Hello,
Following my previous inquiry regarding construction around high field magnets, to which most people said, as we also felt, the less work involving moving metal around in the 5-gauss perimeter the better, that is done the better. Although depending on exactly what is done and where, we may just experience some downtown, but no permanent ill-effects. I now have a question regarding people's experience with retouching cyroshims.
As part of the renovations in our building, architects would like to remove a large metal gantry, part of which definitely sits within the 5-gauss line of our vector-shielded, pumped, 800 MHz magnet. To my knowledge, there were no difficulties bringing the magnet up to field, or getting it shimmed, due to its presence. However, we have been told that removing it would likely result in a need to touch up the cryoshims. The construction budget will cover the associated costs, however we are concerned about opening up our 11-year old magnet when it could be avoided.
We have already had one cyroshim, which suddenly quenched for an unknown reason, redone 3 years ago. That work was done without incident, and the magnet and shims been stable since.
Have any among you had cryoshims (especially on an older, high-field, magnet) redone due to changes in the building/environment around your magnet? Was it a piece of cake, or a long-drawn out hassle?
Thanks for any input,
Tara Sprules
Quebec/Eastern Canada High Field NMR Facility
Montreal, QC
Received on Sat Mar 22 2014 - 09:08:10 MST