三探头组合放射源定位探测系统模拟设计

Simulation Design of Three-Probe Combined Source Location Detection System

采用MCNP法设计了一种由3个探测器组合而成的探测系统。并在3个探测器中间设计了不同形状的屏蔽层,研究不同屏蔽层形状下探测系统的探测灵敏度。理论计算和MCNP模拟结果对比表明:在相同距离下,C型探测系统的灵敏度优于A型和B型;A、B、C型三种探测系统的灵敏度都随距离的增大而降低,但C型探测系统始终优于A型和B型;针对文中建模的探测器尺寸,该结构适用于半径为5 m范围以内的放射源定位工作,通过比较模拟结果C型结构更适合作为便携式放射源准确定位仪器的探测器。

For locating radioactive source, a detector system that consists of three detectors and different shapes of shielding layer between detectors has been designed. The detection sensitivity of the detector under different shielding layer shapes was studied in this paper. The theoretical calculation value and the results of MCNP simulation show that the sensitivity of type C detectors is better than that of type A and B detectors at the same distance. And as the distance increases, the sensitivity of type A, B and C detectors all appear a downward trend, but it always maintains a characteristic that the sensitivity of type C detectors is better than that of type A and B. And the sensitivity of type C detectors decreases with the increase of the distance. In term of the size of model detector in this paper, the structure is applicable to the positioning of radioactive source within a radius of 5 meters. The type C detector can be used as a portable near-range radiation source accurate positioning detector by comparison.