title: Changes in optical transmission caused by gamma ray induced coloring in photoluminescence dosimeter.
abstract: Transmission of visible light and ultraviolet radiation was examined for a phosphate-glass photoluminescence dosimeter irradiated with Co source gamma rays in the dose range of 1-60 Gy (H2O). The transmission for the wavelengths (lambda) less than 600 nm decreased with increasing irradiation dose beginning at 6 Gy. An approximate 20% reduction of transmission was observed for a 60 Gy exposure at the wavelength of ultraviolet radiation used for excitation (lambda = 337 nm). However, no change of transmission was seen in longer wavelength region (lambda > 600 nm), which includes the range of photoluminescence (lambda = 610-710 nm). Relative efficiencies of measured photoluminescence agreed well with estimations that were calculated from the transmission reduction of ultraviolet radiation. This fact indicates that reduction of photoluminescence efficiency induced by high-dose gamma rays is attributable mostly to attenuation of the ultraviolet radiation from an excitation source, rather than saturation of trapping or recombination centers.
authors.affiliation: National Institute of Radiological Sciences, Anagawa 4-9-1, Inage, Chiba-shi 263-8555, Japan. h_yasuda@nirs.go.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yasuda
authors.forename: Michiko
authors.initials: M
authors.lastname: Takami
authors.forename: Tatsuyo
authors.initials: T
authors.lastname: Ishidoya
mesh_terms: D003037:Cobalt Radioisotopes / Q000032:analysis*; D004307:Dose-Response Relationship, Radiation; D019544:Equipment Failure Analysis; D005720:Gamma Rays; D055095:Optics and Photonics / Q000295:instrumentation*; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013819:Thermoluminescent Dosimetry / Q000295:instrumentation*; D014466:Ultraviolet Rays
chemical_list: D003037:Cobalt Radioisotopes