HB2023 - List of Authors (Xu, S.Y.)

Paper	Title	Page
MOA1I3	Intense Beam Issues in CSNS Accelerator Beam Commissioning	16
	L. Huang, H.Y. Liu, X.H. Lu, X.B. Luo, J. Peng, L. Rao IHEP CSNS, Guangdong Province, People’s Republic of China Y.W. An, J. Chen, M.Y. Huang, Y. Li, Z.P. Li, S. Wang IHEP, Beijing, People’s Republic of China S.Y. Xu DNSC, Dongguan, People’s Republic of China
	The China Spallation Neutron Source (CSNS) consists of an 80 MeV H⁻ Linac, a 1.6 GeV Rapid Cycling Synchrotron (RCS), beam transport lines, a target station, and three spectrometers. The CSNS design beam power is 100 kW, with the capability to upgrade to 500 kW. In August 2018, CSNS was officially opened to domestic and international users. By February 2020, the beam power had reached 100 kW, and through improvements such as adding harmonic cavities, the beam power was increased to 140 kW. During the beam commissioning process, the beam loss caused by space charge effects was the most significant factor limiting the increase in beam power. Additionally, unexpected collective effects were observed, including coherent oscillations of the bunches, after the beam power reached 50 kW. Through a series of measures, the space charge effects and collective instabilities causing beam loss were effectively controlled. This paper mainly introduces the strong beam effects discovered during the beam commissioning at CSNS and their suppression methods. It also briefly discusses the research on beam space charge effects and collective effects in the beam dynamics design of CSNS-II project.
	Slides MOA1I3 [8.597 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA1I3
About •	Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 24 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUA4C2	Application of Programmable Trim Quadrupoles in Beam Commissioning of CSNS/RCS	158
	Y. Li, C.D. Deng, S.Y. Xu DNSC, Dongguan, People’s Republic of China Y.W. An, X. Qi, S. Wang, Y.S. Yuan IHEP, Beijing, People’s Republic of China H.Y. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	The China Spallation Neutron Source (CSNS) achieved its design power of 100 kW in 2020 and is currently stably operating at 140 kW after a series of measures. In the process of increasing beam power, 16 programmable trim quadrupoles were installed in the Rapid Cycling Synchrotron (RCS) of CSNS to enable rapid variation of tunes, effective adjustment of Twiss parameters, and restoration of lattice superperiodicity through the machine cycle. This paper provides a detailed introduction to the design of the trim quadrupoles and preliminary results of the machine study. The beam experiments show that the trim quadrupoles play a crucial role in increasing beam power after exceeding 100 kW.
	Slides TUA4C2 [4.136 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4C2
About •	Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 22 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4C1	Beam Loss Studies in the CSNS Linac	297
	J. Peng, X.Y. Feng, Y. Han, H.C. Liu, X.B. Luo IHEP CSNS, Guangdong Province, People’s Republic of China S. Fu, M.Y. Huang, Y. Li, Z.P. Li, X. Liu, S. Wang, Y. Yuan IHEP, Beijing, People’s Republic of China S.Y. Xu DNSC, Dongguan, People’s Republic of China
	The China Spallation Neutron Source¿CSNS¿accelerator comprises an 80MeV linac and a 1.6GeV rapid cycling synchrotron. It started operation in 2018, and the beam power delivered to the target has increased from 20kW to 140kW, step by step. Various beam loss studies have been performed through the accelerator to improve the beam power and availability. For the CSNS linac, the primary source of the beam loss is the halo generated by beam mismatches. In the upgrade plan of the CSNS, the beam current will increase five times, which requires more strict beam loss control. Much work is done during the design phase to keep the loss down to 1W/m of loss limit. This paper will report results obtained from beam experiments and optimization methods applied to the CSNS linac upgrade design.
	Slides WEA4C1 [3.736 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 13 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2C1	Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS	228
	S.Y. Xu, L. Huang, M.Y. Huang, Y. Li, S. Wang IHEP, Beijing, People’s Republic of China
	The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by half-integer resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.
	Slides WEA2C1 [4.710 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA1I1	Performance and Upgrade Considerations for the CSNS Injection	326
