Construction of Response Functions for Various Cylindrical and Spherical NaI (T1) Scintillation Detectors for Gamma Rays and the Test Results

Gamma ray spectra analyses using unfolding techniques and the dose evaluation are performed widely in the fields of environmental radiation monitoring and the relating environmental research. Various sizes and the shapes of NaI (T1) scintillation detectors can be used depending on the dose levels. However, available response functions are generally limited to 3″φ×3″ cylindrical and 3″φ spherical types and the energy range is roughly up to 3MeV. In this paper, the response functions of eight types of cylindrical and spherical NaI (T1) scintillation detectors (1″φ×1″, 2″φ×2″, 3″φ×3″, 4″φ×4″, 5″φ×4″ cylindrical, and 2″φ, 3″φ, 5″φ spherical) were determined. The energy ranges were extended to 10MeV in maximum. The some response functions reported in literatures were unfolded using our response matrices for comparison and the relative characteristics were discussed.