Measurement of emittance at CSNS ion source without analyzing magnet

Shengjin Liu; Yongjia Lv; Fang Li; Huafu Ouyang; Yongchuan Xiao; Kangjia Xue; Xiuxia Cao; Weidong Chen; Ruiyang Qiu; Shunming Liu; Hui Li; Renli Zhu

doi:10.1007/s41605-021-00307-z

Volume 6 Issue 2

Jun. 2022

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Abstract

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Radiation Detection Technology and Methods > 2022 > 6(2): 209-213 > doi: 10.1007/s41605-021-00307-z CSTR: 32043.14.s41605-021-00307-z

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Measurement of emittance at CSNS ion source without analyzing magnet

Shengjin Liu^1,2, ,,
Yongjia Lv^1,2,
Fang Li^1,2,
Huafu Ouyang^1,2,
Yongchuan Xiao^1,2,
Kangjia Xue^1,2,
Xiuxia Cao^1,2,
Weidong Chen^1,2,
Ruiyang Qiu^1,2,
Shunming Liu^1,2,
Hui Li^1,2,
Renli Zhu^1,2

1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, China;
2. Spallation Neutron Source Science Center, Dongguan, 523803, China

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This work was supported by the Program of National Natural Science Foundation of China Grant No. 11875271

More Information

Received Date: July 03, 2021
Revised Date: November 30, 2021
Accepted Date: December 01, 2021
Available Online: October 17, 2022
Published Date: January 23, 2022

Abstract

Abstract

Purpose High current beam is required for CSNS update in future. Over 50 mA H⁻ will be designed to deliver to the linac in CSNS II. For the present state of CSNS ion source, the beam emittance cannot satisfy the requirement of RFQ entrance at the 50 mA H⁻ beam. In order to improve the beam quality, CSNS ion source is required further improvement.
Methods Simulation shows emittance growth due to the space charge force in the intense H⁻ beam when the beam transports through the analyzing magnet. After considering the neutralization of space charge, the emittance growth could be suppressed. The analyzing magnet thus is considered to removed, which might destroy the neutralization of space charge. The beam emittance is measured at the revised CSNS ion source.
Results Measured results show that beam emittance without the analyzing magnet becomes smaller than that of CSNS ion source. At the requirement of 0.2 πmm mrad, beam current is larger than 30 mA. It reveals that analyzing magnet could destroy space charge neutralization and result in the significant increase of emittance.
Conclusions Although the results presented are preliminary, it is important to improve the beam quality. This paper details the ion source improvement and measurement process.
- CSNS ion source,
- Beam emittance,
- High current pulse beam,
- Analyzing magnet

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References (4)

References

[1]	J. Wei et al., China spallation neutron source: design, R&D, and outlook. NIMA 600, 10–13 (2009)
[2]	S. Liu, T. Huang et al., Status of CSNS H- ion source. Chin. Phys. C 39, 057008–057011 (2015)
[3]	S. Yamazaki, K. Ikegami et al., Operation and development status of the J-Parc ion source. Rev. Sci. Instrum. 85, 02B136 (2014)
[4]	Allison, P., Smith, H. V., Sherman, J. D.: Proceedings of the International Symposium on the Production and neutralization of Negative Ion Beams, New York (1980)

Shengjin Liu, Yongjia Lv, Fang Li, et al. Measurement of emittance at CSNS ion source without analyzing magnet[J]. Radiation Detection Technology and Methods, 2022, 6(2): 209-213. DOI: 10.1007/s41605-021-00307-z

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