotope Reaccelerator - ReA3 at Michigan State University

cryomodule, rfq, target, ion

269

X. Wu, B. Arend, C. Compton, A. Facco, M.J. Johnson, D. Lawton, D. Leitner, F. Montes, S. Nash, J. Ottarson, G. Perdikakis, J. Popielarski, J.A. Rodriguez, M.J. Syphers, W. Wittmer, Q. Zhao
NSCL, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Sciences under Cooperative Agreement DE-SC0000661
The National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU) is currently constructing its new rare isotope reaccelerator facility: ReA3, which will provide unique low-energy rare isotope beams by stopping fast rare isotopes in gas stopping systems, boosting the charge state in an Electron Beam Ion Trap (EBIT) and reaccelerating them in a superconducting linac. The rare isotope beams will be producted intially by Coupled Cyclotron Facility (CCF) at NSCL and later by Facility for Rare Isotope Beams (FRIB), currently being designed and constructed at MSU. The accelerator system consists of a Low Energy Beam Transport (LEBT), a room temperature RFQ and a linac utilizing superconducting QWRs. An achromatic High Energy Beam Transport (HEBT) will deliver the reaccelerated beams to the mutiple target stations. Beams from ReA3 will range from 3 MeV/u for heavy nuclei such as uranium to about 6 MeV/u for ions with A<50. The commissioning of the EBIT, RFQ and two cryomodules of the linac is currently underway. The ReA3 accelerator system design and status of commissioning will be presented.

Slides TUO1B05 [6.046 MB]

TUO3B01

Beam Dynamics Design of ESS Warm Linac

rfq, DTL, emittance, proton

274

M. Comunian, F. Grespan, A. Pisent
INFN/LNL, Legnaro (PD), Italy
I. Bustinduy
ESS Bilbao, Bilbao, Spain
L. Celona, S. Gammino, L. Neri
INFN/LNS, Catania, Italy
R. De Prisco
Lund University, Lund, Sweden
M. Eshraqi, R. Miyamoto, A. Ponton
ESS, Lund, Sweden

In the present design of the European Spallation Source (ESS) accelerator, the Warm Linac will accelerate a pulsed proton beam of 50 mA peak current from source at 0.075 MeV up to 80 MeV. Such Linac is designed to operate at 352.2 MHz, with a duty cycle of 4% (3 ms pulse length, 14 Hz repetition period).In this paper the main design choices and the beam dynamics studies for the source up to the end of DTL are shown.

Slides TUO3B01 [17.664 MB]

TUO3B02

Beam Dynamics of the ESS Superconducting Linac

cavity, proton, quadrupole, emittance

278

M. Eshraqi, H. Danared, R. Miyamoto
ESS, Lund, Sweden

The European Spallation Source, ESS, uses a linear accelerator to deliver the high intensity proton beam to the target station. The nominal beam power is 5 MW at an energy of 2.5 GeV. The superconducting part covers more than 95\% of the energy gain and 90\% of the length. The beam dynamics criteria applied to the design of the superconducting part of the linac including the frequency jump at a medium energy of 200 MeV as well as the beam dynamics performance of this structure are described in this paper.

Slides TUO3B02 [4.406 MB]

TUO3B03

Linac4 Beam Commissioning Strategy

emittance, space-charge, DTL, diagnostics

283

J.-B. Lallement, A.M. Lombardi, P.A. Posocco
CERN, Geneva, Switzerland

Linac4 is a 160 MeV H⁻ ion linear accelerator, presently under construction, which will replace the 50 MeV Linac2 as injector of the CERN proton complex. Linac4 is a 90 m long normal-conducting Linac made of a 3 MeV Radio Frequency Quadrupole (RFQ) followed by a 50 MeV Drift Tube Linac (DTL), a 100 MeV Cell-Coupled Drift Tube Linac (CCDTL) and a Pi-Mode Structure (PIMS). Starting in 2013, five commissioning stages, interlaced with installation periods, are foreseen at the energies of 3, 12, 50, 100 and 160 MeV. In addition to the diagnostics permanently installed in the Linac, temporary measurement benches will be located at the end of each structure and will be used for beam commissioning. Comprehensive beam dynamics simulations were carried out through the Linac and the diagnostic benches to define a commissioning procedure, which is summarised in this paper. In particular, we will present a method for emittance reconstruction from profile measurements which keeps into account the effects of space charge and finite diagnostics resolution.

