IPAC2021 - List of Authors (Wang, S.)

Paper	Title	Page
MOPAB054	Start-to-End Simulation of a Free-Electron Laser Driven by a Laser-Plasma Wakefield Accelerator	233
	W. Liu, Y. Jiao, S. Wang IHEP, Beijing, People’s Republic of China
	The rapid development of laser-plasma wakefield accelerator (LPA) has opened up a new possible way to achieve ultra-compact free-electron laser (FEL). To this end, LPA experts have made many efforts to generate electron beams with sub-micrometer emittance and low energy spread. Recently, a new laser modulation method was proposed for generating EUV coherent pulse in an LPA-driven FEL. The simulation demonstration of this scheme is based on the Gaussian beam. However, the distribution of the LPA beam is not Gaussian. To further verify the feasibility of the method mentioned above, a start-to-end simulation is required.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB054
About •	paper received ※ 18 May 2021 paper accepted ※ 27 May 2021 issue date ※ 22 August 2021
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MOPAB055	Generation of Coherent Attosecond X-ray Pulses in the Southern Advanced Photon Source	237
	W. Liu, Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China Y. Jiao, S. Wang IHEP, Beijing, People’s Republic of China
	Southern Advanced Photon Source (SAPS) is a fourth-generation storage ring light source that has been considered for construction in Guangdong province of China, adjacent to the China Spallation Neutron Source. As a low-emittance storage ring, the natural emittance of SAPS is below 100 pm. One of the benefits is that the brightness is about 2 orders high than 3rd generation light sources. However, like many other storage ring-based light sources, the time resolution is limited by the electron bunch length in the range of picoseconds. In this work, we propose a new scheme for the generation of coherent attoseconds X-ray pulses with a high repetition rate in SAPS. A numerical demonstration of the scheme is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB055
About •	paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 26 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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TUPAB044	Preliminary Study of the on-Axis Swap-Out Injection Scheme for the Southern Advanced Photon Source	1447
	Y. Han, X.H. Lu, Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China L. Huang, Y. Jiao, X. Liu, S. Wang IHEP, Beijing, People’s Republic of China
	The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. The extremely low emittance will result in a very small dynamic aperture for the storage ring which makes it difficult to use the conventional off-axis accumulation injection. In this case, it is probably necessary to consider the transverse on-axis injection or the longitudinal injection. In this paper, the transverse on-axis swap-out injection scheme for the SAPS storage ring is presented. The preliminary parameters of the septum magnets and fast kickers are carefully evaluated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB044
About •	paper received ※ 17 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021
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TUPAB045	The Low Energy Injector Design for the Southern Advanced Photon Source	1450
	Y. Han IHEP CSNS, Guangdong Province, People’s Republic of China Y. Jiao, B. Li, X. Liu, S. Wang IHEP, Beijing, People’s Republic of China
	The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. At present, two injector options are under consideration. One is a full energy booster plus a low energy injector, and another is a full energy linac injector. In this paper, a preliminary design of the low energy injector is presented, which consists of an DC thermionic electron gun, a bunching section and an accelerating section. The beam energy at the end of the injector is about 150 MeV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB045
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 18 August 2021
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TUPAB046	Preliminary design of the Full Energy Linac Injector for the Southern Advanced Photon Source	1454
	X. Liu Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China Y. Jiao, B. Li, S. Wang IHEP, Beijing, People’s Republic of China
	A 4th generation mid-energy range diffraction limited storage ring, named as the Southern Advanced Photon Source (SAPS), is under consideration to be built at the same campus as China Spallation Neutron Source (CSNS), providing a charming one-stop solution for fundamental sciences and industrial applications. While the design of the ring is still under study, a full energy Linac has been proposed as one candidate option for its injector, with the capability of being used as an X-ray Free Electron Laser (XFEL) in the near future. In this paper, an overview of the preliminary design of the Linac is given and simulation results are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB046
About •	paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 10 August 2021
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TUPAB047	Bunch Compressor Design in the Full Energy Linac Injector for the Southern Advanced Photon Source	1458
	B. Li IHEP CSNS, Guangdong Province, People’s Republic of China Y. Jiao, X. Liu, S. Wang IHEP, Beijing, People’s Republic of China
	A mid-energy fourth-generation storage ring light source named the Southern Advanced Photon Source (SAPS), has been considered to be built neighboring the China Spallation Neutron Source (CSNS). A full energy linac has been proposed as an injector to the storage ring, with the capability to generate high brightness electron beams to feed a Free Electron Laser (FEL) at a later stage. To achieve the high peak current in FELs, space charge, RF structure wakefield, coherent synchrotron radiation (CSR), RF curvature, and the second-order momentum compaction factor should be carefully considered and optimized during the bunch compression processes. In this paper, physic design and simulation results of the bunch compressors are described.
	Poster TUPAB047 [1.918 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB047
About •	paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 28 August 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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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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TUPAB263	The Phase Loop Status of the RF System in CSNS/RCS	2076
	L. Huang, X. Li, S. Wang IHEP, Beijing, People’s Republic of China M.T. Li, H.Y. Liu IHEP CSNS, Guangdong Province, People’s Republic of China Y. Liu DNSC, Dongguan, People’s Republic of China
	The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator. The acceleration system consists of eight ferrite loaded cavities. The RCS is the space charge dominant machine and it is mitigated through the bunch factor optimization in the beam commissioning, so the injected beam will occupy a larger bucket size and unavoidable mismatch with the bucket, thus the dipole oscillation is excited. The phase loop scheme is designed to restrict the oscillation in the RF system, but the transmission efficiency is reduced by the phase loop and the bunch factor also increases, so the phase loop scheme is studied. To keep the phase loop but also maintain the transmission efficiency, we optimized the original phase loop scheme, but the beam loss still increases small when the loop on.
	Poster TUPAB263 [1.548 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB263
About •	paper received ※ 13 May 2021 paper accepted ※ 02 June 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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THPAB104	Magnetic Error Effects of the Storage Ring for the Southern Advanced Photon Source	3980
	J. Chen, Y. Jiao, X. Liu, S. Wang IHEP, Beijing, People’s Republic of China Y. Zhao IHEP CSNS, Guangdong Province, People’s Republic of China
	There are various magnetic errors in the actual accelerator, which will significantly affect the beam quality and machine performance. The diffraction-limited storage ring (DLSR) of Southern Advanced Photon Source (SAPS) will use a large number of ultra-high gradient quadrupoles and sextupoles, which, in turn, leads to the tight tolerance of beam parameters to magnetic errors. Based on a preliminary designed storage ring lattice of the SAPS, the influence of various magnetic errors on lattice parameters has been evaluated.
	Poster THPAB104 [0.588 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB104
About •	paper received ※ 17 May 2021 paper accepted ※ 23 June 2021 issue date ※ 18 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

