Kernan, Warnick J | Search NASA

DOE OSTI2010

Neutron Detection Alternatives to 3He for National Security Applications

One of the main uses for 3He is in gas proportional counters for neutron detection. Large radiation detection systems deployed for homeland security and proliferation detection applications use such systems. Due to the large increase in use of 3He for homeland security and basic research, the supply has dwindled, and can no longer meet the demand. This has led to the search for an alternative technology to replace the use of 3He-based neutron detectors. In this paper, we review the testing of currently commercially available alternative technologies for neutron detection in large systems used in various national security applications.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗

DOE OSTI2010

Alternatives to 3He for Neutron Detection for Homeland Security

Neutron detection is an essential aspect of interdiction of radiological threats for national security purposes, since plutonium, a material used for nuclear weapons, is a significant source of fission neutrons. Radiation portal monitoring systems, of which there are thousands deployed for homeland security and non-proliferation purposes, currently use 3He gas-filled proportional counters for detecting neutrons. Because of the high usage of 3He for neutron scattering science and national security, the supply has dwindled, and can no longer meet the demand. Consequently, a replacement technology for neutron detection is required in the very near future.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

DOE OSTI2010

Alternative Neutron Detection Testing Summary

Radiation portal monitors used for interdiction of illicit materials at borders include highly sensitive neutron detection systems. The main reason for having neutron detection capability is to detect fission neutrons from plutonium. Most currently deployed radiation portal monitors (RPMs) use neutron detectors based upon 3He-filled gas proportional counters, which are the most common large area neutron detector. This type of neutron detector is used in the TSA and other RPMs installed in international locations and in the Ludlum and Science Applications International Corporation RPMs deployed primarily for domestic applications. There is a declining supply of 3He in the world and, thus, methods to reduce the use of this gas in RPMs with minimal changes to the current system designs and sensitivity to cargo-borne neutrons are being investigated. Four technologies have been identified as being currently commercially available, potential alternative neutron detectors to replace the use of 3He in RPMs. These technologies are: 1) Boron trifluoride-filled proportional counters, 2) Boron-lined proportional counters, 3) Lithium-loaded glass fibers, and 4) Coated wavelength-shifting plastic fibers. Reported here is a summary of the testing carried out at Pacific Northwest National Laboratory on these technologies to date, as well as measurements on 3He tubes at various pressures. Details on these measurements are available in the referenced reports. Sponsors of these tests include the Department of Energy (DOE), Department of Homeland Security (DHS), and the Department of Defense (DoD), as well as internal Pacific Northwest National Laboratory funds.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