TY - JOUR

T1 - Absorbed dose, equivalent dose, measured dose rates, and implications for OSL age estimates

T2 - Introducing the Average Dose Model

AU - Guérin, G.

AU - Christophe, C.

AU - Philippe, A.

AU - Murray, A. S.

AU - Thomsen, K. J.

AU - Tribolo, C.

AU - Urbanova, P.

AU - Jain, M.

AU - Guibert, P.

AU - Mercier, N.

AU - Kreutzer, S.

AU - Lahaye, C.

PY - 2017/8/1

Y1 - 2017/8/1

N2 - Luminescence ages are calculated by dividing an absorbed dose by the dose rate to which the natural dosimeter has been exposed. In practice, one measures an equivalent dose, De; in the absence of an alpha dose contribution, this should be indistinguishable from the dose absorbed in nature. Here we first review the relationship between absorbed dose, equivalent dose and dose rate, and the measurements that lead to their estimation; we restate that, in contrast to recent suggestions, an equivalent dose is not a physically different quantity from a beta or gamma dose absorbed by quartz grains. Statistical analysis of OSL data is of great importance when dealing with single grain data, since such data commonly exhibit significant scatter. However, dose rate measurements provide an arithmetic mean of dose rates absorbed by individual grains; in this article, we propose a new model to estimate the average dose absorbed by the grains. We thus introduce a new model for OSL age estimates: the Average Dose Model (ADM). We argue that ADM ages should be more accurate than Central Age Model (CAM) based ages, and we provide experimental evidence supporting this expectation. We also argue that the use of the Finite Mixture Model should be avoided. Finally, we discuss the implications for multi-grain age estimates derived from well-bleached samples

AB - Luminescence ages are calculated by dividing an absorbed dose by the dose rate to which the natural dosimeter has been exposed. In practice, one measures an equivalent dose, De; in the absence of an alpha dose contribution, this should be indistinguishable from the dose absorbed in nature. Here we first review the relationship between absorbed dose, equivalent dose and dose rate, and the measurements that lead to their estimation; we restate that, in contrast to recent suggestions, an equivalent dose is not a physically different quantity from a beta or gamma dose absorbed by quartz grains. Statistical analysis of OSL data is of great importance when dealing with single grain data, since such data commonly exhibit significant scatter. However, dose rate measurements provide an arithmetic mean of dose rates absorbed by individual grains; in this article, we propose a new model to estimate the average dose absorbed by the grains. We thus introduce a new model for OSL age estimates: the Average Dose Model (ADM). We argue that ADM ages should be more accurate than Central Age Model (CAM) based ages, and we provide experimental evidence supporting this expectation. We also argue that the use of the Finite Mixture Model should be avoided. Finally, we discuss the implications for multi-grain age estimates derived from well-bleached samples

KW - OSL data anlysis

KW - dose rate measurements

KW - central age model

KW - average dose model

U2 - 10.1016/j.quageo.2017.04.002

DO - 10.1016/j.quageo.2017.04.002

M3 - Article

SN - 1871-1014

VL - 41

SP - 163

EP - 173

JO - Quaternary Geochronology

JF - Quaternary Geochronology

ER -