THP137 　加速器土木・放射線防護　 8月9日 大展示ホール 13:10 - 15:10

100 Gyを超える線量の測定に向けた可搬型光刺激ルミネセンス線量測定システムに関する基礎検討

Preliminary study of the portable Optically Stimulated Luminescence dosimetry system for measuring radiation doses more than 100 Gy

○岡崎 徹（長瀬ランダウア(株)），橋詰 拓弥（長瀬ランダウア(株), 総研大），橋本 義徳，白形 政司，中村 一，山崎 寛人（KEK），Vergil LE Cruz，Cheng Wei Hsin（長瀬ランダウア(株)），林 裕晃（金沢大），小林 育夫（長瀬ランダウア(株), 福井大）

○Tohru Okazaki (Nagase-Landauer, Ltd.), Takuya Hashizume (Nagase-Landauer, Ltd., SOKENDAI), Yoshinori Hashimoto, Masashi Shirakata, Hajime Nakamura, Hirohito Yamazaki (KEK), Cruz Vergil Le, Wei Hsin Cheng (Nagase-Landauer, Ltd.), Hiroaki Hayashi (Kanazawa Univ.), Ikuo Kobayashi (Nagase-Landauer, Ltd., Univ. of Fukui)

To monitor the exposure dose around a beam line, we propose to use Optically Stimulated Luminescence dosimeters composed of Al2O3:C. The passive dosimeter is inexpensive and can easily read the radiation dose by stimulation using green LED lights of a OSL reader. The dosimetry system is widely used in personal dosimetry for evaluating doses less than 10 Gy. Thus, we studied the possibility of measuring doses exceeding 100 Gy with the system. The small type OSL dosimeters, nanoDot, were exposed to 0.07 - 2350 Gy of Co-60 gamma-rays installed at Takasaki Advanced Radiation Research Institute (National Institutes of Quantum and Radiological Science and Technology, Gunma, Japan). They were measured by a portable OSL reader, microStar, with an additional neutral density filter to prevent the saturation of the PMT response. The dose response of the nanoDots showed linearity up to 1 Gy and supra linearity up to 30 Gy. In more than 30 Gy, the response of the nanoDots showed sublinear response and it saturated at 250 Gy. Based on the results, we concluded that the OSL dosimetry system can measure the radiation dose from Co-60 gamma-rays for doses less than 250 Gy.