Hello All,
I also encountered similar problems.....When a probe was replaced the
shimming changed. Regardless if the original probe was re installed.
After many days of trouble shooting we found that there was a piece of
magnetic material in the LN2 can. I guess, some time before I had arrived
there was an ice block that needed to be cleared. We assumed something got
left in the can that was magnetic.
We were able to confirm this by the following method........Use a large
piece of magnetic material, and try to make the loose part move while the
probe is shimmed and in place. Obviously if there is a change in the shims,
you have something loose in the magnet.
Good luck
Arnold C.Itkin
NMR Associates
978-632-0312
978-852-8316 Cell
nmr.associates_at_att.net
Professional NMR Products, and Services
Received on Sat Apr 13 2002 - 09:14:41 MST