Dear Colleagues
Recently, we have faced one problem which come from the temperature control in
two shim system of Bruker NMR spectrometer. We have a wide-bore 500 MHz magnetic
for microimaging as well as high resolution liquid NMR. To realize these two
functions, two shim coils have been provided: one for microimaging and another
for high resolution. When the NMR spectrometer was setup, the Bruker engineer
try to use the shim coil of microimaging for everything, everything looks fine
thereafter. But years later, high resolution could not be achieved because of
some unknown reason. We have to switch to the shim coil of high resolution. An
unexpected problem occurred during the low-temperature measurement. When the
sample temperature has dropped to -60 oC or below, a warning message appear
that "the shim coil temperature is too low（lower than 5 oC），then the
experiment is stopped by the topspin. We have checked the setup for gas supply
in the webpage, nothing wrong was found. Shim coil gas is normal and we can
hear the gas sound. We have consulted with local Bruker engineer for help. They
said this problem may be due to no gas flow for the new shim coil and they could
not provide a good solution. I wonder whether anybody have similar experience
which could let the flush gas work both for the two shim coil.
Best wishes
Junfeng Xiang
ICCAS, Beijing China
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Received on Sat May 23 2026 - 05:04:13 MST