Year
2022
Abstract
| To enhance and improve international safeguards, the International Atomic Energy Agency (IAEA) intends to develop and deploy an advanced gamma-ray measurement instrument for fresh nuclear material verification. Specifically, the IAEA is interested in the next generation of the Hand-Held Monitor, Version 6 (a successor to HM-5) and plans to use it as a hardware platform and software environment for a “consolidated gamma-ray spectrometric” system. The HM-6 module will be an advanced gamma spectrometry probe based on a large volume high-performance cadmium-zinc-telluride (CZT) detector, with higher energy resolution. Such detectors have recently become available from the manufacturer H3D, Inc. To support IAEA’s safeguards mission, the performance of the high resolution CZT detector and the enhanced isotopic analysis codes are being evaluated by a multi-laboratory collaboration. The properties of the CZT detector, model M400 consisting of four CZT crystals and an analog ASIC, were evaluated for gamma spectrometry based isotopic analysis of uranium bearing sources. Gamma-ray spectra were acquired at Oak Ridge National Laboratory (ORNL) and Lawrence Livermore National Laboratory (LLNL) using uranium sources of known enrichments and M400 CZT detectors. The sources spanned a wide range of 235U abundances, from 0.29% to 93.2%. The spectra were supplied to the “Analyzing Laboratories” SNL, LANL, LLNL, and PNNL. The capability of gamma spectrometry codes FRAM (LANL), GEM (PNNL), CZTU (LLNL), and GADRAS (SNL) were extended to work with M400 CZT spectra and the performance of the codes has been validated. Random and systematic uncertainties were derived for each code based on an Analysis of Variance (ANOVA). The challenges and advantages of using the high resolution CZT for uranium isotopic analyses are discussed. |