Deterioration of photo-stimulated luminescence signals from materials by radiation

AbstractA photo-stimulated luminescent (PSL) material, BaFBr 0:85 I 0:15 :Eu 2⁄ , was irradiated by 1 and 2 MeV He ⁄ ions. Thedeterioration of PSL signals caused by heavy irradiation was found quite stable for a long time. In situ measurements ofscintillation were also made during He ⁄ ion irradiation. A broad 400 nm peak and a decreasing continuum tail wereobserved for spectra of the scintillation. An afterglow e•ect was also observed as a function of time up to 10 s afterstopping the He ⁄ ion beam. Results are discussed relating with the incomplete erasing and the self generation of PSLsignals which were reported in our previous study. O 2000 Elsevier Science B.V. All rights reserved.PACS: 78.45; 78.90Keywords: Photo-stimulated luminescence (PSL); Scintillation; Radiation deterioration; He ⁄ ions; Incomplete erasing;Self generation of PSL signals; Afterglow e•ect 1. IntroductionSince photo-stimulated luminescent (PSL) ma-terials have been developed for X-ray imaging [1],many studies have been reported on their charac-teristics and responses to various radiation irra-diations [2–5]. Besides those basic studies, excellentperformances of the PSL materials have also beenreported such as wide linearity, simplicity of PSLstatistics and high confidence of stored image in-formation in practical use [6,7].Among varieties of studies, an elucidation ofthe radiation e•ect of the material in PSL andscintillation is the main interest in this study. De-terioration of PSL signals produced by 1 and 2MeV He