Berkeley residents will have to endure the sound of helicopters through Saturday, as a low flying helicopter makes daily flights around the bay area to measure naturally-occurring background radiation levels.

According to a press release by the National Nuclear Security Administration, the flyovers are part of a joint research project between the administration and the Department of Homeland Security’s Domestic Nuclear Detection Office to gather background data for improving aerial radiation measurement capabilities.

The estimated five-day survey — which started Aug. 27 and ends Sept. 1 — will be taken of an approximate 69-square-mile area which includes San Francisco, Pacifica and Oakland during daylight hours.

The twin-engine helicopter, operated by the Remote Sensing Laboratory Aerial Measuring System in Las Vegas, Nev., will fly in a grid pattern over the locations about 300 feet above the ground, the release said.