	M.Y. Huang, S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	Funding: This work is jointly supported by the National Natural Science Foundation of China (Nos. 12075134) and the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120021). For the proton synchrotron, the beam injection is one of the most important issues. Firstly, based on the China Spallation Neutron Source (CSNS), the injection methods have been comprehensively studied, including phase space painting and H⁻ stripping. In order to solve the key difficulties faced when the beam power exceeds 50% of the design value, flexibility in the CSNS design has been exploited to implement the correlated painting by using the rising current curve of the pulse power supply. The effectiveness of the new method has been verified in the simulation and beam commissioning. By using the new method, the beam power on the target has successfully risen to the design value. Secondly, for the CSNS upgrade, the injection energy is increased from 80 MeV to 300 MeV and the injection beam power is increased by about 19 times. Based on the CSNS experience and simulation results, it is hoped that the new injection scheme can not only be compatible with correlated and anti-correlated painting, but also greatly reduces the peak temperature of the stripping foil. After in-depth study, a new painting scheme has been proposed which has been verified to be feasible in the simulation.
	Slides THA1I1 [2.951 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I1
About •	Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 15 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP02	Resonance Extraction Research Based on China Spallation Neutron Source	397
	Y.W. An, L. Huang, Z.P. Li, S.Y. Xu, Y.S. Yuan IHEP, Beijing, People’s Republic of China
	Resonance extraction based on the RCS ring is an important aspect of beam applications. This article proposes a new design of resonance extraction based on the CSNS-RCS ring. By adjusting parameters such as the skew sextupole magnet, beam working point, RF-Kicker, etc., the simulation results from PyOrbit demonstrate the ability to rapidly extract a large number of protons within a few turns.
	Slides THAFP02 [1.497 MB]
	Poster THAFP02 [0.960 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP02
About •	Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP53	Commissioning and Operation of the Collimation System at the RCS of CSNS	615
	S.Y. Xu, J. Chen, S. Wang IHEP, Beijing, People’s Republic of China K. Zhou IHEP CSNS, Guangdong Province, People’s Republic of China
	For high-intensity proton synchrotrons, minimizing particle losses during machine operation is essential to avoid radiation damage. Uncontrolled beam loss posed a significant challenge to achieving higher beam intensity and power for high-intensity proton synchrotrons. The beam collimation system can remove halo particles and to localize the beam loss. The use of collimation system is an important means of controlling uncontrolled beam loss in high-power proton accelerators. To reduce the uncontrolled beam loss, a transverse collimation system was designed for the RCS of CSNS. The design transverse collimator is a two-stage collimator. During the beam commissioning of CSNS, the designed two-stage collimator has been changed to one-stage collimator to overcome the problem of low collimation efficiency caused by insufficient phase shift between the primary and secondary collimators. By optimizing the collimation system, the beam loss is well localized in the collimator area, effectively reducing uncontrolled beam loss. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.
	Poster THBP53 [0.780 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP53
About •	Received ※ 30 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 10 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRA1I2	Design and Beam Commissioning of Dual Harmonic RF System in CSNS RCS	633
	H.Y. Liu, L. Huang IHEP CSNS, Guangdong Province, People’s Republic of China Y. Liu DNSC, Dongguan, People’s Republic of China S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	The CSNS accelerator achieved an average beam power on target of 100 kW in February 2020 and subsequently increased it to 125 kW in March 2022. Building upon this success, CSNS plans to further enhance the average beam power to 200 kW by doubling the particle number of the circulating beam in the RCS, while keeping the injection energy same. The space charge effect is a main limit for the beam intensity increase in high-power particle accelerators. By providing a second harmonic RF cavity with a harmonic number of 4, in combination with the ferrite cavity with a harmonic number of 2, the dual harmonic RF system aims to mitigate emittance increase and beam loss caused by space charge effects, thereby optimizing the longitudinal beam distribution. This paper will concentrate on the beam commissioning for the 140 kW operation subsequent to the installation of the magnetic alloy (MA) cavity. The commissioning process includes the optimization of RF parameters, beam studies, and evaluation of the beam quality and instability.
	Slides FRA1I2 [4.086 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA1I2
About •	Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 27 October 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Intense Beam Issues in CSNS Accelerator Beam Commissioning

