GMC-080, GMC-280 CPM reading does not need a special calibration, as long as the tube voltage is set correctly. The on board hardwae take care the accuracy of CPM.
If you want uSv/h or mR/h reading correctly, the factory default value is for M4011 tube or similar tube such as SBM-20. You do not need to do calibration on those those two tubes. Unless you found the value is offset too much.
Other tubes need a reference source with a known uSv/h. Then place the source with GMC-280 to get CPM, and input this CPM and the known uSv/h in calibration menu. It accepts up to three reference values.
The first calibration data CPM should be always background CPM, then the uSv/h value normally is 0.05 uSv/h. This 0.05 uSv/h value is the typical background radiation dosage value. If you location is near rocky mont, then the value may be higher.
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Calibration
Posted - 01/14/2012 : 22:27:04
