HB2023 - List of Authors (Liu, H.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)

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)

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)