Very high-field short-pulse dipole magnet for compact proton synchrotron

Design of a short-pulse dipole magnet for a compact proton synchrotron dedicated for cancer therapy is presented. Its pulse width and maximum magnetic field are 7 [ms] and 4 [T], respectively. Sextupole coefficient is reduced to 4×10^-4 (32 [T/m²]) at 4 [T] by the optimization of the magnet geometry, which is estimated to be sufficiently small for beam acceleration. Laminated silicon steel ( thickness of 1 [mm]) is enough to suppress the eddy current effect in the yoke and B-constant shape rather than Rogowski´s curve is adopted at the end of the magnet