SAP2023 - Classification: Hadron Accelerators

Paper	Title	Page
MOAA01	Design of the Superconducting Linac for CiADS Facing High Reliability
	Y. He, W.L. Chen, W.P. Dou, G. Huang, H. Jia, S.H. Liu, Y.S. Qin, L.P. Sun, Z.J. Wang, J. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	Funding: Supported by NSF U22A20261, Large Research Infrastructures - China initiative Accelerator Driven System CiADS is the world’s first Accelerator Driven System with a Mega-watt beam power. The linac of CiADS consists of a 500 MeV and 5 mA with five-family superconducting resonators located directly downstream of the Radio Frequency Quadrupole (RFQ). The most significant challenge in designing the superconducting linac for CiADS is to ensure high-reliability operation with minimal beam loss control at 10^-7 level and availability maximization through specifically designed hardware and software. In this presentation, we will discuss the physical design of the superconducting linac, including the fault compensation based on beam loss control and high reliability designs of the RF amplifier and power supply.
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOAA02	Design and Beam Commissioning of Dual Harmonic RF System in CSNS RCS
	H.Y. Liu IHEP CSNS, Guangdong Province, People’s Republic of China
	The design average beam power of the China Spallation Neutron Source (CSNS) is 100 kW, which was achieved in February 2020 and reached 125 kW in March 2022. Building upon this, CSNS plans to increase the average beam power to 200 kW, doubling the circulating beam intensity of the Rapid Cycling Synchrotron (RCS) while keeping the injected energy constant. Space charge effects are important factors that limit the current intensity of high-power particle accelerators. To reduce the increase in beam emittance and beam loss caused by space charge effects, CSNS added a magnetic alloy RF cavity to the RCS in the summer of 2022. This cavity, together with the existing ferrite cavity, forms a dual-harmonic RF system to optimize the longitudinal beam distribution, increase the bunching factor, and mitigate space charge effects. This talk will focus on the beam tuning and simulation results of the CSNS RCS after the installation of the magnetic alloy-loaded high-frequency cavity.
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOAA03	The High-Intensity Heavy-Ion Accelerator R&D
	J.C. Yang IMP/CAS, Lanzhou, People’s Republic of China
	no abstract available
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB020	Introduction of the Accelerator-Based Facility for Radiation Protection Research
	P.Y. Yu, F.G. Chen, R. Guo, H.F. Hao, P.F. Liu, L. Miao, P. Qiao CIRP, Xiaodian District, People’s Republic of China
	The Accelerator-based Facility for Radiation Protection Research is a large research infrastructure constructed by China Institute for Radiation Protection. It consists of three accelerators and eight experimental terminals. As a main part of the facility, the tandem accelerator has a terminal voltage of 6 MV and the energy spread is less than 0.05%. By using three types of ion source, it could provide beams for example 50 ¿A for proton, 2 ¿A for He and 3 ¿A for Au at the target. The 4MV single-ended dynamitron accelerator is capable to produce H, D and He beams with a current of 60~100 ¿A. The 400kV ion planter can deliver particle beams from proton to Au and the maximum current for proton could reach 500 ¿A. Among the eight experimental terminals, four are used to construct neutron radiation field and one for photon radiation field. The other three are ion beam experimental terminals, which includes a microbeam terminal, a triple beam irradiation terminal and a terminal which connects the beamline with the TEM for in-situ observation of materials. The facility is currently under construction and is expected to be fully completed and open to experimental users by mid-2027.
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB021	The Design of a Proton-Heavy Ion Hybrid Synchrotron Upgraded from XiPAF Proton Ring	129
	H.J. Yao, Y. Li, X.Y. Liu, X.W. Wang, Z.J. Wang, S.X. Zheng TUB, Beijing, People’s Republic of China Z.M. Wang NINT, Shannxi, People’s Republic of China
	Xi’an 200MeV Proton Application Facility (XiPAF) has been basically completed at the end of 2020, providing proton beams of 10 to 200 MeV for space radiation effect studies on electronics. To expand its capabilities, XiPAF is undergoing an upgrade to deliver multiple ion species, from proton to Bismuth ion. The upgrade focuses on three aspects. First, the original negative hydrogen linear injector will be remodeled to a proton linear injector. Second, a heavy ion linear injector will be added. Third, the existing proton ring will be retrofitted into a hybrid proton-heavy ion synchrotron. Correspondingly, the beam transport lines will also be modified. This paper details the considerations and physical designs for upgrading the synchrotron. Within the scope, we discuss the challenges and solutions in transforming a specialized proton synchrotron into a multi-ion accelerator under the constraints of existing plant layout and reuse of existing equipment.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB021
About •	Received ※ 29 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 20 September 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB022	Observation of Pilot H⁻ Beam in high power proton linac
	D.Y. Jia, H. Jia, Z.J. Wang IMP/CAS, Lanzhou, People’s Republic of China
