I encountered a problem with our 600 MHz NMR instrument. When acquiring the line shape sample, while spinning, the chloroform peak is split into lines, each one 20 Hz apart (speed at which the sample is spun). Without spinning, the peak is very, very broad. I contacted our service engineer and it seems that there is a dropped cryoshim on the magnet. What exactly does that mean? How could it have happened and can it be corrected? The service engineer will help my tomorrow, but I am just curious in the mean time of what could have gone wrong? Thank you.

I encountered a problem with our 600 MHz NMR instrument. When acquiring the line shape sample, while spinning, the chloroform peak is split into 9 lines, each one 20 Hz apart (speed at which the sample is spun). Without spinning, the peak is very, very broad. I contacted our service engineer and it seems that there is a dropped cryoshim on the magnet. What exactly does that mean? How could it have happened and can it be corrected? The service engineer will help my tomorrow, but I am just curious in the mean time of what could have gone wrong? Thank you.