Hi,
I am becoming an old man with all consequences. -(
So please excuse my Alzheimer.
1. The process described don't happen from today until tomorrow. With a high probability we had the effect twice (no elaborate investigation first time but same observations). It required 7 (first time) or 8 (second time) years to appear.
2. I pointed to high field spectrometers. Of course that's our observation. But I have the feeling to know the reason. The shim coils itself act as a heater, of course shim current dependent. The coils are wound around an aluminium body, which moves the heat up and downward from the coils. And: the higher the field the longer the aluminium body without heating coils ...
Greetings
Rainer
Received on Sat Sep 22 2012 - 02:54:15 MST