Luis Walter Alvarez: 1911-1988: Nuclear Physicist, Inventor, Educator

Some of Alvarez's most significant contributions to physics were the process of K-electron capture, by which he discovered that nuclei gobble up their own electrons, and the development of the mercury vapor lamp, which produced a light wavelength that the U.S. Bureau of Standards adopted as its official measure of length. Among his breakthroughs was the discovery of the east-west effect of cosmic rays, which he and Arthur Compton studied while occupying the roof of Mexico City's Geneva Hotel with a Geiger telescope mounted on a wheelbarrow. In collaboration with Nobel Prize-winning physicist Felix Block of Stanford University, Alvarez produced slow-moving neutrons to determine their magnetic moment.

World War II placed Alvarez at an historic place and time and allowed him the opportunity to assist the war effort through research and invention. He introduced heavy-ion physics by identifying tritium, a radioactive form of hydrogen, and by deducing that helium-3 stabilized ordinary helium. In 1940 he developed radar systems for the U.S. military at the Massachusetts Institute of Technology radiation laboratory. He also developed a narrow radar beam to aid the landing of aircraft by a ground-based controller and produced Vixen, a system that diminished returning radar messages to convince German U-boat commanders that an attack plane was flying out of range. He created the Eagle high-altitude bombing system, a radar-guided means of sighting and dropping bombs on objects out of the pilot's range of vision. His microwave early-warning system solved the problem of sighting aircraft through fog, dust, or heavy cloud banks.

Two years before the end of World War II, as American scientists raced to outmaneuver the Germans in creating deadlier bombs, Alvarez joined the Manhattan Project, a team effort located at Los Alamos, New Mexico. His contribution was a detonator to set off the first plutonium bomb. During the initial atomic test at Alamogordo, New Mexico, on July 16, 1945, he flew with observers in a B-29 bomber. When the army dropped the "Fat Man" bomb on Hiroshima, Japan, on August 6, 1945, Alvarez observed from the B-29 that followed the bomber Enola Gay. The terrifying destruction of the unsuspecting city below alarmed Alvarez, but he maintained that the device was essential to end the war before Japan inflicted lasting harm on the United States. He also supported the creation of a hydrogen bomb to ensure national security.