| 摘要 |
PURPOSE:To reduce source noise so as to enhance the detecting ability of a semiconductor radiation detecting element by forming a trapping circuit and an overcurrent protection resistance between a power source for feeding power to a semiconductor detector and a common electrode formed in the semiconductor detector, and providing a detector circuit and an LPF(low-pass filter) at the rear stage of an inversion amplifier. CONSTITUTION:Of the noise of a semiconductor detector power source HV connected to a common electrode 3 formed in a semiconductor detector 1, since input impedance becomes zero at a series resonance frequency because of a trapping circuit 8 comprising L1 and C2, and no output signal is transmitted, noise components mixed in the power source are reduced. A protective resistance 9 is provided to enable the leak current and characteristic deterioration, etc., of the semiconductor detector 1 due to the influence of overcurrent to be prevented. A signal output from the detector is half-wave rectified using a detector circuit 10 formed at the rear stage of an inversion amplifier 4 and is forced to pass through an LPF 11, thereby only the actual radiation pulse from which noise components are removed can be detected.
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