VAN DE GRAAFF, ROBERT JEMISON

(b. Tuscaloosa, Alabama, 20 December 1901; d Boston Massachusetts, 16 Januaey 1967), physics.

Van de Graaff was born and raised in the cotton country near Tuscaloosa. He studied engineering at the University of Alabama, where he earned the B. S. in 1922 and M.S. in 1923, and physics at the Sorbonne and at Oxford, where he earned the Ph.D. in 1928, and where he conceived the invention of his belt-charged electrostatic high-voltage generator. He was at the threshold of his scientific carrier when, as a National Research fellow at Princeton, he constructed the first working model of the generator, operating at 80,000 volts, in 1929.

Under the encouragement of Karl T. Compton, then president of Massachusetts Institute of Technology, Van de Graaff came to MIT as a research associate in 1931 to start a series of developments of his invention, for the precisely controllable acceleration of charged nuclear particles and electrons to high velocities for nuclear-physics research. He became associate professor of physics in 1934, continuing in that position until he resigned from MIT in 1960.

With John G. Trump, later to become professor of electrical engineering, Van de Graaff adapted the principles of his high-voltage generator to the production of intense, penetrating X rays for the precise treatment of deep-seated tumors. The first clinical installation was a huge 1-MeV X-ray generator at the Huntington Memorial Hospital in Boston, in 1937. Van de Graaff’s association with Trump developed into a close one, enduring until his death.

During World War II, Van de Graaff was the director of the MIT High Voltage Radiographic Project, sponsored by the Office of Scientific Research and Development. In association with one of his protégés, William W. Buechner, he led in the development of the electrostatic generator for the U.S. Navy to use in the radiographic examination of heavy ordnance. Five 2-MeV X-ray generators were constructed for the navy during the war. The experience gained in this project became a basis for the eventual commercial manufacture of Van de Graaff particle accelerators.

Trump and Van de Graaff founded High Voltage Engineering Corporation in late 1946, again with the capable guidance of Compton. Denis M. Robinson, formerly head of the electrical engineering department at the University of Birmingham, England, was appointed president of the company. Van de Graaff served as director and chief physicist (later chief scientist) of the organization, and he devoted his full time to the company after his resignation from MIT.

High Voltage Engineering Corporation was the first company organized with the express purpose of manufacturing particle accelerators. With the counsel of both Van de Graaff and Trump, and under Robinson’s leadership, it made a succession of advances in accelerator technology for nuclear physics, radiation therapy, and the indusrtrial applications of electrons and X rays. Van de Graaff urged the company to undertake the important development of the tandem principle of particle accelerartion (originally invented by Willard Bennett in 1937 and rediscovered by Luis W. Alvarez in 1951).

In the late 1950’s Van de Graaff invented the insulating-core transformer, which can generate powerful direct currents at higher voltages than possible with the conventional transformer-rectifier systems, for application in industrial processing with high-energy elecrons. Modifications of this principle are used also for power-factor correction in the transmission of high-voltage power.

Toward the end of his life, Van de Graaff concentrated on the development of a means for accelerating heavy ions, utilizing the tandem principle, with the objective of providing physicists with a complete freedom in choosing target and projectile nuclei. One ambition, frustrated by his death, was to accelerate uranium nuclei to sufficiently high velocities so that they would coalesce with stationary uranium nuclei, thus possible opening up the field of synthesizing transplutonium isotopes.

BIBLIOGRAPHY

1. Origical Works. Published works by Van de Graaaf are “A 1,500,000 Volt Electrostatic Generator,” in Physical Review, 38 (1931), 1919–1920; “Experiments on the Elastic Single Scattering of Electrons by Nuclei,” ibid., 69 (1946), 452–459, with W. W. Buechner and H. Feshbach; “Calorimetric Experiment on the Radiation Losses of 2-MeV Electrons.” ibid., 70 (1946), 174–177, with W. W. Buechner; “Further Experiments on the Elastic Single Scattering of Electrons by Nuclei,” ibid., 72 (1947), 678–679, with W. W. Buecher, E. A. Burrill, H. Feshbach, and A. Sperduto; “An Investigation of Radiography in the Range From 0.5 to 2.5 Million Volts,” ASTM Bulletin, no. 155 (1948), 54–64, with W. W. Buechner, E. A. Burrill, H. Feshbach, L. R. McIntosh, and A. Sperduto; “Electrostatic Generators for the Acceleration of charged Particles,” in Progress in Physics, 11 (1948), 1–18, with W. W. Buechner and J. G. Trump; “Irradiation of Biological Materials by High Energy Roentgen Rays and Cathode Rays,” in Journal of Applied Physics, 19 (1948), 599–604, with J. G. Trump; “Thick-Target X-Ray Production in the Range From 1250 to 2350 kilovolts,” in Physical review74 (1948), 1348–1352, with W. W. Buechner, E. A. Burrill, and A. Sperduto; “Secondary Electron Emission of Electrons by High-Energy Electrons,” ibid., 75 (1949), 44–45, with J. G. Trump; “Secondary Electron Emission From Metals Under Psitive Ion Bombardment in High Extractive Fields,” in Journal of Applied Physics, 23 (1952), 264–266, with J. G. Trump and E. W. Webster; “Tandem Electrostatic Accelerators,” in Nuclear Instruments and Methods, 8 (1960), 195–202; “High-Voltage Acceleration Tube Utilizing Inclined-Field Principles,” in Nature, 195 (1962), 1292–1293, with P. H. Rose and A. B.wittkower; and “Elecrtrostatic Acceleration of Very Heavy Ions, With Resulting Possibilities for Nuclear Research,” in Bulletin. American Physical Society(Mexico City meeting, August 29, 1966).

II. Secondary Literature. Biographies of Van de Graaff are E. A. Burrill, “Van de Graaff, the Man and His Accelerators,” in Physics Today, 20 (1967), 49–52; N. Felici, “R. J. Van de Graaff: 1901–1967,” in Bulletin commissariat á l’energie atomique (March-April 1967), p. 20; P. H. Rose, “In Memoriam: Robert Jemison Van de Graaff,” in Nuclear Instruments and Methods, 60 (1968), 1–3.

E. Alfred Burrill