Start-to-End Simulation of a Free-Electron Laser Driven by a Laser-Plasma Wakefield Accelerator

233

W. Liu, Y. Jiao, S. Wang
IHEP, Beijing, People’s Republic of China

The rapid development of laser-plasma wakefield accelerator (LPA) has opened up a new possible way to achieve ultra-compact free-electron laser (FEL). To this end, LPA experts have made many efforts to generate electron beams with sub-micrometer emittance and low energy spread. Recently, a new laser modulation method was proposed for generating EUV coherent pulse in an LPA-driven FEL. The simulation demonstration of this scheme is based on the Gaussian beam. However, the distribution of the LPA beam is not Gaussian. To further verify the feasibility of the method mentioned above, a start-to-end simulation is required.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB054

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paper received ※ 18 May 2021 paper accepted ※ 27 May 2021 issue date ※ 22 August 2021

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MOPAB055

Generation of Coherent Attosecond X-ray Pulses in the Southern Advanced Photon Source

237

W. Liu, Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Jiao, S. Wang
IHEP, Beijing, People’s Republic of China

Southern Advanced Photon Source (SAPS) is a fourth-generation storage ring light source that has been considered for construction in Guangdong province of China, adjacent to the China Spallation Neutron Source. As a low-emittance storage ring, the natural emittance of SAPS is below 100 pm. One of the benefits is that the brightness is about 2 orders high than 3rd generation light sources. However, like many other storage ring-based light sources, the time resolution is limited by the electron bunch length in the range of picoseconds. In this work, we propose a new scheme for the generation of coherent attoseconds X-ray pulses with a high repetition rate in SAPS. A numerical demonstration of the scheme is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB055

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paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 26 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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TUPAB044

Preliminary Study of the on-Axis Swap-Out Injection Scheme for the Southern Advanced Photon Source

1447

Y. Han, X.H. Lu, Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China
L. Huang, Y. Jiao, X. Liu, S. Wang
IHEP, Beijing, People’s Republic of China

The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. The extremely low emittance will result in a very small dynamic aperture for the storage ring which makes it difficult to use the conventional off-axis accumulation injection. In this case, it is probably necessary to consider the transverse on-axis injection or the longitudinal injection. In this paper, the transverse on-axis swap-out injection scheme for the SAPS storage ring is presented. The preliminary parameters of the septum magnets and fast kickers are carefully evaluated.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB044

