Detection of Gamma Rays Using Plastic Scintillating Fibers

Abstract

Scintillating optical fibers have several advantages over the conventional materials used for radiation detection. The plastic scintillating fiber of Bicron model BCF-12 with an emission peak of 435nm has been used to detect 137Cs gamma rays. Several types of sensors were constructed by packing in bundle forms different numbers of fibers into aluminum tubes, and tested to detect the gamma rays. The scintillation lights generated in the fiber bundle are transmitted through a low-attenuation fiber to a PMT. Optical coupling between the fiber bundle and the transmitting fiber is made either by direct alignment or by placing as small opticallens between them. In this paper, we report the pulse-height spectra obtained for 137Cs gamma rays with various sensor types of two different optical couplings. Also presented is an analysis the proportionality between the total counts and the activities of 1.2µCi,1. 6µCi and 4.3µCi 137Cs sources in the aspect of their usability for gamma ray detection. The effect of casing material for the sensor is also discussed. Our investigation suggests that the plastic scintillating fiber can be used to develop gamma ray detectors which can function in µCi-level gamma ray fields. © 2014 Atomic Energy Society of Japan.