SAP2014 - List of Authors (Yuan, Y.J.)

Paper	Title	Page
WEPH08	Simulation of Magnet Field Disturbance Effect on the Third Order Resonant Extraction	41
	J. Li, L.J. Mao, R.S. Mao, J. Shi, M.T. Song, J.W. Xia, J.C. Yang, X.D. Yang, Y.J. Yuan, T.C. Zhao IMP, Lanzhou, People's Republic of China
	The third order resonant slow extraction experimental research has progressed at the main ring of HIRFL, but the extracted beam spill intensity is significantly modulated by some periodic disturbances which leaded to large-scale beam break during continuous extraction and hardly decreased beam emittance at external targets. The periodic beam disturbance can be attributed to the main magnet field disturbances by low-frequency ripple of magnet power supplies. The disturbance effect of quadruple and dipole magnetic fields on the extracted beam spill intensity variation and emittance are evaluated by simulation in this paper. The simulation result shows that the current quadruple field disturbance level has a strong impact on both beam spill intensity and extracted beam emittance on the main ring.

WEPH09	Concept Design of the Collimation System in the CSRm	44
	P. Li, Z. Chai, P. Jiang, J. Meng, J.C. Yang, Y.J. Yuan, W.H. Zheng IMP, Lanzhou, People's Republic of China
	Funding: National Natural Science Foundation of China (Projects No. 11305227). The heavy ion beams would be easily lost at the vacuum chamber along the CSRm when it is used to accumulate the intermediate charge state particles. The vacuum pressure bump due to the ion-induced desorption in turn leads to an increase in beam loss rate. In order to avoid the complete beam loss, the collimation system is investigated in the CSRm. The beam loss distribution is simulated considering the particle charge exchanged process. Then the collimation efficiency of the lost particle is calculated and optimized under different collimator's position, geometry, and beam emittance and so on. Furthermore, the closed orbit distortion which is caused by different types of error in the ring will affect the collimation efficiency. The collimation efficiency of the lost particles in the CSRm is investigated by taking real magnet alignment errors into consideration. Two prototype collimators are under designing and will be tested in the CSRm.

WEPH10	Heavy Ions Radiography Facility at IMP	48
	L.N. Sheng, R. Cheng, P. Li, J.W. Xia, G.Q. Xiao, J.C. Yang, Y.J. Yuan, Y.T. Zhao, X.M. Zhou IMP, Lanzhou, People's Republic of China J. Deng, X.G. Jiang, G.J. Yang, L.W. Zhang CAEP/IFP, Mainyang, Sichuan, People's Republic of China T. Wei Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, People's Republic of China Y. Yan Lanzhou University, Lanzhou, People's Republic of China
	In order to identify the density and material type, high energy protons, electron, and heavy ions are used to radiograph dense objects. The transmitted particles through the object undergo the multiple coulomb scattering, and focus on an image plane by a magnetic lens system. A transformed beam line in the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) has been developed for heavy ions radiography. It can radiograph a static object and the spatial resolution is about 65um (σ). This paper presents the heavy ions radiography facility at IMP, including the beam optics, the simulation of radiography by Monte Carlo code and the experiment result with 600 MeV/u carbon ions. In addition, the dedicated beam lines for proton radiography in plan are also introduced.

WEPH11	Study of the Heavy Ion Bunch Compression in CSRm	51
	D.Y. Yin, W.P. Chai, J. Li, P. Li, Y. Liu, P. Shang, J.C. Yang, Y.J. Yuan IMP, Lanzhou, People's Republic of China
	The feasibility of attaining nanosecond pulse length heavy ion beam is studied in the main ring(CSRm) of the Heavy Ion Research Facility in Lanzhou. Such heavy ion beam can be produced by non-adiabatic compression, and it is implemented by a fast rotation in the longitudinal phase space. In this paper, the possible beam parameters during longitudinal bunch compression are studied with the envelope model and Particle in Cell simulation, and the results are compared. The result shows that the short bunch 238U²⁸⁺ with the pulse duration of about 50ns at the energy of 200MeV/u can be obtained

WEPH35	APF DTL Design Besed on iMpAPF	90
	P. Jiang, C. Li, P. Li, Z.J. Wang, Y.J. Yuan IMP, Lanzhou, People's Republic of China
	Alternative phase focusing (APF) DTL has advantages in price and space. However, the designing of APF is difficult because of the jumping phases. In order to design and simulate a proper APF, a code iMpAPF(i Multi-particle APF) has been developed. RK4 is introduced in this code for calculation, and the soul of the code is smoothness. Theoretically, the particle tracing figures out that the theoretic phase advance ratio between longitudinal direction and transversal direction is close to 2. Based on this code, a C⁵⁺, 200 MHz, medium energy APF as a linear injector of a synchrotron used for cancer therapy has been designed. This paper focuses on the development of iMpAPF, and also several results obtained from the code are shown.

