On the measurability of true coincidence summing in the GRIFFIN spectrometer
Year: 2026
Type: article
Abstract: The measurement of gamma-rays from decaying nuclei allow for the investigation into nuclear structure. True coincidence summing occurs when two gamma-rays from a single decay get detected in a single detector and their energies sum together to give false peaks in the energy spectrum. Corrections to this summing effect are crucial for an accurate determination of nuclear decay events. The summing correction formalism of Semkow et al., (1990) is generalized here into the Semkow matrix formalism and is extended into a multiplicity expansion. This formalism is used to calculate the matrix probabilities for 180-degree coincidence events as a method for correcting coincidence summing; in doing so, the deviation between the full correction and this 180-degree correction is shown as a function of multiplicity. This formalism is extended to the partitioned matrix formalism , to calculate probabilities for gated gamma rays; where two gamma-rays of interest are taken in multi-detector coincidence. The summing correction probabilities for gated gamma-rays are provided and the deviation is shown in a manner similar to that of the singles. Terms such as measurability, event equivalence, and ontic and epistemic events are defined. It is shown that within these definitions, coincidence summing is not sufficiently measurable, or rather, its sufficient measurability is statistically bounded by the deviations derived. • This paper address coincidence summing effects present in gamma-ray spectroscopy. • The 180-degree method that is used for correcting coincidence summing by the GRIFFIN collaboration at TRIUMF is outlined and its probabilities are calculated via an extended matrix formalism. • The limits of this correction method are investigated and give remaining deviations on the order of 10 − 3%, showing the validity of this method. • The matrix formalism is further extended to provide theoretical probabilities for general coincidence/gated events and the high-order coincidence summing that occurs therein. • For readers interested in spectroscopic analysis of gamma-rays for the means of creating nuclear levels to understand nuclear structure, knowledge of such gated events and the ability to navigate the combinatorics of them is crucial.
Source: Applied Radiation and Isotopes
Author: Liam L. Schmidt
Institution: University of Guelph
Language: English
Subfield: Radiation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,220
OpenAlex ID: W7128927930