The US Defense Threat Reduction Agency (DTRA’s) detection system couples an active interrogation source of pulsed monoenergetic or bremsstrahlung spectrum gamma rays and low energy neutrons with a series of passive neutron and gamma ray sensors and sensor networks. The design enables the scanning of ships, trucks, airplanes and other cargo carriers at normal transit speeds. A variety of commercially available sensors are compatible with the system, including devices developed in cooperation with DTRA.
The single, intense pulse interrogation of the DTRA system elicits a prompt response from the Special Nuclear Material (SNM), making it possible to interrogate fast moving objects in a matter of seconds. The nature of the pulse also boosts the signal compared to the natural background, and pulse power active interrogation technology is capable of simultaneously producing both neutron and gamma ray probing radiations from a single source.
The detection of SNM, such as uranium-235 and plutonium, is an ongoing national security interest. Radiation portal monitors exceed $150,000 in cost but are susceptible to variations in background radiation and not selective against naturally occurring radioactive material common in commerce. Advanced spectroscopic portals have also been deployed, but they are costly and have a limited production capacity. The DTRA system holds potential to quickly and accurately detect SNM. The development of this technology reflects a DTRA partnership with the Naval Research Laboratory (NRL) and several radiation detector developers.
- Fast: Detection time of three seconds is 40 times faster than a linear accelerator system
- Accurate: Measuring the short duration prompt neutron signal gives a false alarm probability of less than one in a million
- Flexible: A wide variety of existing passive sensors and sensor aggregators can be incorporated to tailor a detection system to a wide array of specific requirements
- US Patent 8,110,807
- Potential for R&D collaboration with DTRA researchers