2021 Volume 46 Issue 4 Pages 164-168
Fiber optic radiation monitors offer advantages of measuring dose rate without use of electronics at the detection part. This characteristic enables to locate the detector in high-temperature and high-dose rate environments, hence it is particularly suitable as a dosimeter for nuclear environment monitoring by placing the optical measurement system several hundred meters away from hazardous areas. However, improvement of the detection sensitivity is required, in order to apply monitors inside the reactor building during the normal operation of the nuclear power plants. In this work, a high-sensitivity fiber optic radiation monitor which operates in a single photon counting mode is designed and experimentally demonstrated. This operating mode improves the sensitivity by applying a long decay time scintillator which had not been suitable as a radiation detector. The prototype detector using GdTaO4:Eu with 885 μs decay time successfully operates in a single photon counting mode and the response linearity was within ± 10.6% at the dose rate range of 7.0 × 10-5 to 1.0 mSv/h.
