Experimental verification of magnetic field measurement probe for RCS bump magnet

Sugita, Moe ; Ueno, Tomoaki*; Horino, Koki*; Takayanagi, Tomohiro   ; Ono, Ayato; Yamamoto, Kazami   ; Kinsho, Michikazu  

In the J-PARC 3 GeV Rapid Cycling Synchrotron (RCS), shift bump magnets are used to merge the injection beam from the LINAC with the circulating orbit of the RCS. The bump magnets are excited with a trapezoidal pulse waveform, that the rise / fall time and the duration of the flat part can be changed. The injection bump orbit is created by the pulse waveform to inject a 1 MW, high intensity beam at a repetition rate of 25 Hz. An issue to achieve the 1 MW beam is suppression of the beam loss. Therefore, a requirement of the accuracy of the magnetic field is less than 0.2%. Since the time structure of the pulse is so fast, we needed a test to select a magnetic probe with a suitable response. In this report, we will show the results of comparing the search coil, Hall probe and integral flux meter. The result indicated that the integral flux meter with a small measurement error is suitable.