HB2012 - List of Keywords (lattice)

Paper	Title	Other Keywords	Page
MOI1C01	Intense-beam Issues in CSNS and C-ADS Accelerators	linac, cavity, emittance, 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]

MOP211	1-MW Beam Operation Scenario in the J-PARC RCS	injection, quadrupole, emittance, controls	68
	H. Hotchi, H. Harada, N. Hayashi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie KEK, Ibaraki, Japan
	The injection energy of the J-PARC RCS will be upgraded from 181 MeV to 400 MeV in the 2013 summer-autumn period. With this upgraded injection energy, we are to aim for 1 MW design output beam power. In this paper, we discuss beam dynamics issues for the 1 MW beam operation and their possible solutions.

MOP215	The Study on Measuring Beta Functions and Phase Advances in the CSNS/RCS	space-charge, kicker, betatron, synchrotron	85
	Y.W. An, S. Wang IHEP, Beijing, People's Republic of China
	As a key component of the China Spallation Neutron Source (CSNS) Project, the Rapid Cycling Synchrotron (RCS) will accumulate and accelerate the proton beams from 80 MeV to 1.6 GeV for extracting and striking the target with a repletion rate of 25 Hz. To check linear optics and locate the quadruple errors, beta function plays an important role in beam diagnostics of a particle accelerate system. The Independent Component Analysis (ICA) is a robust beam diagnosis method by decomposing the samples recorded by turn by turn BPMs (beam position monitors) into the independent components which represent the inherent motion of the beam. The beta functions and phase advances can be derived from the corresponding independent components. Because the linear part of the space charge gives a defocusing effect to the beam, beta function variation will be induced. We find that the ICA method can measure beta functions with a reasonable tolerance under the conditions of strong space charge effects.

MOP221	Physics Design of the C-ADS Main Linac Based on Two Different Injector Design Schemes	linac, emittance, simulation, 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, linac, 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, linac	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.

MOP256	High-power Scaling FFAG Ring Studies	injection, space-charge, scattering, dynamic-aperture	202
	D.J. Kelliher, S. Machida, G.H. Rees STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	High-power scaling FFAG rings have potential application in areas such as neutron spallation, muon production, and accelerator-driven systems. It is proposed to build a model of such a ring in order to study major issues such as space charge and injection. A 20 ' 70 MeV radial DFD FFAG model, that was initially described in , incorporates long straights to facilitate H⁻ charge exchange injection. Bump magnets are used to move the injected beam away from the foil. The effect of the injection process on the beam emittance is considered. The tune depression and emittance blow up resulting from the effect of space charge is also calculated. G.H. Rees et al, ‘A Model for a High-Power Scaling FFAG Ring', IPAC12, New Orleans, 2012, MOPPD020, http://www. JACow.org

MOP258	Simulation of Intense Proton Beams in Novel Isochronous FFAG Designs	space-charge, cyclotron, simulation, extraction	211
	S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom M. Berz, K. Makino MSU, East Lansing, Michigan, USA C. Johnstone Fermilab, Batavia, USA P. Snopok Illinois Institute of Technology, Chicago, Illinois, USA
	Recent developments in the design of non-scaling fixed field alternating gradient (FFAG) accelerators have been focused on achieving isochronous behavior with a small betatron tune excursion. These advances are particularly interesting for applications requiring CW beams, such as Accelerator Driven Systems for energy generation or waste transmutation. The latest advances in lattice design have resulted in a 330 MeV to 1 GeV lattice, isochronous to better than ± 1 percent. This paper reports on simulations of recent lattice designs incorporating 3D space charge effects.

TUO3B04	End to End Beam Dynamics and Design Optimization for CSNS Linac	DTL, 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]

TUO3C06	The Result of Beam Commissioning in J-PARC 3-GeV RCS	injection, collimation, scattering, extraction	339
	H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, T. Koseki, Y. Sato, K. Satou, M.J. Shirakata KEK, Ibaraki, Japan S. Kato Tohoku University, Graduate School of Science, Sendai, Japan
	J-PARC 3-GeV RCS has started the beam commissioning since Oct. 2007. In the beam commissioning, the beam tuning for basic parameters and high-intensity operation has been continuously performed. This presentation will describe the results of the beam-loss reduction and minimization for high-intensity operation.
	Slides TUO3C06 [7.753 MB]

