Atomic mass spectrometry dating
This isotope has six protons and eight neutrons and, crucially, is radioactive; over time, it decays to nitrogen-14 (with seven protons and seven neutrons).The half-life of carbon-14 is about 5,730 years, which means it takes that long for half the radioactive C atoms in a substance to decay.Carbon dating works because there are three naturally-occurring isotopes, or forms, of carbon, known as carbon-12, -13, and -14.Carbon-12, with six protons and six neutrons, makes up the vast majority of carbon on Earth, nearly 99 percent."That would allow us to track the sources and fates of carbon at the molecular scale." .The Penn State Accelerator Mass Spectrometry Laboratory will be administered by Penn State's Institutes for Energy and the Environment.Soon, Penn State will complete the preparation process by converting the carbon dioxide to graphite targets that will be analyzed by the new AMS.By the time the Penn State AMS facility is running at full tilt, it will be able to process and analyze up to 10,000 samples a year, from forensic cases, archaeological digs, and studies involving soil, sediment, water, and air.
"Eventually, we'd like to be able to look at individual molecules," says Freeman.Carbon-13, a stable, nonradioactive isotope with six protons and seven neutrons, makes up another one percent.The tiny amount left, only one carbon atom in a trillion, is carbon-14.It can take up to six months to have a sample tested.The new Penn State lab, featuring a powerful Pelletron accelerator built by the Wisconsin-based National Electrostatics Corporation, should ease that crunch considerably.
Search for atomic mass spectrometry dating:
Katherine Freeman, distinguished professor of geosciences at Penn State, uses it to follow crude oil compounds released from the 2010 Deepwater Horizon oil spill that were taken up by microbes living in sediments of the Gulf of Mexico.