Performance Characteristics of a Third Generation Portable

236 Performance Characteristics of a Third Generation Portable Radionuclide Identifier Ronald M. Keyser and Timothy R. Twomey ORTEC, 801 South Illinois Avenue, Oak Ridge, TN 37830 ABSTRACT The continuing need for a hand-held, portable radionuclide identifier for use in countering illicit nuclear trafficking and in positive identification of radioactive materials, benign or threat, has fostered the development of a next generation of instruments. Changes from the existing instrument have been made in response to the evolving needs of various users of the previous identifiers, but without reducing any performance with regard to ANSI N42.34. To address the requirements of front-line operators, the instrument was made significantly lighter and smaller, but the same HPGe gamma-ray detector crystal size has been retained, meaning previous performance data is still valid. In order to increase the ruggedness of the instrument the previous COTS PDA has been replaced with a custom, built-in processor. The instrument housing is now waterproof, with all connector apertures being sealed with plugs. The instrument capability has been improved by expanding the library to include nuclides recently adopted in medical procedures and encountered by reach-back teams, as well as other nuclides of interest identified during the millions of operating hours logged by the existing germanium-based identifiers. Battery lifetime was increased by using newer battery technology, new electronics for cooler controls and signal processing. The overall system has been further reduced in size and complexity by incorporating the battery charger internal to the instrument itself. The Detective family has already undergone extensive testing and the new instrument, the Micro-Detective, was subjected to some of the same tests. The results of testing with common gamma-ray sources and neutron sources is shown and compared with the results of previous instruments, showing compliance with ANSI N42.34.The continuing need for a hand-held, portable radionuclide identifier for use in countering illicit nuclear trafficking and in positive identification of radioactive materials, benign or threat, has fostered the development of a next generation of instruments. Changes from the existing instrument have been made in response to the evolving needs of various users of the previous identifiers, but without reducing any performance with regard to ANSI N42.34. To address the requirements of front-line operators, the instrument was made significantly lighter and smaller, but the same HPGe gamma-ray detector crystal size has been retained, meaning previous performance data is still valid. In order to increase the ruggedness of the instrument the previous COTS PDA has been replaced with a custom, built-in processor. The instrument housing is now waterproof, with all connector apertures being sealed with plugs. The instrument capability has been improved by expanding the library to include nuclides recently adopted in medical procedures and encountered by reach-back teams, as well as other nuclides of interest identified during the millions of operating hours logged by the existing germanium-based identifiers. Battery lifetime was increased by using newer battery technology, new electronics for cooler controls and signal processing. The overall system has been further reduced in size and complexity by incorporating the battery charger internal to the instrument itself. The Detective family has already undergone extensive testing and the new instrument, the Micro-Detective, was subjected to some of the same tests. The results of testing with common gamma-ray sources and neutron sources is shown and compared with the results of previous instruments, showing compliance with ANSI N42.34.