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

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 40K, 232Th, 238U and stable Pb were investigated. Until now, background contributions dust particulate have largely been estimated models assumed composition. Our utilizes variety low collection media in locations interest, followed by surface leaching leachate analysis using inductively coupled plasma mass spectrometry (ICP-MS). The was validated applied selected at Pacific Northwest National Laboratory (PNNL) SNOLAB underground facility. A comparison between data obtained ICP-MS measurements those current model-based predictors is also performed. Discrepancies one order magnitude or higher are observed directly measured accumulation rates.