Design of the pulsed dipole magnet for KEK electron/positron injector linac 24-degree beam merger line

This paper reports on the design study of the pulsed bending magnets for the 24-degree beam merger line of the two pre-injectors in the KEK electron/positron injector linac. These pulsed bending magnets are indispensable for pulse-by-pulse switching of the beams from the pre-injectors. The existing pulsed bending magnets are operated less than or equal to 25 Hz to mitigate excessive heating in the coils. It is lower than the maximum beam repetition 50 Hz and restricts flexible beam switching. We are designing new pulsed bending magnets operable at 50 Hz pulse repetition. Details of the design study are described. (author)