Resonance Ionization Spectroscopy for Dating Very Old Groundwater
When cosmic rays hit the Earth’s atmosphere a number of radioisotopes such as 14C, 39Ar, 10Be and 39C1 are produced, which are extensively used in isotope geophysics as natural tracers and for dating various materials from organic substances in archeology to old groundwater and polar ice core samples. The concentration of these trace substances is usually extremely low, requiring very sensitive detection techniques. Low background proportional counters and more recently accelerator mass spectrometry have successfully been used. With both these techniques, however, it is not possible to detect 81Kr, which is another cosmic-ray produced radioisotope of great potential, especially for use in groundwater- and polar ice core dating. Its half-life of 210,000 years would enable studies of natural archives back to about one million years.
KeywordsCold Spot Accelerator Mass Spectrometry Resonance Ionization Spectroscopy Isotopic Selectivity 81Kr Atom
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