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

After WWII, Alvarez returned to Berkeley to assume a full professorship and research high-energy nuclear physics. Applying the methods of Ernest Lawrence and Ernest Rutherford, he developed LINEAC, also called the Alvarez accelerator, which increased proton velocity. He tinkered with the mechanism until it became operational in 1947 and used it and the university's Bevatron to advance post-war physics. His advancement of nuclear physics distinguished Berkeley as a center of subatomic particle study. In the college laboratory, he constructed a synchrocyclotron, which boosted particulate speed to new levels.

After meeting with physicist Donald Glaser of the University of Michigan in 1953, Alvarez increased the capabilities of the first bubble chamber, a one-inch container of superheated ether in which observers could track the paths of subatomic particles. After replacing ether with liquid hydrogen, he invented equipment that recorded particle movements to within one billionth of a second. Within five years, he enlarged the bubble chamber to 72 inches and initiated its use in 1959, when he recorded a series of observations of baryons, mesons, and other minute particles in resonance states. As he worked on projects affecting national security, Alvarez received access to National Security Agency data, a trust that made him proud. His skillful problem-solving in the study of subatomic particles within cloud chambers earned him the 1968 Nobel Prize for physics, which he accepted in the company of his second wife, Janet Landis Alvarez, mother of their children, Donald and Helen. Sten von Friesen of the Swedish academy of Science credited Alvarez with opening paths to a whole field of discoveries in high-energy physics.

Alvarez applied highly theoretical research to unusual problems. He joined the Warren Commission in 1963 to establish that President John F. Kennedy was assassinated by a lone gunman rather than a team of shooters. In 1965 he aided paleontologists of an American and Egyptian expedition in a study of King Kefren's pyramid at Giza. By channeling subatomic particles called muons through the stone tomb, he deduced that there is no hidden burial chamber in the structure.

In 1980 Alvarez worked with his son, Walter, a professor of geology at the University of California Berkeley, to determine and explain the existence of an inch-deep sediment of iridium-laced clay on rocky hillsides in Italy.

The presence of the rare metal convinced the two scientists that an asteroid or comet deposited it after colliding with earth 65 million years ago. They theorized that the impact raised so thick a cloud of dust and smoke that it blocked out sunlight and lowered temperatures, causing plants to shrivel and herbivorous dinosaurs to die of starvation and extreme cold. They surmised that the event obliterated 70 percent of earth's species. Highly debated at first, the theory was eventually corroborated by scientists who located the Chiczulub crater in the Yucatan, Mexico. Good-humoredly, Alvarez tweaked paleontologists for missing the telltale layer and called them poor scientists more suited to stamp collecting.