-ray imaging system for Fukushima Daiichi Nuclear Power Plant using silicon strip detector

Kaburagi, Masaaki   ; Sato, Yuki  ; Yoshihara, Yuri*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Torii, Tatsuo  

Six years have been passed since the Fukushima Daiichi Nuclear Power Plant accident, the decommissioning remains concern. Radiation measurements are important technique to accelerate the decommissioning and ensure low radiation exposure to workers. Our -ray imaging system is for detecting and obtaining the 3D radioactive distributions of the nuclear fuel debris, measuring high energy -ray (greater than 1 MeV -ray). Silicon semiconductor detector is one of the candidate detectors in our system, because of its radiation hardness and high counting capacity. We have been developed the stacked a-Si/c-Si heterojunction silicon strip detector, which is position sensitive detector with the 1 mm or 1.2 mm sensitivities. The position sensitivity and energy discrimination ability of our detector were evaluated by experiments and Monte Carlo simulation. We also studied the spectra of the detector of Cs and Co sources.