Glass fiber sensors for detecting special nuclear materials at portal and monitor stations

Nuclear Safeguards and Security Systems LLC (NucSafe) participated in the Illicit Trafficking Radiation Assessment Program (ITRAP) recently conducted by the Austrian Research Center, Seibersdorf (ARCS) for IAEA, INTERPOL, and the World Customs Organization (IAEA, in press). This presentation reviews ITRAP test results of NucSafe instrumentation. NucSafe produces stationary, mobile, and hand-held systems that use neutron and gamma ray sensors to detect Special Nuclear Materials. Neutron sensors are comprised of scintillating glass fibers (trade name 'PUMA' for Pu Materials Analysis), which provide several advantages over 3He and 10BF3 tubes. PUMA 6Li glass fiber sensors offer greater neutron sensitivity and dynamic counting range with significantly less microphonic susceptibility than tubes, while eliminating transport and operational hazards. PUMA sensors also cost less per active area than gas tubes, which is important since rapid neutron detection at passenger, freight, and vehicle portals require large sensor areas to provide the required sensitivity. Two PUMA glass fiber neutron and gamma ray sensor systems were designed that exceed the ITRAP detection and ancillary requirements for continuous SNM monitoring of: 1) vehicles and 2) pedestrians. Monte Carlo and first principal calculations were applied to model detection limits for both systems. Modeling results for the glass fiber neutron sensors evaluated for the Vehicle Monitoring System are shown