| 摘要 |
PURPOSE:To test a radiation measuring instrument without interrupting measuring operation by detecting a fault of a radiation detection part with a fault signal and calibrating a measurement part with a calibration signal. CONSTITUTION:An arithmetic circuit 16 consisting of a gate circuit 12 and an AND circuit 14 performs logical operation between a reference signal 7a and the detection signal 4a of the radiation detection part 5 to outputs a calibration signal 14a corresponding to the signal 7a when the signal 7a is in a pulse generation state or a measurement signal 12a corresponding to the signal 4a when the signal 7a is in a pulse extinction state. For the purpose, the signal 14a is inputted to the measurement part 15 through a changeover switch 13 to calibrate the measurement part 15; and the signal 12a is inputted to the measurement part 15 and the signal 14a is inputted to a measurement part to be calibrated, so that the measurement part to be calibrated is calibrated while a measurement is taken by the measurement part 15. Further, if the detection part 5 gets out of order, a NOR circuit 10 performs logical operation between the signal 7a and the output signal 9d of an FF circuit 9 and sends out its output signal 10a as a fault signal, so that the fault is displayed 11.
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