DARPA Completes First City-Scale Round of SIGMA Tests
“Incorporating more data will further improve the ability of the SIGMA system to differentiate between safe and illicit radiation sources and increase our capabilities to monitor wide areas for radiological and nuclear threats," said John Donnelly, D.C. Fire and EMS deputy fire chief.
The Defense Advanced Research Projects Agency's SIGMA program, which aims to prevent radiological "dirty bomb" attacks and other nuclear threats, completed its largest test deployment of vehicle-mounted radiation detectors in Washington, D.C., in February, the agency announced March 1. For about seven months starting in July 2016, the fleet of D.C. Fire and Emergency Medical Services ambulances was outfitted with DARPA-developed nuclear and radiological detectors, "providing the first city-scale, dynamic, real-time map of background radiation levels throughout the Capital as well as identifying any unusual spikes that could indicate a threat," according to the announcement.
The test involved up to 73 large detectors on emergency vehicles; they logged some 100,000 hours of detector operation covering more than 150,000 miles and identified thousands of radiation sources in real time. "Items as innocuous as natural granite used in construction, as well as lingering radiation after certain medical treatments, can trigger positive responses. SIGMA detectors can readily distinguish between these kinds of benign sources and threatening ones. Equally important, the SIGMA detectors provided detailed background radiation maps of the [District of Columbia] against which future sources may be more easily detected. The deployment also offered an opportunity to test and refine the wireless data fusion aspects of the system, which constantly fed information about vehicle location and radiation readings to a central command post," DARPA reported.
"D.C. Fire and EMS was an invaluable partner and test bed for SIGMA's vehicle-scale detectors," explained Vincent Tang, theDARPA program manager. "The data gathered during the D.C. deployment are helping to further fine tune the SIGMA system for potential deployment in major cities across the country and for emergency use by active-duty military units and National Guard civil support teams."
"Historically, increases to detection capabilities came from improved individual detectors," said John Donnelly, D.C. Fire and EMS deputy fire chief. "The most significant capability gain since 9/11 was spectroscopic detectors for first responders. D.C. Fire and EMS was interested in the SIGMA program because DARPA approached the problem differently. By not only putting more spectrometers into the field, but also networking them so that the data is continuously collected and analyzed with other, and prior, information as a whole, SIGMA laid the groundwork for a monitoring system that can incorporate intelligence holistically into risk assessment. Incorporating more data will further improve the ability of the SIGMA system to differentiate between safe and illicit radiation sources and increase our capabilities to monitor wide areas for radiological and nuclear threats."
DARPA reported that the SIGMA system has developed two types of radiation detectors—a larger size like those deployed in the emergency vehicle tests and inexpensive, smartphone-sized mobile devices that can be worn on a belt by police officers or others. "The devices run on advanced software that can detect the tiniest traces of radioactive materials. Those devices, networked with detectors along major roadways, bridges, and other fixed infrastructure, promise significantly enhanced awareness of radiation sources and greater advance warning of possible threats. The SIGMA detectors themselves do not emit radiation but detect gamma and neutron radiation emanating from sources," according to the agency, which reported that it plans more tests of SIGMA's wide-area monitoring capability and will transition the operational system to local, state, and federal entities during 2017 and 2018.