Slides TUO3B03 [2.951 MB]

TUO3B04

End to End Beam Dynamics and Design Optimization for CSNS Linac

DTL, lattice, quadrupole, rfq

286

J. Peng, S. Fu, H.C. Liu, H.F. Ouyang, X. Yin
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) will use a linear accelerator delivering a 15mA beam up to 80MeV for injection into a rapid cycling synchrotron (RCS). Since each section of the linac was determined individually, a global optimization based on end-to-end simulation results has refined some design choices, including the drift-tube linac (DTL) and the medium energy beam transport (MEBT). The simulation results and reasons for adjustments are presented in this paper.

Slides TUO3B04 [1.131 MB]

TUO1C02

Online Monitoring System for the Waste Beam in the 3-GeV RCS of J-PARC

injection, monitoring, proton, target

297

P.K. Saha, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, K. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

We have established two independent methods for monitoring the waste beam of only about 0.4% in the 3 GeV Rapid Cycling Synchrotron of the Japan Proton Accelerator. Although using conventional monitor systems, the measurement technique made it possible for clearly measuring such a waste beam even with significantly low error. One of the method uses a current transformer to measure the waste beam as a whole, while the other one uses a multi-wire profile monitor for clearly measuring beam profiles of both un-stripped and partially stripped components of the waste beam. While the raw signal measured by a CT (current transformer) contains a large noise, an FFT (Fast Fourier Transformation) analysis made it possible to clearly identify the beam signal corresponding to the frequency of the intermediate pulse. The waste beam was measured to be (0.38±0.03)%. Being non destructive, the 1st method is efficiently operating for online monitoring of the waste beam during the RCS user operation so as to directly know the the stripper foil condition and would have great importance for higher power operation.

Slides TUO1C02 [2.687 MB]

TUO1C03

The Beam Diagnostics of CSNS

diagnostics, emittance, injection, neutron

302

T.G. Xu, J.N. Bai, C. Chen, L.X. Han, F. Li, P. Li, M. Meng, J.L. Sun, J.M. Tian, A.X. Wang, B. Wang, M.H. Xu, Zh.H. Xu, X.Y. Yang, L. Zeng
IHEP, Beijing, People's Republic of China

CSNS project is in the construction stage. The overview of CSNS beam diagnostics is presented which includes linac, RCS and both transport beam line. also some predevelopment of CSNS beam diagnostics is presented.

Slides TUO1C03 [8.366 MB]

TUO1C06

Instrumentation Developments and Beam Studies for the Fermilab Proton Improvement Plan Linac Upgrade and New RFQ Front-End

rfq, proton, ion-source, instrumentation

315

V.E. Scarpine, D.S. Bollinger, K.L. Duel, N. Eddy, P.R. Karns, N. Liu, W. Pellico, A. Semenov, C.-Y. Tan, R.E. Tomlin
Fermilab, Batavia, USA

Funding: This work was supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359.
Fermilab is developing a Proton Improvement Plan (PIP) to increase throughput of it's the proton source. The plan addresses hardware modifications to increase repetition rate and improve beam loss while ensuring viable operation of the proton source through 2025. The first phase of the PIP will enable the Fermilab proton source to deliver 1.8·10¹⁷ protons per hour by mid-2013. As part of this initial upgrade, Fermilab plans to install a new front-end consisting of dual H⁻ ion sources and a 201 MHz pulsed RFQ. This talk will present beam studies measurements of this new front-end as well as present new beam instrumentation upgrades for the Fermilab linac.

