Sensitization of the photostimulable x-ray storage-phosphor CsBr:Eu~(2+) following room-temperature hydration

摘要

The x-ray storage-phosphor CsBr:Eu~(2+) has been found to exhibit a strong increase in photostimulated-luminescence (PSL) intensity following hydration at room temperature. The sensitivity increases by a factor of 25 following a 60 min exposure to an atmosphere of 99% relative humidity, which is considered to be due to an incorporation of H_2O molecules within the CsBr: Eu~(2+) matrix, which are orientated by and enhance the electric fields surrounding (Eu~(2+)-O~(2-))-dipoles, increasing their charge trapping cross sections. Following irradiation the PSL increase is accompanied by the formation of mobile V_K-centers, which decrease the F-center population by a recombination process, which appear as an intrinsic 360 nm emission from the CsBr matrix in low temperature thermoluminescence measurements.