ESR dating of Lower Pleistocene fossil teeth: Limits of the single saturating exponential (SSE) function for the equivalent dose determination

In ESR dating of tooth enamel, a single saturating exponential (SSE) function is generally used to fit the dose response data points. This study shows several analytical and physical limits of this function when applied on Lower Pleistocene samples with expected ages in excess of one million years. We have checked other mathematical functions to obtain a closer fit to the analytical data. Indeed, the choice of the fitting function becomes crucial as this has a strong influence on the D_E value. Among the functions used, the combination of a double saturating exponential (DSE) function provided the best approximation to the experimental points. The use of just one SSE function seems to lead to D_E systematic overestimations if the D_E values are >300 Gy.