Recently, the ICON-NMR queue on BigSur has been failing more often than usual. Sarah traced these errors to spinning problems. She tried our usual methods (recalibrating spins) to solve this problem. However, error messages still disrupt the queue. This afternoon, I took more drastic measures. I removed the probe to check for a cracked insert. The quartz insert was fine. Then, with help from Nadia of the APL lab I removed the shimstack.
HOLY COW. It was the most gunked up shimstack I have ever see. I'm shocked samples would spin at all. I cleaned the shimstack and reinserted into the magnet. After a 3D topshim (presumably necessary because I didn't get the shimstack back into the magnet at the same angle I took it out) I tested the shims on the lineshape sample. My results are 0.28; 3.5/10.9, just missing spec. But close enough to use.
Justin
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