HB2023 - List of Authors (Li, Y.)

Paper	Title	Page
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)

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)

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)

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)

Paper

Title

Page

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)

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)

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)

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)