Beam instability suppression in the 3-GeV RCS of J-PARC

J-PARC 3GeVシンクロトロンにおけるビーム不安定性の抑制

Saha, P. K.   ; 菖蒲田 義博   ; 發知 英明  ; 原田 寛之  

Saha, P. K.; Shobuda, Yoshihiro; Hotchi, Hideaki; Harada, Hiroyuki

The transverse impedance of the extraction kicker magnets is a significant beam instability source in the 3-GeV RCS of J-PARC. The ORBIT code was successfully updated for space charge and beam instability simulations by introducing all realistic time dependent machine parameters. The simulation results showed very critical beam instability situation, especially for the designed 1 MW beam power. Systematic simulation and measurement studies were performed in order to determine a realistic strategy to accomplish 1 MW beam power. The simulation results were well reproduced in the measurements, while an acceleration of 1 MW beam power has also been successfully accomplished. Recently, further suppression of the beam instability for a flexible choice on the parameter space in order to improve the extraction beam quality is also studied.