The U.S. Department of Energys Argonne National Laboratory has developed a small, portable detector for finding concealed nuclear weapons and materials. When the device is completed, it could assist international inspectors charged with preventing smuggling and unauthorized use of nuclear weapons and materials. The heart of the Argonne device is a small wafer of gallium arsenide (GaAs), a semiconducting material similar to silicon. When coated with boron or lithium, GaAs can detect neutrons, such as those emitted by the fissile materials that fuel nuclear weapons. Patents are pending on several detectors and their components.
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