SBIR-STTR Award

DOE neutron facilities, such as the Spallation Neutron Source, (SNS) will be either coming online or upgraded in the next few years. For these facilites, a need exists for neutron scintillator detectors having improvements in detection efficiency, neutron-gamma discrimination, high counting rate capability, cost, and adaptability to unusual geometries. In previous work, a volumetric detector for neutron detection has been demonstrated, based on the loading of lithium-6 in a sol-gel with fluorescent compounds, both inorganic and organic. This project will develop and characterize scintillators based upon this technology with the aim of ultimately developing detectors with gamma rejection, comparable to He-3 tubes, with fast response times. Phase I will make scintillator test elements using a variety of different activators based upon the sol-gel technology. The test elements will be characterized in terms of neutron-gamma discrimination and light output, and the best combination of sol-gel formulation and activator will be selected for continued development in Phase II. Commercial Applications And Other Benefits as described by awardee: The coupling of volumetric detection with the photomultipliers that observe scintillation pulses should significantly improve neutron cross section capture. The volumetric detectors should fine use at DOE neutron beam facilities and at others around the world.

The efficient detection of neutrons over a large area of several square meters is required to allow the goals of the Spallation Neutron Source (SNS) to be achieved. This project will develop a large area, position-sensitive neutron detector for the SNS, based upon manufacturing a solid film that contains both scintillating and neutron absorbing material. In Phase I, two organic and eight inorganic scintillators were identified as having the short fluorescence, <100 ns, needed to achieve high neutron detection rates. A chemistry was developed to allow the scintillators to be mixed into a lithiated sol-gel and a stabilization coating was identified. Experimental measurements demonstrated neutron detection in every lithiated sol-gel film. Films containing a MINOS polystyrene organic scintillator had the fastest response. Of the inorganics, the CaS:Ce, the LSO, and the YAG yielded neutron detection efficiencies that could be utilized in the SNS. Phase II will experimentally test the scintillators/lithiated-glass-film combinations in order to identify formulations that can be manufactured in volume at a commercially viable cost. The test program will be tailored to the practical needs of the SNS for their facility.

Commercial Applications and Other Benefits as described by the awardee:
The primary application is for use at the Spallation Neutron Source being constructed in Oak Ridge, TN. The sol-gel glass films should have secondary application to national defense needs for locating fissile material hidden in containers that could be smuggled into the United States or across borders