Mass Correlation of Presumed Twin Air Filters for Emergency Response Applications

摘要

The progeny of radon (~(222)Rn) and thoron (~(220)Rn) (primarily bismuth and polonium) are known interferents during rapid evaluation of transuranic content on air filters. These difficulties stem from the alpha particles emitted by the progeny radionuclides whose energies overlap the transuranic region of interest (3-5.5 MeV) and can overwhelm the spectra. In radiological emergency response scenarios, airborne radioactivity concentrations are determined through rapid deployments and analysis of portable air samplers. Radon concentrations are not consistent over time or geographic location which affect the activity but do not necessarily correlate with ambient aerosol concentrations (and therefore the mass) deposited on the filter. Known complexities in radon concentrations include wind speed, temperature, barometric pressure and humidity producing diurnal and seasonal variations [1]. However, these radon levels are noted to be cyclic over time [2]. Thoron levels in the environment are typically about one-tenth that of radon concentrations [3]. Interest lies in determination of the correlation between two air filters which are presumed to contain twin activity loadings. This is evaluated here based on both activity and mass of paired air sample results. Applications for emergency response scenarios are discussed in support of ongoing work.