THAMH5	Design and Commissioning of a CW Heavy Ion RFQ Accelerator	106
	K. Zhu, Z.Y. Guo, G. Liu, Y.R. Lu, Z. Wang, X.Q. Yan PKU, Beijing, People's Republic of China H. Du, Y. He, X. Yin, Y.J. Yuan, X.H. Zhang IMP, Lanzhou, People's Republic of China
	A CW RFQ for heavy ions is designed as the new injector for Separated Sector Cyclotron(SSC) at Institute of Modern Physics, Lanzhou, China. Now the RFQ have been installed in the main hall and the beam commissioning has been done. This paper will introduce the design consideration of the beam dynamics, the HF structure and the cooling structure design, measurement of the cold model, high power test of RFQ and the beam commissioning result.

THPMH2	Electron Cooling Experiments at HIRFL-CSR	113
	L.J. Mao, J. Li, X.M. Ma, J.W. Xia, T.L. Yan, J.C. Yang, X.D. Yang, Y.J. Yuan IMP, Lanzhou, People's Republic of China
	Two new-generation electron coolers have been operated at main ring and experimental ring of HIRFL-CSR facility, respectively. The electron beam with a variable profile helps to get an ion beam with the emittance and intensity that meet the demands of specific physical experiments. Fast transverse cooling of the hot ion beam after horizontal multiturn of stripping injection allows beam accumulation at the injection energy. After optimization of the accumulation and cooling process an current increase by more than one order of magnitude has been achieved. Momentum spread in the 10^-4 range has been demonstrated. In this paper, the longitudinal cooling force and the transverse cooling time measurements, the intrabeam scattering effect measurements were introduced.

Paper

Title

Page

Simulation of Magnet Field Disturbance Effect on the Third Order Resonant Extraction

41

J. Li, L.J. Mao, R.S. Mao, J. Shi, M.T. Song, J.W. Xia, J.C. Yang, X.D. Yang, Y.J. Yuan, T.C. Zhao
IMP, Lanzhou, People's Republic of China

The third order resonant slow extraction experimental research has progressed at the main ring of HIRFL, but the extracted beam spill intensity is significantly modulated by some periodic disturbances which leaded to large-scale beam break during continuous extraction and hardly decreased beam emittance at external targets. The periodic beam disturbance can be attributed to the main magnet field disturbances by low-frequency ripple of magnet power supplies. The disturbance effect of quadruple and dipole magnetic fields on the extracted beam spill intensity variation and emittance are evaluated by simulation in this paper. The simulation result shows that the current quadruple field disturbance level has a strong impact on both beam spill intensity and extracted beam emittance on the main ring.

WEPH09

Concept Design of the Collimation System in the CSRm

44

P. Li, Z. Chai, P. Jiang, J. Meng, J.C. Yang, Y.J. Yuan, W.H. Zheng
IMP, Lanzhou, People's Republic of China

Funding: National Natural Science Foundation of China (Projects No. 11305227).
The heavy ion beams would be easily lost at the vacuum chamber along the CSRm when it is used to accumulate the intermediate charge state particles. The vacuum pressure bump due to the ion-induced desorption in turn leads to an increase in beam loss rate. In order to avoid the complete beam loss, the collimation system is investigated in the CSRm. The beam loss distribution is simulated considering the particle charge exchanged process. Then the collimation efficiency of the lost particle is calculated and optimized under different collimator's position, geometry, and beam emittance and so on. Furthermore, the closed orbit distortion which is caused by different types of error in the ring will affect the collimation efficiency. The collimation efficiency of the lost particles in the CSRm is investigated by taking real magnet alignment errors into consideration. Two prototype collimators are under designing and will be tested in the CSRm.

