Absolute standardization of 57Co and analysis of the results obtained in two international comparisons

Maria Sahagia; Aurelian Luca; Andrei Antohe; Mihail-Razvan Ioan

doi:10.1016/j.apradiso.2018.07.005

Absolute standardization of ⁵⁷Co and analysis of the results obtained in two international comparisons

Appl Radiat Isot. 2018 Oct:140:146-150. doi: 10.1016/j.apradiso.2018.07.005. Epub 2018 Jul 6.

Authors

Maria Sahagia¹, Aurelian Luca², Andrei Antohe², Mihail-Razvan Ioan²

Affiliations

¹ Horia Hulubei National Institute of R&D for Physics and Nuclear Engineering, IFIN-HH, Reactorului str.30,Magurele, Ilfov RO 077125, Romania. Electronic address: msahagia@nipne.ro.
² Horia Hulubei National Institute of R&D for Physics and Nuclear Engineering, IFIN-HH, Reactorului str.30,Magurele, Ilfov RO 077125, Romania.

PMID: 30015044
DOI: 10.1016/j.apradiso.2018.07.005

Abstract

The absolute standardization of Co-57 by the 4π(PC)-γ coincidence method, in efficiency extrapolation variant, is presented. An original, improved method, based on the use of the equivalent decay scheme, was applied; apart from the enhancement of efficiency, a diminution of extrapolation slope was obtained, lowering the extrapolation uncertainty. The results obtained in the participation at the supplementary comparison CCRI(II)-S6.Co-57 and at the key comparison code BIPM.RI(II)-K1.Co-57 are presented. The method allows to simplify the treatment of ⁵⁶Co and ⁵⁸Co impurities' correction, which influences significantly the measurements in a CENTRONIC type ionization chamber. An example of treatment of this mixture, where the influence of impurities on results was analyzed, will be presented.

Keywords: (57)Co standardization; Equivalent decay scheme; Influence of impurities; Key and supplementary comparisons.