Comparison between the measurements by the fiber-optic gamma radiation sensors with the sensing probes of different height

This study developed a fiber-optic radiation sensor (FORS) to make real-time measurement of gammaradiation at the nuclear facility decommissioned site. The FORS consisted of a sensing probe, a transmitting plastic optical fiber, a measuring device and a laptop computer. The sensing probe of the FORS was hexahedron form and fabricated using LYSO:Ce inorganic scintillator, mixture of epoxy and hardener as light guide, and aluminum foil as a reflector. Two sensing probes with different heights, 0.3 mm and 15 mm, were prepared. The light transmitted through the plastic optical fiber was converted by the photomultiplier tube and amplified by an amplifier. A multi-channel analyzer (MCA) with the GENIE2000 program was used for the data acquisition and analysis. The FORSs were applied to measure a Co-60 disk source (92.43 μCi, 2015.02). The measurements showed that the sensing probe with the height of 15 mm was better in terms of detection efficiency.