Detection of radioactive hotspots inside the Fukushima Daiichi Nuclear Power Station Unit 3 reactor building using an optical fiber radiation sensor based on wavelength-resolving analysis

寺阪 祐太   ; 佐藤 優樹  

Terasaka, Yuta; Sato, Yuki

We have developed a new method for the inverse estimation of incident position of radiation on an optical fiber by utilizing the wavelength dependence of light attenuation within the fiber. Our sensor captures the emission wavelength spectrum of the scintillation photon by connecting a spectrometer to the fiber's end. The shape of the wavelength spectrum changes with the photon's transmission distance inside the optical fiber. Hence, the incident position of radiation along the optical fiber can be determined by applying an unfolding procedure to the emission wavelength spectrum. We applied this sensor to examine the distribution of radioactive sources inside the Fukushima Daiichi Nuclear Power Station (FDNPS) Unit 3 reactor building.