Scientists have found a way to use neutrons, the uncharged particles found in all known atoms except hydrogen, to scan contents of freight containers.
About 6.5 million tons of container cargo pass through United States ports on any given day. Currently, only 2 percent of containers are actually inspected for explosives or other hazardous substances. Since Sept. 11, the US Coast Guard has been looking for a better way to inspect containers without unduly slowing commerce.
Ancore Corp., of Santa Clara, Calif., has developed a new scanning technology that uses neutrons to "read" the chemical composition of the contents of such things as trucks and cargo containers. A computer then analyzes the signals from the scanning to determine whether drugs or explosives are present, based on material-specific images, says Douglas Brown, vice president for programs and business development at Ancore.
"Detection based on material-specific images eliminates the shortcomings of X-rays, which only recognize distinguishable shapes," Mr. Brown says. "And computer-based detection eliminates human error." Computer databases store the material-specific images to identify threatening items. The database can be continuously updated. If a new explosive is developed, its signature can be added to that of substances the system is programmed to look for.
US efforts to counter drug trafficking spurred the development of this technology. The first use of neutron scanning to look specifically for explosives occurred after the 1995 Oklahoma City bombing.
It is estimated that for between $50 million and $80 million, 40 port inspection facilities could be installed. This would let inspectors increase the share of incoming containers they check to 20 percent.