Slides TUO1C06 [2.546 MB]

TUO3C03

Characterizing and Controlling Beam Losses at the LANSCE Facility

DTL, proton, beam-losses, neutron

324

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

Funding: Work supported by DOE under contract DE-AC52-06NA25396.
The Los Alamos Neutron Science Center (LANSCE) currently provides 100-MeV H⁺ and 800-MeV H⁻ beams to several user facilities that have distinct beam requirements, e.g. intensity, micropulse pattern, duty factor, etc.. Minimizing beam loss is critical to achieving good performance and reliable operation, but can be challenging in the context of simultaneous multi-beam delivery. This presentation will discuss various aspects related to the observation, characterization and minimization of beam loss associated with normal production beam operations.

Slides TUO3C03 [3.534 MB]

TUO3C04

Beam Loss Mitigation in the Oak Ridge Spallation Neutron Source

quadrupole, DTL, neutron, injection

329

M.A. Plum
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.
The Oak Ridge Spallation Neutron Source (SNS) accelerator complex routinely delivers 1 MW of beam power to the spallation target. Due to this high beam power, understanding and minimizing the beam loss is an ongoing focus area of the accelerator physics program. In some areas of the accelerator facility the equipment parameters corresponding to the minimum loss are very different from the design parameters. In this presentation we will summarize the SNS beam loss measurements, the methods used to minimize the beam loss, and a compare the design vs. the loss-minimized equipment parameters.

Slides TUO3C04 [4.617 MB]

TUO3C05

Beam Commissioning Plan for CSNS Accelerators

DTL, injection, optics, target

334

S. Wang, S. Fu, H.F. Ouyang, J. Peng
IHEP, Beijing, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11175193)
The China Spallation Neutron Source (CSNS) is now under construction, and the beam commissioning of ion source will start from the end of 2013, and will last several years for whole accelerator. The commissioning plan for CSNS accelerators will be presented in the presentation, including the commissioning correlated parameters, the goal at different commissioning stages and some key commissioning procedures for each part of accelerators. The detailed schedule for commissioning will be also given.

Slides TUO3C05 [3.574 MB]

WEO3A02

Beam Loss and Collimation in the ESS Linac

proton, simulation, DTL, collimation

368

R. Miyamoto, B. Cheymol, H. Danared, M. Eshraqi, A. Ponton, J. Stovall, L. Tchelidze
ESS, Lund, Sweden
I. Bustinduy
ESS Bilbao, Bilbao, Spain
A.I.S. Holm, S.P. Møller, H.D. Thomsen
ISA, Aarhus, Denmark

The European Spallation Source (ESS), to be built in Lund, Sweden, is a spallation neutron source based on a 5 MW proton linac. A high power proton linac has a tight tolerance on beam losses to avoid activation of its components and it is ideal to study patterns of the beam loss and prepare beam loss mitigation schemes at the design stage. This paper presents simulations of the beam loss in the ESS linac as well as beam loss mitigation schemes using collimators in beam transport sections.

Slides WEO3A02 [6.377 MB]

WEO3B01

FRIB Accelerator Beam Dynamics Design and Challenges

ion, target, solenoid, rfq

404

Q. Zhao, A. Facco, F. Marti, E. Pozdeyev, M.J. Syphers, J. Wei, X. Wu, Y. Yamazaki, Y. Zhang
FRIB, East Lansing, Michigan, USA

Funding: This material is based upon work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
The Facility for Rare Isotope Beams (FRIB) will be a new national user facility for nuclear science. This cw, high power, superconducting (SC), heavy ion driver linac consists of a frontend to provide various highly charged ions at 0.5 MeV/u, three SC acceleration segments connected by two 180° bending systems to achieve an output beam energy of ≥200 MeV/u for all varieties of stable ions, and a beam delivery system to transport multi-charge-state beams to a fragmentation target at beam power of up to 400 kW. The linac utilizes four types of low-beta resonators with one frequency transition from 80.5 to 322 MHz after Segment 1, where ion charge state(s) is boosted through a stripper at ≤20 MeV/u. The beam dynamics design challenges include simultaneous acceleration of multi-charge-state beams to meet beam-on-target requirements, efficient acceleration of high intensity, low energy heavy ion beams, limitation of uncontrolled beam loss to <1 W/m, accommodation of multiple charge stripping scenarios, etc. We present the recent optimizations on linac lattice, the results of end-to-end beam simulations with machine errors, and the simulation of beam tuning and fault conditions.

