Hi guys,
The biggest problem for good vacuum in transfer lines is helium in the vacuum
region of the transfer line. Everything else, except maybe for hydrogen gas
should cryopump out once liquid helium started flowing through the line.
after several rounds of evacuating the transfer line, it is a good idea to
let dry air or nitrogen into the transfer line before hooking it up to the
vacuum pump. The nitrogen will help in 'dragging' the helium gas out as the
line is evacuated.
Cheers
Yong-Wah Kim
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Received on Tue Aug 05 2025 - 11:00:38 MST