IPAC2021 - List of Authors (Xu, S.Y.)

Paper	Title	Page
MOPAB198	Study on Magnet Sorting of the CSNS/RCS Dipoles	665
	Y. Li, Y.W. An IHEP, Beijing, People’s Republic of China Z.P. Li, S.Y. Xu DNSC, Dongguan, People’s Republic of China
	The 1.6GeV rapid cycling synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high-power pulsed proton machine aiming for 500kW output beam power. Now, the routine output beam power has been increased to 100kW. However, the horizontal bare orbit in the ring is large (15mm) and the number of correctors is small, which brings great challenges to the ramp-up of beam power. It is found that the bare orbit in AC mode is 3-4mm larger than that in DC mode. The reason is that the AC dipoles field error is larger than DC dipoles field error. Therefore, it is proposed to sort dipoles again according to the AC dipoles field error. In order to reduce the risk of beam commissioning, fewer magnets should to be moved to achieve smaller orbit. The best results of moving two to six magnets were calculated. After sorting, the orbit can be reduced by 3-4mm, which reduces the difficulty of orbit correction.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB198
About •	paper received ※ 16 May 2021 paper accepted ※ 21 May 2021 issue date ※ 14 August 2021
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MOPAB200	Parameters Measurements of Proton Beam Extracted from CSNS/RCS	668
	Z.P. Li, Y.W. An, M.Y. Huang IHEP, Beijing, People’s Republic of China Y. Li, S.Y. Xu DNSC, Dongguan, People’s Republic of China H.Y. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	In order to study the emittance evolution of the circulating beam in the fast-cycling synchrotron (RCS) of the Chinese Spallation Neutron Source (CSNS), parameter measurements of the beam extracted at different times were carried out. The measurements were mainly based on wire-scanners mounted in RCS to target transport line (RTBT) for beam profile measurement, and different methods were applied in the solution processes. The emittance and C.S parameters of the extracted beam at different times were obtained and studied, which provided an important reference basis for the beam commissioning of RCS. The beam envelope along the RTBT has been matched and re-measured, which was in good agreement with the design optics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB200
About •	paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 25 August 2021
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TUPAB262	The Characteristic of the Beam Position Growth in CSNS/RCS	2073
	L. Huang, S. Wang IHEP, Beijing, People’s Republic of China S.Y. Xu DNSC, Dongguan, People’s Republic of China
	Funding: Work supported by NNSF of China: N0. U1832210 An instability of the beam position growth is observed in the beam commissioning of the Rapid Cycling Synchrotron of the China Spallation Neutron Source. To simplify the study, a series of measurements have been performed to characterize the instability in the DC mode with consistent energy of 80 MeV. The measurement campaign is introduced in the paper and it conforms to the characteristics of the coupled bunch instability.
	Poster TUPAB262 [3.748 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB262
About •	paper received ※ 13 May 2021 paper accepted ※ 02 June 2021 issue date ※ 22 August 2021
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MOPAB075	Proposal of the Southern Advanced Photon Source and Current Physics Design Study	300
	S. Wang, J. Chen, L. Huang, Y. Jiao, B. Li, Z.P. Li, W. Liu, S.Y. Xu IHEP, Beijing, People’s Republic of China Y. Han, X.H. Lu, Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China X. Liu Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan
	It has been considered to build a mid-energy fourth-generation storage ring light source neighbouring the China Spallation Neutron Source, in Guangdong Province, the south of China. The light source is named the Southern Advanced Photon Source (SAPS). Preliminary physics design studies on the SAPS have been implemented for a few years. In this paper, we will describe considerations of technical roadmap and key parameter choice for this light source, and introduce the up-to-date lattice designs and related physics studies on the SAPS.
	Poster MOPAB075 [1.689 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB075
About •	paper received ※ 12 May 2021 paper accepted ※ 20 May 2021 issue date ※ 21 August 2021
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TUPAB192	Studies on Momentum Collimation for CSNS-RCS Upgrades	1855
	Y.W. An, J. Chen, S.Y. Xu, Y. Yuan IHEP, Beijing, People’s Republic of China X.H. Lu, J.B. Yu IHEP CSNS, Guangdong Province, People’s Republic of China
	The CSNS project was a high intensity pulsed facility, and achieved the the design goal of 100kW in 2020. The upgrades of the CSNS are proposed, and the momentum collimator is a component of the upgrades. This paper will show the design scheme of the momentum collimator and the simulation results are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB192
About •	paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 28 August 2021
