WASHINGTON: The US has developed a tiny portable neutron device that could detect the hidden presence of nuclear materials.
Designed to help governments and international inspectors prevent the smuggling and unauthorised use of nuclear weapons and materials, the device is undergoing trials in the US department of energy's Argonne National Laboratory in Illinois.
According to official sources, the device is built around a small wafer of gallium arsenide, a semi-conducting material similar to silicon. When coated with boron or lithium, gallium arsenide can detect the neutrons emitted by the fissile materials that fuel nuclear weapons.
"The working portion of the wafer is about the diameter of a collar button but thinner," according to Raymond Klann, who leads the group from Argonne's technology development division that developed the wafer and detector.
"It is fairly straightforward to make full-sized detector systems the size of a deck of cards, or even smaller. Something that small can be used covertly, if necessary, by weapons inspectors to monitor nuclear facilities."
The key to detection, he said, is to coat the gallium arsenide with something like boron or lithium. When neutrons strike the coating, they produce a cascade of charged particles that is easy to detect.
The wafers are made by inexpensive, conventional microchip-processing techniques,
Klann said. They can be tailor-made for specific applications by varying the type and thickness of the coating. Compared to other neutron detectors, Mr Klann's detector has a number of advantages.
Argonne National Laboratory, America's first national laboratory, conducts basic and applied scientific research across a wide spectrum of disciplines, ranging from high-energy physics to climatology and biotechnology.