HB2012 - List of Keywords (DTL)

Paper	Title	Other Keywords	Page
MOI1C03	Beam Loss Mechanisms in High Intensity Linacs	linac, 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]

MOP229	Design of the MEBT1 for C-ADS Injector II	quadrupole, emittance, rfq, simulation	115
	H. Jia, Y. He, S.C. Huang, C.L. Luo, M.T. Song, Y.J. Yuan, X. Zhang IMP, Lanzhou, People's Republic of China
	The MEBT1 of Chinese ADS Injector II is described. It transports a 2.1 MeV, 10 mA CW proton beam through a series of 7 quadruples and two buncher cavities from the RFQ to the superconducting DTL. For emittance preservation, a compact mechanical design is required. Details of the beam dynamics and mechanical design will be given.

MOP231	Study of Non-equi-partitioning Lattice Setting and IBS Effects for J-PARC Linac Upgrade	emittance, lattice, linac, simulation	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.

MOP235	Medium Energy Beam Transport Design Update for ESS	cavity, quadrupole, linac, 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.

TUO3B01	Beam Dynamics Design of ESS Warm Linac	linac, rfq, 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]

TUO3B03	Linac4 Beam Commissioning Strategy	emittance, linac, space-charge, 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	lattice, linac, 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]

TUO3B05	Beam Dynamics of the 13 MeV/50 mA Proton Linac for the Compact Pulsed Hadron Source at Tsinghua University	rfq, proton, simulation, target	289
	Q.Z. Xing, X. Guan, C. Jiang, C.-X. Tang, X.W. Wang, H.Y. Zhang, S.X. Zheng TUB, Beijing, People's Republic of China J.H. Billen, J. Stovall, L.M. Young TechSource, Santa Fe, New Mexico, USA G.H. Li NUCTECH, Beijing, People's Republic of China
	Funding: Work supported by the Major Research plan of the National Natural Science Foundation of China (Grant No. 91126003) We present the start-to-end simulation result on the high-current proton linac for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The CPHS project is a university-based proton accelerator platform (13 MeV, 16 kW, peak current 50 mA, 0.5 ms pulse width at 50 Hz) for multidisciplinary neutron and proton applications. The 13 MeV proton linac contains the ECR ion source, LEBT, RFQ, DTL and HEBT. The function of the whole accelerator system is to produce the proton beam, accelerate it to 13 MeV, and deliver it to the target where one uniform round beam spot is obtained with the diameter of 5 cm.
	Slides TUO3B05 [7.715 MB]

TUO3C03	Characterizing and Controlling Beam Losses at the LANSCE Facility	linac, 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, linac, 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	linac, 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	linac, proton, simulation, 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]

THO3A01	High Intensity Aspects of J-PARC Linac Including Re-commissioning after Earthquake	linac, simulation, multipactoring, 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]

THO1C05	Status and Beam Commissioning Plan of PEFP 100 MeV Proton Linac	linac, proton, 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]

THO3C04	Longitudinal Beam Diagnosis with RF Chopper System	cavity, linac, neutron, acceleration	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	linac, rfq, emittance, 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]

Paper

Title

Other Keywords

Page

MOI1C03

Beam Loss Mechanisms in High Intensity Linacs

linac, 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]

MOP229

Design of the MEBT1 for C-ADS Injector II

quadrupole, emittance, rfq, simulation

115

H. Jia, Y. He, S.C. Huang, C.L. Luo, M.T. Song, Y.J. Yuan, X. Zhang
IMP, Lanzhou, People's Republic of China

The MEBT1 of Chinese ADS Injector II is described. It transports a 2.1 MeV, 10 mA CW proton beam through a series of 7 quadruples and two buncher cavities from the RFQ to the superconducting DTL. For emittance preservation, a compact mechanical design is required. Details of the beam dynamics and mechanical design will be given.

MOP231

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

emittance, lattice, linac, simulation

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.

MOP235

Medium Energy Beam Transport Design Update for ESS

cavity, quadrupole, linac, 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.

TUO3B01

Beam Dynamics Design of ESS Warm Linac

linac, rfq, 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]

TUO3B03

Linac4 Beam Commissioning Strategy

emittance, linac, space-charge, 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

lattice, linac, 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]

TUO3B05

Beam Dynamics of the 13 MeV/50 mA Proton Linac for the Compact Pulsed Hadron Source at Tsinghua University

rfq, proton, simulation, target

289

Q.Z. Xing, X. Guan, C. Jiang, C.-X. Tang, X.W. Wang, H.Y. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China
J.H. Billen, J. Stovall, L.M. Young
TechSource, Santa Fe, New Mexico, USA
G.H. Li
NUCTECH, Beijing, People's Republic of China

Funding: Work supported by the Major Research plan of the National Natural Science Foundation of China (Grant No. 91126003)
We present the start-to-end simulation result on the high-current proton linac for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The CPHS project is a university-based proton accelerator platform (13 MeV, 16 kW, peak current 50 mA, 0.5 ms pulse width at 50 Hz) for multidisciplinary neutron and proton applications. The 13 MeV proton linac contains the ECR ion source, LEBT, RFQ, DTL and HEBT. The function of the whole accelerator system is to produce the proton beam, accelerate it to 13 MeV, and deliver it to the target where one uniform round beam spot is obtained with the diameter of 5 cm.

Slides TUO3B05 [7.715 MB]

TUO3C03

Characterizing and Controlling Beam Losses at the LANSCE Facility

linac, 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, linac, 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

linac, 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

linac, proton, simulation, 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]

THO3A01

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

linac, simulation, multipactoring, 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]

THO1C05

Status and Beam Commissioning Plan of PEFP 100 MeV Proton Linac

linac, proton, 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]

THO3C04

Longitudinal Beam Diagnosis with RF Chopper System

cavity, linac, neutron, acceleration

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

linac, rfq, emittance, 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]