Abstract: A long-range method and a system for reliably detecting and identifying special nuclear materials is provided that relies on the emission of delayed neutrons present in the decay of fission products (delayed neutron precursors) as a unique signature for the special nuclear materials, such as highly enriched uranium (235/238U). The method relies on a time-of-flight measurement in the first 1 ?s after the inducing radiation pulse, and pulse height data analysis for both neutrons and gamma rays that can be done at a much higher data rate than in traditional pulse processing systems. The thermal neutron fission within the time regime of 100-500 ?s provides a unique signature of special nuclear materials such as the highly enriched uranium.

Abstract: A ?-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive ?-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a ?-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the ?-radiation. Subsequently, it is determined whether a coincidence exists between the ?-particles and ?-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the ?-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.

Abstract: A long-range method and a system for reliably detecting and identifying special nuclear materials is provided that relies on the emission of delayed neutrons present in the decay of fission products (delayed neutron precursors) as a unique signature for the special nuclear materials, such as highly enriched uranium (235/238U). The method relies on a time-of-flight measurement in the first 1 ?s after the inducing radiation pulse, and pulse height data analysis for both neutrons and gamma rays that can be done at a much higher data rate than in traditional pulse processing systems. The thermal neutron fission within the time regime of 100-500 ?s provides a unique signature of special nuclear materials such as the highly enriched uranium.

Abstract: A ?-radiation detection system that includes at least one semiconductor detector such as HPGe-Detector, a position-sensitive ?-Detector, a TOF Controller, and a Digitizer/Integrator. The Digitizer/Integrator starts to process the energy signals of a ?-radiation sent from the HPGe-Detector instantly when the HPGe-Detector detects the ?-radiation. Subsequently, it is determined whether a coincidence exists between the ?-particles and ?-radiation signal, based on a determination of the time-of-flight of neutrons obtained from the ?-Detector and the HPGe-Detector. If it is determined that the time-of-flight falls within a predetermined coincidence window, the Digitizer/Integrator is allowed to continue and complete the energy signal processing. If, however, there is no coincidence, the Digitizer/Integrator is instructed to be clear and reset its operation instantly.