Time-resolved infrared optically stimulated luminescence (IR-OSL) signals of K- and Na-feldspar samples extracted from sediments were measured in UV, blue and red detection windows, using a fast photon counter and pulsed IR stimulation (lambda = 875 nm). We observe that the relative contribution of long lifetime (similar to 20 mu s) components in K-feldspars is greater than that in Na-feldspars at each detection wavelength. From any one feldspar sample, red and blue IR-OSL signals have a greater contribution of long lifetime components than UV IR-OSL. We found this long lifetime component was significantly more stable than shorter lifetime components, by comparing natural/regenerated and prompt/delayed time-resolved IR-OSL. We also compared both pulsed and continuous wave (CW) equivalent dose (D-e) values from four feldspar samples. For pulsed IR-OSL, the signal was collected between 10 and 100 mu s after the diodes were switched off, to avoid all contributions from short lifetime components. In all cases, the pulsed D-e values were larger than the CW D-e values, regardless of the type of the feldspar and the detection wavelength; the pulsed D-e values were also all consistent with those calculated from the quartz D-e. It is possible that the long lifetime component from feldspars do not show anomalous fading. (c) 2006 Elsevier Ltd. All rights reserved.
Radiation Measurements, 2006, Vol 41, Issue Sp. Iss., p. 790-795
Diagnostik og behandling
Main Research Area:
11th International Conference on Luminescence and Electron Spin Resonance Dating, 2006