| 摘要 |
PURPOSE:To enhance the size reduction and economy of a semiconductor gamma ray dosimeter by enabling to suitably switching of a change-over switch for a power source applied with a reverse bias for forming a depletion layer and obtaining a range of wide desage linearity according to one detecting element. CONSTITUTION:A reverse bias voltage is applied by a DC power source 6 or 7 connected through a change-over switch 6 to a detector 1 composed of an aluminum electrode 3, and a metallic electrode 4 on a P type silicon substrate 2. 21, 22 represent the states of depletion layers formed by DC power sources 6, 7. When the gamma rays are emitted to such detector 1, the rays are detected as pulse current, are thus counted by a detecting meter 8 formed of amplifier and counter, and counting rate is obtained. When the incident gamma dosage is small (less than 10R/h), the power source 6 is connected (e.g., 100V), and when the incident gamma ray dosage is larger than that, the power source 7 is connected (e.g., 5V). |
