[2B13-19] Homeland Security and Nuclear Reactor Measurement 2

[2B16] Development of elemental technologies for criticality proximity monitoring monitor for decommissioning of Fukushima Daiichi Nuclear Power Station (1)

γ-ray irradiation experiments on diamond radiation detectors

*Yusuke Kobayakawa¹, Kengo oda¹, Junichi Higedon Kaneko¹, Kenichi Watanabe², Akiyoshi Chayahara³, Hitoshi Umezawa³, Tetsuichi Kishishita⁴, Masayoshi Shoji⁴, Kazuya Tauchi⁴, Tomohiro Endo⁵ (1. Hokkaido Univ., 2. Kyushu Univ., 3. AIST, 4. KEK, 5. Nagoya Univ.)

Keywords:Fukushima Daiichi Nuclear Power Station Decommissioning Project, Criticality proximity monitor, Neutron detector, diamond, Gamma-ray response

We are developing elemental technologies for criticality proximity monitoring in reactor containment vessels through narrow penetrations by combining neutron detectors based on diamond radiation detectors with radiation-resistant silicon semiconductors developed by KEK.In this study, we tested the operation of a diamond radiation detector manufactured by Hokkaido University in the ⁶⁰Co irradiation field of Nagoya University, assuming a high γ-ray dose field where a maximum of 1 kGy/h is expected. By improving the crystal quality of the diamond using ion beam etching and the electrode structure of the detector, stable operation at 850 Gy/h for one hour was successfully achieved.