Slides WEO3B01 [7.899 MB]

WEO3B02

Acceleration and Transportation of Multiple Ion Species at Ebis-based Preinjector

ion, rfq, booster, emittance

409

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

A new heavy ion pre-injector at Brookhaven National Laboratory consist of an electron Beam Ion Source (EBIS), RFQ and IH Linac and a short transport line. This pre-injector provide any ion Helium to Uranium at energy of 2 MeV/u for Relativistic Heavy Ion Collider (RHIC) and the NASA Space Radiation Laboratory (NSRL). EBIS produces multiple charge states of an ion of interested. These charge states are accelerated through RFQ (300 keV/u) and IH Linac (2 MeV/u) and transported to booster. Charge desecration occurs just before the injection into the booster. This paper discusses implication of acceleration and transports of multiple charge state ions.

Slides WEO3B02 [5.825 MB]

WEO3B04

RFQ Beam Dynamics Design for Large Science Facilities and Accelerator-Driven Systems

rfq, proton, bunching, ion

419

C. Zhang
IAP, Frankfurt am Main, Germany

Serving as the front-end of large science facilities and Accelerator-Driven Systems (ADS), the Radio-Frequency Quadrupole (RFQ) accelerator usually needs to reach low beam losses, good beam quality, high reliability, and cost savings such design goals at high beam intensities. To address the challenges for modern RFQs, a special beam dynamics design technique characterized by a reasonable and efficient bunching process with balanced space-charge forces has been developed as an alternative to the classic Four-Section Procedure proposed by Los Alamos National Laboratory (LANL). In this paper, the design studies of some recent RFQ projects will be presented as examples.

Slides WEO3B04 [3.698 MB]

THO3A01

High Intensity Aspects of J-PARC Linac Including Re-commissioning after Earthquake

simulation, multipactoring, DTL, rfq

497

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

We had a massive earthquake in March 2011, which forced us to shutdown J-PARC accelerators for nearly nine months due to its resultant damages. After significant restoration effort, we resumed the beam operation of J-PARC linac in December 2011 and user operation in January 2012. Subsequently, we restored the same beam power as just before the earthquake in March 2012. In the course of the beam commissioning after the earthquake, we have experienced beam losses which were not observed before the earthquake. We discuss the experimentally observed beam losses and its comparison with particle simulations.

Slides THO3A01 [5.249 MB]

THO3A02

Beam Dynamics of China ADS Linac

cavity, rfq, lattice, emittance

502

Z. Li
Private Address, Beijing, People's Republic of China
P. Cheng, H. Geng, Z. Guo, C. Meng, B. Sun, J.Y. Tang, F. Yan
IHEP, Beijing, People's Republic of China

Funding: Supported by China ADS Program(XDA03020000), National Natural Science Fundation of China (10875099) and IHEP Special Fundings(Y0515550U1)
An ADS study program is approved by Chinese Academy of Sciences at 2011, which aims to design and built an ADS demonstration facility with the capability of more than 1000 MW thermal power within the following 25 years. The 15 MW driver accelerator will be designed and constructed by the Institute of High Energy Physics (IHEP) and Institute of Modern Physics (IMP) of China Academy of Sciences. This linac is characterized by the 1.5 GeV energy, 10 mA current and CW operation. It is composed by two parallel 10 MeV injectors and a main linac integrated with fault tolerance design. The superconducting acceleration structures are employed except the RFQ. The general considerations and the beam dynamics design of the driver accelerator will be presented.

