Design improvement of bipolar correction magnet with permanent magnets

Kuriyama, Yasutoshi*; Iwashita, Yoshihisa*; Fuwa, Yasuhiro   ; Terunuma, Nobuhiro*

We are developing a correction magnet for charged particle beams using permanent magnets. By rotating the rod of the permanent magnet that generates the magnetic field, the magnetic field can be changed to bipolarity. To verify the principle of this bi-polarity change, a prototype was built, and its performance was evaluated. The performance evaluation of the prototype machine revealed that the inhomogeneity of the remanent magnetization of the permanent magnet has a significant effect on the multipole component. To suppress this effect, a compensating magnet with additional anisotropic intermediate poles is being considered.