Contextual Isotope Ranking Criteria for Peak Identification in Gamma Spectroscopy Using a Large Database

Abstract

Isotope identification is a recurrent problem in γ spectroscopy with high purity germanium detectors. In this work, new strategies are introduced to facilitate this type of analysis. Five criteria are used to identify the parent isotopes making a query on a large database of γ-lines from a multitude of isotopes producing an output list whose entries are sorted so that the γ-lines with the highest chance of being present in a sample are placed at the top. A metric to evaluate the performance of the different criteria is introduced and used to compare them. Two of the criteria are found to be superior than the others: one based on fuzzy logic, and another that makes use of the γ relative emission probabilities. A program called histoGe implements these criteria using a SQLite database containing the γ-lines of isotopes which was parsed from WWW Table of Radioactive Isotopes. histoGe is Free Software and is provided along with the database so they can be used to analyze spectra obtained with generic γ-ray detectors.