Radiocarbon Dating with Liquid CO2 as Diluent in a Scintillation Solution

Publisher Website
Google Scholar
Abstract
The use of the scintillation technique for radiocarbon dating has until now been retarded by the difficulties encountered in the chemical procedure. This paper shows it to be feasible to use the carbon dioxide obtained by combustion of the sample, without any further chemical conversion, as a diluent in a scintillation solution. Up to 80% by weight and possibly more liquid carbon dioxide can be dissolved in toluene+5 g/l diphenyloxazole (PPO). However, the presence of CO2 in the scintillator interferes somewhat with the light emission in such a way that the decrease in pulse height, as compared with pure toluene+5 g/l PPO, is 50% for 20% by weight dissolved CO2. This limits the percentage of CO2 that can be used effectively to about 30%. The counting rate due to modern carbon is 9.1 c/min, and the background is 15.5 c/min. Measurements indicate however that both these figures can be improved considerably, so as to make this technique at least comparable with the gas‐counting technique.