Nuclear security helicopter travels Boston Marathon route for radiation

This morning, a Department of Energy helicopter flew over towns and suburbs in eastern Massachusetts, looking for radiation before the 125^e Boston Marathon. The sweep is part of the security preparations to help first responders identify possible “dirty bombs” and other terrorist activity before they claim their lives.

The flight began with a thorough scan of the start line in the western suburbs of Hopkinton before traveling the 26.2 mile route to the finish line in Boston, where the helicopter conducted another full survey . The craft flew at low altitude the entire time, diving below 100 feet on several occasions, according to FlightAware.

The twin-engine Bell 412 (tail number N412DE) is operated by the National Nuclear Security Administration, a division of the Department of Energy that is responsible for everything from non-proliferation to maintaining the country’s nuclear stockpile. The helicopter is part of the agency’s aerial measurement system, which regularly performs radiological surveys before major events, including presidential inaugurations, Super Bowls and New Year’s celebrations in Las Vegas.

The NNSA will conduct additional surveys in the Boston area over the next three days, including Monday, when the marathon takes place. Today’s flight is intended to develop a map of background radiation sources, which will help the helicopter and other ground sensors detect any unusual radiological activity on race day, including “dirty bombs.” Which use traditional explosives to disperse radioactive materials.

Map sources

Background radiation maps are essential in these situations because the earth is constantly emitting varying levels of radiation. Some types of rocks emit more than others, and when near or on the earth’s surface, they can cause spikes that could otherwise trigger detectors and distract first responders. The National WWII Memorial in Washington, DC, for example, is made of copious amounts of granite and emits enough radiation to merit special mention in the 2009 Presidential Inauguration Radiation Investigation Report.

On board the AMS helicopter, two pilots fly the craft while a mission scientist and equipment operator monitor sensors and computers from behind. Fully loaded, the helicopter can fly for about two and a half hours before needing to refuel. Two modules suspended from the sides house four sodium iodide sensor modules which record gamma radiation once per second. The helicopter can also fly with helium-3 sensors used to detect neutron radiation.

The entire AMS fleet consists of two Bell 412 helicopters and three Beechcraft BN-350 planes spread between Joint Base Andrews in Maryland and Nellis Air Force Base in Nevada.

The Boston Marathon has become a high security event since two National Terrorists detonated homemade pressure cooker bombs at the finish line in 2013, killing three people and injuring more than 250. The attack sparked a hunt. the multi-day man who resulted in a shootout in nearby Watertown. While AMS investigations likely cannot detect the types of explosives used in the 2013 bombing, the investigations are part of a larger effort to secure the event. The Commonwealth has designated the route as a “drone-free zone” and police are stationed throughout the race. Checkpoints are scattered around high traffic areas where officers can search bags and coolers for weapons or explosives.

It might sound like a lot of safety for a race, but not many people in the Boston area are complaining. I crossed the finish line area less than an hour before the 2013 bombing and holed up for the following days of lockdown. I always attend the race to cheer on the runners, and every year I am happy to see federal and state law enforcement prepare for a series of possible incidents, however distant they may seem.