Beam optical system of the polarized electron source of the Amsterdam pulse stretcher AmPS

The beam optical system of a Polarized Electron Source (PES) is described. The PES is used for nuclear physics experiments with internal gas targets o n the MEA-AmPS acceleration facility at NIKHEF. The PES beam optical system consists of a 100 keV photoelectron gun, a 100 keV beam line, and a 400 ke V post-accelerator. Both the electrostatic and the beam trajectory calculat ions in the gun have been performed with the SAM code. To calculate the bea m envelope in the PES beam line the MAD code was used. The input for MAD wa s obtained from beam trajectory calculations in the gun, extrapolated for a beam with non-zero initial emittance, Results of the beam line performance test are given. (C) 1999 Elsevier Science B.V. All rights reserved.