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TUPAB194	Operation Status of CSNS/RCS Transverse Collimation System	1862
	J.B. Yu, J.X. Chen, L. Liu, X.J. Nie, C.J. Ning, G.Y. Wang, A.X. Wang, J.S. Zhang IHEP CSNS, Guangdong Province, People’s Republic of China L. Kang, Q.B. Wu, S.Y. Xu IHEP, Beijing, People’s Republic of China
	Funding: Natural Science Foundation of Guangdong Province 2018A030313959 In order to meet the requirements of daily maintenance of CSNS/RCS, the transverse collimation system was designed to concentrate the uncontrollable beam loss in this region. Based on physical parameters, considering the processing technology, the area was rationally arranged; combined with the requirements of physical and radiation protection, under the premise of meeting the use requirements, fully consider the limit switch, mechanical hard limit and other components, increasing the output control signals of rotary encoder and displacement sensor, the movement of the absorbers were monitored. At present, the beam collimation system has been running with no mechanical failure for two years on CSNS, and it plays an active role in beam power boost and beam loss control, which proves that the structural design of the system is reasonable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB194
About •	paper received ※ 17 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021
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TUPAB195	Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning	1865
	Y.W. An, Y. Li, S.Y. Xu, Y. Yuan IHEP, Beijing, People’s Republic of China M.T. Li IHEP CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.
	Poster TUPAB195 [2.279 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195
About •	paper received ※ 13 May 2021 paper accepted ※ 17 June 2021 issue date ※ 01 September 2021
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TUPAB196	Achievement of 100-kW Beam Operation in CSNS/RCS	1869
	S.Y. Xu, Y.W. An, J. Chen, L. Huang, M.Y. Huang, Y. Li, S. Wang IHEP, Beijing, People’s Republic of China H.Y. Liu, X.H. Lu IHEP CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) is an accelerator-based science facility. CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy, striking a solid metal target to produce spallation neutrons. CSNS has two major accelerator systems, a linear accelerator (80 MeV Linac) and a 1.6 GeV rapid cycling synchrotron(RCS). The RCS accumulates and accelerates the proton beam to 1.6 GeV and then extracts the beam to the target at the repetition rate of 25 Hz. The Beam commissioning of CSNS/RCS had been started since April 2017. The most important issue in high-power beam commissioning is the beam loss control, as well as the control of induced activities, to meet the requirement of manual maintenance. A series of beam loss optimization work had been done to reduce the uncontrolled beam loss. At the end of February 2020, the CSNS reached the design beam power of 100 kW with very low uncontrolled beam loss.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB196
About •	paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021
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TUPAB261	The Ferrite Loaded Cavity Impedance Simulation	2070
	L. Huang, X. Li, S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China B. Wu IHEP CSNS, Guangdong Province, People’s Republic of China
	Funding: Work supported by NNSF of China: N0. U1832210 The Rapid Cycling Synchrotron of the China Spallation Neutron Source is a high-intensity proton accelerator, it accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV in 20 ms. The transverse coupling bunch instability is observed in beam commissioning. The source has been investigating from the commissioning. The RF acceleration system consists of eight ferrite-loaded cavities. The impedance is simulated and there is a narrow-band impedance of the ferrite cavity at about 17 MHz
	Poster TUPAB261 [1.145 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB261
About •	paper received ※ 13 May 2021 paper accepted ※ 31 May 2021 issue date ※ 21 August 2021
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WEPAB199	Study on the Important Technologies of 300MeV Upgrade for the CSNS Injection System	3089
	M.Y. Huang, C.D. Deng, L. Kang, L. Liu, Y. Liu, X. Qi, S. Wang, Q.B. Wu, Y.W. Wu, S.Y. Xu, W.Q. Zhang, Y.L. Zhang IHEP, Beijing, People’s Republic of China J.X. Chen, T. Huang, H.C. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	Funding: This work was supported by National Natural Science Foundation of China (Project Nos. U1832210 and 12075134). The China Spallation Neutron Source (CSNS-I) have achieved the design goal of 100kW beam power on the target in Feb., 2020. As the second phase of the CSNS, CSNS-II will achieve a beam power on the target of 500 kW. The injection energy of CSNS-II will be increased from 80 MeV to 300 MeV and the average beam current of the Linac will increase 5 times. Therefore, the injection system will require a complete upgrade. In this paper, the design scheme of the injection system for CSNS-II will be introduced. The key technologies of the upgrade injection system will be carefully analyzed and pre-developed, such as the pulse power supplies and their magnets, the special-shaped ceramic vacuum chambers, the main stripping foil, the stripped electron collection, and so on.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB199
