High intensity beam trial of up to 540 kW in J-PARC RCS

Hotchi, Hideaki  ; Harada, Hiroyuki  ; Hayashi, Naoki  ; Kinsho, Michikazu  ; Saha, P. K.   ; Shobuda, Yoshihiro   ; Tamura, Fumihiko   ; Yamamoto, Kazami   ; Yamamoto, Masanobu   ; Yoshimoto, Masahiro  ; Irie, Yoshiro*; Kato, Shinichi*

In November 2012, we have performed a high intensity beam trial of up to 540 kW. The beam loss for 540 kW intensity beam was well reduced from 30% to 2% by injection painting. This remaining beam loss of 2%, arising from foil scattering and 100-kHz field ripple induced by injection bump field, corresponds to 650 W in power, which is still less than 1/6 of the current collimator capability of 4 kW. The numerical simulation well reproduced the experimental results. Accelerator modelling and quantitative benchmarking between experiment and numerical simulation becomes feasible. The numerical simulation very much helped us to understand the mechanism of observed beam loss. Also several beam loss mitigation ideas were proposed with a help of numerical simulation and verified by experiment.