Paleodose determination is essential for ESR dating

and the DE value is influenced by the mathematical functions used for dose response data points fitting.At present

single saturation exponential(SSE) fitting is commonly used for ESR dating.It is valid when the number of trap sites is constant

but when the increasing irradiation dose induces new traps

the dose response curve will not follow a unique SSE function.In this study

in addition to SSE

the double saturation exponential(DSE) and exponential plus linear(EPL) functions were used to fit the ESR data of eight tooth fossil samples from Longgupo early Pleistocene site in Wushan

Chongqing.The results show that the DE values calculated by SSE fitting function are systematically higher than DSE and EPL

and the residual sum of square of SSE is larger than the other two.Compared with known reference dose value

we found that DSE has the smallest relative deviation among the three functions

and the SSE has the largest deviation.The study indicates that the SSE function overestimates DE value of tooth fossil samples from old sites

while the DE value determined by DSE functions seems closer to the true value of paleodose.