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 21 August 2021
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WEPAB200	Study on the Measurement and Residual Dose of the CSNS Stripping Foil	3093
	M.Y. Huang, L. Kang, S. Wang, Q.B. Wu, S.Y. Xu, Y.L. Zhang IHEP, Beijing, People’s Republic of China J.X. Chen, W.L. Huang, H.C. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	Funding: This work was supported by National Natural Science Foundation of China (Project Nos. 12075134 and U1832210). In this paper, firstly, the application and service life of the main stripping foil for the China Spallation Neutron Source (CSNS) were introduced. The stripping efficiency of the main stripping foil have been measured and studied. Then, by using the codes FLUKA and ORBIT, the particle scattering of the main stripping foil has been simulated and the theoretical residual doses in the injection region caused by the foil scattering were obtained. By weekly measurement of the residual doses in the injection region, the actual residual doses near the main stripping foil were given. The residual doses comparison results have confirmed that the particle scattering of the main stripping foil is the most important source of the residual doses in the injection region.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB200
About •	paper received ※ 09 May 2021 paper accepted ※ 25 August 2021 issue date ※ 23 August 2021
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THPAB185	Solution to Beam Transmission Decline in the CSNS Linac Operation Using Measurements and Simulations	4134
	J. Peng, M.T. Li, X.H. Lu, X.B. Luo IHEP CSNS, Guangdong Province, People’s Republic of China Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan IHEP, Beijing, People’s Republic of China
	The CSNS linac operation at its design average power currently. However, the beam transmission is declining and the beam loss is increasing during the operation. With simulations and experiments, we found there is a long longitudinal tail exist in the beam bunch output from the RFQ. And this tail caused the beam loss in the following linac. After inhibition of the longitudinal tail in the beam bunch, the beam transmission in operation can keep stable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB185
About •	paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 02 September 2021
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THPAB207	Beam Dynamics Simulation about the Dual Harmonic System by PyORBIT	4194
	H.Y. Liu, X.Y. Feng, L. Huang, M.T. Li, X.H. Lu IHEP CSNS, Guangdong Province, People’s Republic of China S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	The space charge effect is a strong limitation in high-intensity accelerators, especially for low- and medium-energy proton synchrotrons. And for CSNS-II, the number of particles in the RCS is 3.9·10¹³ ppp, which is five times of CSNS. To mitigate the effects of the strong space charge effect, CSNS-II/RCS (Rapid Cycling Synchrotron) will use a dual harmonic system to increase the bunching factor during the injection and the initial acceleration phase. For studying the beam dynamics involved in a dual harmonic RF system, PyORBIT is used as the major simulation code, which is developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. We modified parts of the code to make it applicable to the beam dynamic in RCS. This paper includes the major code modification of the Dual Harmonic RF system and some benchmark results. The preliminary simulation results of the dual-harmonic system in CSNS-II/RCS simulated by the particle tracking code PyORBIT will also be discussed.
	Poster THPAB207 [0.354 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB207
About •	paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 11 August 2021
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THPAB224	The Correction of Time-Dependent Tune Shift by Harmonic Injection	4234
	X.H. Lu IHEP CSNS, Guangdong Province, People’s Republic of China J. Chen, S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	In the Rapid Cycling Synchrotron(RCS) of China Spallation Neutron Source(CSNS), transverse painting injection is employed to suppress the space-charge effects. The beta-beating caused by edge focusing of the injection bump magnets leads to tune shift. A new method based on the harmonic injection is firstly introduced to correct the time-dependent tune shift caused by the edge focusing effect of the chicane bump magnets in RCS. The simulation study was done on the application of the new method to the CSNS/RCS, and the results show the validity and effectiveness of the method.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB224
About •	paper received ※ 19 May 2021 paper accepted ※ 16 July 2021 issue date ※ 10 August 2021
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Paper

