Radon Equilibrium Equivalent Concentration Uncertainty of Calibration System With Alpha Self-Absorption Consideration

Abstract

The measurement of radon decay products level in dwellings or working places separately is not preferable. The estimation of radon equivalent equilibrium concentration (EECRn) is more simple and quick technique. In this work, the uncertainty of calibration system for EECRn measurements will present and the reduction will be suggesting. The calibration system for EECRn measurements was presented and described in previous work with gamma spectrometer as a reference measuring device. The influence of alpha particles absorption in filters materials and filter efficiency taken into account. The measurements of EECRn by gamma spectrometry and improved alpha radiometry are in good agreement and the systematic shift between average values is observed and resolved. The total standard uncertainty of EECRn measurements with gamma spectroscopy is 3.8%. About 71% of this total uncertainty value is related to the uncertainty of the count rate at full absorption peak with gamma spectroscopy. If the time between the end of sampling and gamma spectroscopy measurements reduced to 2000s not 4000 s, this value will reduce to 1.6% and the total standard uncertainty of EECRn will be 2.6%.