| 摘要 |
PROBLEM TO BE SOLVED: To prevent breakdown of breakdown voltage of a switching element connected to a capacitor, by connecting a bias electrode of a conversion layer comprising an amorphous semiconductor layer having charge multiplying action to a bias power supply via an impedance element. SOLUTION: A resistance R (impedance element) is connected between a bias power supply E and a bias electrode 4. Electron-hole pairs (electric charge) are generated in a conversion layer 1 by incoming X-rays and electric charge is stored in a capacitor 8 connected to a signal electrode 5 on the negative- electrode side while a current flows from the power supply E to the bias electrode 4 on the positive-electrode side via the resistance R to produce a voltage drop, and an electric field in the conversion layer 1 is thereby mitigated. This reduces charge multiplying action in an amorphous semiconductor layer 3 of the conversion layer 1 due to an avalanche effect at the time of charge shift, and therefore storage of charge in the capacitor 8 is suppressed. As a result, saturation of the capacitor 8 with stored charge amount and a rise in a voltage imposed on the capacitor 8 can be prevented.
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