Title

Page

Study on Magnet Sorting of the CSNS/RCS Dipoles

665

Y. Li, Y.W. An
IHEP, Beijing, People’s Republic of China
Z.P. Li, S.Y. Xu
DNSC, Dongguan, People’s Republic of China

The 1.6GeV rapid cycling synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high-power pulsed proton machine aiming for 500kW output beam power. Now, the routine output beam power has been increased to 100kW. However, the horizontal bare orbit in the ring is large (15mm) and the number of correctors is small, which brings great challenges to the ramp-up of beam power. It is found that the bare orbit in AC mode is 3-4mm larger than that in DC mode. The reason is that the AC dipoles field error is larger than DC dipoles field error. Therefore, it is proposed to sort dipoles again according to the AC dipoles field error. In order to reduce the risk of beam commissioning, fewer magnets should to be moved to achieve smaller orbit. The best results of moving two to six magnets were calculated. After sorting, the orbit can be reduced by 3-4mm, which reduces the difficulty of orbit correction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB198

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paper received ※ 16 May 2021 paper accepted ※ 21 May 2021 issue date ※ 14 August 2021

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MOPAB200

Parameters Measurements of Proton Beam Extracted from CSNS/RCS

668

Z.P. Li, Y.W. An, M.Y. Huang
IHEP, Beijing, People’s Republic of China
Y. Li, S.Y. Xu
DNSC, Dongguan, People’s Republic of China
H.Y. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

In order to study the emittance evolution of the circulating beam in the fast-cycling synchrotron (RCS) of the Chinese Spallation Neutron Source (CSNS), parameter measurements of the beam extracted at different times were carried out. The measurements were mainly based on wire-scanners mounted in RCS to target transport line (RTBT) for beam profile measurement, and different methods were applied in the solution processes. The emittance and C.S parameters of the extracted beam at different times were obtained and studied, which provided an important reference basis for the beam commissioning of RCS. The beam envelope along the RTBT has been matched and re-measured, which was in good agreement with the design optics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB200

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paper received ※ 19 May 2021 paper accepted ※ 21 May 2021 issue date ※ 25 August 2021

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TUPAB262

The Characteristic of the Beam Position Growth in CSNS/RCS

2073

L. Huang, S. Wang
IHEP, Beijing, People’s Republic of China
S.Y. Xu
DNSC, Dongguan, People’s Republic of China

Funding: Work supported by NNSF of China: N0. U1832210
An instability of the beam position growth is observed in the beam commissioning of the Rapid Cycling Synchrotron of the China Spallation Neutron Source. To simplify the study, a series of measurements have been performed to characterize the instability in the DC mode with consistent energy of 80 MeV. The measurement campaign is introduced in the paper and it conforms to the characteristics of the coupled bunch instability.

Poster TUPAB262 [3.748 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB262

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paper received ※ 13 May 2021 paper accepted ※ 02 June 2021 issue date ※ 22 August 2021

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MOPAB075

Proposal of the Southern Advanced Photon Source and Current Physics Design Study

300

S. Wang, J. Chen, L. Huang, Y. Jiao, B. Li, Z.P. Li, W. Liu, S.Y. Xu
IHEP, Beijing, People’s Republic of China
Y. Han, X.H. Lu, Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China
X. Liu
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama, Japan

It has been considered to build a mid-energy fourth-generation storage ring light source neighbouring the China Spallation Neutron Source, in Guangdong Province, the south of China. The light source is named the Southern Advanced Photon Source (SAPS). Preliminary physics design studies on the SAPS have been implemented for a few years. In this paper, we will describe considerations of technical roadmap and key parameter choice for this light source, and introduce the up-to-date lattice designs and related physics studies on the SAPS.

Poster MOPAB075 [1.689 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB075

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paper received ※ 12 May 2021 paper accepted ※ 20 May 2021 issue date ※ 21 August 2021

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TUPAB192

Studies on Momentum Collimation for CSNS-RCS Upgrades

1855

Y.W. An, J. Chen, S.Y. Xu, Y. Yuan
IHEP, Beijing, People’s Republic of China
X.H. Lu, J.B. Yu
IHEP CSNS, Guangdong Province, People’s Republic of China

The CSNS project was a high intensity pulsed facility, and achieved the the design goal of 100kW in 2020. The upgrades of the CSNS are proposed, and the momentum collimator is a component of the upgrades. This paper will show the design scheme of the momentum collimator and the simulation results are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB192

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paper received ※ 18 May 2021 paper accepted ※ 15 June 2021 issue date ※ 28 August 2021

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TUPAB194

Operation Status of CSNS/RCS Transverse Collimation System

1862

J.B. Yu, J.X. Chen, L. Liu, X.J. Nie, C.J. Ning, G.Y. Wang, A.X. Wang, J.S. Zhang
IHEP CSNS, Guangdong Province, People’s Republic of China
L. Kang, Q.B. Wu, S.Y. Xu
IHEP, Beijing, People’s Republic of China

