The researchers are using a small, potentially portable accelerator located on campus to produce the neutrons, which are also being used in a separate study to detect corrosion in metals. Dr. Lanza noted that the MIT accelerator is of the same type that was to be used in the canceled superconducting supercollider, and was in fact manufactured by the same company. So by analyzing the gamma rays, researchers can identify the general composition of materials inside an object. That could indicate an explosive, because explosives tend to have high amounts of both nitrogen and oxygen as compared to more common materials, like sausages. Dr. Lanza stresses, however, that the technique is far from ready for use in an airport.
Many technical issues have yet to be resolved.
For example, the researchers are currently building different gamma-ray detectors for the accelerator to determine which will work best. Using a technique borrowed from X-ray astronomers, they hope to improve sensitivity by a factor of ten or more over previous work. Even if the technique can be made to consistently detect certain explosives or drugs, there's a catch. As a result, Dr. Lanza sees the neutron technique as one of many tools that could be used together to detect contraband. Nuclear engineering graduate students Erik B. Iverson, David W. Fink and Li Zhang are working with Dr. Lanza on the aircraft-security research, which is sponsored by the Federal Aviation Administration Technical Center in Atlantic City.