Intercomparison studies of Instrumental Neutron Activation Analysis using singles and gamma–gamma coincidence spectrometry for trace element determination in sodalime glass and sediment matrices and utilization of coincidence method for rapid automobile glass forensics

Abstract Instrumental Neutron Activation Analysis (INAA) using research reactor neutrons is a powerful nuclear analytical technique for multi-elemental determination in diverse matrices. In the present work, two different matrix samples namely sodalime glass and sediment samples have been analyzed by INAA using neutrons from research reactors at BARC. Samples were assayed by γ - γ coincidence spectrometry besides conventional (singles) counting using HPGe detector systems due to the presence of higher background from medium and long-lived activation products including 24Na. Accuracies of both the methods were evaluated by analyzing geological Certified Reference Material USGS CRM G2. INAA method with singles counting could give trace elemental concentrations of sixteen elements with about 10 days cooling period compared to nine elements by γ - γ coincidence method with a minimum of 4 days cooling period. Results of elemental concentrations are reported by both the methods along with experimental detection limits. Five automobile (sodalime) glass fragments were analyzed by INAA using γ - γ coincidence method for forensic applications utilizing seven trace elements of interest in grouping study. Concentrations of Sc and elemental concentration ratios like La/Sc indicated that five glasses fall into two major groups, which was confirmed by statistical cluster analysis. Though both the approaches of INAA are authentic for forensic applications for provenance study utilizing determined concentrations of trace elements, γ - γ coincidence INAA is helpful for giving results with less turnaround time of analysis.