An Improved Handheld Radioisotope Identifier (RID) for Both Locating and Identifying Radioactive Materials


R. M. Keyser, T. R. Twomey, D. L. Upp


The two initial steps in any program designed to interdict illicit trafficking of radioactive and nuclear materials are location and identification. Many handheld radioisotope identifiers (RIDs) have been introduced that claim to perform both of these tasks for gamma-emitting sources, yet only a few locate neutron sources and still fewer perform well as identification tools due to the low resolution gamma-ray detectors employed. An HPGe-based RID (Detective) has been shown to give superior performance in the identification of radionuclides in static conditions, that is, once the source has been located, according to the test processes given in ANSI 42.34. It has been generally thought that large systems, such as the NaI-based NAI-SS system or a plastic scintillator-based portal monitor would be used for the location even though the RID specifications include a search mode. We tested the Detective-EX in its search mode for both gamma- and neutron-emitting sources and compared the results to an NaI-based RID. The tests were done using single nuclide sources (Cs-137, Co-60) and a neutron source (Cf-252) in shielded and unshielded situations. The systems were moved past the sources at specified distances to simulate the actual search operation at an inspection station.


This abstract was presented at the 38th Annual Midyear Meeting, "Materials Control and Security: Risk Assessment, Handling, and Detection", Advances in Instrumentation, Materials Detection and Measurement Session, 2/13/2005 - 2/16/2005, held in New Orleans, LA.

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