Shimming with UXNMR
Alan Boyd (cheasfb@bonaly.hw.ac.uk)
Fri, 27 Oct 95 10:54:08 BST
Dear Bruker Users,
Here is a problem which has puzzled me for some time,
and for which Bruker has so far not provided an answer. It concerns
computer shimming using the simplex method with UXNMR. In the 1991
UXNMR manual, p.423, it is stated that the SET command is used to
define the 'maximum allowed step width' of a shim gradient. Hoewever
in the example shim program provided, (called by Bruker a 'tune file'),
version 1.3 dated 910319, it states that the SET command is used to set
the 'smallest step size used'.
Now, I don't think it can be both. My own
observation of the values shown by the computer and the BSMS unit
during the shimming operation lead me to think that it is neither.
Considering that shimming a magnet is the most tedious and tiresome
chore that can be suffered, good control of computer shimming is
essential if any vestige of sanity is to be retained after the damage
done by the rest of UXNMR. Therefore, can anyone shed any light on
this particular piece of Bruker doublespeak?
Best wishes,
Alan
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UXNMR - its fundamental design flaws are completely
hidden by its superficial design flaws
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Dr A S F Boyd Chemistry Department
NMR Spectroscopist Heriot-Watt University
phone: +44-131-451 3214 Riccarton
fax: +44-131-451 3180 Edinburgh
cheasfb@bonaly.hw.ac.uk EH14 4AS
http://dava.che.hw.ac.uk/ Scotland
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