Since that time, CALIB, now renamed Int Cal, has been refined several times--as of this writing (January 2017), the program is now called Int Cal13.Int Cal combines and reinforces data from tree-rings, ice-cores, tephra, corals, and speleothems to come up with a significantly improved calibration set for c14 dates between 12,000 and 50,000 years ago.
A man called Willard F Libby pioneered it at the University of Chicago in the 50's. This is now the most widely used method of age estimation in the field of archaeology.We should see some interesting results in the very near future. Carbon-14 dating can be used on objects ranging from a few hundred years old to 50,000 years old.- the direct chemisorption into a Li alloy of carbonaceous gases produced by the controlled thermo-destruction of organic materials under vacuum conditions.- Above technology widened application of conventional C-14 analyse equipment for different kind of materials.Lake Suigetsu's annually formed sediments hold detailed information about environmental changes over the past 50,000 years, which radiocarbon specialist PJ Reimer believes will be as good as, and perhaps better than, samples cores from the Greenland Ice Sheet. report 808 AMS dates based on sediment varves measured by three different radiocarbon laboratories.The dates and corresponding environmental changes promise to make direct correlations between other key climate records, allowing researchers such as Reimer to finely calibrate radiocarbon dates between 12,500 to the practical limit of c14 dating of 52,800.The latest curves were ratified at the 21st International Radiocarbon Conference in July of 2012.Within the last few years, a new potential source for further refining radiocarbon curves is Lake Suigetsu in Japan.The half-life of an isotope like C14 is the time it takes for half of it to decay away: in C14, every 5,730 years, half of it is gone.So, if you measure the amount of C14 in a dead organism, you can figure out how long ago it stopped exchanging carbon with its atmosphere.