For small samples, blank contribution as a fraction of sample mass becomes a more important term, so a mass balance blank correction is applied.
Due to counting and measurement errors for the blanks and samples, statistical errors are higher for very old samples.
Thus, ages are limited by the age of the process blanks (more on that below) and by the statistical uncertainty of the C ratios of the blank, the sample and the modern reference, respectively.
In brief, radiocarbon dating compares the amount of c14 in a dead animal or plant to the available carbon in the atmosphere. But, carbon in the atmosphere has fluctuated over time, and so raw RCYBP dates must be calibrated to a more accurate time value. This glossary entry is part of the Dictionary of Archaeology.
In general, radiocarbon dates can be calibrated by using comparable dendrochronological dates or other known dating systems.
The surface of the graphite is sputtered with heated, ionized cesium and the ions produced are extracted and accelerated in the AMS system.
After acceleration and removal of electrons, the emerging positive ions are magnetically separated by mass and the C counts per second are collected.
Common Abbreviations for RCYBP: C14 ka BP, 14C ka BP, B. Read more about the Radiocarbon Revolution, part of the Timing is Everything short course on archaeological dating.
Also, see the online calculator called CALIB; the original program was developed by Minze Stuiver and colleagues over 20 years ago and is probably the best known.
Numerous software programs have been developed to complete the calibrations for the investigator, including a new online version of the best known software CALIB. Pearson 1986 High-precision calibration of the radiocarbon time scale, AD 1950-500 BC.