Luis Alvarez (1911–1988). An American experimental physicist who joined the faculty of the University of California, Berkeley in 1936, Dr. Alvarez was responsible for the design and construction of the Berkeley 40-foot proton linear accelerator, which was completed in 1947. In the 1960s he developed the world’s largest Hydrogen Bubble chamber and used it to discover a host of elementary particle resonances. In 1968 he was awarded the Nobel Prize for this work. Together with his son, Walter Alvarez, he showed that the demise of the dinosaurs was due to the impact of an asteroid some sixty-five million years ago.