Tests of the U.S. Department of Homeland Security’s (DHS) next-generation radiation portal detectors slated for use at the country’s ports of entry yielded mixed results, spurring the government’s watchdog agency to recommend further testing and phased fielding of the devices.
At the request of Congress, the U.S. Government Accountability Office (GAO) reviewed DHS testing of its new advanced spectroscopic portal (ASP) radiation detection monitors. DHS plans to replace its existing polyvinyl toluene (PVT) portal monitors with ASP devices.
PVT devices detect radiation in a vehicle but cannot pinpoint its location. This results in what DHS calls “innocent alarms,” in which a machine successfully detects radiation, but from a harmless source such as earthenware dishes or kitty litter, requiring a time-consuming physical inspection of the vehicle.
DHS testing of ASP devices produced mixed results, while GAO took issue with the rigor of the tests themselves.
The tests showed that ASP machines are slightly more sensitive to radioactive threats when they are concealed at a modest, baseline level. But when the threats are shielded less or more, ASP’s advantage over PVT is erased, according to GAO.
Overall, ASP machines are five times less likely to produce false alarms. U.S. Rep. Bennie Thompson, D-MS, chairman of the House Homeland Security Committee, said that advantage must be weighed against a nearly three-fold increase in cost.
"At a current cost of $308,000 each for the current system to $822,000 for each new machine is not a small matter. The taxpayer must be assured that an extra one half million dollars per machine will benefit our national security and the public’s safety," Thompson said.
GAO further found that DHS tested the new machines against the agency’s standard, somewhat dated PVT devices. DHS should have tested the new machines against PVT devices that have current upgrades for maximum sensitivity, investigators said.
GAO predicted hiccups when DHS fields the new devices at ports of entry, and therefore recommended a phased roll out. DHS agreed with that recommendation but disagreed with two others: testing of ASP against PVT machines at their full potential and revision of the schedule for full testing and certification of ASP.
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