William Webster Hansen was an American physicist and scientist. He is regarded as one of the founders of microwave technology.
Background
William Webster Hansen was born on May 27, 1909 in Fresno, California. He was the older of two surviving sons of William George Hansen and Laura Louise (Gillogly) Hansen. His paternal grandfather had immigrated to the United States from Denmark after the German annexation of Schleswig-Holstein. His mother, the daughter of a non-Mormon missionary to Utah, encouraged her children to be independent.
As a boy Hansen showed a precocious interest in electrical devices and a special aptitude for mathematics. From his father, a hardware merchant, he acquired a familiarity with and love for machine tools.
Education
Hansen completed his high school course in two years, at the age of fourteen, but stayed on for an additional year at the Fresno Technical High School before entering Stanford University in 1925. Except for one year at Fresno State College, he remained at Stanford, where he began studying electrical engineering but shifted to physics; he received the Bachelor of Arts degree in 1929 and the Ph. D. in January 1933.
Appointed a National Research Fellow, he spent eighteen months studying at the Massachusetts Institute of Technology (M. I. T. ) and at the University of Michigan.
Career
Hansen returned to Stanford in 1934 as assistant professor of physics. He was made associate professor in 1937 and professor in 1942. At M. I. T. , Hansen became interested in mathematical methods of analyzing emission and absorption of atomic radiation. At the time of his return to Stanford, plans were being made for research on atomic nuclei by bombarding them with particles accelerated to energies of about a million volts. Hansen proposed to attain this voltage by means of electro-magnetic resonance at very high radio frequencies, using a cavity resonator that he conceived for the purpose. The "rhumbatron, " as he called it, was to consist of a hollow space bounded with copper walls. Just as Hansen was well started on the design of such an accelerator, his close friend Russell H. Varian saw the possibility of using two rhumbatrons as resonators in a new device - which he called the "klystron" - to generate radio frequency energy at very short wavelengths.
Hansen's interest was challenged, and he quickly designed and built a tube that demonstrated Varian's ideas to be highly practical. For the first time (1937), a substantial amount of "radio" energy became available at wavelengths of the order of 10 cm. One immediate practical application of the klystron was the use of reflected radio waves to locate aircraft, the system now called radar. A group headed by Hansen and Varian, with support from the Sperry Gyroscope Company, vigorously pursued this concept at Stanford until early in 1941, when they moved east to Sperry's plant on Long Island.
With the increasing probability of American entry into World War II, the klystron research took on new importance. Promptly after his arrival in the East, Hansen was invited to M. I. T. 's Radiation Laboratory, which had been formed the previous fall to exploit the possibilities of microwave radar. From then until the end of the war he commuted between Cambridge and Long Island almost every week, while simultaneously carrying full-time responsibility in Sperry's microwave radar program.
At the Radiation Laboratory, Hansen performed a unique role. The laboratory's leadership consisted of a group of brilliant physicists and engineers who had worked on cyclotrons and X-rays, but who in general knew little or nothing about microwaves. In a very real sense, Hansen became their tutor, at weekly lectures and informal conferences. In the summer of 1943 he also spent some weeks at the University of California as consultant on aspects of atomic energy problems for the Manhattan Project.
After the war ended, Hansen returned to Stanford as director of the microwave laboratory being established there. In the first months he took time out from his own research to help in an investigation being carried out by Felix Bloch, a Stanford colleague. Hansen devised the instrumentation Bloch used in discovering the existence of nuclear magnetic resonance and made many valuable suggestions that contributed to the successful demonstration of the method of nuclear induction in 1946. Bloch subsequently (1952) received the Nobel Prize for work in this field.
Hansen realized that the microwave technology he had helped create could be used to make an electron accelerator far superior to anything he had dreamed of a decade earlier, when he invented the cavity resonator. A relatively short accelerator built in the spring of 1947 proved the soundness of his underlying ideas and was soon followed by a longer section.
Late in 1948 the Office of Naval Research agreed to finance the construction of a linear accelerator 220 feet in length, designed to produce about 750 million electron volts. In early 1949 Stanford started construction of a building to house this machine, with its associated shops, laboratories, and offices. Finished after Hansen's death, it became the model for Stanford's later 10, 000-foot, $110 million linear electron accelerator.
Since his youth Hansen had suffered periods of illness, the result of bronchiectasis and fibrosis of the lungs. The disease was progressive, and he died of a heart attack at his home on the Stanford campus a few days before his fortieth birthday. His ashes were scattered from an airplane over the Golden Gate area.
Achievements
William Webster Hansen was a noted physicist and scientist who contributed greatly to the development of radar and is regarded as the founder of microwave technology.
The value of his work was recognized by the award of the Morris N. Liebmann Prize of the Institute of Radio Engineers in 1945 and by the President's Certificate of Merit in 1948.
The W. W. Hansen Laboratories of High Energy Physics at Stanford University are named in his honor.
Hansen was elected to the National Academy of Sciences in 1949.
Personality
Hansen possessed a remarkable spectrum of talents well exemplified in his twenty-nine published papers. He had great originality, and his inventiveness always had a practical quality. He was an excellent theoretical physicist but, unlike most theoreticians, was also skilled with apparatus, had extraordinary knowledge of shop processes, and superb ability as a design engineer.
His pioneering contributions to the technology of microwave electronics resulted from this unusual combination of qualities. He was also an excellent classroom teacher, whose lucid and stimulating lectures excited even the Ph. D. physicists at M. I. T. 's Radiation Laboratory.
Connections
On October 18, 1938, Hansen married Betsy Ann Ross, the younger daughter of Professor Perley A. Ross of Stanford, with whom he had collaborated in X-ray studies as a graduate student. Their only child, a son born in 1947, died six weeks after birth.