Funding: Natural Science Foundation of Guangdong Province 2018A030313959
In order to meet the requirements of daily maintenance of CSNS/RCS, the transverse collimation system was designed to concentrate the uncontrollable beam loss in this region. Based on physical parameters, considering the processing technology, the area was rationally arranged; combined with the requirements of physical and radiation protection, under the premise of meeting the use requirements, fully consider the limit switch, mechanical hard limit and other components, increasing the output control signals of rotary encoder and displacement sensor, the movement of the absorbers were monitored. At present, the beam collimation system has been running with no mechanical failure for two years on CSNS, and it plays an active role in beam power boost and beam loss control, which proves that the structural design of the system is reasonable.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB194

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paper received ※ 17 May 2021 paper accepted ※ 11 June 2021 issue date ※ 17 August 2021

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TUPAB195

Local Orbit Correction Application for CSNS-RCS High Intensity Commissioning

1865

Y.W. An, Y. Li, S.Y. Xu, Y. Yuan
IHEP, Beijing, People’s Republic of China
M.T. Li
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) is a high intensity hadron pulse facility which achieved the design goal in March, 2020. The Rapid Cycling Synchrotron (RCS) is the important part of the CSNS which accelerates the proton beam from 80MeV to 1.6GeV. During the high intensity commissioning of the RCS, an local orbit correction application was developed. Because of the good performance of the local orbit controlling at the ramping stage, the beam loss was optimized effectively in the process of the acceleration. In the paper, the efficiency of the beam loss optimization during the acceleration is given and the future plans were proposed.

Poster TUPAB195 [2.279 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB195

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paper received ※ 13 May 2021 paper accepted ※ 17 June 2021 issue date ※ 01 September 2021

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TUPAB196

Achievement of 100-kW Beam Operation in CSNS/RCS

1869

S.Y. Xu, Y.W. An, J. Chen, L. Huang, M.Y. Huang, Y. Li, S. Wang
IHEP, Beijing, People’s Republic of China
H.Y. Liu, X.H. Lu
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) is an accelerator-based science facility. CSNS is designed to accelerate proton beam pulses to 1.6 GeV kinetic energy, striking a solid metal target to produce spallation neutrons. CSNS has two major accelerator systems, a linear accelerator (80 MeV Linac) and a 1.6 GeV rapid cycling synchrotron(RCS). The RCS accumulates and accelerates the proton beam to 1.6 GeV and then extracts the beam to the target at the repetition rate of 25 Hz. The Beam commissioning of CSNS/RCS had been started since April 2017. The most important issue in high-power beam commissioning is the beam loss control, as well as the control of induced activities, to meet the requirement of manual maintenance. A series of beam loss optimization work had been done to reduce the uncontrolled beam loss. At the end of February 2020, the CSNS reached the design beam power of 100 kW with very low uncontrolled beam loss.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB196

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paper received ※ 19 May 2021 paper accepted ※ 31 May 2021 issue date ※ 28 August 2021

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TUPAB261

The Ferrite Loaded Cavity Impedance Simulation

2070

L. Huang, X. Li, S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China
B. Wu
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: Work supported by NNSF of China: N0. U1832210
The Rapid Cycling Synchrotron of the China Spallation Neutron Source is a high-intensity proton accelerator, it accumulates the 80 MeV proton beam and accelerates it to 1.6 GeV in 20 ms. The transverse coupling bunch instability is observed in beam commissioning. The source has been investigating from the commissioning. The RF acceleration system consists of eight ferrite-loaded cavities. The impedance is simulated and there is a narrow-band impedance of the ferrite cavity at about 17 MHz

Poster TUPAB261 [1.145 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB261

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paper received ※ 13 May 2021 paper accepted ※ 31 May 2021 issue date ※ 21 August 2021

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WEPAB199

Study on the Important Technologies of 300MeV Upgrade for the CSNS Injection System

3089

M.Y. Huang, C.D. Deng, L. Kang, L. Liu, Y. Liu, X. Qi, S. Wang, Q.B. Wu, Y.W. Wu, S.Y. Xu, W.Q. Zhang, Y.L. Zhang
IHEP, Beijing, People’s Republic of China
J.X. Chen, T. Huang, H.C. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: This work was supported by National Natural Science Foundation of China (Project Nos. U1832210 and 12075134).
The China Spallation Neutron Source (CSNS-I) have achieved the design goal of 100kW beam power on the target in Feb., 2020. As the second phase of the CSNS, CSNS-II will achieve a beam power on the target of 500 kW. The injection energy of CSNS-II will be increased from 80 MeV to 300 MeV and the average beam current of the Linac will increase 5 times. Therefore, the injection system will require a complete upgrade. In this paper, the design scheme of the injection system for CSNS-II will be introduced. The key technologies of the upgrade injection system will be carefully analyzed and pre-developed, such as the pulse power supplies and their magnets, the special-shaped ceramic vacuum chambers, the main stripping foil, the stripped electron collection, and so on.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB199

