A permanent-magnet focused X-band photoinjector

A Plane-Wave-Transformer (PWT), integrated photo-injector operating at an X-band frequency (8.547 GHz) is being developed by DULY Research Inc. in a DOE SBIR project, in collaboration with UCLA and UCD/ILSA. Upward frequency scaling from an S-band PWT photo-injector would result in a compact photo-injector with unprecedented brightness. Challenging technological innovations are required at X-band. In particular, water cooling capacity, mechanical support strength, and materials properties do not scale linearly with frequency. Instead of using large solenoids, we have successfully designed the required focusing for an X-band PWT using a compact, permanent magnet system. Also described in this paper is a system design of the X-band photo-injector, including the RF system and the cooling/support of the PWT structure.