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冠城 雅晃; 佐藤 優樹; 吉原 有里*; 島添 健次*; 高橋 浩之*; 鳥居 建男
Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.405 - 414, 2018/11
On March 11, 2011, a massive earthquake occurred in the Tohoku region of Japan, and a large tsunami hit the Fukushima Daiichi Nuclear Power Plant (1F), resulting in a nuclear accident. Despite the years that have passed since the accident, decommissioning remains a concern. Radiation measurement techniques are very important for accelerating the decommissioning and ensuring low radiation exposure to workers. Our gamma-ray imaging system is the detection device for determining the three dimensional radioactive distributions of nuclear fuel debris, measuring high-energy gamma rays (greater than 1 MeV). Silicon semiconductor detectors are among the candidate detectors for radiation measurements in our system because of their radiation-hardness and high counting rate capability. We have been developing a stacked amorphous-silicon (Si)/crystal-Si heterojunction Si strip detector, which has 1-mm-pitch striped electrodes (0.5 mm wide) and 1.2-mm-pitch stacked technology. The detector consists of an Si strip mounted on a thin printed circuit board, front-end readout electronics with a complementary metal oxide semiconductor application specific integrated circuit, and a field programmable gate array. The threshold level of energy deposition of each pulse signal in each channel can be set from the application-specific integrated circuit, and gamma-ray images with energy discrimination can be obtained. The energy threshold level for discrimination of 
Co gamma rays from 
Cs gamma rays was investigated experimentally and by means of simulation, and it was found to be about 500 keV. Therefore, our Si strip detector has the required position sensitivity and energy discrimination ability for identifying high-energy gamma-ray source distributions.
Irmler, C.*; 谷田 聖; 他98名*
Journal of Instrumentation (Internet), 11(1), p.C01087_1 - C01087_9, 2016/01
被引用回数：4 パーセンタイル：51.49(Instruments & Instrumentation)The Belle II Silicon Vertex Detector comprises four layers of double-sided silicon strip detectors (DSSDs), consisting of ladders with two to five sensors each. All sensors are individually read out by APV25 chips with the Origami chip-on-sensor concept for the central DSSDs of the ladders. The chips sit on flexible circuits that are glued on the top of the sensors. This concept allows a low material budget and an efficient cooling of the chips by a single pipe per ladder. We present the construction of the first SVD ladders and results from precision measurements and electrical tests.
-ray imaging system for Fukushima Daiichi Nuclear Power Plant using silicon strip detector冠城 雅晃; 佐藤 優樹; 吉原 有里*; 島添 健次*; 高橋 浩之*; 鳥居 建男
no journal, ,
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.
