Bulk Composite Materials for Detection of Gamma Radiation
Small Business Information
TETRAMER TECHNOLOGIES, LLC
657 S. Mechanic Street, Pendleton, SC, 29670
AbstractDevelop economical industrial-scale process for production of bulk gamma radiation detectors based on composite material(s) that have characteristics comparable to large single-crystal detectors. DESCRIPTION: The current generations of moderate- and high-resolution detectors for gamma radiation are based on single crystals of semiconductor or scintillator material. Examples include high-purity germanium, cadmium-zinc telluride (CZT), mercuric iodide, thallium bromide, rare-earth halides, and cesium lithium yttrium chloride (CLYC). For wide band-gap semiconductors capable of operating at ambient temperature, achievable energy resolution for gamma detection is less than 1% FWHM at 662 keV. For single crystal scintillators, 3% energy resolution has been demonstrated. National security applications require large bulk crystals of similar energy resolution with sufficient stopping power for efficient near-real time detection of gamma energies up to 3 MeV. Large single crystals of many materials have proved difficult to produce consistently and reliably on an industrial scale, and consistent production of some crystals is possible only in small batches at relatively high cost. Composite or nano-composite materials potentially offer attractive radiation-detection characteristics, such as high energy resolution and high stopping power for high gamma energies, without the need or high cost of producing large single crystals. Composite materials could potentially be produced in large sizes at lower cost, be configured in sizes and shapes appropriate for unique radiation-detection applications, and have durable physical properties that would enable radiation detectors to operate in the harsh environments encountered in military operations. In general, large batch production of composite materials requires small, even nano-scale sized materials with appropriate and consistent radiation-detection properties. These small particles must then be combined at relatively high density with a binder that makes feasible the efficient extraction of electronic charge or of light proportional to the amount of radiation energy deposited in the material. For many thin-film nano-materials, the available thickness of the product typically has insufficient stopping power for the higher energy gamma rays. Furthermore, layering thin-film devices to create thick detectors is not always feasible or economical. A detector made of composite materials should have attractive radiation detection properties comparable to detectors based on single crystals, including energy resolution, detection efficiency, response time, and stopping power. The economical scaling of nano- or micro-scale process to a large bulk material is also important. PHASE I: Demonstrate consistent production of a composite material(s) in small batches Measure the radiation response of a sample of the proposed material for several gamma energies up to and including 662 keV Produce a detailed plan for volume production of the material into a bulk configuration of sufficient size to reliably stop 3 MeV gamma rays PHASE II: Demonstrate consistent medium batch-scale production of composite material Demonstrate high-energy gamma detection characteristics of the bulk material comparable to single-crystal detectors Demonstrate capability for scaling to an industrial-scale process, including a full cost analysis supporting industrial scale process Deliver a prototype detector demonstrating marketable configurations for military applications Provide a planned commercialization path forward PHASE III DUAL USE APPLICATIONS: Potential additional national security applications for a successful low-cost, bulk-composite radiation detector would include homeland security, forensics, and local state and federal responders to a possible radiation incident. Additional applications beyond national security could include medical imaging, physics experiments, and radiation contamination mapping. REFERENCES: 1. Glenn Knoll, "Radiation Detection and Measurement", 3rd Edition, New York: John Wiley and Son, 2000
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