	Chinese ADS Front End (CAFe) is a demo high-power proton superconducting linac for ADS project. During high-power beam commissioning of CAFe, unexpected irradiation dose was observed at the vacuum valve at the exit of the dipole magnet opposite to the proton beam deflection direction. The reason of the irradiation cannot be explained by neutron induced reaction or the operation history of the dipole magnet. A gamma-ray analysis of radionuclides is performed with the wipe sample from the valve, excluding the possibility of the neutron induced activation and verifying the proton induced reaction. Thus, it is supposed that H¿ beam is generated at the low energy transport section and accelerated simultaneously with proton beam in the superconducting linac. In this paper, The accelerating efficiency of pilot H⁻ beam is studied with multi-particle simulation software, Tracewin. The yield of H⁻ beam is obtained by cross section calculation of proton beam with residual gas at low energy transport section. The accumulated dose at the vacuum valve is calculated by FLUKA code and compared to the simulation result.
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB023	Beam Instability and mitigation in CSNS/RCS
	L. Huang IHEP CSNS, Guangdong Province, People’s Republic of China
	Funding: Work supported by the Guangdong Basic and Applied Basic Research Foundation, China (2021B1515140007) The Rapid Cycling Synchrotron (RCS) in the China Spallation Neutron Source (CSNS) is a high-intensity synchrotron accelerator that has experienced instability, which limits the machine’s performance. Systematic research was conducted during beam commissioning and machine studies, identifying it as head-tail instability, and multiple mitigations were successfully implemented. The RCS impedance was thoroughly evaluated through simulations and impedance measurements, identifying the source of the instability. This report also discusses the challenges of beam instability as the power of the RCS will significantly increase in the CSNS-II.
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB024	Electron Cooling for Future High-energy Hadron Accelerators	133
	H. Zhao IMP/CAS, Lanzhou, People’s Republic of China
	Funding: National Natural Science Foundation of China (No. 12275323) Electron cooling is an important method to reduce the emittance and momentum spread of hadron beams, and it has been successfully applied in several facilities around the world. In 2019, the world¿s first RF-based electron cooler (LEReC) was commissioned at BNL for the RHIC BES-II project, and the integrated luminosity of RHIC is finally doubled. In addition, electron cooling is also a must for the future Electron-Ion Collider (BNL EIC). However, the high energy requirement of the electron beam (150 MeV) is far beyond what all present coolers can achieve (<4.3 MeV). For that, an electron ring cooler with strong radiation damping is proposed and designed, in which the non-magnetized and dispersive cooling techniques are applied. In this talk, I will introduce the experimental and simulation results of the two facilities. Mainly, I will introduce several new phenomena that were first observed in LEReC, such as the beam heating effect and the ion beam focusing effect. Besides, some new theories that were developed for the ring cooler will also be discussed.
	Poster TUPB024 [1.769 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB024
About •	Received ※ 04 July 2023 — Revised ※ 09 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 14 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB025	Influence of Transverse Distribution of Electron Beam on the Distribution of Proton Beam in the Process of Electron Cooling	137
	X.D. Yang IMP/CAS, Lanzhou, People’s Republic of China
	Funding: National Natural Science Foundation of China No.12275325 The electron cooling process of 20GeV proton beam in EicC was simulated for the eight transverse distribution of electron beam with the help of electron cooling simulation code. The transverse cooling time was obtained in the different transverse distribution of electron beam. The final transverse distribution of proton beam was demonstrated. The simulated results reveal that the transverse distribution of electron beam influences the distribution of proton beam in the process of electron cooling. In the future, this idea was expected to apply to the longitudinal distribution of electron beam. The longitudinal distribution of proton beam was attempted to be controlled by the longitudinally modulated electron beam. As a result, the peak current and longitudinal distribution of proton beam will be controlled by the electron beam. The loss of proton beams will be reduced, and the stored lifetime of proton beam in the storage ring will be extended. The intensity of the proton beam will be maintained for a longer time.
	Poster TUPB025 [2.048 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB025
About •	Received ※ 28 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 06 June 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPB026	Design of a Synchrotron for Proton FLASH Radiotherapy Based on Fast Variable-Energy Bunch Splitting	141
	Y. Li, X.W. Wang, Q.Z. Xing, H.J. Yao, S.X. Zheng TUB, Beijing, People’s Republic of China
	Ultra-high dose rate (FLASH) radiotherapy not only guarantees effective tumor treatment but also greatly enhances the protection of normal tissue. Moreover, it is a convenient procedure for tumor patients that has enhanced the benefits provided by medical institutions. Proton FLASH radiotherapy, which combines the Bragg peak effect of proton spatial dose distribution with the unique temporal effect advantage of FLASH, is an attractive tumor treatment approach. To achieve proton FLASH discrete pencil beam scanning in a 1-L volume, taking into account the 5-mm point interval, 9261 points would need to be irradiated within 500 ms, which is beyond the capability of existing medical devices. To meet these requirements, based on a fast cycle synchrotron with a period of 25 Hz, we simultaneously combined variable-energy, fast splitting, and extraction beam bunches, and proposed a scanning method suitable for continuous variable-energy extraction bunches. The proposed technique meet the requirements of proton FLASH discrete pencil beam scanning within a volume of 1 L.
DOI •	reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB026
About •	Received ※ 29 June 2023 — Revised ※ 10 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 28 May 2024
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

