Cambridge carbon dating
Calibration is not only done before an analysis but also on analytical results as in the case of radiocarbon dating—an analytical method that identifies the age of a material that once formed part of the biosphere by determining its carbon-14 content and tracing its age by its radioactive decay.Carbon-14 is a naturally occurring isotope of the element carbon.The tree rings were dated through dendrochronology.At present, tree rings are still used to calibrate radiocarbon determinations.Libraries of tree rings of different calendar ages are now available to provide records extending back over the last 11,000 years.The trees often used as references are the bristlecone pine (Pinus aristata) found in the USA and waterlogged Oak (Quercus sp.) in Ireland and Germany.And indeed, results of calibration are often given as an age range rather than an absolute value.
Carbon consists of 99% carbon-12, 1% carbon-13, and about one part per million carbon-14.
Radiocarbon dating laboratories have been known to use data from other species of trees.
In principle, the age of a certain carbonaceous sample can be easily determined by comparing its radiocarbon content to that of a tree ring with a known calendar age.
The NERC Radiocarbon Facility (East Kilbride) is a central facility for the UK's Natural Environment Research Council (NERC), providing dating support in the environmental sciences.
The laboratory has an "open-door" policy for all existing and potential users of its facilities at all stages of their research projects, and collaboration is strongly encouraged.