The Doublet III Neutral Beam Source Cryopanel System
A cryogenic pumping system is designed to provide 1.4 × 106 l/sec. of hydrogen pumping speed for the Doublet III neutral beam ion source. The cryopump is made up of two elements; a cylindrical unit which uses a "Santeler" type of liquid nitrogen shield and a flat chevron shielded disk. Liquid helium and liquid nitrogen are circulated by forced flow. The liquid helium is circulated at 0.6 atm absolute pressure for cryopump operation at 3.8°K.