Hand-held gamma spectrometer HM-5 Experiences in nuclear Safeguards application, challenges, requirements for the future

The hand-held gamma-ray spectrometer HM-5 has become an important and widely used tool for nuclear Safeguards inspectors. In this presentation, the experiences gained in nuclear Safeguards application are discussed. The challenges of its use in the additional IAEA mandate of complementary access (CA) are detailed as well. The HM-5 functionality was of a mainly qualitative nature until U-enrichment determination capability was added. The NaIGEM (NaI Gamma Enrichment Measurements) software (developed by R. Gunnink) was used which implements the enrichment meter principle by fitting the 186keV peak of 235U, and relies on reference material for one point calibration. Consistency tests were made on a variety of enrichments and uncertainties are recorded. The paper gives an overview of tests made under laboratory and in-field conditions and the results obtained. Although HM-5 has been continuously improved since its initial deployment, advances in detector crystal materials, digital electronics, computing power, interface and connectivity devices and concepts, software standardisation etc. call for the design and development of a successor of HM-5, dubbed HM-6. This document also aims at providing a vision and discusses user requirements for such an instrument.