Optically stimulated luminescence properties of nanocrystalline Y 3 Al 5 O 12 phosphor exposed to b radiation E. De la Rosa a, * , R.A. Rodrı ´guez b , L.A. Dı ´az-Torres a , P. Salas c , R. Mele ´ndrez d , M. Barboza-Flores d a Centro de Investigaciones en O ´ ptica A.C., Lomas del Bosque 115, A.P. 1-948, Leo ´n, Gto. 37150, Mexico b Universidad de Guadalajara en Lagos, Lagos de Moreno, Jalisco 47460, Mexico c Instituto Mexicano del Petro ´leo Eje Central La ´zaro Ca ´rdenas 152, C.P. 07730, Me ´xico, D.F., Mexico d Centro de Investigacio ´n en Fı ´sica, Universidad de Sonora, P.O. Box 5-088, Hermosillo, Sonora 83190, Mexico Received 20 October 2004; accepted 10 November 2004 Available online 29 January 2005 Abstract The optically stimulated luminescence (OSL) characterization of undoped Y 3 Al 5 O 12 (YAG) nanocrystals, exposed to b radiation up to a dose of 0.6 kGy was performed. Previously b-irradiated samples showed a strong OSL intensity when stimulated with 470 nm light. The OSL intensity is comparable and in some cases exceeds that of thermoluminescence (TL) intensity build up under the same irradiation conditions. The integrated OSL decay curve was found to be a function of the irradiation dose exposure and it showed low OSL fading. This property along with the all optical readout dose determination and the lack of thermal quenching effects makes the YAG nanocrystals a very prospective optically stimulated luminescence dosimeter (OSLD) with great advantages over the TLD systems. Ó 2004 Elsevier B.V. All rights reserved. Keywords: YAG; Optically stimulated luminescence; Thermoluminescence; Dosimeter; Nanocrystals and phosphor 1. Introduction It is a well known fact that some phosphor materials like LiF:Ti,Mg and a-Al 2 O 3 :C exhibit good thermolumi- nescence (TL) response to UV light and to ionizing radi- ation. The TL properties have been studied very intensely and they share a commercial competitive place in the environmental, personnel monitoring and clinical dosimetry applications. In spite of being these materials widely used there is still a considerable amount of re- search involved with the search of new phosphors mate- rials with better thermoluminescence and dosimetric properties. Room temperature fading, thermal quench- ing, re-usability, dose response and sensitivity are those properties suitable for optimization in new TL phosphors. The primary step in both TL and OSL dosimeters relies in the trapping of charge carrier capability of the phosphor materials after exposure to irradiation. The electron hole pairs initially created are eventually trapped by some defects which remain stable at room temperature. The number of trapped charge carriers is proportional to the irradiation dose exposures which in turns, by thermal or optical stimulation, some charge carriers may be de-trapped and eventually recombined radiatively given rise to the emission of light. The thermally stimulated emission process is usually called themoluminescence and the optically 0925-3467/$ - see front matter Ó 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.optmat.2004.11.018 * Corresponding author. Tel.: +52 477 773 1017; fax: +52 477 717 5000. E-mail address: elder@cio.mx (E. De la Rosa). www.elsevier.com/locate/optmat Optical Materials 27 (2005) 1245–1249