16

L. Huang, H.Y. Liu, X.H. Lu, X.B. Luo, J. Peng, L. Rao
IHEP CSNS, Guangdong Province, People’s Republic of China
Y.W. An, J. Chen, M.Y. Huang, Y. Li, Z.P. Li, S. Wang
IHEP, Beijing, People’s Republic of China
S.Y. Xu
DNSC, Dongguan, People’s Republic of China

The China Spallation Neutron Source (CSNS) consists of an 80 MeV H⁻ Linac, a 1.6 GeV Rapid Cycling Synchrotron (RCS), beam transport lines, a target station, and three spectrometers. The CSNS design beam power is 100 kW, with the capability to upgrade to 500 kW. In August 2018, CSNS was officially opened to domestic and international users. By February 2020, the beam power had reached 100 kW, and through improvements such as adding harmonic cavities, the beam power was increased to 140 kW. During the beam commissioning process, the beam loss caused by space charge effects was the most significant factor limiting the increase in beam power. Additionally, unexpected collective effects were observed, including coherent oscillations of the bunches, after the beam power reached 50 kW. Through a series of measures, the space charge effects and collective instabilities causing beam loss were effectively controlled. This paper mainly introduces the strong beam effects discovered during the beam commissioning at CSNS and their suppression methods. It also briefly discusses the research on beam space charge effects and collective effects in the beam dynamics design of CSNS-II project.

Slides MOA1I3 [8.597 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-MOA1I3

About •

Received ※ 01 October 2023 — Revised ※ 05 October 2023 — Accepted ※ 10 October 2023 — Issued ※ 24 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUA4C2

Application of Programmable Trim Quadrupoles in Beam Commissioning of CSNS/RCS

158

Y. Li, C.D. Deng, S.Y. Xu
DNSC, Dongguan, People’s Republic of China
Y.W. An, X. Qi, S. Wang, Y.S. Yuan
IHEP, Beijing, People’s Republic of China
H.Y. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

The China Spallation Neutron Source (CSNS) achieved its design power of 100 kW in 2020 and is currently stably operating at 140 kW after a series of measures. In the process of increasing beam power, 16 programmable trim quadrupoles were installed in the Rapid Cycling Synchrotron (RCS) of CSNS to enable rapid variation of tunes, effective adjustment of Twiss parameters, and restoration of lattice superperiodicity through the machine cycle. This paper provides a detailed introduction to the design of the trim quadrupoles and preliminary results of the machine study. The beam experiments show that the trim quadrupoles play a crucial role in increasing beam power after exceeding 100 kW.

Slides TUA4C2 [4.136 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-TUA4C2

About •

Received ※ 27 September 2023 — Revised ※ 07 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 22 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA4C1

Beam Loss Studies in the CSNS Linac

297

J. Peng, X.Y. Feng, Y. Han, H.C. Liu, X.B. Luo
IHEP CSNS, Guangdong Province, People’s Republic of China
S. Fu, M.Y. Huang, Y. Li, Z.P. Li, X. Liu, S. Wang, Y. Yuan
IHEP, Beijing, People’s Republic of China
S.Y. Xu
DNSC, Dongguan, People’s Republic of China

The China Spallation Neutron Source¿CSNS¿accelerator comprises an 80MeV linac and a 1.6GeV rapid cycling synchrotron. It started operation in 2018, and the beam power delivered to the target has increased from 20kW to 140kW, step by step. Various beam loss studies have been performed through the accelerator to improve the beam power and availability. For the CSNS linac, the primary source of the beam loss is the halo generated by beam mismatches. In the upgrade plan of the CSNS, the beam current will increase five times, which requires more strict beam loss control. Much work is done during the design phase to keep the loss down to 1W/m of loss limit. This paper will report results obtained from beam experiments and optimization methods applied to the CSNS linac upgrade design.

Slides WEA4C1 [3.736 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA4C1

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 13 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEA2C1

Tune Optimization for Alleviating Space Charge Effects and Suppressing Beam Instability in the RCS of CSNS

228

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

The design betatron tune of the Rapid Cycling Synchrotron (RCS) of China Spallation Neutron Source (CSNS) is (4.86, 4.80), which allows for incoherent tune shifts to avoid serious systematic betatron resonances. When the operational bare tune was set at the design value, serious beam instability in the horizontal plane and beam loss induced by half-integer resonance in the vertical plane under space charge detuning were observed. The tunes over the whole acceleration process are optimized based on space charge effects and beam instability. In the RCS, manipulating the tune during the beam acceleration process is a challenge due to the quadrupole magnets being powered by resonant circuits. In the RCS of CSNS, a method of waveform compensation for RCS magnets was investigated to accurately manipulate the magnetic field ramping process. The optimized tune pattern was able to well control the beam loss induced by space charge and beam instability. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.

