William Hansen and brothers Russell and Sigurd Varian invented the klystron tube, a high-frequency amplifier for generating microwaves. It revolutionized high-energy physics and microwave research and led to the airborne radar used in aircraft today. The klystron also has been used in satellite communications, airplane and missile guidance systems, and telephone and television transmission.
Stanford researchers in 1939 examine their invention, a klystron. Standing from left to right are Sigurd Varian, physicists David Webster and William Hansen, and in the front are Russell Varian, left, also a physicist, and John Woodyard, an engineering graduate student. Photo: Stanford News Service archives