Vincent Tang and the SIGMA Team

Physicist Vincent Tang has a clear and laser-focused goal: “Not even once” would a major United States city or world capital fall victim to a terrorist’s radiological dirty bomb or nuclear device that could threaten our very way of life.

Tang and his team at the Defense Advanced Research Projects Agency are following through on that objective. They have developed and successfully tested a network system with mobile, low-cost, monitoring units the size of a smartphone that first responders can use to detect the smallest traces of radiological and nuclear materials. This system—called SIGMA—promises to provide greater protection for highly populated cities in the United States and around the world.

“The technology that Vincent Tang and the SIGMA team have created and deployed has made it so that bringing in the materials needed for a dirty bomb will be like trying to bring a blimp in unnoticed,” said Bill Regli, the acting director of DARPA’s Defense Sciences Office. “Everyone will be safer from weapons of mass destruction and terror.”

Before the SIGMA team’s breakthrough, the latest state-of-the art detection technology was the size of a shoebox and cost tens of thousands of dollars per unit, making deployment on a large scale very difficult. The new wearable devices, costing $400 each, are the size of a cell phone, easily networked and can determine whether detected radiation poses a threat or is commonplace.

Another key advancement is the system’s connectivity and scalability to many thousands of nodes. Algorithms connect the individual detectors into a network that provides officials with an “eye-in the-sky” picture of where radiological threats are and how to combat them. 

The mobile detectors, when networked along with larger detectors deployed in vehicles, could provide continuous and real-time coverage of a city. The new system can process incoming data at rates akin to Twitter’s global network of 6,000 feeds per second, with the goal of more than 10,000 feeds per second by 2018.

James Griglio is a police lieutenant at the Port Authority of New York and New Jersey, which has been one of SIGMA’s initial partners. “The technology cuts down and almost completely limits frivolous alarms,” he said.

Such frivolous alarms, he added, “can be very cumbersome, tedious and labor-intensive to track down.” SIGMA, he said, “is like jumping from a black-and-white TV to a smart TV in one day.”

Tang’s task was formidable. Not only was he attempting to transform the state of detection technology, he had to manage relationships across the private and public sectors, and with international governments, to build and deploy the system successfully.

The physicist also knew that he and his team could not closet themselves in a lab to develop the new technology and present it as a fait accompli. Tang knew he needed to test it in the real world, yet he was cautioned not to test SIGMA that way, he said.

“They told me to build a mock city,” he said. But he rejected such suggestions. He knew it was vital to pilot the system in actual places, in real time, to learn what tweaks needed to be made, and so the team could hear directly from first responders if there were any red flags. “From the very beginning, we worked with operators and first responders, folks who would carry it in the field,” Tang said.

The project began in 2014 and has been tested in the New York City and Washington, D.C. metropolitan areas, and will also be piloted outside the U.S.

During a month-long demonstration at a Port Authority of New York and New Jersey transportation hub in 2016, their success locating and identifying sources of radiation increased a hundredfold compared with the detection system already in place.

About 73 detectors also were installed last year on emergency vehicles in Washington, D.C. that together logged more than 100,000 hours of detector operations and covered more than 150,000 miles. DARPA also oversaw a successful one-day test of more than 1,000 SIGMA detectors, during which volunteers walked for several hours in the vicinity of the National Mall.

The current plan is to transition the operational system to local, state and federal entities later this year and through 2018.

Those who have worked with Tang marvel at his attention to every detail involved in this project as well as his diplomatic skills.

“Dr. Tang had to overcome other people in government who were holed into territories,” said John Donnelly, deputy fire chief for the District of Columbia. “He simplified what he was doing into an explanation a lot of people could take. He isn’t threatening. He asks questions and listens to answers. He has persistence and won’t give up.”

Stefanie Tompkins, DARPA’s acting deputy director, called Tang “the glue that holds it all together.” Regli of the Defense Sciences Office, said, “Vincent exudes such deep commitment and sincerity that people line up to help him.”

For Tang, SIGMA has been the highlight of his career thus far. “It has been an amazing experience working with the team and interagency partners like the Domestic Nuclear Detection Office to bring SIGMA to fruition, and to know that we are making a substantial difference to our national security,” he said.