Radiocarbon From Cosmic Radiation

Studies in Glycine-2-C14 Metabolism in Man. I. The Pulmonary Excretion of C14o21

“…Furthermore, in all four patients by the end of 40 to 75 days there was no significant measurable activity in the breath; i.e., less than 0.04 dis./ (10,11); however, this could represent only a small fraction of the administered dose. The relation of these three different rate processes to known biochemical processes is not known.…”

Developments in Radiocarbon Technologies: From the Libby Counter to Compound-Specific AMS Analyses

“…At about the same time, the mass spectrometry problem was again being approached with a suggestion (Hall et al 1978) for laser isotope enrichment of 14 C to overcome some of the problems of the very small 14 C/C ratio in natural samples. Isotope enrichment benefits the beta-ray counting method too, as was found at the beginning of the 14 C development (Anderson et al 1947). In addition, the tandem accelerator had been proposed (Purser 1977) for mass spectrometry to reach very low abundance levels of stable isotopes by molecular dissociation during high-voltage charge changing.…”

Archaeology: Date with history

“…The fog began to lift in the middle of the twentieth century, when US chemist Willard Libby and his colleagues 4 showed that all formerly living things bear a clock powered by radioactive carbon-14. Organisms incorporate tiny amounts of this isotope as they grow, and they maintain a constant ratio between it and other, non-radioactive, carbon isotopes throughout their lives.…”