PASSINGS

Seth H. Neddermeyer, Atom Bomb Physicist

Seth H. Neddermeyer, 80, a physicist credited with developing the implosion trigger that enabled the atomic bomb to be detonated. He was working for the National Bureau of Standards when J. Robert Oppenheimer tapped him for the Manhattan Project in Los Alamos, N.M., which built the bomb. Neddermeyer, who had studied earlier at Caltech, left in 1946 to become a professor at the University of Washington, where his research on cosmic rays helped lead to the discovery of subatomic particles called muons. “I get so overwhelmed by a feeling of terrible guilt when I think about the history of the bomb,” he said in 1983. “I’m terribly worried now about the current world situation. What the hell can we do about it?” The U.S. Department of Energy gave him its highest scientific honor, the Enrico Fermi Award, in 1983. In Seattle on Friday of the complications of Parkinson’s disease.