gamma-ray spectroscopy of trinitite using an upgraded gamma-X coincidence detection system

Precise radiation spectroscopy is essential for nuclear forensics and material characterization. The Gamma-X Version 3 coincidence detection array at SUNY Geneseo—developed in 2014 by a collaboration between SUNY Geneseo and the University of Rochester’s Laboratory for Laser Energetics—has undergone a major upgrade to improve spectral resolution and coincidence discrimination. The original configuration, comprised of three coaxial pairs of NaI(Tl) detectors placed in an orthogonal configuration within a aluminum clad lead shielding enclosure, has been modified by replacing a pair of NaI(Tl) detectors with two high-purity germanium (HPGe) detectors along the vertical axis.



To benchmark the enhanced system performance, gamma-ray spectroscopic analysis of trinitite was performed on the 80th anniversary month of the Trinity test. The HPGe detectors have identified discrete gamma emissions consistent with isotopes such as Eu-152, Cs-137, and Pu-239, characteristic of fission and activation products associated with plutonium-based detonations. Notably, additional spectral features inconsistent with canonical trinitite signatures have emerged, suggesting the presence of either unidentified nuclides, instrumental anomalies, or long-lived radioactive daughter products. Ongoing analysis aims to resolve these features and assess the utility of the upgraded system for high-resolution nuclear spectroscopy.