A new method of measuring Kr-81 and Kr-85 abundances in environmental samples - art. no. 2068

摘要

1] We demonstrate a new method for determining the Kr-81/Kr ratio in environmental samples based upon two measurements: the Kr-85/Kr-81 ratio measured by Atom Trap Trace Analysis (ATTA) and the (85) Kr/Kr ratio measured by Low-Level Counting (LLC). This method can be used to determine the mean residence time of groundwater in the range of 10(5) - 10(6) a. It requires a sample of 100 mul STP of Kr extracted from approximately two tons of water. With modern atmospheric Kr samples, we demonstrate that the ratios measured by ATTA and LLC are directly proportional to each other within the measurement error of +/- 10%; we calibrate the Kr-81/Kr ratio of modern air measured using this method; and we show that the Kr-81/Kr ratios of samples extracted from air before and after the development of the nuclear industry are identical within the measurement error. [References: 13