WEO3C04	Long Baseline Neutrino Experiment Target Material Radiation Damage Studies Using Energetic Protons of the Brookhaven Linear Isotope Production (BLIP) Facility	proton, target, neutron, radiation	471
	N. Simos BNL, Upton, Long Island, New York, USA P. Hurh Fermilab, Batavia, USA Z. Kotsina NCSR Demokritos, Attiki, Greece
	One of the future multi-MW accelerators is the LBNE Experiment where Fermilab plans to produce a beam of neutrinos with a 2.3 MW proton beam as part of a suite of experiments associated with ProjectX. Specifically, the LBNE Neutrino Beam Facility aims for a 2⁺ MW, 60-120 GeV pulsed,high intensity proton beam produced in the ProjectX accelerator intercepted by a low Z solid target to facilitate the production of low energy neutrinos. The multi-MW level LBNE proton beam will be characterized by intensities of the order of 1.6·10⁺¹⁴ p/pulse, σ_radius of 1.5-3.5 mm and a 9.8 μs pulse length. These parameters are expected to push many target materials to their limit thus making the target design very challenging. Recent experience from operating high intensity beams on targets have indicated that several critical design issues exist namely thermal shock,heat removal, radiation damage,radiation accelerated corrosion effects,and residual radiation within the target envelope. A series of experimental studies on radiation damage and thermal shock response conducted at BNL and focusing on low-Z materials have unraveled potential issues regarding the damageability from energetic particle beams which may differ significantly from thermal reactor experience. Irradiation damage results for low-Z materials associated with the LBNE and other high power experiments will be presented.
	Slides WEO3C04 [3.965 MB]

THO1A02	Effects of Magnetic Field Tracking Errors and Space Charge on Beam Dynamics at CSNS/RCS	space-charge, quadrupole, simulation, resonance	484
	S.Y. Xu, N. Wang, S. Wang IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) is an accelerator-based facility. It operates at 25 Hz repetition rate with an design beam power of 100 kW. CSNS consists of a 1.6-GeV Rapid Cycling Synchrotron (RCS) and a 80-MeV linac. The lattice of the CSNS/RCS is triplet based four-fold structure. The preferred working points of CSNS/RCS are (4.86, 4.78) which can avoid the major low-order structure resonances. But because of the chromatic tune shift, space-charge incoherent tune shift and the tune shift caused by magnetic field tracking errors between the quadrupoles and the dipoles, some structure resonances are unavoidable. The chromaticity, space charge effects and magnetic field tracking errors can also induce beta function distortion, and influence the transverse acceptance and the collimation efficiency of the collimation system. In this paper we show results of space-charge simulations introducing magnetic field tracking errors and discuss the combined effects of chromaticity, magnetic field tracking errors and space charge on the beam dynamics for CSNS/RCS.
	Slides THO1A02 [1.613 MB]

THO3A02	Beam Dynamics of China ADS Linac	linac, cavity, rfq, 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]

Paper

Title

Other Keywords

Page

MOI1C01

Intense-beam Issues in CSNS and C-ADS Accelerators

linac, cavity, emittance, 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]

MOP211

1-MW Beam Operation Scenario in the J-PARC RCS

injection, quadrupole, emittance, controls

68

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

The injection energy of the J-PARC RCS will be upgraded from 181 MeV to 400 MeV in the 2013 summer-autumn period. With this upgraded injection energy, we are to aim for 1 MW design output beam power. In this paper, we discuss beam dynamics issues for the 1 MW beam operation and their possible solutions.

MOP215

The Study on Measuring Beta Functions and Phase Advances in the CSNS/RCS

space-charge, kicker, betatron, synchrotron

85

Y.W. An, S. Wang
IHEP, Beijing, People's Republic of China

As a key component of the China Spallation Neutron Source (CSNS) Project, the Rapid Cycling Synchrotron (RCS) will accumulate and accelerate the proton beams from 80 MeV to 1.6 GeV for extracting and striking the target with a repletion rate of 25 Hz. To check linear optics and locate the quadruple errors, beta function plays an important role in beam diagnostics of a particle accelerate system. The Independent Component Analysis (ICA) is a robust beam diagnosis method by decomposing the samples recorded by turn by turn BPMs (beam position monitors) into the independent components which represent the inherent motion of the beam. The beta functions and phase advances can be derived from the corresponding independent components. Because the linear part of the space charge gives a defocusing effect to the beam, beta function variation will be induced. We find that the ICA method can measure beta functions with a reasonable tolerance under the conditions of strong space charge effects.

MOP221

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

linac, emittance, simulation, 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, linac, 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, linac

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.

