Thoron standard source

Robert Lindsay; Elmughera Elhag; Robert J de Meijer; Joash N Ongori; Peane P Maleka

doi:10.1016/j.apradiso.2019.01.028

Thoron standard source

Appl Radiat Isot. 2019 May:147:99-104. doi: 10.1016/j.apradiso.2019.01.028. Epub 2019 Feb 1.

Authors

Robert Lindsay¹, Elmughera Elhag², Robert J de Meijer³, Joash N Ongori⁴, Peane P Maleka⁵

Affiliations

¹ Department of Physics and Astronomy, University of the Western Cape, Bellville, South Africa. Electronic address: rlindsay@uwc.ac.za.
² Department of Physics and Astronomy, University of the Western Cape, Bellville, South Africa; Centre for Science and Technology, Ahfad University for Women, Po.Box167, Omdurman, Sudan.
³ Department of Physics and Astronomy, University of the Western Cape, Bellville, South Africa; Stichting EARTH, Weehorsterweg 2, 9321 XS, Peize, the Netherlands.
⁴ Department of Physics and Astronomy, University of the Western Cape, Bellville, South Africa.
⁵ iThemba LABS, National Research Foundation, PO Box 722, 7129, Somerset West, South Africa.

PMID: 30826732
DOI: 10.1016/j.apradiso.2019.01.028

Abstract

Thoron (²²⁰Rn) has been identified as a possible health concern in specific places such as monazite processing plants and (rare-earth) mines. The short half-life of thoron (55.8 s) makes thoron calibration sources and thoron chambers less common than the corresponding radon (²²²Rn) ones. In this paper an inexpensive and straight forward but accurate thoron source is described that can easily be set up in typical nuclear environmental laboratories. The source of thoron is a solution of Th(NO₃)₄ in water. Thoron is extracted by bubbling air through the solution using an aerator. The gamma rays from the solution are measured at the same time. The thoron activity concentration in the exit stream follows from the reduction in the intensity of the gamma rays from the progeny of thoron over time.

Keywords: Gamma spectroscopy; Thorium nitrate; Thoron measurements; Thoron source.