MOAA01

Design of the Superconducting Linac for CiADS Facing High Reliability

Y. He, W.L. Chen, W.P. Dou, G. Huang, H. Jia, S.H. Liu, Y.S. Qin, L.P. Sun, Z.J. Wang, J. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

Funding: Supported by NSF U22A20261, Large Research Infrastructures - China initiative Accelerator Driven System
CiADS is the world’s first Accelerator Driven System with a Mega-watt beam power. The linac of CiADS consists of a 500 MeV and 5 mA with five-family superconducting resonators located directly downstream of the Radio Frequency Quadrupole (RFQ). The most significant challenge in designing the superconducting linac for CiADS is to ensure high-reliability operation with minimal beam loss control at 10^-7 level and availability maximization through specifically designed hardware and software. In this presentation, we will discuss the physical design of the superconducting linac, including the fault compensation based on beam loss control and high reliability designs of the RF amplifier and power supply.

Cite •

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

MOAA02

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

H.Y. Liu
IHEP CSNS, Guangdong Province, People’s Republic of China

The design average beam power of the China Spallation Neutron Source (CSNS) is 100 kW, which was achieved in February 2020 and reached 125 kW in March 2022. Building upon this, CSNS plans to increase the average beam power to 200 kW, doubling the circulating beam intensity of the Rapid Cycling Synchrotron (RCS) while keeping the injected energy constant. Space charge effects are important factors that limit the current intensity of high-power particle accelerators. To reduce the increase in beam emittance and beam loss caused by space charge effects, CSNS added a magnetic alloy RF cavity to the RCS in the summer of 2022. This cavity, together with the existing ferrite cavity, forms a dual-harmonic RF system to optimize the longitudinal beam distribution, increase the bunching factor, and mitigate space charge effects. This talk will focus on the beam tuning and simulation results of the CSNS RCS after the installation of the magnetic alloy-loaded high-frequency cavity.

