February 5, 1915, is the birthdate of Robert Hofstadter, a clear-thinking and resourceful physicist whose discoveries about the shape and structure of the atom’s nucleus won him half the Nobel Prize for Physics in 1961.
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Robert Hofstadter was born in New York to Louis Hofstadter and the former Henrietta Koenigsberg, both Jewish immigrants from Poland. Louis owned a cigar shop.
Robert attended public schools in New York, and as a child he loved nature, collecting rocks, insects and leaves.
At age 20, he graduated magna cum laude from City College, where he studied both mathematics and physics. Three years later, in 1938, he received his master’s and doctoral degrees in physics from Princeton University.
Hofstadter’s first teaching job out of graduate school was at the University of Pennsylvania.
There, in Philadelphia, he met Nancy Givan, a neighbor who became interested when she heard the recorded jazz music coming through his apartment door. They married in 1942, and had three children, one of whom is the cognitive scientist Douglas Hofstadter, author of the popular “Goedel, Escher and Bach” (1979).
War work: Missile defense
During World War II, Hofstadter worked first at the National Bureau of Standards and later at the Norden company. At both he was involved in developing proximity fuses, which use radar to detonate defensive missiles when they detect approaching objects. He also developed an altitude sensor for airplanes that he himself tested by flying at low altitudes.
Hofstadter had short tenures on the faculty at his two alma maters, City College and Princeton. He arrived at Stanford in 1950 and remained there until he retired in 1985.
The shape of the nucleus
Hofstadter’s Nobel Prize, shared with the German physicist Rudolf Moessbauer, was awarded for his discoveries of the precise shape and size of neutrons and protons (the two particles in an atom’s nucleus) and for providing a “reasonably consistent” description, in the Nobel committee’s words, of the structure of the nucleus itself.
He made these discoveries with the use of electron-scattering procedures, by which it was possible to measure the angles by which accelerated electrons were deflected from a neutron, and thus to infer the shape of the nucleus.
Hofstadter’s use of accelerators led to his proposal that Stanford build what eventually became a two-mile-long (3.2 kilometers) particle accelerator. But he was involved in its operation only minimally because of disagreements with his colleagues about the role that federal grants should play in university research, and specifically his fears that university science departments could become, in effect, government subcontractors.
Hofstadter was probably proudest of his advances in the invention of the gamma-ray spectrometer, which enabled medical-diagnostic tools like the PET scanner. When mounted on a Space Shuttle - as was done in 1991, several months after his death - the spectrometer could be used in a powerful telescope employed to study the physics of celestial bodies.
In general, his imagination enabled him to propose solutions to problems that often seemed outlandish at the time but that in retrospect demonstrated his farsightedness.
Another example of this was Hofstadter’s involvement in a private company, in the 1970s, that attempted to generate electricity through clean, safe nuclear fusion. The effort was foiled, in part by circumstances and in part by opposition from the federal government.
The Hofstadter family owned a 700-acre ranch near Flournoy, in northern California, where they raised cattle and horses, and also a large grove of oil trees.
Robert also sat on the board of governors of both the Weizmann Institute and the Technion-Israel Institute of Technology.
Robert Hofstadter died of a heart attack on November 17, 1990, at the age of 75.