DEVICE FOR STABILIZING AMPLIFICATION FACTOR OF PHOTOMULTIPLIER TUBE

摘要

PURPOSE:To correct the amplification factors of the photomultiplier tube PMT and to stabilize various properties by classifying the PMT groups into plural groups under a rule that mutually adjoining PMTs belong to different groups, obtaining sum signals for the groups and thereby controlling the amplification factors. CONSTITUTION:The arrangement is such that the mutually adjoining PMTs 3 belong to different groups and the sum signals of the groups are obtained. In actually correcting the amplification factors of the PMTs, gamma rays are uniformly irradiated on the overall field of view so that counting is executed for each of the PMTs 3 in a counter memory 15. The changes in the amplification factor of the amplifier system of each PMT 3 can be statistically measured from the count values obtained in the counter memory 15. The contents of a register 17 can be corrected by a data processing circuit 16 such that each PMT 3 has an optimum amplification factor.