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paper received ※ 17 May 2021 paper accepted ※ 10 June 2021 issue date ※ 27 August 2021

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TUPAB045

The Low Energy Injector Design for the Southern Advanced Photon Source

1450

Y. Han
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Jiao, B. Li, X. Liu, S. Wang
IHEP, Beijing, People’s Republic of China

The Southern Advanced Photon Source (SAPS) is a project under design, which aims at constructing a 4th generation storage ring with emittance below 100 pm.rad at the electron beam energy of around 3.5 GeV. At present, two injector options are under consideration. One is a full energy booster plus a low energy injector, and another is a full energy linac injector. In this paper, a preliminary design of the low energy injector is presented, which consists of an DC thermionic electron gun, a bunching section and an accelerating section. The beam energy at the end of the injector is about 150 MeV.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB045

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 18 August 2021

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TUPAB046

Preliminary design of the Full Energy Linac Injector for the Southern Advanced Photon Source

1454

X. Liu
Institute of High Energy Physics, CAS, Guangdong, People’s Republic of China
Y. Jiao, B. Li, S. Wang
IHEP, Beijing, People’s Republic of China

A 4th generation mid-energy range diffraction limited storage ring, named as the Southern Advanced Photon Source (SAPS), is under consideration to be built at the same campus as China Spallation Neutron Source (CSNS), providing a charming one-stop solution for fundamental sciences and industrial applications. While the design of the ring is still under study, a full energy Linac has been proposed as one candidate option for its injector, with the capability of being used as an X-ray Free Electron Laser (XFEL) in the near future. In this paper, an overview of the preliminary design of the Linac is given and simulation results are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB046

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paper received ※ 18 May 2021 paper accepted ※ 10 June 2021 issue date ※ 10 August 2021

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TUPAB047

Bunch Compressor Design in the Full Energy Linac Injector for the Southern Advanced Photon Source

1458

B. Li
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Jiao, X. Liu, S. Wang
IHEP, Beijing, People’s Republic of China

A mid-energy fourth-generation storage ring light source named the Southern Advanced Photon Source (SAPS), has been considered to be built neighboring the China Spallation Neutron Source (CSNS). A full energy linac has been proposed as an injector to the storage ring, with the capability to generate high brightness electron beams to feed a Free Electron Laser (FEL) at a later stage. To achieve the high peak current in FELs, space charge, RF structure wakefield, coherent synchrotron radiation (CSR), RF curvature, and the second-order momentum compaction factor should be carefully considered and optimized during the bunch compression processes. In this paper, physic design and simulation results of the bunch compressors are described.

Poster TUPAB047 [1.918 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB047

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paper received ※ 15 May 2021 paper accepted ※ 09 June 2021 issue date ※ 28 August 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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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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TUPAB263

The Phase Loop Status of the RF System in CSNS/RCS

2076

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

The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) is a high intensity proton accelerator. The acceleration system consists of eight ferrite loaded cavities. The RCS is the space charge dominant machine and it is mitigated through the bunch factor optimization in the beam commissioning, so the injected beam will occupy a larger bucket size and unavoidable mismatch with the bucket, thus the dipole oscillation is excited. The phase loop scheme is designed to restrict the oscillation in the RF system, but the transmission efficiency is reduced by the phase loop and the bunch factor also increases, so the phase loop scheme is studied. To keep the phase loop but also maintain the transmission efficiency, we optimized the original phase loop scheme, but the beam loss still increases small when the loop on.

Poster TUPAB263 [1.548 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB263

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paper received ※ 13 May 2021 paper accepted ※ 02 June 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

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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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THPAB104

Magnetic Error Effects of the Storage Ring for the Southern Advanced Photon Source

3980

J. Chen, Y. Jiao, X. Liu, S. Wang
IHEP, Beijing, People’s Republic of China
Y. Zhao
IHEP CSNS, Guangdong Province, People’s Republic of China

There are various magnetic errors in the actual accelerator, which will significantly affect the beam quality and machine performance. The diffraction-limited storage ring (DLSR) of Southern Advanced Photon Source (SAPS) will use a large number of ultra-high gradient quadrupoles and sextupoles, which, in turn, leads to the tight tolerance of beam parameters to magnetic errors. Based on a preliminary designed storage ring lattice of the SAPS, the influence of various magnetic errors on lattice parameters has been evaluated.

Poster THPAB104 [0.588 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB104

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paper received ※ 17 May 2021 paper accepted ※ 23 June 2021 issue date ※ 18 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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