Search this article
We can use mainly two methods, phosphate decomposition and thermal decomposition, to get CO_2 from calcium carbonate samples for ^<14>C dating. It is generally considered that the former is better to get CaCO_3-C selectively. However, it takes much longer time (several hours) to complete phosphate decomposition of calcium carbonate than thermal decomposition (a few hours). For four calcium carbonate samples, we prepared elemental carbon by these two different methods and compared ^<14>C dates of them. ^<14>C dates of elemental carbon prepared by the two methods are consistent with one sigma errors (67% confidence level) for 3 samples, FB-50,FB-80,TAKAS-1. For FB-18 sample, the difference between ^<14>C dates by the two methods is a little larger, but is negligible if two sigma errors (95% confidence level) are used. We want to continue this kind of experiments to confirm that the difference of ^<14>C dates is negligible between the two methods.
タンデトロン加速器質量分析計業境報告 Summaries of Researches Using AMS
名古屋大学加速器質量分析計業績報告書 4 73-75, 1993-03