Equivalent dose estimation using a single aliquot of polymineral fine grains

We have tested the suitability of a new single-aliquot regenerative-dose protocol for estimating the equivalent dose (D-e) in polymineral fine grains extracted from colluvia from various sites in Germany. First, we report the behaviour of three OSL signals: (i) blue-stimulated, (ii) infrared-stimulated luminescence, and (iii) blue-stimulated luminescence following infrared (IR) stimulation, using a near-UV (290-380 nm) detection window in each case. For these three signals, there is a significant change in sensitivity with regeneration cycle; this change can be compensated for using the response to a fixed test dose after each natural or regenerated measurement. The source of the three luminescence signals is then investigated using pulse-anneal and elevated-temperature experiments. Fading tests on laboratory-induced signals show that although the IR signals fade by up to 23% in 15 days at 100 degreesC, the post-IR blue signals are stable. The preheat dependence of estimates of D-e obtained using fine grains is presented for the first time, for both blue- and IR-derived signals. Our results are compared with D-e estimates derived from multiple-aliquot additive-dose IR luminescence data, obtained using a blue detection window, and also with expected values of D-e based on independent age estimates and measured dose rates. We conclude that post-IR blue-stimulated luminescence provides reliable estimates of D-e, and that these are probably superior to the IRSL estimates obtained using both near-UV and blue detection windows. (C) 2001 Elsevier Science Ltd. All rights reserved.