California GAMA Special Study. Development of a Capability for the Analysis of Krypton-85 in Groundwater Samples

doi:10.2172/1252619

GSTDTAP > 地球科学

DOI	10.2172/1252619
报告编号	LLNL-TR--665865
来源ID	OSTI ID: 1252619
	California GAMA Special Study. Development of a Capability for the Analysis of Krypton-85 in Groundwater Samples
	Visser, Ate; Bibby, Richard K.; Moran, Jean E.; Singleton, Michael J.; Esser, Bradley K.
	2015-06-01
出版年	2015
页数	25
语种	英语
国家	美国
领域	地球科学
英文摘要	A capability for the analysis of krypton-85 (⁸⁵Kr) in groundwater samples was developed at LLNL. Samples are collected by extracting gas from 2000-4000 L of groundwater at the well, yielding approximately 0.2 cm³ STP krypton. Sample collection takes 1 to 4 hours. Krypton is purified in the laboratory using a combination of molecular sieve and activated charcoal traps, and transferred to a liquid scintillation vial. The ⁸⁵Kr activity is measured by liquid scintillation on a Quantulus 1220 liquid scintillation counter from PerkinElmer. The detection limit for a typical 0.2 cm³Kr sample size is 11% of the present day activity in air, corresponding to the decay corrected activity in air in 1987. The typical measurement uncertainty is below 10% for recently recharged samples. Six groundwater samples were collected, purified and counted. ⁸⁵Kr was not detected in any of the samples counted at LLNL. ⁸⁵Kr was detected by the low level counting laboratory of Bern University in all samples between 1.5 and 6.6 decays per minute per cm³ krypton, corresponding to decay corrected activities in air between 1971 and 1985. The new capability is an excellent complement to tritium-helium, expanding the existing suite of age dating tools available to the GAMA program (³⁵S, ³H/³He, ¹⁴C and radiogenic helium). ⁸⁵Kr can replace ³H/³He in settings where ³H/³He ages are impossible to determine (for example where terrigenic helium overwhelms tritiogenic helium) and provides additional insight into travel time distributions in complex mixed groundwater systems.
URL	查看原文
来源平台	US Department of Energy (DOE)
引用统计
文献类型	科技报告
条目标识符	http://119.78.100.173/C666/handle/2XK7JSWQ/6815
专题	地球科学
推荐引用方式 GB/T 7714	Visser, Ate,Bibby, Richard K.,Moran, Jean E.,et al. California GAMA Special Study. Development of a Capability for the Analysis of Krypton-85 in Groundwater Samples,2015.