Back in April/May this year, there was a lot of discussion of soft vacuums
(vacui/vacua?), high He boiloff, and quenches. The general flavor of this
was that one should monitor the He boiloff as an indicator of magnet
health.
My (possibly related) question is: Under what circumstances might one
expect higher-than-normal N2 boiloff ? We seem to be experiencing this on
our Oxford/GN-300 widebore - 1986 vintage. I haven't verified it with a
dipstick, but the level meter rate of change has gone from about 7% per day
a year or more ago, to about 11% per day now. He consumption remains
normal.
If I get some responses I'll try to summarize.
Thanks!
Carl Gregory
Biomedical Magnetic Resonance Laboratory
College of Medicine
University of Illinois
1307 W Park St
Urbana, IL 61801
TEL: (217)-244-2350, 244-0600, FAX: 244-1330