3″φ×3″NaI (Tl) シンチレーションスペクトロメーターによる微弱漏洩γ線線量評価の新しい方法 (I)

バックグラウンド推定法の原理

抄録

A new method for evaluating weak leakage gamma-ray dose without background measurement was developed. A pulse height distribution obtained by a 3″φ×3″ NaI (Tl) scintillation spectrometer was converted to the incident gamma-ray energy spectrum by the response matrix method. Weak leakage gamma-ray dose rate with background was directly calculated from the energy spectrum. On the other background exposure rate was evaluated from natural activity concentrations deduced by the peak of ⁴⁰K, ²¹⁴Bi (U) and ²⁰⁸Tl (Th) in the energy spectrum. The results of measurement showed that this method was practically satisfiable technique.