Standardization of 241Am by digital coincidence counting, liquid scintillation counting and defined solid angle counting

TL;DR

This paper compares three methods—digital coincidence counting, liquid scintillation counting, and solid angle counting—for standardizing 241Am, demonstrating their consistency within 0.3% and analyzing uncertainties in detail.

Contribution

It introduces a comprehensive comparison of three standardization techniques for 241Am, highlighting their agreement and detailed uncertainty analysis.

Findings

All three methods agree within 0.3%

Uncertainty analysis detailed for each method

Solution will be sent to the International Reference System

Abstract

The nuclide 241Am decays by alpha emission to 237Np. Most of the decays (84.6 %) populate the excited level of 237Np with energy of 59.54 keV. Digital Coincidence Counting was applied to standardize a solution of 241Am by alpha-gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional counter and the results were compared with two other independent techniques: Liquid Scintillation Counting using the logical sum of double coincidences in a TDCR array and Defined Solid Angle Counting taking into account activity inhomogeneity in the active deposit. The results show consistency between the three methods within a limit of a 0.3%. An ampoule of this solution will be sent to the International Reference System (SIR) during 2009. Uncertainties were analysed and compared in detail for the three applied methods.