Large-Volume Cadmium Zinc Telluride Modules for Safeguards Verification of Unirradiated
Nuclear Material

The main techniques to date for the non-destructive assay (NDA) verification of fresh nuclear material to support IAEA safeguards verification requirements are primarily based on various high-, medium- and lowresolution gamma spectrometry systems (e.g., high-purity germanium, lanthanum bromide, sodium iodide). The IAEA’s objective is to reduce the miscellany of systems and to provide inspectors with spectrometric tools based on advanced technologies capable of covering multiple verification contexts, while offering a user-friendly interface requiring only limited training. The Department of Safeguards developed user requirements for a compact instrument operable at room temperature and capable of reaching uncertainty performance targets within a measurement time optimized by a combination of high detection efficiency and superior energy resolution. Thus far, the M400 CZT modules offered by H3D, Inc. (USA) have been the only technical solution able to meet such demanding requirements. After a thorough evaluation of all the required characteristics and performance of the CZT modules, with emphasis on the stability of their detection efficiency over a large temperature range, the IAEA is introducing the MCA-Touch-based CZT Module (MCCM) as its primary solution for NDA verification of unirradiated nuclear material. The MCCM is a gamma spectrometry system based on the M400 CZT and operated by the MCAT acquisition software developed by GBS Elektronik (Germany) hosted on a miniature PC. Including its specially developed tungsten collimator and external battery, the MCCM weighs less than 2 kg and represents a highly portable instrument providing inspectors with a dramatically improved usability experience compared to current systems based on electrically cooled germanium or lanthanum bromide detectors. This paper reports on MCCM system performance and the initial efforts to achieve readiness for deployment to inspectors for field use of this new instrument. It details the process that the IAEA undertook to introduce the system, from the initial determination of the requirements, through assessment and verification of actual instrument performance, demonstration of suitability for envisaged safeguards verification methods, and other activities related to its integration into the IAEA safeguards instrumentation environment.