J.C. Hayes¹ , K. Silvers¹ , C. Aalseth¹ , T. Alexander¹ , H. Back¹ , M. Foxe¹ , L. Lidey¹ , J. Mendez¹ , D. Stephenson¹ , R. Suarez¹ , G. Whyatt¹

¹Pacific Northwest National Laboratory

Abstract:

PNNL is exploring the use of 37Ar for detecting nuclear explosion, including for use in the International Monitoring System (IMS). A high throughput 37Ar separation and measurement system was developed at Pacific Northwest National Laboratory (PNNL) to detect 37Ar activity generated from an underground nuclear explosion. Argon-37 is an activation product generated when neutrons interact with calcium in the soil surrounding an underground nuclear explosion. As a noble gas, argon is unreactive and migrates through the earth and can be released into the atmosphere with the radioxenon fission gases that are also produced during a nuclear explosion. Detection of 37Ar can be a confirmatory measurement for a nuclear test, and when combined with radioxenon isotopes from the same sample the confidence that a nuclear explosion occurred improves significantly. PNNL has performed a large number of soil gas and atmospheric background measurements to understand gas migration of naturally occurring Ar-37 in the soil and for experiments where 37Ar and 127Xe were injected into a nuclear test cavity. PNNL will present on the newly developed Argon-37 High Throughput system as well as discuss measurements made at locations throughout the northwest region of the United States.