The system has a new Oxford Type 3 cryostat and 400/54 magnet that was
drop-shipped to our facility in June. Installation started on Aug. 1.
The vacuum on the dewar was in the E-6 range before filling with liquid
nitrogen. The Varian installer reports that removing nitrogen from the
helium can took considerably longer and consumed more He gas than
"normal." Now, on liquid helium transfer, the plume suggests the dewar
is full but flutter tube measurements indicate LT 50% fill and the
liquid level is not increasing in the magnet dewar.
Amy Abe
Lake Forest College
708-735-5089
abe@lfmail.lfc.edu