Radiocarbon dating can be used to determine the age of
In this process, nitrogen-14 (7 protons and 7 neutrons) gains a neutron and loses a proton, producing carbon-14 (6 protons and 8 neutrons).
The proportion of carbon-14 to carbon-12 in the atmosphere therefore remains relatively stable at about 1.5 parts per billion.
In Arizona, virtually all dating is performed by the Arizona Accelerator Mass Spectrometry (AMS) Laboratory at the University of Arizona in Tucson.
Most carbon atoms have six protons and six neutrons in their nuclei and are called carbon 12. But a tiny percentage of carbon is made of carbon 14, or radiocarbon, which has six protons and eight neutrons and is not stable: half of any sample of it decays into other atoms after 5,700 years.In recent years, dating methods based on cosmogenic isotopes other than carbon (such as beryllium-10 and chlorine-36) have been developed, which allow for the dating of a wider variety of objects over much longer time scales.There are eight AMS laboratories currently operating in the Unites States.To correct for this, scientists have compared radiocarbon dates from objects who's age is known by other means, such as artifacts from Egyptian tombs, and growth rings from ancient trees.In this way, calibration tables have been developed that eliminate the discrepancy.
Search for radiocarbon dating can be used to determine the age of:
Archaeologists are acutely aware of these and other potential difficulties, and take extreme care in the selection and handling of objects to be dated. In the 1970s a new technique was developed called Accelerator-based Mass Spectrometry (AMS), which counts the number of carbon-14 atoms directly.