Workshop on Polarized Electron Sources and Polarimeters

eam dump. The main purpose of the simulations is to minimize beam losses,
especially in the gun vicinity. The losses are required to be less than 10 -6 in the first
straight section and less than 10 -5 in the rest of the beam line with different emission
pattern (flat-shaped beam, Gaussian beam, ring-shaped beam).
Additionally, the ion trajectories are calculated and the expected damage pattern
estimated. The gun geometry and the emission pattern will be optimized to reduce the
overlap of the emission pattern and the damage pattern.
A special test chamber is designed to study the cathode cooling. The cooling agent
(fluid with very low electrical conductivity) will be delivered to the cathode via
ceramic tubes. High Voltage and Ultra High Vacuum compatibilities will be tested, as
well as a cooling efficiency.
ACKNOWLEDGMENTS
The work is partially supported by DOE grant DE-FG02-94ER40818. The author
would like to thank the staff of Bates laboratory for a constant help and support. The
author is grateful to C. Sinclair for his comments.
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