Experimental results of the shift bump magnet in the J-PARC 3-GeV RCS

Takayanagi, Tomohiro   ; Ueno, Tomoaki; Irie, Yoshiro; Kinsho, Michikazu  ; Takeda, Osamu; Yamazaki, Yoshishige; Yoshimoto, Masahiro  ; Kamiya, Junichiro   ; Watanabe, Masao  ; Kuramochi, Masaya

The shift bump magnet produces a fixed main bump orbit to merge the injection beam into the circulating beam. In order to control the injection beam for the short injection time (500 microseconds) with sufficient accuracy, the shift bump magnet needs a wide uniform magnetic field and the high speed exciting pattern of the high current. The magnetic field design and the structural analysis of the shift bump magnet have been performed using the three-dimensional electromagnetic analysis code and the mechanical analysis code, respectively. The magnetic field distributions were measured with a long search coil, thus giving a BL product over the magnet gap area. The temperature distributions at the various points of the magnet were measured by the thermocouples over 24 hours till they saturated. General trend of these measurements agrees well with calculations.