Jerry,
This is one of my main concerns. EPR spectrometers, at least the simple
ones like ours, are field sweep instruments. They are routinely swept over
hundreds or even thousnads of gauss. One is relying on the fact that most
of the flux is in the iron yoke of the EPR magnet. I was quite surprised to
find that none of the labs that have EPR's near NMR's have experienced any
problems. My supposition is that the stray field from the EPR doesn't make
much inhomogeneity and the lock takes care of the field shift. Noone
reported having done the test to see if the NMR lines move or the lineshape
changes when the NMR is unlocked and you run the EPR field up and down. We
sometimes run unlocked for one reason or another. If anyone has or is
willing to run such a test, I'd be very interested.
Charlie
Charles L. Mayne
University of Utah
Dept. of Chemistry
B103 HEB
Salt Lake City, UT 84112
Voice: (801)581-7413
FAX: (801)581-4763 or 8433
E-mail: mayne@chemistry.utah.edu