Slides THO3A02 [5.822 MB]

THO3A04

Beam Halo Definitions and its Consequences

emittance, beam-losses, injection, space-charge

511

P.A.P. Nghiem, N. Chauvin, D. Uriot
CEA/DSM/IRFU, France
W. Simeoni
CEA/IRFU, Gif-sur-Yvette, France

In high-intensity accelerators, much attention is paid to the beam halo: formation, growth interaction with the beam core, etc. Indeed, beam losses, a critical issue for those high-power accelerators, directly depend on the beam halo behaviour. But in the presence of very strong space-charge forces, the beam distribution takes very different shapes along the accelerator, often very far from any regular distributions, with very varied halo extensions. The difficulty is then to find a general definition of the halo capable of describing any distribution type. This paper proposes a definition of the beam halo, studies its consequences and compares it to the most usual ones.

Slides THO3A04 [9.030 MB]

THO3B02

SRF Technology Challenge and Development

cavity, SRF, HOM, ion

536

A. Facco
INFN/LNL, Legnaro (PD), Italy
A. Facco
FRIB, East Lansing, USA

SRF technology in particle accelerators is in continuous evolution, providing a large variety of high gradient- low loss resonators with large apertures, suitable for many different beam current and energy regimes. Recent development was aiming not only at highest gradient and Q but also at improving field quality, reliability and cost reduction for large production. The SRF R&D effort, once concentrated mostly in the high energy electron machines, is increasingly focused to heavy ion linacs, energy recovery linacs and also to cavities for special applications. A concise overview of the present state of the art will be given.

Slides THO3B02 [1.712 MB]

THO3B03

SRF Cavity Research for Project X

cavity, SRF, cryomodule, proton

541

R.D. Kephart
Fermilab, Batavia, USA

Project X is a new SRF linac based multi-MW class proton source proposed for construction at Fermilab. It consists of a 3 MW, 1 mA CW H⁻ SRF linac that feeds an intensity frontier Physics program and a 3-8 GeV pulsed linac that accelerates ~5% of the output of the CW linac to 8 GeV for injection into the Fermilab Main Injector synchrotron resulting in an additional 2 MW of beam power at 60-120 GeV in support of a world class long baseline neutrino program. The project has chosen operating frequencies that are sub-harmonics of 1.3 GHz and is developing 6 separate cavity designs for acceleration of H⁻ particles with various velocities. An R&D program is in progress to develop these cavities; the associated cryomodules; and the required fabrication and test infrastructure. A status and progress report on this R&D program will be presented.

Slides THO3B03 [4.034 MB]

THO1C05

Status and Beam Commissioning Plan of PEFP 100 MeV Proton Linac

proton, DTL, target, site

570

J.-H. Jang, S. Cha, Y.-S. Cho, D.I. Kim, H.S. Kim, H.-J. Kwon, Y.M. Li, B.-S. Park, J.Y. Ryu, K.T. Seol, Y.-G. Song, S.P. Yun
KAERI, Daejon, Republic of Korea

Funding: This work was supported by Ministry of Education, Science and Technology of the Korean government.
The proton engineering frontier project (PEFP) is developing a 100 MeV proton linac which consists of a 50 keV injector, a 3 MeV RFQ (radio frequency quadrupole), and a 100 MeV DTL (drift tube linac). The installation of the linac was finished on March this year. The other elements including the high power RF components will be installed after completing the other part of the accelerator building. The beam commissioning is scheduled at the end of this year. This work summarized the status of the PEFP linac development and the beam commissioning plan.

