Dating by LSC

Liquid Scintillation Counting

Benzene is prepared from the sample and its 14C activity (beta-decay) measured by LSC. The benzene is produced as follows: carbon dioxide, obtained by burning the sample, reacts with metallic lithium to form lithium carbide. The lithium carbide is hydrolysed to acetylene which is subseqently converted to benzene by catalytic trimerisation. A small amount of carbon dioxide is taken during the above process to enable the measurement of the stable isotope ratio 13C / 12C. This is to correct for any fractionation that may have occurred during the preparation process (with any change of state, various isotopes sometimes react differently thus, the normal isotope ratio could be changed). Scintillation counting results are statistically analysed and reported as corrected radiocarbon ages.

The sample is burnt in our double tube system and the resulting carbon dioxide frozen out with liquid nitrogen.