Patent ID: 6064068
Filing Date: 2000-05-16
Classification: G01T

Abstract:
A measuring system comprising a primary source and a scintillation detector, and including means for monitoring the stability of the scintillation detector simultaneously with the operation of the measuring system, said means for monitoring the stability of the scintillation detector being arranged to operate simultaneously with the measuring system of which the primary source and scintillation detector form a part, and providing two beams of gamma rays from a subsidiary source distinguishable because of their time relationship from the primary source from which the rays primarily detected by the scintillation detector originate, the two beams being of similar energies and oriented in different directions with one directed into the scintillation detector and one acting as a reference beam and directed to a reference beam counter, and means to compare the ratio of the detector-count rate to the reference count rate to provide an indication of any drift in the scintillation detector.