Speaker: Grant Ford
Research Engineer, Nuclear Security Science and Policy Institute (NSSPI), Texas A&M University

Abstract Summary:

In order to increase the capability to detect material with a low signal-to-noise ratio, such as Highly Enriched Uranium (HEU), researchers at Texas A&M are developing a new neutron detector concept that is direction sensitive. This capability would lower the detection threshold of HEU and allow for faster response time and recovery. The angular information is generated using the Doppler broadening of the 477 keV gamma ray produced from the (n,α) reaction in ¹⁰B. This reaction results in an alpha particle and ⁷Li particle which is in an excited state 94% of the time. The ⁷Li reaches the ground state through the emission of a 477 keV gamma ray whose final kinetic energy will be affected by the kinetic energy and direction of the initial ⁷Li particle. It is this difference that results in the Doppler broadened energy spectrum of the gamma ray. If the energy of the gamma ray, alpha particle, and ⁷Li can be measured accurately, then this information can be combined with the location of the detectors to determine the initial direction of the incoming neutron. If a solid state neutron detector "doped" with Boron can be developed and coupled with an energy sensitive gamma detector then this concept could prove very effective in detecting low signature neutron sources.