Maximum dating age equation
The terms "%Modern", or "pm C" and D14C are shown related in this diagram along with the Radiocarbon age in years BP (Before 1950 AD).If the reservoir corrected conventional radiocarbon age calculated is within the past 200 years, it should by convention be termed 'Modern' (Stuiver and Polach, 192).Much of the information presented in this section is based upon the Stuiver and Polach (1977) paper "Discussion: Reporting of C14 data". 1890 wood was chosen as the radiocarbon standard because it was growing prior to the fossil fuel effects of the industrial revolution.A copy of this paper may be found in the Radiocarbon Home Page The radiocarbon age of a sample is obtained by measurement of the residual radioactivity. T (National Institute of Standards and Technology; Gaithersburg, Maryland, USA) Oxalic Acid I (C). The activity of 1890 wood is corrected for radioactive decay to 1950.It is vital for a radiocarbon laboratory to know the contribution to routine sample activity of non-sample radioactivity.
'Normalized' means that the activity is scaled in relation to fractionation of the sample, or its delta C13 value.
In order to make allowances for background counts and to evaluate the limits of detection, materials which radiocarbon specialists can be fairly sure contain no activity are measured under identical counting conditions as normal samples.