IPAC2013 - List of Authors (Wang, S.)

Paper

Title

Page

Transport Line Orbit Correction for CSNS/RTBT

154

Y. Li, Y.W. An, Z.P. Li, W.B. Liu, S. Wang
IHEP, Beijing, People's Republic of China

Dipole field kicks arisen from the construction and alignment of the magnets may cause the orbit distortion and reduce the efficiency of beam extraction and striking target in RTBT transport line of CSNS. In this paper, orbit correction is done based on XAL Orbit Correction application with the algorithm modified partially and the result was according with by AT toolbox. Meanwhile, the orbit correction before the target was special considered for the beams striking the target center vertically.

MOPEA037

Theoretical Study on the Two-stage Collimation System Design

157

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

Two-stage collimation system is widely used in high intensity machines to localize the beam losses in a restricted area. In the well-known theory, the optical constrains are expressed by the betatronic phase advances between primary and secondary collimators, which minimize the size of the secondary halo. In this paper, the physical model is developed considering the characteristic of the space charge dominated beams. Numerical studied are performed to verify the theoretical model.

MOPFI030

Study of the Beam Injection and Extraction of the Proton Irradiation Accelerator

348

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

The proton irradiation accelerator is widely founded for industry application, and the extracted beam is required to have large intensity as a pulse beam or uniform distribution for scanning. A multi-turn injection is adopted and the proton beam is injected into the ring with the energy of 10MeV. In order to increase injection beam intensity, local bump orbit including two-bump, three-bump and four-bump is well studied and optimized, and the septum magnet thickness and localization are also studied for an effective injection. A RF knock-out method is used for slow extraction due to the fast response character. In order to decrease the global spill, double RF kicker and the control of the aptitude modulation (AM) function of the transverse RF field are well studied.

MOPFI032

Electron Emission of the Stripping Foil and Collimation System for CSNS/RCS

354

M.Y. Huang, Y.D. Liu, N. Wang, S. Wang
IHEP, Beijing, People's Republic of China

For the Rapid Cycling Synchrotron of the China Spallation Neutron Source (CSNS/RCS), the electron emission plays an important role in the accelerator limitation. The interactions between the proton beam and the stripping foil were studied, and the electron scattering processes were simulated by the ORBIT and FLUKA codes. Then, the electron energy distribution and the electron yielding rate can be given. Furthermore, the interactions between the proton beam and the collimation system were studied, and the electron scattering processes were simulated. Then, the energy distribution of the primary electron emission can be given and the yielding rate of the primary electron can be obtained.

TUPME021

Optimization Parameter Design of a Circular e⁺e⁻ Higgs Factory

1616

D. Wang, Y.W. An, J. Gao, H. Geng, Y.Y. Guo, Q. Qin, N. Wang, S. Wang, M. Xiao, G. Xu, S.Y. Xu
IHEP, Beijing, People's Republic of China

Funding: NSFC:11175192
In this paper we will show a genral method of how to make an optimized parameter design of a circular e⁺e⁻ Higgs Factory by using analytical expression of maximum beam-beam parameter and beamstrahlung beam lifetime started from given design goal and technical limitations. A parameter space has been explored.

TUPWA014

The Status of Coupling Impedance Measurement for the CSNS/RCS Extraction Kicker Prototype*

1754

L. Huang, Y. Li, R.H. Liu, Y.D. Liu, S. Wang, O. Xiao
IHEP, Beijing, People's Republic of China

Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, with average beam power of 100kW. In order to high intensity beam operation, the beam coupling impedance of the extracted kickers must be controlled. Longitudinal and transverse impedance of extracted kicker prototype with power supply had been roughly measured by coaxial-wire and dual-wire methods respectively. At the same time, impedance of window has been analyzed theoretically and simulated based on CST PARTICLE STUDIO.

TUPWO022

Space Charge Effects Study and Optimization in CSNS/LRBT

1928

Z.P. Li, N. Huang, W.B. Liu, S. Wang
IHEP, Beijing, People's Republic of China

The linac to ring beam transport line (LRBT) of China Spallation Neutron Source (CSNS) connecting the linac and the rapid cycling synchrotron (RCS) transports 80 MeV negative hydrogen ions (H⁻) beams for RCS injection. Space charge effect in LRBT is significant due to small emittance and high current density of the beam, which is a major cause of emittance growth and beam loss. An achromatic transverse optical matching was performed by TRACE 3D code. Emittance growths of beams with different initial distributions in different LRBT lattices were studied separately. Simulation results show that the LRBT design with triplet can mitigate the emittance growth by lattice optimization of the front matching section and no beam loss occurs at 15mA. The location and parameters of the debuncher in LRBT were also optimized to reduce the momentum spread and energy jitter.

