The Remarkable Metrological History of 14C Dating: From Ancient Egyptian Artifacts to Particles of Soot and Grains of Pollen
Lloyd A. Currie
Radiocarbon dating would not have been possible if 14C had not had the wrong half-life -- a fact that delayed its discovery. Following the discovery of this 5730 year radionuclide in laboratory experiments by Rumen and Kamen, it became clear to W. F. Libby that 14C should exist in nature, and that it could serve as a quantitative means for dating artifacts and events marking the history of civilization. The search for natural radiocarbon was a metrological challenge; the level in the living biosphere [ca. 230 Bq/kg] lay far beyond the then current state of the measurement art. This article traces the metrological history of radiocarbon, from the initial breakthrough devised by Libby, to minor (evolutionary) and major (revolutionary) advances that have brought 14C measurement from a crude, bulk [8g carbon] dating tool, to a refined probe for dating tiny amounts of precious artifacts, and for molecular dating at the 10-100 υg level. The metrological advances led to opportunities and surprises, such as the non-monotonic dendrochronological calibration curve and the bomb effect, that spawned new multidisciplinary areas of application, ranging from cosmic ray physics to oceanography to the reconstruction of environmental history. Following a brief exposition of each of these advances, the paper concludes with a glimpse at research by NIST and collaborators on fundamental 14C metrology [e.g., gas chromatography/accelerator mass spectrometry; unique reference materials], plus applications to industrial and atmospheric source identification, and new research directed toward extraction of the recent history of fossil and biomass burning from soot particles trapped in polar and mid-latitude ice cores.
The Remarkable Metrological History of <sup>14</sup>C Dating: From Ancient Egyptian Artifacts to Particles of Soot and Grains of Pollen, Czechoslovak Journal of Physics
(Accessed June 1, 2023)