ESR measurement of carbonated hydroxyapatite for dosemeter

線量計開発のための炭酸アパタイトのESR測定

清藤 一*; 横塚 恵莉*; 岡 壽崇   ; 北辻 章浩  ; 長澤 尚胤*

Seito, Hajime*; Yokozuka, Eri*; Oka, Toshitaka; Kitatsuji, Yoshihiro; Nagasawa, Naotsugu*

生物由来原料から作製した炭酸アパタイトへのCoガンマ線照射を行い、アラニンやフリッケ線量計に替わる線量計として利用可能か調べた。照射によって生成する炭酸ラジカルの収量は照射後に20%減衰したが、7日でほぼ一定になることがわかった。炭酸ラジカル収量と吸収線量の関係は、10Gyから1000Gyの範囲で線形関係にあり、炭酸アパタイトは化学線量計として利用可能であることが示された。

We have examined dosimetric characteristics of bio-inspired carbonated hydroxyapatite (COHAp), which is a main component of calcified tissues like tooth enamel. COHAp powder samples were exposed to gamma-ray with radiation doses ranging from 1 Gy to 1000 Gy at room temperature, and ESR spectra were measured immediately after irradiation and subsequently measured each 1 day during 90 days. The post-irradiation fading resulted in significant 20% decay of the signal amplitude, which stabilised within 7 days after irradiation, and the intensity approached a constant. The sample has good linear dose response in the experiment range of 10 Gy - 1000 Gy. Our results indicate that the COHAp materials is suitable for chemical dosimetry.