Robert Jemison Van de Graaff was born on December 20, 1901 in Tuscaloosa, Alabama. His mother was Minnie Cherokee Hargrove and his father was Adrian Sebastian Van de Graaff. Robert attended the Tuscaloosa public schools and then attended the University of Alabama where he received a BS degree in 1922 and an MS degree in 1923. Both degrees were in mechanical engineering.

After graduating from college he worked for the Alabama Power Company for a year as a research assistant. He studied at the Sorbonne in Paris from 1924 to 1925 and while there, attended lectures by Marie Curie on radiation. In 1925 he went to Oxford University in England as a Rhodes Scholar. At Oxford he received a BS in physics in 1926 and a Ph.D. in physics in 1928. While at Oxford, he became aware of the hope of nuclear experimenters such as Ernest Rutherford, that particles could someday be accelerated to speeds sufficient to disintegrate nuclei. By disintegrating atomic nuclei much could be learned about the nature of individual atoms. It is from these ideas that Robert Van de Graaff saw the need for a particle accelerator.

In 1929 Van de Graaff returned to the United States to join the Palmer Physics Laboratory at Princeton University as a National Research Fellow. In the fall of that year he constructed the first working model of his electrostatic accelerator which developed 80,000 volts. Improvements were made to the basic design and in November, 1931 at the inaugural dinner of the American Institute of Physics, a demonstration model was exhibited that produced over 1,000,000 volts.

When Karl T. Compton became president of Massachusetts Institute of Technology, Van de Graaff was invited to come to MIT as a research associate. Van de Graaff constructed his first large machine in an aircraft hangar in South Dartmouth, Massachusetts. The machine used two polished aluminum spheres, each 15 feet in diameter mounted on 25 foot high insulating columns, which were 6 feet in diameter. The columns were mounted on railway trucks that boosted the spheres to 43 feet above ground level. The machine had its debut on November 28, 1933 and was able to produce 7,000,000 volts. This accomplishment was reported in the New York Times for November 29, 1933 in a story titled "Man Hurls Bolt of 7,000,000 Volts". In 1937 the machine was moved to a pressurized enclosure at MIT.

John D. Cockcroft and Ernest Walton of the Cavendish Laboratory in England had built a successful particle accelerator in 1932. This machine used voltage-multiplier circuits to produce the required high voltages for particle acceleration. It was bulky and complicated and limited in its voltage capability. In contrast to the Cockcroft-Walton machine, the Van de Graaff machine was simple and compact and was easier to regulate and capable of producing higher voltages and therefore higher accelerations.

In 1935 Van de Graaff received a patent for his invention. He was guided in the preparation of the patent application by Karl T. Compton and Vannevar Bush who was vice president of MIT. Van de Graaff also worked with John G. Trump, a professor of electrical engineering at MIT and with William W. Buechner, a professor of physics at MIT. A medical Van de Graaff used to produce X rays for treating cancerous tumors with precisely penetrating radiation was first used clinically in 1937 at Harvard Medical School. In 1936 Van de Graaff married Catherine Boyden. They had two sons, John and William.

During WW II Van de Graaff was director of the High Voltage Radiographic Project. Along with William W. Buechner he directed the adaptation of the electrostatic generator to precision radiographic examination of U.S. Navy ordnance. After the war, in 1945, Van de Graaff received a Rockefeller Foundation grant for the development of an improved accelerator at MIT. On December 19, 1946 Van de Graaff and Trump formed the High Voltage Engineering Corporation (HVEC) in Burlington, Massachusetts. HVEC was formed for the commercial production of particle accelerators. Denis M. Robinson, a professor of electrical engineering from England, became president of the new corporation. John G. Trump became technical director and Van de Graaff became chief physicist and a board member. HVEC became the leading supplier of electrostatic generators that were used in cancer therapy, industrial radiography and in the study of nuclear structure. In 1947 Van de Graaff received the Duddel Medal of the Physical Society of Great Britain.

In 1951 Luis W. Alvarez of the University of California at Berkeley rediscovered the tandem principle first developed by Willard Bennett in 1937. A tandem Van de Graaff machine accelerates a negatively charged particle(typically having a charge of -1 or having 1 extra electron) toward a positively charged terminal. As the particle passes through the terminal, electrons are removed from the particle. This causes the particle to become positively charged and therefore accelerated away from the positively charged terminal. When heavy ions such as gold or uranium are used as many as 25 to 30 electrons may be removed. The high voltage terminal is thus used to accelerate the ion twice (tandem).

In the late 1950s Van de Graaff invented the insulating core transformer. The insulating core transformer generated high voltage direct current using magnetic flux rather than electrostatic charging. Van de Graaff also devised many methods of controlling particle beams during and after acceleration so they could be adapted to individual research requirements. Using Van de Graaff accelerators physicists accumulated vast quantities of information on nuclear disintegrations and reactions. This data led directly to sophisticated theories of nuclear structure.

Van de Graaff remained an associate professor of physics at MIT until 1960 when he resigned to devote himself to his increasing involvement with HVEC. In 1966 he was awarded the Tom W. Bonner Prize for his contribution and continued development of the electrostatic accelerator, "a device that has immeasurably advanced nuclear physics" by the American Physical Society. The prize was named for a scientist who had used the Van de Graaff particle accelerator to achieve the results of his fundamental research.

Robert J. Van de Graaff died on the morning of January 16, 1967 in Boston at the age of 65. At the time of his death there were over 500 Van de Graaff particle accelerators in use in more than 30 countries.

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