PNNL

Abstract

The International Monitoring System (IMS) is a verification component of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), and in addition to a series of radionuclide monitoring stations, contains sixteen radionuclide laboratories capable of verification of radionuclide station measurements. This paper presents an overview of a new commercially obtained low-background detector system for radionuclide aerosol measurements recently installed in a shallow (>30 meters water equivalent) underground clean-room facility at Pacific Northwest National Laboratory. Specifics such as low-background shielding materials, active shielding methods, and improvements in sensitivity to IMS isotopes will be covered.