Radiocarbon dating tooth enamel nuclear radiation carbon dating
It is rarely possible to directly radiocarbon date skeletal remains from hot environments as collagen rapidly degrades.
Although able to survive in the majority of burial environments for longer, unburnt biological apatites frequently produce inaccurate radiocarbon dates due to contamination from carbonate in the groundwater.
To extract carbon for measurement, researchers at CAMS turn a sample into carbon dioxide through either combustion or a chemical process and then reduce the carbon dioxide to graphite—a form of carbon—on an iron catalyst.
“The graphite is what we measure,” says Livermore scientist Bruce Buchholz, who helped pioneer this technique at CAMS.
Bruce Buchholz loads a wheel of samples into the spectrometer at the Laboratory’s Center for Accelerator Mass Spectrometry (CAMS) to determine the materials’ concentration of carbon-14. its inception 25 years ago, the Center for Accelerator Mass Spectrometry (CAMS) at Lawrence Livermore has supported scientific research for a diverse range of disciplines.
The precise measurement capabilities at CAMS allow researchers to identify the isotopic composition of a given sample.
Carbon exists naturally in three forms (or isotopes).
Remember, in non-ionized atoms the number of negatively charged electrons spinning around the nucleus is equal to the number of positively charged protons in the nucleus.
One important research endeavor involves determining the precise age of biological material generated in the past 60 years by measuring the ratio of radiocarbon (or carbon-14) to the carbon-12 and carbon-13 in samples.Livermore researcher Bruce Buchholz and colleagues at the Karolinska Institute are looking at victim's teeth to determine how old they are at the time of death.Using the Lawrence Livermore's Center for Accelerator Mass Spectrometry, Buchholz determined that the radioactive carbon-14 produced by above-ground nuclear testing in the 1950s and 1960s remains in the dental enamel, the hardest substance in the body.The radiocarbon analysis showed that dating the teeth with the carbon-14 method would estimate the birth date within one year.Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster, because the age at death, birth date, and year of death, as well as gender, can guide investigators to the correct identity among a large number of possible matches.
Though these projects approach the questions from somewhat different angles, they will undoubtedly help us gain a greater understanding of early hominin diets, behavior and environment.