| 摘要 |
PROBLEM TO BE SOLVED: To provide a pocket dosimeter whose reliability is enhanced and in which an adjusting man-hour can be reduced by a method wherein a threshold value uses an analog voltage value by a digital-to-analog conversion circuit and an opening part in the electromagnetic shield of a detection circuit is eliminated. SOLUTION: When a radiation such asγ-rays or the like is incident, a current is generated in a silicon detector 1 so as to be converted into a voltage by an amplifier 2. Its analog signal is sent to a comparator 3 so as to be compared with a threshold value 4. The threshold value 4 is digital-to-analogconverted by sending a control signal to a digital potentiometer 5 from a CPU 6. In addition, a detection circuit part is housed inside a metallic electromagnetic shield. When the digital potentiometer 5 is used, it does not comprise an opening part so as to be set in a sealed-up state, and it is hardly subjected to a disturbance noise. Thereby, since the threshold value is not changed due to a fall, a vibration or the like, the radiation sensitivity of this pocket dosimeter is not changed. In addition, it is not required to open an armor case when the threshold value or the like is changed, and a man-hour can be saved.
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