Liquid scintillation counter for measuring environmental tritium and radiocarbon

大气中的天然和人为(热核)氚和放射性碳是水循环中极好的示踪剂。现代地下水的循环速率可以通过在补给过程中从大气中并入的氚的衰变(Tç=12.3年)来测量。放射性碳(Tç=5730年)是地下水以及包括洞穴沉积和有机物质在内的古气候指标的测年工具。测量这些重要示踪剂的常规方法是用液体闪烁计数器(LSC)对放射性衰变进行计数。这项提议是购买LSC以支持环境和地球资源研究，包括：通过供养北极鲑鱼产卵栖息地的永冻层的地下水循环，污染物通过分水岭的移动，北部的矿产勘探，以及在深层基岩中掩埋放射性废物。这个LSC还将用于筛选氚样品，我们可以通过在我们的氦同位素质谱仪上植入3He子体来测量到非常低的检测下限。

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.