Hansen, W. W. (William Webster), 1909-1949

Physicist (microwave electronics). Professor of Physics and Director of the Microwave Laboratory at Stanford University, 1929-1949.

William Webster Hansen was Professor of Physics and Director of the Microwave Laboratory at Stanford University, 1929-1949.

Biographical Note

Memorial Resolution for William Webster Hansen.

William Webster Hansen died May 23, 1949. Although he had not been in the best of health since the middle of the war, Hansen's death was unexpected; only two days before it, he had inspected the office made ready for his use in the Microwave Laboratory. He is survived by his parents and his wife Betsy, daughter of the late Professor P. A. Ross of the Stanford Physics Department.

Hansen was born May 27, 1909, at Fresno, California, and received his elementary schooling in that city. Coming to Stanford, he received the A.B. in 1929, and the Ph.D. in 1933 when only 23 years of age, and then studied as a National Research Council Fellow at the Massachusetts Institute of Technology until 1935, when he returned to Stanford as an assistant professor. He became associate professor here in 1937 and professor in 1942.

Hansen's most important work has been in the border line between physics and engineering involving electromagnetic theory, electron ballistics, and advance circuit theory. He originated the cavity resonator, so important in microwave radar and radio. He contributed to the klystron tube not only the cavity resonator, but also numerous design features that are now typical of all klystron tubes. He made many contributions to the field of microwave measurements, and also originated many important mathematical developments in the theory of radio circuits and antennas. In 1944 he was recognized for this work by the Institute of Radio Engineers with the Morris Liebmann Memorial Prize.

Direct utility won recognition for the cavity resonator and for many of his improvements in radio and radar engineering; but direct utility was not Hansen's own chief interest. Primarily, he was a pure scientist. His first acquaintance with scientific things was with the fine machine tools sold by his father. From them his temperament led him naturally to the study of their principles. In this study he was greatly benefited by his father's wide experience with such matters, and by most enthusiastic aid and encouragement from both his father and his mother.

When Hansen came to Stanford as a student, his interest in the underlying principles of physical things led him to work as a research laboratory assistant; and soon the search for new laws of physics became his lifelong objective.

The cavity resonator, in fact, took shape first only in his mind, as a set of abstract mathematical functions, attractive primarily for their mathematical elegance. Then his clear vision of the meanings of mathematics showed him that real metal, made in the image of these functions, could be used with real electrons for further discoveries in physics.

Only the shadow of the coming war, which Hansen's rugged intellectual honesty forced him to recognize as real, away back in 1937, made him divert the cavity resonator and himself to military duty. This duty took him to the research laboratory of the Sperry Gyroscope Company and the Massachusetts Institute of Technology Radiation Laboratory. Returning to Stanford in 1945, Hansen combined the principles of his cavity resonator with many others learned or discovered in the meantime, and resumed his prewar purpose of developing apparatus for accelerating electrons to unprecedentedly high kinetic energy. The device he designed for this purpose is well known as the linear electron accelerator. A short section of the long linear chain of cavities in which the electrons will be accelerated has already been built. It works exactly as predicted by Hansen. This gives confidence that the rest of his plan for electrons at the equivalent of hundreds of millions of volts will be realized.

This device we shall not explain here. Hansen could. The clarity of his explanations was amazing; so, too, was their brevity. Sometimes his clear, brief explanations looked like guesswork, but they never were unless he said so. They were insight into the real essentials. Behind any explanation he did not specifically call a guess, there was always a good, thorough mathematical analysis. Moreover, he never lost the practical engineering instincts which he had acquired in his early contact with his father's work. He combined in one man the qualities of an able mathematical physicist, an equally outstanding experimentalist, and a distinguished radio engineer. He was noted among scientists because his ideas always worked.

He was noted also as a good friend, and not only among scientists. He was ready to lend a hand, or his ears, or brain, in any worthy problem, and to enliven it with unexpected humor. Bill's merry laugh shook off the troubles of many a research. It loosened thought which had bogged down. It helped us get going again along new lines.

In the war Hansen's conscientious thoroughness was increased by his sense of military duty. Regardless of risk, he went ahead in work that brought on the illness which has now proved fatal. Though not in uniform, he was a good soldier.

Edward Leonard Ginzton

Frederick Emmons Terman

David Locke Webster, Chairman

Biography

William Webster Hansen was Professor of Physics and Director of the Microwave Laboratory at Stanford University, 1929-1949.