Calibration Model Development and Performance Evaluation of Portable Multichannel Analyzer for In-Situ Nuclear Forensics

Abstract

The rapid response to nuclear security incidents necessitates precise, field-deployable instrumentation capable of quantifying nuclear material. This study evaluated the Portable Multichannel Analyzer (PMCA) equipped with a NaI(Tl) detector as a first-responding tool for nuclear forensics. Tertiary standards of natural and depleted uranium (0.5–30 g) were measured under varying acquisition times (60–1200 s) to establish calibration curves and determine performance metrics. Key performance indicators, including Relative Standard Deviation (RSD), uncertainty, and detection limits, were compared across linear and polynomial models. The PMCA demonstrated high precision with RSDs <8% for uranium masses >3 g. Polynomial calibration curves achieved superior accuracy (R² > 0.99), significantly reducing uncertainty compared to linear models. Benchmark comparisons with HPGe spectrometry and destructive potentiometric titration validated PMCA measurements, showing <5% deviation in uranium concentration. The findings established PMCA's viability as a rapid, reliable instrument for in-field nuclear forensic investigations, bridging the gap between laboratory-grade systems and field-deployable solutions.