Cite •

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

MOAA03

The High-Intensity Heavy-Ion Accelerator R&D

J.C. Yang
IMP/CAS, Lanzhou, People’s Republic of China

no abstract available

Cite •

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

TUPB020

Introduction of the Accelerator-Based Facility for Radiation Protection Research

P.Y. Yu, F.G. Chen, R. Guo, H.F. Hao, P.F. Liu, L. Miao, P. Qiao
CIRP, Xiaodian District, People’s Republic of China

The Accelerator-based Facility for Radiation Protection Research is a large research infrastructure constructed by China Institute for Radiation Protection. It consists of three accelerators and eight experimental terminals. As a main part of the facility, the tandem accelerator has a terminal voltage of 6 MV and the energy spread is less than 0.05%. By using three types of ion source, it could provide beams for example 50 ¿A for proton, 2 ¿A for He and 3 ¿A for Au at the target. The 4MV single-ended dynamitron accelerator is capable to produce H, D and He beams with a current of 60~100 ¿A. The 400kV ion planter can deliver particle beams from proton to Au and the maximum current for proton could reach 500 ¿A. Among the eight experimental terminals, four are used to construct neutron radiation field and one for photon radiation field. The other three are ion beam experimental terminals, which includes a microbeam terminal, a triple beam irradiation terminal and a terminal which connects the beamline with the TEM for in-situ observation of materials. The facility is currently under construction and is expected to be fully completed and open to experimental users by mid-2027.

Cite •

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

TUPB021

The Design of a Proton-Heavy Ion Hybrid Synchrotron Upgraded from XiPAF Proton Ring

129

H.J. Yao, Y. Li, X.Y. Liu, X.W. Wang, Z.J. Wang, S.X. Zheng
TUB, Beijing, People’s Republic of China
Z.M. Wang
NINT, Shannxi, People’s Republic of China

Xi’an 200MeV Proton Application Facility (XiPAF) has been basically completed at the end of 2020, providing proton beams of 10 to 200 MeV for space radiation effect studies on electronics. To expand its capabilities, XiPAF is undergoing an upgrade to deliver multiple ion species, from proton to Bismuth ion. The upgrade focuses on three aspects. First, the original negative hydrogen linear injector will be remodeled to a proton linear injector. Second, a heavy ion linear injector will be added. Third, the existing proton ring will be retrofitted into a hybrid proton-heavy ion synchrotron. Correspondingly, the beam transport lines will also be modified. This paper details the considerations and physical designs for upgrading the synchrotron. Within the scope, we discuss the challenges and solutions in transforming a specialized proton synchrotron into a multi-ion accelerator under the constraints of existing plant layout and reuse of existing equipment.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB021

About •

Received ※ 29 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 20 September 2024

Cite •

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

TUPB022

Observation of Pilot H⁻ Beam in high power proton linac

D.Y. Jia, H. Jia, Z.J. Wang
IMP/CAS, Lanzhou, People’s Republic of China

Chinese ADS Front End (CAFe) is a demo high-power proton superconducting linac for ADS project. During high-power beam commissioning of CAFe, unexpected irradiation dose was observed at the vacuum valve at the exit of the dipole magnet opposite to the proton beam deflection direction. The reason of the irradiation cannot be explained by neutron induced reaction or the operation history of the dipole magnet. A gamma-ray analysis of radionuclides is performed with the wipe sample from the valve, excluding the possibility of the neutron induced activation and verifying the proton induced reaction. Thus, it is supposed that H¿ beam is generated at the low energy transport section and accelerated simultaneously with proton beam in the superconducting linac. In this paper, The accelerating efficiency of pilot H⁻ beam is studied with multi-particle simulation software, Tracewin. The yield of H⁻ beam is obtained by cross section calculation of proton beam with residual gas at low energy transport section. The accumulated dose at the vacuum valve is calculated by FLUKA code and compared to the simulation result.

Cite •

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

TUPB023

Beam Instability and mitigation in CSNS/RCS

L. Huang
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: Work supported by the Guangdong Basic and Applied Basic Research Foundation, China (2021B1515140007)
The Rapid Cycling Synchrotron (RCS) in the China Spallation Neutron Source (CSNS) is a high-intensity synchrotron accelerator that has experienced instability, which limits the machine’s performance. Systematic research was conducted during beam commissioning and machine studies, identifying it as head-tail instability, and multiple mitigations were successfully implemented. The RCS impedance was thoroughly evaluated through simulations and impedance measurements, identifying the source of the instability. This report also discusses the challenges of beam instability as the power of the RCS will significantly increase in the CSNS-II.

