Carbon-14 is produced in the upper atmosphere when cosmic rays bombard nitrogen atoms.
The ensuing atomic interactions create a steady supply of c14 that rapidly diffuses throughout the atmosphere.
This carbon-14 is radioactive and decays with a half-life of 5730 years.
For historical reasons, uncalibrated radiocarbon measurements are often referred to a half-life of 5568 years.
Radiocarbon is the best and often the only way to quantify rates of exchange of carbon among reservoirs.
Data on the isodensity and sedimentation rate of ‘fossilized’ recent pollen from twelve tree taxa are also presented, and the potential for separating a single taxon from pollen assemblages is demonstrated.
In 2001, ESS/CGECR researchers Ellen Druffel, John Southon and Susan Trumbore were awarded million by the W. Keck Foundation for the development of an accelerator mass spectrometry (AMS) facility – the Keck-Carbon Cycle AMS facility - for radiocarbon measurements in support of carbon cycle research at University of California, Irvine.
This article is reproduced from Nuclear News, June 19998, and is based on a paper presented at the ANS Winter Meeting, held November 16-20, 1997, in Albuquerquete N. AMS has become an accurate and precise method for dating many types of materials - including such interesting items as the Shroud of Turin and the Dead Sea Scrolls, which will be discussed laterwhere only a small sample can be spared.
Accelerator mass spectrometry (AMS) is a technique for direct measurement of the concentration of radioisotopes.