Kevin Schultz|on September 2, 2015
A large, two-engine helicopter has been buzzing over the Bay Area this week at speeds up to 80 mph and at elevations as low as 300 feet.
The flyovers are part of a research project to measure and record naturally occurring background radiation levels throughout the area — and use those levels as a baseline to identify any new sources of radiation as a matter of public safety.
The work is being done by researchers at the Department of Homeland Security and Lawrence Berkeley National Laboratory who have equipped the copter with gamma radiation-sensing technology. The helicopter is flying across a gridded route spanning San Francisco, Oakland, Berkeley, Richmond and Pacifica.
“It’s important for our national safety to have better technology to detect even weak sources of radiation on the ground,” said Kai Vetter, a UC Berkeley professor of nuclear engineering who is participating in the research.
The chopper flew over San Francisco on Tuesday and Berkeley on Wednesday.
Residents and UC students in Berkeley took to their phones to complain or question City Hall about the copter’s presence and to find out why it was flying so close to the ground.
“I heard the deep rumble over the loud music playing in my car as I saw it come up from behind in my rear view going down Shattuck Avenue,” said Berkeley resident Gavin Wolfe, who eventually took to Twitter to share news of the helicopter.
Berkeley city officials said they received calls, even though they sent out a release to notify residents in advance.
“Obviously, you start wondering what’s going on when you see a helicopter flying so low around the city,” said Jennifer Coats, Berkeley police spokeswoman.
San Francisco city officials also knew in advance that the flyovers were going to take place.
“I knew about this before,” said Albie Esparza, San Francisco police spokesman. “So I proactively sent information to the Department of Emergency Management.
“They only fly over for about two hours. That’s a very minimal amount of time.”
Still, Kristin Hogan, a spokeswoman for San Francisco’s Department of Emergency Management, said a handful of residents called to report or ask about the helicopter during Tuesday’s flyovers.
“Most were just general inquiries,” she said. “Being in San Francisco, most of the public is used to helicopters. We really didn’t get any calls from people who were too worried.”
The chopper is scheduled to fly over the Presidio and Pacifica on Thursday and over Twin Peaks and Noe Valley on Friday.
The helicopter made similar sweeps over the Bay Area in 2012 and has collected flyover data in other cities such as Las Vegas and Washington, D.C.
Read Full ArticleVetter said there are two main reasons for this week’s flyovers.
“One is to evaluate and demonstrate this new technology,” he said.
The Bay Area’s diverse geological features — such as the mix of cityscapes, mountains and shorelines — helps to fine-tune the radiation-tracking technology, he said.
“The second,” Vetter said, “is to map the background radiations.”
He said that levels may have changed since 2012 and that this week’s flyovers provide an opportunity to find out. In fact, he said, changes in levels have been detected, but all of those differences involve natural sources of radiation.
The technology could identify amounts of radiation from other sources — for example, from a nuclear power plant meltdown. A former version of this technology recorded some of the first readings in Japan from the 2011 Fukushima nuclear disaster.
This initiative, the Aerial Radiological Survey, has been going on for three years. The Bay Area’s flyovers should finish by Friday.
The Department of Homeland Security declined to comment.
Kevin Schultz is a San Francisco Chronicle staff writer. E-mail: KSchultz@sfchronicle.com Twitter: @KevinEdSchultz