Slides THO1C05 [5.104 MB]

THO3C02

Momentum Spread Determination of Linac Beams Using Incoherent Components of the Bunch Signals

cavity, synchrotron, pick-up, bunching

583

P. Kowina, P. Forck, M. Schwickert
GSI, Darmstadt, Germany
F. Caspers
CERN, Geneva, Switzerland

Measurements of the momentum spread of the beam particles are of great importance when optimizing linac settings for high current operation with controlled longitudinal phase space occupation. A new method of momentum spread determination was tested at the GSI heavy ion linear accelerator UNILAC. The method is based on an analysis of incoherent components of the bunch signal. A significant enhancement of the signal-to-noise ratio was achieved by means of a resonant pick-up of pill-box shape. Spectra were analyzed on the 36th harmonics of the linac rf-frequency, i.e. at 1.3 GHz. Thus, the contribution of coherent components in the frequency spectrum of the bunched beam, e.g. due to common mode, was significantly damped. Fast digital processing and gating synchronized to the bunch train allowed for a drastic reduction of the measurement time and, additionally, suppressed noise signals in the frequency spectrum. This contribution describes the measurement setup and discusses first results obtained with heavy ion beams.

Slides THO3C02 [2.131 MB]

THO3C04

Longitudinal Beam Diagnosis with RF Chopper System

cavity, neutron, acceleration, DTL

591

T. Maruta
JAEA/J-PARC, Tokai-mura, Japan
M. Ikegami
KEK, Ibaraki, Japan

J-PARC linac has a chopper system between RFQ and DTL, which utilizes an RF deflector cavity instead of a usual slow wave kicker. Taking advantage of this unique feature of the chopper system, we have experimentally measured the longitudinal full width of phase direction at the chopper cavity. In this presentation, I would like to discuss the measurement technique and measurement results.

Slides THO3C04 [2.495 MB]

FRO1A02

WG-B: Beam Dynamics In High Intensity Linacs

rfq, emittance, DTL, resonance

612

D. Raparia
BNL, Upton, Long Island, New York, USA
Z. Li
IHEP, Beijing, People's Republic of China
P.A.P. Nghiem
CEA/DSM/IRFU, France

Emittance coupling, equipartioning and losses were a few topics, which were discussed thoroughly during parallel session for beam dynamics in high intensity linacs (Group B). Linac designs for the future, under construction, upgrade and the existing linacs from around the world were presented in three working sessions. A total of 18 talks were presented. Five presentations are general beam dynamics in nature and twelve talks were project specific. The detail of each contribution can be found in these proceedings. Here we report the summary of the discussions and some concluding remarks of the general interest to all the projects presented in the working group.

Slides FRO1A02 [14.464 MB]

FRO1B01

Summary of the Working Group on Commissioning and Operation

beam-losses, injection, proton, simulation

620

R. Schmidt
CERN, Geneva, Switzerland
M.A. Plum
ORNL, Oak Ridge, Tennessee, USA
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The Working Group D summary report focussed on answering the following issues:

observation of beam losses (e.g. time structure, other parameters,…),
reducing beam losses with operational parameters away from the design set points,
reducing beam losses (or concentrating beam losses at a few locations) using collimators,
minimizing beam losses due to beam transfer from one accelerator to the following accelerator - what parameters are important?

The issue of reducing beam losses with operational parameters away from the design set points is especially valuable as it is rarely discussed.

Slides FRO1B01 [0.426 MB]

FRO1B02

Qinclosing Plenary Summary of Working Group E:Diagnostics and Instrumentation for High-Intensity Beams

diagnostics, beam-losses, instrumentation, proton

625

R. Dölling
PSI, Villigen PSI, Switzerland
N. Hayashi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
V.E. Scarpine
Fermilab, Batavia, USA

Working Group E Summary: Working group E was charged with presentations and discussions on diagnostics and instrumentation of high intensity beams. We had 2 sessions, consisting of a total of 12 talks, each of 20 minutes for presentation followed by some discussion. One session was followed by a discussion session of two hours. All sessions took place in parallel with the sessions of WG-D (Commissioning, operations and performance), inevitably preventing some possibly useful overlap. In addition, seven posters, regarding beam diagnostics, were presented in the single poster session.

Slides FRO1B02 [18.507 MB]