Bias in 238U decay chain members measured by γ-ray spectrometry due to 222Rn leakage

Grzegorz Poręba; Konrad Tudyka; Agata Walencik-Łata; Aleksander Kolarczyk

doi:10.1016/j.apradiso.2019.108945

Bias in ²³⁸U decay chain members measured by γ-ray spectrometry due to ²²²Rn leakage

Appl Radiat Isot. 2020 Feb:156:108945. doi: 10.1016/j.apradiso.2019.108945. Epub 2019 Oct 16.

Authors

Grzegorz Poręba¹, Konrad Tudyka², Agata Walencik-Łata³, Aleksander Kolarczyk⁴

Affiliations

¹ Silesian University of Technology, Institute of Physics - Centre for Science and Education, Division of Radioisotopes, Ul. S. Konarskiego 22B, 44-100, Gliwice, Poland. Electronic address: grzegorz.poreba@polsl.pl.
² Silesian University of Technology, Institute of Physics - Centre for Science and Education, Division of Radioisotopes, Ul. S. Konarskiego 22B, 44-100, Gliwice, Poland. Electronic address: konrad.tudyka@polsl.pl.
³ University of Silesia, Institute of Physics, Department of Nuclear Physics and Its Applications, Ul. 75 Pułku Piechoty 1, 41-500, Chorzów, Poland.
⁴ MiDose Solutions, Ul. Wolności 234b/4, 41-800, Zabrze, Poland.

PMID: 31732423
DOI: 10.1016/j.apradiso.2019.108945

Abstract

In this work we investigate and quantify how effectively the noble gas ²²²Rn is trapped inside measurement beakers used in high-resolution gamma-ray spectrometry. We test six types of different beakers commonly utilized in γ spectrometry, including one novel construction, the γBeaker. We assessed ²²²Rn leakage by injecting ²²²Rn rich air into the examined beakers and investigated the abnormal decrease in ²²²Rn daughters - ²¹⁴Pb and ²¹⁴Bi. The measured decay times were used to estimate the ²²²Rn leakage. In addition, we investigated the influence of an additional beaker sealed with tape. However, the additional beaker sealing only slightly reduced the ²²²Rn escape and was not reproducible. Almost every tested beaker exhibited heavy ²²²Rn leakage. This may lead to an underestimation and radioactivity over-dispersion of ²³⁸U decay chain members when they are measured via their ²²²Rn daughter products.

Keywords: Emanation; Gamma; Gas tightness; HPGe; Leakage; Radon; γBeaker.