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 21 August 2021

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WEPAB200

Study on the Measurement and Residual Dose of the CSNS Stripping Foil

3093

M.Y. Huang, L. Kang, S. Wang, Q.B. Wu, S.Y. Xu, Y.L. Zhang
IHEP, Beijing, People’s Republic of China
J.X. Chen, W.L. Huang, H.C. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: This work was supported by National Natural Science Foundation of China (Project Nos. 12075134 and U1832210).
In this paper, firstly, the application and service life of the main stripping foil for the China Spallation Neutron Source (CSNS) were introduced. The stripping efficiency of the main stripping foil have been measured and studied. Then, by using the codes FLUKA and ORBIT, the particle scattering of the main stripping foil has been simulated and the theoretical residual doses in the injection region caused by the foil scattering were obtained. By weekly measurement of the residual doses in the injection region, the actual residual doses near the main stripping foil were given. The residual doses comparison results have confirmed that the particle scattering of the main stripping foil is the most important source of the residual doses in the injection region.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB200

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paper received ※ 09 May 2021 paper accepted ※ 25 August 2021 issue date ※ 23 August 2021

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THPAB185

Solution to Beam Transmission Decline in the CSNS Linac Operation Using Measurements and Simulations

4134

J. Peng, M.T. Li, X.H. Lu, X.B. Luo
IHEP CSNS, Guangdong Province, People’s Republic of China
Y.W. An, S. Fu, L. Huang, M.Y. Huang, Y. Li, Z.P. Li, S. Wang, S.Y. Xu, Y. Yuan
IHEP, Beijing, People’s Republic of China

The CSNS linac operation at its design average power currently. However, the beam transmission is declining and the beam loss is increasing during the operation. With simulations and experiments, we found there is a long longitudinal tail exist in the beam bunch output from the RFQ. And this tail caused the beam loss in the following linac. After inhibition of the longitudinal tail in the beam bunch, the beam transmission in operation can keep stable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB185

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 02 September 2021

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THPAB207

Beam Dynamics Simulation about the Dual Harmonic System by PyORBIT

4194

H.Y. Liu, X.Y. Feng, L. Huang, M.T. Li, X.H. Lu
IHEP CSNS, Guangdong Province, People’s Republic of China
S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

The space charge effect is a strong limitation in high-intensity accelerators, especially for low- and medium-energy proton synchrotrons. And for CSNS-II, the number of particles in the RCS is 3.9·10¹³ ppp, which is five times of CSNS. To mitigate the effects of the strong space charge effect, CSNS-II/RCS (Rapid Cycling Synchrotron) will use a dual harmonic system to increase the bunching factor during the injection and the initial acceleration phase. For studying the beam dynamics involved in a dual harmonic RF system, PyORBIT is used as the major simulation code, which is developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. We modified parts of the code to make it applicable to the beam dynamic in RCS. This paper includes the major code modification of the Dual Harmonic RF system and some benchmark results. The preliminary simulation results of the dual-harmonic system in CSNS-II/RCS simulated by the particle tracking code PyORBIT will also be discussed.

Poster THPAB207 [0.354 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB207

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paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 11 August 2021

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THPAB224

The Correction of Time-Dependent Tune Shift by Harmonic Injection

4234

X.H. Lu
IHEP CSNS, Guangdong Province, People’s Republic of China
J. Chen, S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

In the Rapid Cycling Synchrotron(RCS) of China Spallation Neutron Source(CSNS), transverse painting injection is employed to suppress the space-charge effects. The beta-beating caused by edge focusing of the injection bump magnets leads to tune shift. A new method based on the harmonic injection is firstly introduced to correct the time-dependent tune shift caused by the edge focusing effect of the chicane bump magnets in RCS. The simulation study was done on the application of the new method to the CSNS/RCS, and the results show the validity and effectiveness of the method.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB224

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paper received ※ 19 May 2021 paper accepted ※ 16 July 2021 issue date ※ 10 August 2021

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