| 摘要 |
PURPOSE:To improve the activity rate of a device by automatically correcting the correctable gain variation in abnormal output and dealing it as normal, and by dealing only the abnormal outputs which are hard to be corrected as abnormal. CONSTITUTION:The upper and lower limits of the values of pulse wave heights in single channel wave height analyzers 11 and 12 are located on both sides of the peak value (which means a boundary) of a wave height distribution curve of a beta-ray. Adjustment is performed so that the output of a subtracting circuit 17 becomes about zero when the beta-ray is irradiated. When the gain is varied, judgement as to whether the gain is increased or decreased is performed based on whether the output of the subtracting circuit 17 is positive or negative. The gain of a main amplifier 7 is automatically adjusted by the output level of the subtracting circuit 17. When a dark current is increased, the output of a counting rate meter 16 is increased. If the value of the output exceeds a preset value, a warning circuit 19 is actuated and warning is issued. |
