Dear Perry,
We have Bruker 400/54, 600/54 & Oxford 400/89, 500/54 magnets. The oldest magnet have been worked since 1994.
In my experience and operation practice, the Helium evaporation rate is very consistence. You may ignore the level meter and build up your own calibration curve by manual measurement with the dip measurement tube. Plot the depth via time frame.
In most case, I switched off the helium meter to save Helium lost in each automatic measurement.
Best regards,
Alfred Kwan
>>> "Pellechia, Perry" <pellechia_at_mail.chem.sc.edu> 13/1/2010 23:21 >>>
Hello all,
I have two magnets (Bruker 300/52 & Oxford 400/54) that have older analog
Oxford Helium level meters and for some reason neither can be properly
calibrated to give accurate readings. We have lived with this situation for
several years and tried multiple times to calibrate them but can only
conclude they will not work with the probes we have. I have been
considering new Oxford ILM210 meters for these magnets but really do not
want to spend over $2600 for each.
My research came up with several alternatives that include:
American Magnetics Inc. 135 series
Cryomagnetics Inc. LM-500
Scientific Magnetics HLM
However, none of these can provide the necessary current to drive the probes
that we have (Bruker ~120mA ; Oxford 100-115mA).
I also found an item on a German website that looks promising but this is
the only place where I have seen this unit.
http://www.nmr-service.de/?Supplies_%26amp%3B_Accessories:Helium_Level_Meter
_ILM-300
http://tinyurl.com/ykkmjaa
If anyone out there in AMMRL land has this meter I would appreciate your
opinions on it and if you know of other sources. I would also be interested
in hearing if you have any alternatives that I might have missed. Finally,
if anyone has an unused meter(s) and would be interested in
donating/selling/bartering I would be interested in that too.
Thanks,
Perry.
--
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Perry J. Pellechia
Director of NMR Services
University of South Carolina
Department of Chemistry and Biochemistry
<mailto:pellechia_at_sc.edu>
<http://homer.chem.sc.edu/perry>
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Received on Wed Jan 13 2010 - 19:36:48 MST