Lyon Natural Radiocarbon Measurements VIII

This list includes most of the measurements made in 1977 and 1978 using the two Packard liquid scintillation spectrometers described in Lyon VII (R, 1978, v 20, p 19). The backgrounds of both spectrometers decreased by about 30% with new photomultipliers, giving 1.9 ± 0.1cpm and 2.4 ± 0.2 cpm, respectively, for 3ml C 6 H 6 (depending on counting vessels). Proportional detectors are only used for very small samples. Counting procedures are described in the text. Dilution ratios indicate the amount of sample versus the total quantity of C 6 H 6 or CO 2 introduced in the detectors. No change was made either in chemical treatment or in the calculation method (half-life: 5570 ± 0, one standard deviation, standard 13 C correction only for bones).