Slides WEA2C1 [4.710 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-WEA2C1

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 23 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THA1I1

Performance and Upgrade Considerations for the CSNS Injection

326

M.Y. Huang, S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

Funding: This work is jointly supported by the National Natural Science Foundation of China (Nos. 12075134) and the Guangdong Basic and Applied Basic Research Foundation (No. 2021B1515120021).
For the proton synchrotron, the beam injection is one of the most important issues. Firstly, based on the China Spallation Neutron Source (CSNS), the injection methods have been comprehensively studied, including phase space painting and H⁻ stripping. In order to solve the key difficulties faced when the beam power exceeds 50% of the design value, flexibility in the CSNS design has been exploited to implement the correlated painting by using the rising current curve of the pulse power supply. The effectiveness of the new method has been verified in the simulation and beam commissioning. By using the new method, the beam power on the target has successfully risen to the design value. Secondly, for the CSNS upgrade, the injection energy is increased from 80 MeV to 300 MeV and the injection beam power is increased by about 19 times. Based on the CSNS experience and simulation results, it is hoped that the new injection scheme can not only be compatible with correlated and anti-correlated painting, but also greatly reduces the peak temperature of the stripping foil. After in-depth study, a new painting scheme has been proposed which has been verified to be feasible in the simulation.

Slides THA1I1 [2.951 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THA1I1

About •

Received ※ 01 October 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 15 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THAFP02

Resonance Extraction Research Based on China Spallation Neutron Source

397

Y.W. An, L. Huang, Z.P. Li, S.Y. Xu, Y.S. Yuan
IHEP, Beijing, People’s Republic of China

Resonance extraction based on the RCS ring is an important aspect of beam applications. This article proposes a new design of resonance extraction based on the CSNS-RCS ring. By adjusting parameters such as the skew sextupole magnet, beam working point, RF-Kicker, etc., the simulation results from PyOrbit demonstrate the ability to rapidly extract a large number of protons within a few turns.

Slides THAFP02 [1.497 MB]

Poster THAFP02 [0.960 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THAFP02

About •

Received ※ 01 October 2023 — Revised ※ 08 October 2023 — Accepted ※ 11 October 2023 — Issued ※ 01 November 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THBP53

Commissioning and Operation of the Collimation System at the RCS of CSNS

615

S.Y. Xu, J. Chen, S. Wang
IHEP, Beijing, People’s Republic of China
K. Zhou
IHEP CSNS, Guangdong Province, People’s Republic of China

For high-intensity proton synchrotrons, minimizing particle losses during machine operation is essential to avoid radiation damage. Uncontrolled beam loss posed a significant challenge to achieving higher beam intensity and power for high-intensity proton synchrotrons. The beam collimation system can remove halo particles and to localize the beam loss. The use of collimation system is an important means of controlling uncontrolled beam loss in high-power proton accelerators. To reduce the uncontrolled beam loss, a transverse collimation system was designed for the RCS of CSNS. The design transverse collimator is a two-stage collimator. During the beam commissioning of CSNS, the designed two-stage collimator has been changed to one-stage collimator to overcome the problem of low collimation efficiency caused by insufficient phase shift between the primary and secondary collimators. By optimizing the collimation system, the beam loss is well localized in the collimator area, effectively reducing uncontrolled beam loss. The beam power of CSNS achieved the design value of 100 kW with small uncontrolled beam loss.

Poster THBP53 [0.780 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-THBP53

About •

Received ※ 30 September 2023 — Revised ※ 06 October 2023 — Accepted ※ 09 October 2023 — Issued ※ 10 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRA1I2

Design and Beam Commissioning of Dual Harmonic RF System in CSNS RCS

633

H.Y. Liu, L. Huang
IHEP CSNS, Guangdong Province, People’s Republic of China
Y. Liu
DNSC, Dongguan, People’s Republic of China
S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

The CSNS accelerator achieved an average beam power on target of 100 kW in February 2020 and subsequently increased it to 125 kW in March 2022. Building upon this success, CSNS plans to further enhance the average beam power to 200 kW by doubling the particle number of the circulating beam in the RCS, while keeping the injection energy same. The space charge effect is a main limit for the beam intensity increase in high-power particle accelerators. By providing a second harmonic RF cavity with a harmonic number of 4, in combination with the ferrite cavity with a harmonic number of 2, the dual harmonic RF system aims to mitigate emittance increase and beam loss caused by space charge effects, thereby optimizing the longitudinal beam distribution. This paper will concentrate on the beam commissioning for the 140 kW operation subsequent to the installation of the magnetic alloy (MA) cavity. The commissioning process includes the optimization of RF parameters, beam studies, and evaluation of the beam quality and instability.

Slides FRA1I2 [4.086 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-HB2023-FRA1I2

About •

Received ※ 30 September 2023 — Revised ※ 09 October 2023 — Accepted ※ 14 October 2023 — Issued ※ 27 October 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)