Blackwell B A, Schwarcz H P
Dept of Geology, McMaster University, Hamilton, Ontario, Canada.
Appl Radiat Isot. 1993 Jan-Feb;44(1-2):243-52. doi: 10.1016/0969-8043(93)90227-2.
The radiation sensitive ESR signal at g = 2.0018 in fossil enamel can be used to date teeth absolutely, providing a suitable U uptake model can be selected, and the external dose rate, Dext, can be accurately calculated. Apart from the uptake model, the most obvious uncertainty lies in Dext. With the isochron method, Dext can be derived easily during the ESR analysis. By plotting the AD vs. the total internal dose rate for teeth where multiple subsamples have been analyzed, a regression line, the isochron, can be determined for each model age calculation. Each isochron slope represents the sample age, while its y-intercept gives the total external dose, Aext.
化石牙釉质中g = 2.0018处对辐射敏感的电子自旋共振（ESR）信号可用于对牙齿进行绝对年代测定，前提是能够选择合适的铀摄取模型，并且能够准确计算外部剂量率Dext。除摄取模型外，最明显的不确定性在于Dext。采用等时线法，在ESR分析过程中可以轻松得出Dext。通过绘制已分析多个子样本的牙齿的AD与总内部剂量率的关系图，可以为每个模型年龄计算确定一条回归线，即等时线。每条等时线的斜率代表样本年龄，而其y轴截距给出总外部剂量Aext。
