Published online by Cambridge University Press: 18 July 2016
Measurements have continued with the same proportional counter system, sample pretreatment procedure, methane preparation and measurement, and calculation using a half-life of 5568 ± 30 yr as described previously (R., 1970, v. 12, p. 298-318). Uncertainties quoted are single standard deviations originating from standard, sample, background counting rates and half-life. No C13/C12 ratios were measured.