Optically stimulated luminescence in KMgF/sub 3/:Ce/sup 3+/. Comparison of dosimetric characteristics with Al/sub 2/O/sub 3/:C

Abstract

Ce/sup 3+/ doped KMgF/sub 3/ crystals have been investigated as a new material for dosimetry of ionizing radiation. Previous studies have focused on their thermoluminescence (TL) properties. This paper shows that the stored energy in this compound can also be read by visible light. Its sensitivity was found to be one order of magnitude greater than Al/sub 2/O/sub 3/:C, which can be considered as the standard dosimetric material based on optically stimulated luminescence (OSL). The greater sensitivity was due to a larger wavelength difference between stimulation and emission wavelengths, which results in a better separation of useful signal from scattered light. Time response characteristics were also significantly better than Al/sub 2/O/sub 3/:C, which allows in principle fast pulsed and multiple readouts. Unfortunately, the high self-dose (/spl sim/1.5 /spl mu/Gy/h) due to the natural abundance of /sup 40/K isotope is a major drawback for the application of this material in environmental dosimetry. Some features of the mechanism have been studied with different spectroscopic techniques. The luminescent centers have been clearly identified with Ce/sup 3+/ ions. It has been shown that the main trapping centers involved in OSL mechanism are the same as those involved in TL mechanism.