Direct method for the quantitative analysis of surface contamination on ultra-low background materials from exposure to dust

TL;DR

This paper introduces a direct, ICP-MS-based method for quantifying dust-borne radionuclide fallout on materials, improving accuracy over previous model-based estimates in low-background environments.

Contribution

It presents a novel direct measurement technique for surface contamination from dust, validated at PNNL and SNOLAB, enhancing precision in low-background material analysis.

Findings

Validated method for radionuclide fallout measurement.

Applied method successfully in underground and laboratory settings.

Provides more accurate contamination assessments than previous models.

Abstract

In this work we present a method for the direct determination of contaminant fallout rates on material surfaces from exposure to dust. Naturally occurring radionuclides K-40, Th-232, U-238 and stable Pb were investigated. Until now, background contributions from dust particulate have largely been estimated from fallout models and assumed dust composition. Our method utilizes a variety of low background collection media for exposure in locations of interest, followed by surface leaching and leachate analysis using inductively coupled plasma mass spectrometry (ICP-MS). The method was validated and applied in selected locations at Pacific Northwest National Laboratory (PNNL) and the SNOLAB underground facility.