WEPEA023

Space Charge Effects for Different CSNS/RCS Working Points

2549

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

The China Spallation Neutron Source (CSNS) operates at 25 Hz repetition rate with the design beam power of 100 KW. CSNS consists of an 80-MeV linac and a 1.6-GeV Rapid Cycling Synchrotron (RCS). Due to the high beam density and high repetition rate for CSNS/RCS, the rate of beam loss must be controlled to a very low level. The major source of beam loss is associated with resonances. Thus, choosing he best suitable working points on the tune diagram is important to reach low beam loss. Different tune areas are explored and compared by considering resonances and the effects of space charge, which can drive particles into the excited resonances. Different working points are simulated and compared by using the codes ORBIT and SIMPSONS.

WEPEA024

Combine Effects of Space Charge and Chromaticity Sextupoles at CSNS/RCS

2552

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

Most high current proton synchrotrons, such as The Rapid Cycling Synchrotron (RCS) of The China Spallation Neutron Source (CSNS), are operated under the transition energy, and the natural chromaticity is small. These proton synchrotrons can work without chromatic correction. To reduce the tune spread produced by the chromaticity, chromatic correction is considered by using chromaticity sextupoles for this type of proton synchrotrons, such as J-PARC and SNS. Many chromatic correction schemes are compared for the CSNS/RCS, and the harmonic sextupoles are considered to correct nonlinear effect of chromaticity sextupoles. The dynamic aperture is obtained by particle tracking, and the combine effects of sextupole field and space charge effects are investigated by using the code ORBIT and SIMPSONS.

THOAB203

100 MeV/100kW Electron Linear Accelerator Driver of the NSC KIPT Neutron Source

3121

A.Y. Zelinsky, N. Ayzatsky, O. Bezditko, I.M. Karnaukhov, V.A. Kushnir, V. Mitrochenco
NSC/KIPT, Kharkov, Ukraine
Y.L. Chi, X.W. Dai, C.D. Deng, M. Hou, X.C. Kong, R.L. Liu, W.B. Liu, C. Ma, G. Pei, S. Pei, H. Song, S. Wang, J.B. Zhao, Z.S. Zhou
IHEP, Beijing, People's Republic of China
Y. Gohar
ANL, Argonne, USA

In NSC KIPT, Kharkov, Ukraine a neutron source based on a subcritical assembly driven by a 100MeV/100kW electron linear accelerator will be constructed. This neutron source is an USA (ANL)-Ukraine (KIPT) Joint project, and its Accelerator will be designed and constructed by Institute of High Energy Physics (IHEP), China. The design and construction of such a Accelerator with high average beam current and low beam power losses is a technical challenging task. In the paper, the main accelerator features and current status are under discussion.

Slides THOAB203 [8.585 MB]

THPWO045

Commissioning Plan for the CSNS Linac

3869

J. Peng, S. Fu, J. Li, Y. Li, H.C. Liu, H.F. Ouyang, N. Wang, S. Wang, T.G. Xu
IHEP, Beijing, People's Republic of China

The linac of the China Spallation Neutron Source(CSNS) will be commissioned from October 2013. The linac will be commissioned in three phases. The delivery of beam to the RCS is planned for October 2015. This paper describes the commissioning plans for the MEBT and DTL parts of the linac. Techniques for finding the RF set-point, matching and steering are presented, as well as codes to assist in the beam commissioning.

THPWO046

The Preparation for the Commissioning of CSNS Accelerators

3872

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

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 accelerators. The commissioning plan for the CSNS accelerators will be presented, including the commissioning correlated parameters, beam instrumentation in used commissioning, the goal at different commissioning stages. The development of high level application software will also be presented.

FRXAB201

Status of CSNS Project

3995

S. Fu, H. Chen, Y.W. Chen, H. Dong, S.X. Fang, K.X. Huang, W. Kang, J. Li, H.C. Liu, L. Ma, H.F. Ouyang, H. Qu, H. Sun, J.Y. Tang, C.H. Wang, Q.B. Wang, S. Wang, T.G. Xu, Z.X. Xu, C. Zhang, J. Zhang
IHEP, Beijing, People's Republic of China

The China Spallation Neutron Source (CSNS) accelerator is designed to accelerate proton beam pulses to 1.6 GeV at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator provides a beam power of 100 kW on the target in the first phase and then 500 kW in the second phase by increasing the average beam intensity 5 times while raising the linac output energy. The project construction has been formally launched in 2011 and it is planed to complete the project in March 2018. It is one of the high intensity proton accelerator projects in the world and it imposes a great challenge to Chinese accelerator community. This presentation will cover the status and challenges of the CSNS project.

