Modeling of an RF electron accelerator

Summary form only given, as follows. An RF e-beam accelerator intended to eventually yield a high-energy (100-MeV), high-current (hundreds of amperes), short-pulse (tens of picoseconds), and low-emittance (25π mm-rad, normalized) electron beam for use in a free electron laser has been modeled. The design approach relies upon RF focusing by photocathode shaping to minimize the number of injector focus solenoids. The simulation code ISIS models particle motion within the first two injector RF cavities, where space charge effects are most significant and need to be treated precisely. Body-fitted coordinates in the ISIS code make modeling variations of the RF cavity shapes particularly straightforward. A scheme for initializing RF cavity fields in ISIS was used. The particles are followed into the remainder of the accelerator (through RF cavities. solenoids and quadrupole focus magnets, drifts, bends, etc.) using an e-beam accelerator code PARMELA. This combination of codes provides the requisite accuracy and flexibility needed to optimize the large number of design parameters involved