HB2012 - List of Keywords (solenoid)

Paper	Title	Other Keywords	Page
MOP218	Dynamics of Particles in a Tilted Solenoidal Focusing Channel	focusing, emittance, linac, 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, linac, cavity, simulation	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.

MOP220	Local Compensation-rematch for Major Element Failures in the C-ADS Accelerator	cavity, quadrupole, emittance, focusing	102
	B. Sun, Z. Li, J.Y. Tang, F. Yan IHEP, Beijing, People's Republic of China
	In order to achieve the required reliability and availability for the C-ADS accelerator, a fault tolerance design is pursued. The effects of cavity failure in different locations have been studied and the schemes of compensation by means of local compensation have been investigated. After one cavity failure, by adjusting the settings of the neighboring cavities and the focusing elements to make sure that the Twiss parameters and energy are approximately recovered to that of the nominal ones at the matching point. We find the normalized RMS emittance and emittances including 99.9% and 100% particles have no obvious growth after applying the compensation with the RMS rematching in each section of the main linac. However, the conclusions above are drawn from the simulation results with the TraceWin code, which doesn't consider the phase difference. A code based on Matlab is under developing. By applying the code on the cavity failure in the middle part of spoke021 section, a fully compensated scheme with good dynamics results is obtained. The space charge effect is still not implanted in the code, and further study and optimization of the code will be performed in the next step.

MOP232	Optimization of the Superconducting Section of Injector Ⅱ for C-ADS	emittance, simulation, lattice, 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.

MOP233	Error and Tolerance Studies for Injector II of C-ADS	linac, simulation, 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.

WEO3B01	FRIB Accelerator Beam Dynamics Design and Challenges	ion, linac, target, 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]

THO3B04	Beam Dynamics Studies of H⁻ Beam Chopping in a LEBT for Project X	ion, emittance, simulation, ion-source	546
	Q. Ji, D.P. Grote, A.R. Lambert, D. Li, T. Schenkel, J.W. Staples LBNL, Berkeley, California, USA
	Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231. Project X is proposed as a high intensity proton facility at Fermilab to support a world-leading program in neutrino and flavor physics over the next several decades. The front-end consists of an H⁻ ion source, low-energy beam transport (LEBT), and 162.5 MHz CW Radio-Frequency-Quadrupole (RFQ) accelerator. The LEBT design, currently under study at LBNL, would comprise two solenoids, a dipole magnet and a chopper. The LEBT chopper is designed to achieve 1 MHz beam chopping of a partially neutralized 30 keV, 5 mA H⁻ beam. Preliminary simulation studies show that chopping the beam before the second solenoid is more efficient in terms of chopper bias voltages. However, the space charge neutralization will be lost along the beam after the chopper and through the second solenoid. A beam dynamics study, using WARP 3D (a Particle-in-cell simulation code), has been carried out to investigate both the time-dependence of the partial neutralization in the segment after the chopper, as well as the beam stability and emittance growth. Benchmark experiments are ongoing and simulation and experimental results will be presented in this Workshop.
	Slides THO3B04 [1.868 MB]

Paper

Title

Other Keywords

Page

MOP218

Dynamics of Particles in a Tilted Solenoidal Focusing Channel

focusing, emittance, linac, 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, linac, cavity, simulation

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.

MOP220

Local Compensation-rematch for Major Element Failures in the C-ADS Accelerator

cavity, quadrupole, emittance, focusing

102

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

In order to achieve the required reliability and availability for the C-ADS accelerator, a fault tolerance design is pursued. The effects of cavity failure in different locations have been studied and the schemes of compensation by means of local compensation have been investigated. After one cavity failure, by adjusting the settings of the neighboring cavities and the focusing elements to make sure that the Twiss parameters and energy are approximately recovered to that of the nominal ones at the matching point. We find the normalized RMS emittance and emittances including 99.9% and 100% particles have no obvious growth after applying the compensation with the RMS rematching in each section of the main linac. However, the conclusions above are drawn from the simulation results with the TraceWin code, which doesn't consider the phase difference. A code based on Matlab is under developing. By applying the code on the cavity failure in the middle part of spoke021 section, a fully compensated scheme with good dynamics results is obtained. The space charge effect is still not implanted in the code, and further study and optimization of the code will be performed in the next step.

MOP232

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

emittance, simulation, lattice, 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.

MOP233

Error and Tolerance Studies for Injector II of C-ADS

linac, simulation, 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.

WEO3B01

FRIB Accelerator Beam Dynamics Design and Challenges

ion, linac, target, 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]

THO3B04

Beam Dynamics Studies of H⁻ Beam Chopping in a LEBT for Project X

ion, emittance, simulation, ion-source

546

Q. Ji, D.P. Grote, A.R. Lambert, D. Li, T. Schenkel, J.W. Staples
LBNL, Berkeley, California, USA

Funding: This work is supported by the Office of Science, United States Department of Energy under DOE contract DE-AC02-05CH11231.
Project X is proposed as a high intensity proton facility at Fermilab to support a world-leading program in neutrino and flavor physics over the next several decades. The front-end consists of an H⁻ ion source, low-energy beam transport (LEBT), and 162.5 MHz CW Radio-Frequency-Quadrupole (RFQ) accelerator. The LEBT design, currently under study at LBNL, would comprise two solenoids, a dipole magnet and a chopper. The LEBT chopper is designed to achieve 1 MHz beam chopping of a partially neutralized 30 keV, 5 mA H⁻ beam. Preliminary simulation studies show that chopping the beam before the second solenoid is more efficient in terms of chopper bias voltages. However, the space charge neutralization will be lost along the beam after the chopper and through the second solenoid. A beam dynamics study, using WARP 3D (a Particle-in-cell simulation code), has been carried out to investigate both the time-dependence of the partial neutralization in the segment after the chopper, as well as the beam stability and emittance growth. Benchmark experiments are ongoing and simulation and experimental results will be presented in this Workshop.

Slides THO3B04 [1.868 MB]