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Performance of Doublet III neutral beam injector cryopumping system

Journal Article · · J. Vac. Sci. Technol., A; (United States)
DOI:https://doi.org/10.1116/1.572700· OSTI ID:6730627
The Doublet III neutral beam injector system is based on three beamlines; each beamline employs two 80 kV/80 A hydrogen ion sources. Two liquid helium (LHe) cooled cryopanel arrays were designed as an integral part of the beamline in order to provide high differential pumping of hydrogen gas along the beamline. The cryopanel arrays consist of a front (nearer to the torus) disk panel (3 m/sup 2/ each side) with liquid nitrogen (LN/sub 2/) cooled chevrons and a rear cylindrical panel of modified Santeler panels (8 m/sup 2/) which also employs LN/sub 2/ cooled surfaces shielding LHe cooled surfaces. These cryopanels are piped in series. The LHe delivery is based on a closed-loop, forced-flow scheme intended for variable panel temperatures (3.7 to 4.3 K). It uses small tubes for mechanical flexibility and thermal resiliency providing ease of economic defrosting. The cryogenic system consists of a liquefier (100 l/h), a large Dewar, a heat exchanger, and a liquid ring pump. Three beamlines are serviced simultaneously by the system. Pumping speeds measured locally at ionization gauges, were well in excess of the 1.4 x 10/sup 6/ l/s design goal.
Research Organization:
GA Technologies Inc., San Diego, California 92138
OSTI ID:
6730627
Journal Information:
J. Vac. Sci. Technol., A; (United States), Journal Name: J. Vac. Sci. Technol., A; (United States) Vol. 2:2; ISSN JVTAD
Country of Publication:
United States
Language:
English