A Kicker impedance reduction scheme with diode stack and resistor at the RCS in J-PARC

Shobuda, Yoshihiro   ; Harada, Hiroyuki  ; Saha, P. K.   ; Takayanagi, Tomohiro   ; Tamura, Fumihiko   ; Togashi, Tomohito; Watanabe, Yasuhiro ; Yamamoto, Kazami   ; Yamamoto, Masanobu   

At the 3-GeV Rapid Cycling Synchrotron (RCS) within the Japan Proton Accelerator Research Complex (J-PARC), kicker impedance causes beam instability. A 1-MW beam with a large emittance can be delivered to the Material and Life Science Experimental Facility (MLF) by suppressing beam instabilities without the need for a transverse feedback system - simply by turning off the sextuple magnets. However, we require other high-intensity and high-quality beams with smaller emittances for the Main Ring (MR). To address this, we proposed a scheme for suppressing the kicker impedance using a diode stack and resistors, which effectively reduces beam instability. Importantly, these devices have a negligible effect on the extracted beam from the RCS.