CZT 반도체 검출기를 활용한 중성자 및 감마선 측정과 분석 기술에 관한 연구

• Published in: 방사선기술과학 Vol. 45; no. 1; pp. 57 - 67
• Main Authors: 진동식(Dong-Sik Jin), 홍용호(Yong-Ho Hong), 김희경(Hui-Gyeong Kim), 곽상수(Sang-Soo Kwak), 이재근(Jae-Geun Lee)
• Format: Journal Article
• Language: Korean
• Published: 대한방사선과학회(구 대한방사선기술학회) 28.02.2022; KOREAN SOCIETY OF RADIOLOGICAL TECHNOLOGY; 대한방사선과학회
• Subjects: 방사선과학; 감속재; Moderator; CZT 검출기; 속중성자; 감마선; Gamma-ray; Fast neutron; 열중성자; Thermal neutron; CZT detector; CZT
• ISSN: 2288-3509; 2384-1168

CZT detectors, which are compound semiconductors that have been widely used recently for gamma-ray detection purposes, are difficult to detect neutrons because direct interaction with them does not occur unlike gamma-rays. In this paper, a method of detecting and determining energy levels (fast neutrons and thermal neutrons) of neutrons, in addition of identifying energy and nuclide of gamma-rays, and evaluating gamma dose rates using a CZT semiconductor detector is described. Neutrons may be detected by a secondary photoelectric effect or compton scattering process with a characteristic gamma-ray of 558.6 keV generated by a capture reaction (113Cd + 1n → 114Cd + ) with cadmium (Cd) in the CZT detector. However, in the case of fast neutrons, the probability of capture reaction with cadmium (Cd) is very low, so it must be moderated to thermal neutrons using a moderator and the material and thickness of moderator should be determined in consideration of the portability and detection efficiency of the equipment. Conversely, in the case of thermal neutrons, the detection efficiency decreases due to shielding effect of moderator itself, so additional CZT detector that do not contain moderator must be configured. The CZT detector that does not contain moderator can be used to evaluate energy, nuclide, and gamma dose-rate for gamma-rays. The technology proposed in this paper provides a method for detecting both neutrons and gamma-rays using a CZT detector.