Liquid scintillation counter for measuring environmental tritium and radiocarbon

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Natural and anthropogenic (thermonuclear) tritium and radiocarbon from the atmosphere are excellent tracers in the hydrological cycle. The rate of circulation of modern groundwater can be measured by the decay of tritium (T½ = 12.3 years) which is incorporated from the atmosphere during recharge. Radiocarbon (T½ = 5730 years) is a dating tool for groundwaters as well as paleoclimate indicators including cave deposits and organic material. Measuring these important tracers is routinely done by counting radioactive decay with a liquid scintillation counter (LSC). This proposal is to purchase a LSC to support environmental and Earth resources research including: groundwater circulation through permafrost that feeds salmon spawning habitat in the Arctic, the movement of contaminants through watersheds, mineral exploration in the north, and the burial of radioactive waste in deep bedrock. This LSC will also be used to screen tritium samples that we can measure to very low detection limits by ingrowth of the daughter, 3He, on our helium isotope mass spectrometer.