The ultrafast OSL component in quartz: Origins and implications

Most irradiated quartz samples show a last decaying CW-OSL (continuous-wave optically stimulated luminescence) signal known as the fast component (FC, sigma(470) nm similar to 2.3 x 10(17) cm(2)) which is well separated from the more slowly decaying components and is commonly used for dosimetry. Some quartz samples additionally show an OSL signal that decays much more rapidly than the FC, termed as the ultrafast component (UFC). In this paper we report on the physical characteristics of the UFC in two different sets of samples from South Korea and Sweden using various measurement techniques. We Conclude that the UFC arises from a shallow electron trap distinct from the FC. Since it rapidly depletes (thermally) at the room temperature, the presence of UFC in the OSL signal can lead to significant dose underestimation; it is recommended that UFC be removed by high temperature preheat (> 200 degrees C) and/or rejection of the very initial OSL signal. (C) 2008 Elsevier Ltd. All rights reserved.