WEPH10

Heavy Ions Radiography Facility at IMP

48

L.N. Sheng, R. Cheng, P. Li, J.W. Xia, G.Q. Xiao, J.C. Yang, Y.J. Yuan, Y.T. Zhao, X.M. Zhou
IMP, Lanzhou, People's Republic of China
J. Deng, X.G. Jiang, G.J. Yang, L.W. Zhang
CAEP/IFP, Mainyang, Sichuan, People's Republic of China
T. Wei
Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan, People's Republic of China
Y. Yan
Lanzhou University, Lanzhou, People's Republic of China

In order to identify the density and material type, high energy protons, electron, and heavy ions are used to radiograph dense objects. The transmitted particles through the object undergo the multiple coulomb scattering, and focus on an image plane by a magnetic lens system. A transformed beam line in the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences (CAS) has been developed for heavy ions radiography. It can radiograph a static object and the spatial resolution is about 65um (σ). This paper presents the heavy ions radiography facility at IMP, including the beam optics, the simulation of radiography by Monte Carlo code and the experiment result with 600 MeV/u carbon ions. In addition, the dedicated beam lines for proton radiography in plan are also introduced.

WEPH11

Study of the Heavy Ion Bunch Compression in CSRm

51

D.Y. Yin, W.P. Chai, J. Li, P. Li, Y. Liu, P. Shang, J.C. Yang, Y.J. Yuan
IMP, Lanzhou, People's Republic of China

The feasibility of attaining nanosecond pulse length heavy ion beam is studied in the main ring(CSRm) of the Heavy Ion Research Facility in Lanzhou. Such heavy ion beam can be produced by non-adiabatic compression, and it is implemented by a fast rotation in the longitudinal phase space. In this paper, the possible beam parameters during longitudinal bunch compression are studied with the envelope model and Particle in Cell simulation, and the results are compared. The result shows that the short bunch 238U²⁸⁺ with the pulse duration of about 50ns at the energy of 200MeV/u can be obtained

WEPH35

APF DTL Design Besed on iMpAPF

90

P. Jiang, C. Li, P. Li, Z.J. Wang, Y.J. Yuan
IMP, Lanzhou, People's Republic of China

Alternative phase focusing (APF) DTL has advantages in price and space. However, the designing of APF is difficult because of the jumping phases. In order to design and simulate a proper APF, a code iMpAPF(i Multi-particle APF) has been developed. RK4 is introduced in this code for calculation, and the soul of the code is smoothness. Theoretically, the particle tracing figures out that the theoretic phase advance ratio between longitudinal direction and transversal direction is close to 2. Based on this code, a C⁵⁺, 200 MHz, medium energy APF as a linear injector of a synchrotron used for cancer therapy has been designed. This paper focuses on the development of iMpAPF, and also several results obtained from the code are shown.

THAMH5

Design and Commissioning of a CW Heavy Ion RFQ Accelerator

106

K. Zhu, Z.Y. Guo, G. Liu, Y.R. Lu, Z. Wang, X.Q. Yan
PKU, Beijing, People's Republic of China
H. Du, Y. He, X. Yin, Y.J. Yuan, X.H. Zhang
IMP, Lanzhou, People's Republic of China

A CW RFQ for heavy ions is designed as the new injector for Separated Sector Cyclotron(SSC) at Institute of Modern Physics, Lanzhou, China. Now the RFQ have been installed in the main hall and the beam commissioning has been done. This paper will introduce the design consideration of the beam dynamics, the HF structure and the cooling structure design, measurement of the cold model, high power test of RFQ and the beam commissioning result.

THPMH2

Electron Cooling Experiments at HIRFL-CSR

113

L.J. Mao, J. Li, X.M. Ma, J.W. Xia, T.L. Yan, J.C. Yang, X.D. Yang, Y.J. Yuan
IMP, Lanzhou, People's Republic of China

Two new-generation electron coolers have been operated at main ring and experimental ring of HIRFL-CSR facility, respectively. The electron beam with a variable profile helps to get an ion beam with the emittance and intensity that meet the demands of specific physical experiments. Fast transverse cooling of the hot ion beam after horizontal multiturn of stripping injection allows beam accumulation at the injection energy. After optimization of the accumulation and cooling process an current increase by more than one order of magnitude has been achieved. Momentum spread in the 10^-4 range has been demonstrated. In this paper, the longitudinal cooling force and the transverse cooling time measurements, the intrabeam scattering effect measurements were introduced.