Cite •

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

TUPB024

Electron Cooling for Future High-energy Hadron Accelerators

133

H. Zhao
IMP/CAS, Lanzhou, People’s Republic of China

Funding: National Natural Science Foundation of China (No. 12275323)
Electron cooling is an important method to reduce the emittance and momentum spread of hadron beams, and it has been successfully applied in several facilities around the world. In 2019, the world¿s first RF-based electron cooler (LEReC) was commissioned at BNL for the RHIC BES-II project, and the integrated luminosity of RHIC is finally doubled. In addition, electron cooling is also a must for the future Electron-Ion Collider (BNL EIC). However, the high energy requirement of the electron beam (150 MeV) is far beyond what all present coolers can achieve (<4.3 MeV). For that, an electron ring cooler with strong radiation damping is proposed and designed, in which the non-magnetized and dispersive cooling techniques are applied. In this talk, I will introduce the experimental and simulation results of the two facilities. Mainly, I will introduce several new phenomena that were first observed in LEReC, such as the beam heating effect and the ion beam focusing effect. Besides, some new theories that were developed for the ring cooler will also be discussed.

Poster TUPB024 [1.769 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB024

About •

Received ※ 04 July 2023 — Revised ※ 09 July 2023 — Accepted ※ 11 July 2023 — Issued ※ 14 December 2023

Cite •

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

TUPB025

Influence of Transverse Distribution of Electron Beam on the Distribution of Proton Beam in the Process of Electron Cooling

137

X.D. Yang
IMP/CAS, Lanzhou, People’s Republic of China

Funding: National Natural Science Foundation of China No.12275325
The electron cooling process of 20GeV proton beam in EicC was simulated for the eight transverse distribution of electron beam with the help of electron cooling simulation code. The transverse cooling time was obtained in the different transverse distribution of electron beam. The final transverse distribution of proton beam was demonstrated. The simulated results reveal that the transverse distribution of electron beam influences the distribution of proton beam in the process of electron cooling. In the future, this idea was expected to apply to the longitudinal distribution of electron beam. The longitudinal distribution of proton beam was attempted to be controlled by the longitudinally modulated electron beam. As a result, the peak current and longitudinal distribution of proton beam will be controlled by the electron beam. The loss of proton beams will be reduced, and the stored lifetime of proton beam in the storage ring will be extended. The intensity of the proton beam will be maintained for a longer time.

Poster TUPB025 [2.048 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB025

About •

Received ※ 28 June 2023 — Revised ※ 09 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 06 June 2024

Cite •

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

TUPB026

Design of a Synchrotron for Proton FLASH Radiotherapy Based on Fast Variable-Energy Bunch Splitting

141

Y. Li, X.W. Wang, Q.Z. Xing, H.J. Yao, S.X. Zheng
TUB, Beijing, People’s Republic of China

Ultra-high dose rate (FLASH) radiotherapy not only guarantees effective tumor treatment but also greatly enhances the protection of normal tissue. Moreover, it is a convenient procedure for tumor patients that has enhanced the benefits provided by medical institutions. Proton FLASH radiotherapy, which combines the Bragg peak effect of proton spatial dose distribution with the unique temporal effect advantage of FLASH, is an attractive tumor treatment approach. To achieve proton FLASH discrete pencil beam scanning in a 1-L volume, taking into account the 5-mm point interval, 9261 points would need to be irradiated within 500 ms, which is beyond the capability of existing medical devices. To meet these requirements, based on a fast cycle synchrotron with a period of 25 Hz, we simultaneously combined variable-energy, fast splitting, and extraction beam bunches, and proposed a scanning method suitable for continuous variable-energy extraction bunches. The proposed technique meet the requirements of proton FLASH discrete pencil beam scanning within a volume of 1 L.

DOI •

reference for this paper ※ doi:10.18429/JACoW-SAP2023-TUPB026

About •

Received ※ 29 June 2023 — Revised ※ 10 July 2023 — Accepted ※ 12 July 2023 — Issued ※ 28 May 2024

Cite •

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