| 摘要 |
PURPOSE:To provide a preamplifier of a radiation detector which has a reset function to electronically discharge the electric charge stored in a feedback electrostatic capacity, can prevent the mixture of noises, and can secure the high resolution and a high counting rate. CONSTITUTION:A radiation detecting preamplifier of a charge integration type applies the feedback to the gate of an n-channel field effect transistor FET 2 from an output terminal of an inverted amplifier which is connected to a radiation detector 1 and contains the FET 2 at the first stage via an electromagnetic capacity Cf. A reset means 4 is added to the preamplifier to forcibly increase the voltage Vo of the output terminal. Then the potential of the gate is increased by the means 4 and with use of the feedback function secured through the capacity Cf. Thus the forward junction is secured between the gate and the source of the FET 2 and the electric charge stored in the capacity Cf discharged to the source side to reset the FET 2 and to maintain the continuous operations of the FET 2.
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