Nanosecond infrared laser stimulation of luminescence in rare-earth doped sulfides

Abstract

Optically stimulated luminescence (OSL) from CaS:Eu,Sm and SrS:Eu,Sm phosphors, previously exposed to ionizing radiation, is shown to occur with response and decay times of less than 50-ns full width at half-maximum. This result indicates that fast high-resolution OSL imaging of spatial dose distributions is possible via stimulation of the dose proportional luminescence with a tightly focused scanning laser beam. The two phosphors investigated are efficiently stimulated with the beam from a Nd:yttrium aluminum garnet (YAG) laser. The large dynamic dose range of these materials represents a distinct advantage of OSL imaging over conventional x-ray radiography. In addition, the laser scanning technique readily lends itself to image digitalization and processing. Real-time imaging appears feasible.