State-of-the-art beam loss minimization at high-intensity beam operation of the 3 GeV rapid cycling synchrotron at the Japan Proton Accelerator Research Complex

J-PARC 3GeVシンクロトロンの高強度ビーム運転における最先端のビーム損失最小化

Saha, P. K.   ; 原田 寛之  ; 田村 文彦   ; 岡部 晃大  ; 吉本 政弘  ; 菖蒲田 義博   ; 沖田 英史  ; 小島 邦洸 ; 仲野谷 孝充  ; 畠山 衆一郎; 高柳 智弘   ; 山本 風海   ; 發知 英明*

Saha, P. K.; Harada, Hiroyuki; Tamura, Fumihiko; Okabe, Kota; Yoshimoto, Masahiro; Shobuda, Yoshihiro; Okita, Hidefumi; Kojima, Kunihiro; Nakanoya, Takamitsu; Hatakeyama, Shuichiro; Takayanagi, Tomohiro; Yamamoto, Kazami; Hotchi, Hideaki*

In this research, the beam loss in the J-PARC 3-GeV Rapid Cycling Synchrotron (RCS) has been significantly mitigated at the designed 1 MW beam power. It was possible by identifying all beam loss sources and implementing appropriate measures based on numerical simulations and systematic beam studies. The major one includes of using a smaller size charge-exchange foil and optimizing the injection beam to minimize foil scattering uncontrolled beam loss, modifications of the transverse and longitudinal beam painting parameters to mitigate the high-intensity effects. The beam loss as compared to 1 MW trial operation in 2020 was 80% reduced and perfectly localized at the designated collimator area. The beam loss power is only less than 0.1 kW as compared to the collimator limit of 4 kW. As a result. the residual radiation throughout the ring is substantially reduced for achieving a sustainable operation of the RCS with nearly 99% availability.