MOP256

High-power Scaling FFAG Ring Studies

injection, space-charge, scattering, dynamic-aperture

202

D.J. Kelliher, S. Machida, G.H. Rees
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

High-power scaling FFAG rings have potential application in areas such as neutron spallation, muon production, and accelerator-driven systems. It is proposed to build a model of such a ring in order to study major issues such as space charge and injection. A 20 ' 70 MeV radial DFD FFAG model, that was initially described in *, incorporates long straights to facilitate H⁻ charge exchange injection. Bump magnets are used to move the injected beam away from the foil. The effect of the injection process on the beam emittance is considered. The tune depression and emittance blow up resulting from the effect of space charge is also calculated.
* G.H. Rees et al, ‘A Model for a High-Power Scaling FFAG Ring', IPAC12, New Orleans, 2012, MOPPD020, http://www. JACow.org

MOP258

Simulation of Intense Proton Beams in Novel Isochronous FFAG Designs

space-charge, cyclotron, simulation, extraction

211

S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
M. Berz, K. Makino
MSU, East Lansing, Michigan, USA
C. Johnstone
Fermilab, Batavia, USA
P. Snopok
Illinois Institute of Technology, Chicago, Illinois, USA

Recent developments in the design of non-scaling fixed field alternating gradient (FFAG) accelerators have been focused on achieving isochronous behavior with a small betatron tune excursion. These advances are particularly interesting for applications requiring CW beams, such as Accelerator Driven Systems for energy generation or waste transmutation. The latest advances in lattice design have resulted in a 330 MeV to 1 GeV lattice, isochronous to better than ± 1 percent. This paper reports on simulations of recent lattice designs incorporating 3D space charge effects.

TUO3B04

End to End Beam Dynamics and Design Optimization for CSNS Linac

DTL, 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]

TUO3C06

The Result of Beam Commissioning in J-PARC 3-GeV RCS

injection, collimation, scattering, extraction

339

H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, T. Koseki, Y. Sato, K. Satou, M.J. Shirakata
KEK, Ibaraki, Japan
S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan

J-PARC 3-GeV RCS has started the beam commissioning since Oct. 2007. In the beam commissioning, the beam tuning for basic parameters and high-intensity operation has been continuously performed. This presentation will describe the results of the beam-loss reduction and minimization for high-intensity operation.

Slides TUO3C06 [7.753 MB]

WEO3C04

Long Baseline Neutrino Experiment Target Material Radiation Damage Studies Using Energetic Protons of the Brookhaven Linear Isotope Production (BLIP) Facility

proton, target, neutron, radiation

471

N. Simos
BNL, Upton, Long Island, New York, USA
P. Hurh
Fermilab, Batavia, USA
Z. Kotsina
NCSR Demokritos, Attiki, Greece

One of the future multi-MW accelerators is the LBNE Experiment where Fermilab plans to produce a beam of neutrinos with a 2.3 MW proton beam as part of a suite of experiments associated with ProjectX. Specifically, the LBNE Neutrino Beam Facility aims for a 2⁺ MW, 60-120 GeV pulsed,high intensity proton beam produced in the ProjectX accelerator intercepted by a low Z solid target to facilitate the production of low energy neutrinos. The multi-MW level LBNE proton beam will be characterized by intensities of the order of 1.6·10⁺¹⁴ p/pulse, σ_radius of 1.5-3.5 mm and a 9.8 μs pulse length. These parameters are expected to push many target materials to their limit thus making the target design very challenging. Recent experience from operating high intensity beams on targets have indicated that several critical design issues exist namely thermal shock,heat removal, radiation damage,radiation accelerated corrosion effects,and residual radiation within the target envelope. A series of experimental studies on radiation damage and thermal shock response conducted at BNL and focusing on low-Z materials have unraveled potential issues regarding the damageability from energetic particle beams which may differ significantly from thermal reactor experience. Irradiation damage results for low-Z materials associated with the LBNE and other high power experiments will be presented.

Slides WEO3C04 [3.965 MB]

THO1A02

Effects of Magnetic Field Tracking Errors and Space Charge on Beam Dynamics at CSNS/RCS

space-charge, quadrupole, simulation, resonance

484

S.Y. Xu, N. Wang, S. Wang
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) is an accelerator-based facility. It operates at 25 Hz repetition rate with an design beam power of 100 kW. CSNS consists of a 1.6-GeV Rapid Cycling Synchrotron (RCS) and a 80-MeV linac. The lattice of the CSNS/RCS is triplet based four-fold structure. The preferred working points of CSNS/RCS are (4.86, 4.78) which can avoid the major low-order structure resonances. But because of the chromatic tune shift, space-charge incoherent tune shift and the tune shift caused by magnetic field tracking errors between the quadrupoles and the dipoles, some structure resonances are unavoidable. The chromaticity, space charge effects and magnetic field tracking errors can also induce beta function distortion, and influence the transverse acceptance and the collimation efficiency of the collimation system. In this paper we show results of space-charge simulations introducing magnetic field tracking errors and discuss the combined effects of chromaticity, magnetic field tracking errors and space charge on the beam dynamics for CSNS/RCS.

Slides THO1A02 [1.613 MB]

THO3A02

Beam Dynamics of China ADS Linac

linac, cavity, rfq, 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]