Optimization of the pole shape for corrector quadrupole magnet in the J-PARC 3-GeV RCS

Tani, Norio  ; Watanabe, Yasuhiro  ; Hotchi, Hideaki  ; Takayanagi, Tomohiro   ; Togashi, Tomohito; Horino, Koki

Field measurement was implemented in order to confirm performance of the pulse corrector quadrupole magnet (QDT) in the RCS. A result of the field measurement showed a 20% difference against the design value. We investigated the cause and made a study to restore the performance. We challenged a new approach to install shims on the pule magnet. Shims were produced with a laminating steel sheet. We found the permissible value by field calculation in as installation accuracy greatly depended on the performance. A shim has a sharp and long edge with a complicated shape. Therefore it was difficult to make a structure that can tolerate installation works. We made various trial manufactures and adopted a processing method with an adhesion steel sheet. The homogeneity of field became less than 1% by measurement and a QDT which laminated shims were installed showed a fully satisfactory performance. In this presentation I will report optimization of the pole shape and the result of the field measurement carried out afterward.