1-MW beam operation at J-PARC RCS with minimum beam loss

J-PARC RCSにおけるビーム損失を最小限に抑えた1MWビーム運転

Saha, P. K.   ; 原田 寛之  ; 岡部 晃大  ; 沖田 英史  ; 菖蒲田 義博   ; 田村 文彦   ; 山本 風海   ; 吉本 政弘  ; 發知 英明*

Saha, P. K.; Harada, Hiroyuki; Okabe, Kota; Okita, Hidefumi; Shobuda, Yoshihiro; Tamura, Fumihiko; Yamamoto, Kazami; Yoshimoto, Masahiro; Hotchi, Hideaki*

In the 3-GeV RCS of J-PARC we have performed a systematic experimental studies and numerical beam simulations to minimize the beam loss at the designed 1 MW beam power. We have optimized and modified both longitudinal and transverse injection paintings and succeeded obtaining a significant beam loss mitigation throughout the RCS. The beam loss at the collimator and the 1st arc section is reduced to be as much as more than 60% as compared to that using original painting methods. The residual beam loss at 1 MW is estimated to be as low as well below than 0.1%, which is dominated by the beam loss caused by foil scattering of the circulating beam. As a result, we obtained a very stable user operation of the RCS with nearly 1 MW beam power to the MLF with low beam loss and less machine activation.