John Alexander Simpson

John Alexander Simpson (November 3, 1916 – August 31, 2000) was an American physicist and science educator. He was deeply committed to educating the public and political leaders about science and its implications, most notably as a principal founder of the ''Bulletin of the Atomic Scientists'' and a long-time member of the organizations Board of Sponsors.

He is known for inventions such as the gas flow α-particle proportional counter (for measuring plutonium yields in the presence of high intensity fission products), and the neutron monitor, and for having several of the instruments he created launched into space, such a dust flux monitor aboard the ''Stardust'' spacecraft.

Simpson spent his career as an instructor and researcher for the University of Chicago's Enrico Fermi Institute and Department of Physics, where he conducted experiments in nuclear physics and with cosmic rays. His research continued up until a few weeks prior to his death. He died of pneumonia which he contracted in the hospital following a successful heart surgery. The year he died, his instruments in space had been sending data back for nearly 40 years. Provided by Wikipedia