Characterisation of sealed radioactive source for nuclear forensic purposes

Abstract

A study characterized sealed radioactive sources (60Co, 137Cs, and 241Am) for nuclear forensic analysis, focusing on their physical, macroscopic, and radiological properties. Results revealed specific features, such as stamped or engraved information, that served as valuable signatures for nuclear forensic investigation. Corrosion observations provide valuable insights into the condition of the source and historical context. Gamma-ray spectra analysis revealed clear distinctions, including a scattering peak in cylindrical 60Co and 137Cs disk sources (200-500 keV), which was absent in the cup-style 241Am source. Unusual peaks in the gamma spectra of 60Co, 137Cs, and 241Am sources suggested potential impurities or background radiation. This was indicated by non-Gaussian shapes and significant counts per second at specific energy levels. X-ray radiography effectively highlights nuclear material characteristics, emphasizing density, uniformity, and internal structure. This analysis contributed to the development of a National Nuclear Forensic Library (NNFL) and enhanced Malaysia’s capability in nuclear forensic investigations related to radioactive sources found outside regulatory control.