Luis Alvarez was an experimental physicist who was awarded the Nobel Prize for Physics in 1968.
Luis Walter Alvarez was born on 13 June 1911 in San Francisco. He was the son of the well-known physician and newspaper columnist Walter C. Alvarez, and the grandson of Luis F. Alvarez, a Spanish immigrant to the United States who was trained in medicine at Cooper Union Medical School and practiced in Hawaii. Alvarez’s aptitude for invention was stimulated by the mechanical and electrical instruments in his father’s laboratories at the Hooper Foundation in San Francisco and the Mayo Clinic in Rochester, Minnesota. By the time he was ten, he could use all the small tools in his father’s little home shop, measure resistances on a Wheatstone Bridge, and construct circuits. The next year he and his father built a crystal radio together. He first heard of physics when he was high school and his father suggested a career in the area. Alvarez improved his mechanical skills by two high-school summers spent in the Mayo Clinic instrument shop. Alvarez chose to study at the University of Chicago, where he received his BSc, MS, and PhD in physics.
As his senior thesis, he built a Geiger counter—then only recently invented and not yet in commercial production. This was to set the pattern for his career in physics: Alvarez had a knack for thinking up practical experiments to test the latest physics theories, and for building the devices necessary to make these experiments. In a time when the equipment available for physicists was still extraordinarily primitive, this mechanical flair served him well.
Alvarez worked on microwave radar research at the Massachusetts Institute of Technology, Cambridge (1940–43), and participated in the development of the atomic bomb at the Los Alamos Scientific Laboratory, Los Alamos, New Mexico, in 1944–45. He suggested the technique for detonating the implosion type of atomic bomb. He also participated in the development of microwave beacons, linear radar antennas, the ground-controlled landing approach system, and a method for aerial bombing using radar to locate targets. After World War II Alvarez helped construct the first proton linear accelerator. In this accelerator, electric fields are set up as standing waves within a cylindrical metal “resonant cavity,” with drift tubes suspended along the central axis. The electric field is zero inside the drift tubes, and, if their lengths are properly chosen, the protons cross the gap between adjacent drift tubes when the direction of the field produces acceleration and are shielded by the drift tubes when the field in the tank would decelerate them. The lengths of the drift tubes are proportional to the speeds of the particles that pass through them. In addition to this work, Alvarez also developed the liquid hydrogen bubble chamber in which subatomic particles and their reactions are detected.
In 1968, Alvarez was awarded the Nobel Prize in Physics for his bubble-chamber work and the resulting discoveries. On 1 September 1988, a year after he completed his autobiography, Alvarez died of cancer in Berkeley, California. His work in high-energy physics had transformed experimental practice by importing collaborative research into the laboratory, and contributed to the triumph of “big science” in the twentieth century.
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