Slides FRXAB201 [4.320 MB]

Paper	Title	Page
MOPEA036	Transport Line Orbit Correction for CSNS/RTBT	154
	Y. Li, Y.W. An, Z.P. Li, W.B. Liu, S. Wang IHEP, Beijing, People's Republic of China
	Dipole field kicks arisen from the construction and alignment of the magnets may cause the orbit distortion and reduce the efficiency of beam extraction and striking target in RTBT transport line of CSNS. In this paper, orbit correction is done based on XAL Orbit Correction application with the algorithm modified partially and the result was according with by AT toolbox. Meanwhile, the orbit correction before the target was special considered for the beams striking the target center vertically.

MOPEA037	Theoretical Study on the Two-stage Collimation System Design	157
	N. Wang, S. Wang IHEP, Beijing, People's Republic of China
	Two-stage collimation system is widely used in high intensity machines to localize the beam losses in a restricted area. In the well-known theory, the optical constrains are expressed by the betatronic phase advances between primary and secondary collimators, which minimize the size of the secondary halo. In this paper, the physical model is developed considering the characteristic of the space charge dominated beams. Numerical studied are performed to verify the theoretical model.

MOPFI030	Study of the Beam Injection and Extraction of the Proton Irradiation Accelerator	348
	Y.W. An, H.F. Ji, S. Wang IHEP, Beijing, People's Republic of China
	The proton irradiation accelerator is widely founded for industry application, and the extracted beam is required to have large intensity as a pulse beam or uniform distribution for scanning. A multi-turn injection is adopted and the proton beam is injected into the ring with the energy of 10MeV. In order to increase injection beam intensity, local bump orbit including two-bump, three-bump and four-bump is well studied and optimized, and the septum magnet thickness and localization are also studied for an effective injection. A RF knock-out method is used for slow extraction due to the fast response character. In order to decrease the global spill, double RF kicker and the control of the aptitude modulation (AM) function of the transverse RF field are well studied.

MOPFI032	Electron Emission of the Stripping Foil and Collimation System for CSNS/RCS	354
	M.Y. Huang, Y.D. Liu, N. Wang, S. Wang IHEP, Beijing, People's Republic of China
	For the Rapid Cycling Synchrotron of the China Spallation Neutron Source (CSNS/RCS), the electron emission plays an important role in the accelerator limitation. The interactions between the proton beam and the stripping foil were studied, and the electron scattering processes were simulated by the ORBIT and FLUKA codes. Then, the electron energy distribution and the electron yielding rate can be given. Furthermore, the interactions between the proton beam and the collimation system were studied, and the electron scattering processes were simulated. Then, the energy distribution of the primary electron emission can be given and the yielding rate of the primary electron can be obtained.

TUPME021	Optimization Parameter Design of a Circular e⁺e⁻ Higgs Factory	1616
	D. Wang, Y.W. An, J. Gao, H. Geng, Y.Y. Guo, Q. Qin, N. Wang, S. Wang, M. Xiao, G. Xu, S.Y. Xu IHEP, Beijing, People's Republic of China
	Funding: NSFC:11175192 In this paper we will show a genral method of how to make an optimized parameter design of a circular e⁺e⁻ Higgs Factory by using analytical expression of maximum beam-beam parameter and beamstrahlung beam lifetime started from given design goal and technical limitations. A parameter space has been explored.

TUPWA014	The Status of Coupling Impedance Measurement for the CSNS/RCS Extraction Kicker Prototype*	1754
	L. Huang, Y. Li, R.H. Liu, Y.D. Liu, S. Wang, O. Xiao IHEP, Beijing, People's Republic of China
	Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator, with average beam power of 100kW. In order to high intensity beam operation, the beam coupling impedance of the extracted kickers must be controlled. Longitudinal and transverse impedance of extracted kicker prototype with power supply had been roughly measured by coaxial-wire and dual-wire methods respectively. At the same time, impedance of window has been analyzed theoretically and simulated based on CST PARTICLE STUDIO.

TUPWO022	Space Charge Effects Study and Optimization in CSNS/LRBT	1928
	Z.P. Li, N. Huang, W.B. Liu, S. Wang IHEP, Beijing, People's Republic of China
	The linac to ring beam transport line (LRBT) of China Spallation Neutron Source (CSNS) connecting the linac and the rapid cycling synchrotron (RCS) transports 80 MeV negative hydrogen ions (H⁻) beams for RCS injection. Space charge effect in LRBT is significant due to small emittance and high current density of the beam, which is a major cause of emittance growth and beam loss. An achromatic transverse optical matching was performed by TRACE 3D code. Emittance growths of beams with different initial distributions in different LRBT lattices were studied separately. Simulation results show that the LRBT design with triplet can mitigate the emittance growth by lattice optimization of the front matching section and no beam loss occurs at 15mA. The location and parameters of the debuncher in LRBT were also optimized to reduce the momentum spread and energy jitter.

