Simulation of a cw positron source for cebaf

A positron source for the 6 GeV (and 12 GeV upgrade) recirculating linacs at Jefferson Lab is presented. The proposed 100 nA CW positron source has several unique characteristics; high incident electron beam power (100 kW), 10 MeV/c incident electron beam momentum,CW incident beam and CW production. Positron production with 10 MeV/c electrons has several advantages; the energy is below neutron threshold activation so the production target and the optical system will not become activated during use; CEBAF requires a very low energy spread, so the absolute energy spread is bounded by the low incident energy. These advantages are offset by the large angular distribution of the outgoing positrons. Results of simulations of the positron production and capture are presented. Energy flow, power deposition and thermal management of the elements present a challenge and are included in the simulations.