SPEAKING OF MY VXR....my vacuum (Indium) seals are shot again, and
my man from Varian is coming out to do another $10,000 seal, pump, and
re-energize job...(second time in UNDER 2 years!!!!)...OUCH! Varian
has this policy of ONLY rough-pumping warm magnets, prior to adding cryogens,
and I think it's pretty dumb. It seems to me that if PV=nRT, and you get
a couple of more decimal places out of "P", and IF the diffusion rate which
increases "n" is roughly constant, it would really help to put a turbo, or
diff. pump on there!! I KNOW that there's no mylar in there, ...and all of
the other standard Varian lines, but I haven't heard a reasonable argument
against pumping to high vac. yet.
I would be interested in hearing from other R2D2 magnet owners who have
an opinion on this issue....I might be off the wall on this, but (frankly)
it seem to me that Varian is just trying to make excuses to save a few bucks
on pumping stations (IMHO, of course). I must also admit that my current
opinion may be slightly clouded by my having to dish out another $10K in only
a year and a half after the last time!
Best Regards (I don't have the time, nor the desire to try to compete
with Bill's Santa-n-Sleigh signoff!)
Richard Shoemaker, Ph.D. Phone--(402) 472-6255
Instrumentation Director, Chemistry FAX---- -9402
University of Nebraska-Lincoln