WEPEA023	Space Charge Effects for Different CSNS/RCS Working Points	2549
	S.Y. Xu, N. Wang, S. Wang IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) operates at 25 Hz repetition rate with the design beam power of 100 KW. CSNS consists of an 80-MeV linac and a 1.6-GeV Rapid Cycling Synchrotron (RCS). Due to the high beam density and high repetition rate for CSNS/RCS, the rate of beam loss must be controlled to a very low level. The major source of beam loss is associated with resonances. Thus, choosing he best suitable working points on the tune diagram is important to reach low beam loss. Different tune areas are explored and compared by considering resonances and the effects of space charge, which can drive particles into the excited resonances. Different working points are simulated and compared by using the codes ORBIT and SIMPSONS.

WEPEA024	Combine Effects of Space Charge and Chromaticity Sextupoles at CSNS/RCS	2552
	S.Y. Xu, S. Wang IHEP, Beijing, People's Republic of China
	Most high current proton synchrotrons, such as The Rapid Cycling Synchrotron (RCS) of The China Spallation Neutron Source (CSNS), are operated under the transition energy, and the natural chromaticity is small. These proton synchrotrons can work without chromatic correction. To reduce the tune spread produced by the chromaticity, chromatic correction is considered by using chromaticity sextupoles for this type of proton synchrotrons, such as J-PARC and SNS. Many chromatic correction schemes are compared for the CSNS/RCS, and the harmonic sextupoles are considered to correct nonlinear effect of chromaticity sextupoles. The dynamic aperture is obtained by particle tracking, and the combine effects of sextupole field and space charge effects are investigated by using the code ORBIT and SIMPSONS.

THOAB203	100 MeV/100kW Electron Linear Accelerator Driver of the NSC KIPT Neutron Source	3121
	A.Y. Zelinsky, N. Ayzatsky, O. Bezditko, I.M. Karnaukhov, V.A. Kushnir, V. Mitrochenco NSC/KIPT, Kharkov, Ukraine Y.L. Chi, X.W. Dai, C.D. Deng, M. Hou, X.C. Kong, R.L. Liu, W.B. Liu, C. Ma, G. Pei, S. Pei, H. Song, S. Wang, J.B. Zhao, Z.S. Zhou IHEP, Beijing, People's Republic of China Y. Gohar ANL, Argonne, USA
	In NSC KIPT, Kharkov, Ukraine a neutron source based on a subcritical assembly driven by a 100MeV/100kW electron linear accelerator will be constructed. This neutron source is an USA (ANL)-Ukraine (KIPT) Joint project, and its Accelerator will be designed and constructed by Institute of High Energy Physics (IHEP), China. The design and construction of such a Accelerator with high average beam current and low beam power losses is a technical challenging task. In the paper, the main accelerator features and current status are under discussion.
	Slides THOAB203 [8.585 MB]

THPWO045	Commissioning Plan for the CSNS Linac	3869
	J. Peng, S. Fu, J. Li, Y. Li, H.C. Liu, H.F. Ouyang, N. Wang, S. Wang, T.G. Xu IHEP, Beijing, People's Republic of China
	The linac of the China Spallation Neutron Source(CSNS) will be commissioned from October 2013. The linac will be commissioned in three phases. The delivery of beam to the RCS is planned for October 2015. This paper describes the commissioning plans for the MEBT and DTL parts of the linac. Techniques for finding the RF set-point, matching and steering are presented, as well as codes to assist in the beam commissioning.

THPWO046	The Preparation for the Commissioning of CSNS Accelerators	3872
	S. Wang, S. Fu, H.F. Ouyang, J. Peng IHEP, Beijing, People's Republic of China
	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 accelerators. The commissioning plan for the CSNS accelerators will be presented, including the commissioning correlated parameters, beam instrumentation in used commissioning, the goal at different commissioning stages. The development of high level application software will also be presented.

FRXAB201	Status of CSNS Project	3995
	S. Fu, H. Chen, Y.W. Chen, H. Dong, S.X. Fang, K.X. Huang, W. Kang, J. Li, H.C. Liu, L. Ma, H.F. Ouyang, H. Qu, H. Sun, J.Y. Tang, C.H. Wang, Q.B. Wang, S. Wang, T.G. Xu, Z.X. Xu, C. Zhang, J. Zhang IHEP, Beijing, People's Republic of China
	The China Spallation Neutron Source (CSNS) accelerator is designed to accelerate proton beam pulses to 1.6 GeV at 25 Hz repetition rate, striking a solid metal target to produce spallation neutrons. The accelerator provides a beam power of 100 kW on the target in the first phase and then 500 kW in the second phase by increasing the average beam intensity 5 times while raising the linac output energy. The project construction has been formally launched in 2011 and it is planed to complete the project in March 2018. It is one of the high intensity proton accelerator projects in the world and it imposes a great challenge to Chinese accelerator community. This presentation will cover the status and challenges of the CSNS project.
	Slides FRXAB201 [4.320 MB]