The Department of Homeland Security (DHS) Domestic Nuclear Detection Office (DNDO) is continually innovating technologies to improve radiation/nuclear detection while reducing costs. When it comes to mobile radiation detectors, a key component is the scintillator, or semiconductor crystal, which converts the incoming radiation into a spectra, or measurable electrical signal. Improvements in the performance and reduction in cost of these crystals could have a significant impact across much of the mission space of DNDO.
Elpasolites (el'pasō,līt) refer to a family of crystal structures, named after the site of discovery: El Paso County, Colo. Many of the elpasolites can be made into scintillators which exhibit several remarkable traits. First, the crystals respond to both gamma rays and neutrons, and can clearly differentiate between these two types of radiation. Second, the crystals provide much better energy resolution than what is currently in use, as the spectra created by these crystals are brighter and have less variation, which can be used to make faster and more accurate detectors.
The special density and dual gamma ray/neutron detection quality of elpasolite scintillators will one day eliminate the need for first responders to carry more than one compact detector. In addition, the crystal’s simple cubic structure is relatively easy to grow and less expensive than other scintillators. The reduced cost could allow for DNDO to acquire more mobile radiation units and expand the deployment of radiation detection capabilities.
Over the past three years, the Transformational and Applied Research (TAR) Directorate at DNDO, together with Defense Threat Reduction Agency (DTRA), has been working to raise awareness and acceptance for the material among the radiation and nuclear community and integrate it into detectors for evaluation. An Advanced Technology Demonstration (ATD) program is currently utilizing these crystals for development of advanced mobile detector handhelds; however the crystals may also be utilized in mobile detector backpack units. In the last year, over 51 large crystals (1" diameter by 1" long) have been provided to the ATD program via an Exploratory Research program which is developing this technology. Commercialization activities with a number of large companies that are manufacturers of radiation detection instruments are ongoing.