위치에 민감한 대면적 RPM(Radiation Portal Monitor) 기초연구

Abstract

The inspection method of the radioactive material can be categorized into two groups: the active detection method using the personal inspection system and the passive detection method using the radiation portal monitor (RPM). An RPM, whichis a passive inspection method, is a system for monitoring the movement of radioactive materials at an airport, seaport, border, etc. [1]. To detect a γ-ray, an RPM using the plastic scintillator is generally used. The method of γ-ray detection using an RPM with a plastic scintillator is to measure lights generated by an incident γ-ray in the scintillator [2]. Generally, a large-area RPM uses one or two photomultiplier tubes (PMT) for light collection. However, in this study, we developed a 4-ch RPM that can measure the radiation signal using 4 PMTs. The reason for using 4 PMTs is to calculate the position of the radiation source. In addition, we developed an electric device for acquisition of a 4-ch outputsignal at the same time. To estimate the performance of the developed RPM, we performed an RPM test using a 60Co γ-ray check source.