방사선 펄스의 고안정 계측 및 분석 기술에 관한 연구

Abstract

The objective of this thesis is to develope an integrated data acquisition and analysis system for radioisotope application technology. The system developed in this study makes use of radioisotope of the low activity exempted from domestic atomic law and consists of a detection circuit for gamma-rays and neutrons, a high voltage supply unit, a digital signal processor, and a PC-base program.

The high voltage supply unit can generate DC voltage up to 1,500[V] at 5[V] input, and have a series voltage regulator to maintain the output voltage constantly. The neutron pulse detection circuit consists of an active integrator, a pole-zero circuit, and a 3-stage amplifier of 60[dB], and its frequency bandwidth is from 37[Hz] to 300[KHz]. Gamma-ray detection circuit can count pulse up to 10,000[pps].

Also, pulse height distributions and pulse numbers are very important data in analyzing radioactive pulses. In this study, A/D converter of 12[bit], 100[ns] and 60[MHz] DSP are used to analyze the pulse height distribution and the analytic system is fabricated to be operated in personal computer.

Radioactive pulse has superior penetration ability to almost all kinds of materials, and it is also possible to evaluate the soundness of electrical insulation materials by analyzing the pulse numbers and/or pulse height distributions.

In the experiment, pulse numbers counted by the gamma source and pulse height distributions by the neutron source are applied to evaluate the condition of materials such as power cables, insulators, and ZnO blocks. From the experimental results, it is proven that the measurement of pulse numbers and pulse height distributions for radioactive pulse make possible to diagnose the soundness of materials.