Robert Jemison Van De Graaff

http://en.wikipedia.org/wiki/Robert_J._Van_de_Graaff

Robert Jemison Van de Graaff (December 20, 1901 – January 16, 1967), was an American physicist, noted for his design and construction of high voltage generators, who taught at Princeton University and MIT.

Biography

Robert Jemison Van de Graaff was born at the Jemison-Van de Graaff Mansion in Tuscaloosa, Alabama, from Dutch descent. In Tuscaloosa, he received his BS and Masters degrees from The University of Alabama where he was a member of The Castle Club (later became Mu Chapter of Theta Tau). After a year at the Alabama Power Company, Van de Graaff studied at the Sorbonne. In 1926 he earned a second BS at Oxford University on a Rhodes Scholarship, completing his PhD in 1928.

Van de Graaff was the designer of the Van de Graaff generator, a device which produces high voltages. In 1929, Van de Graaff developed his first generator (producing 80,000 volts) with help from Nicholas Burke at Princeton University. By 1931, he had constructed a larger generator, generating 7 million volts. He was a National Research Fellow, and from 1931 to 1934 a research associate at the Massachusetts Institute of Technology. He became an associate professor in 1934 (staying there until 1960). He was awarded the Elliott Cresson Medal in 1936.

During WWII, Van de Graaff was director of the High Voltage Radiographic Project. After WWII, he co-founded the High Voltage Engineering Corporation (HVEC). During the 1950s, he invented the insulating-core transformer (producing high-voltage direct current). He also developed tandem generator technology. The American Physical Society awarded him the T. Bonner prize (1965) for the development of electrostatic accelerators.

Van de Graaff died January 16, 1967 in Boston, Massachusetts.

Van de Graaff Generator

Main article: Van de Graaff generator http://en.wikipedia.org/wiki/Van_de_Graaff_generator

The Van de Graaff generator uses a motorized insulating belt (usually made of rubber) to conduct electrical charges from a high voltage source on one end of the belt to the inside of a metal sphere on the other end. Since electrical charge resides on the outside of the sphere, it builds up to produce an electrical potential much higher than that of the primary high voltage source. Practical limitations restrict the potential produced by large Van de Graaff generators to about 7 million volts. Van de Graaff generators are used primarily as DC power supplies for linear atomic particle accelerators in nuclear physics experiments. Tandem Van de Graaff generators are essentially two generators in series, and can produce about 15 million volts.

The Van de Graaff generator is a simple mechanical device. Small Van de Graaff generators are built by hobbyists and scientific apparatus companies and are used to demonstrate the effects of high DC potentials. Even small hobby machines produce impressive sparks several centimeters long. The largest air insulated Van de Graaff generator in the world, built by Van de Graaff himself, is operational and is on display at the Boston Museum of Science. Demonstrations throughout the day are a popular attraction. More modern Van de Graaff generators are insulated by pressurized dielectric gas, usually freon or sulfur hexafluoride. In recent years, Van de Graaff generators have been slowly replaced by solid-state DC power supplies without moving parts. The energies produced by Van de Graaff atomic particle accelerators are limited to about 30 MeV, even with tandem generators accelerating doubly charged (for example alpha) particles. More modern particle accelerators using different technology produce much higher energies, thus Van de Graaff particle accelerators have become largely obsolete. They are still used to some extent for graduate student research at colleges and universities and as ion sources for high energy bursts.

Education

B.S. 1922 — University of Alabama

Master's degree (Mechanical Engineering, 1923) — University of Alabama

Marie Curie lectures (1925) — La Sorbonne

Doctorate of Philosophy (Physics, 1928) — Oxford University

Patents

http://en.wikipedia.org/wiki/Robert_J._Van_de_Graaff#Patents

http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=105876003&ref...

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Robert Jemison Van de Graaff (1901-1967) was an Alabama-born physicist who developed an electrostatic generator, named for him, that accelerated subatomic particles for use in nuclear physics research. He also co-founded the High Voltage Engineering Corporation, served as the company's chief physicist and chief scientist, and conducted important research in nuclear physics throughout his life. Researchers have used Van de Graaff particle accelerators since the 1930s to obtain information about nuclear disintegrations and reactions and to develop sophisticated theories of the structure of atomic nuclei. Van de Graaff was born in Tuscaloosa, Tuscaloosa County, on December 20, 1901, to Adrian Sebastian Van de Graaff, an attorney and judge, and Minnie Cherokee Hargrove Van de Graaff. He attended Tuscaloosa public schools.

Coming from an athletic family, Van de Graaff was severely injured playing football his senior year, curtailing his ability to play competitively. His three brothers, however, went on to notable careers playing for the Crimson Tide at the University of Alabama (UA). William was the first football player from the school to be named an all-American. A gifted athlete, brother Coleman was also a World War I Army veteran for whom Van de Graaff Field (present-day Tuscaloosa Regional Airport) was named in 1941. Brother Adrian played football for Alabama and also served in World War I. Sister Cherokee married John Asa Rountree Jr., who was director of aeronautics in Alabama and whose father was instrumental in the Good Roads Movement.

Robert van de Graaff attended UA and earned a bachelor's degree in mechanical engineering in 1922 and master's degree in mechanical engineering in 1923. After graduation, he spent a year as a research assistant for the Alabama Power Company and then enrolled at the Sorbonne, in Paris, France. In 1925, after winning a Rhodes Scholarship, he transferred to Oxford University and earned a second bachelor's degree in 1926 and a doctorate in 1928, both in physics. While at Oxford, Van de Graaff became acquainted with the work of New Zealand physicist Ernest Rutherford, considered the father of nuclear physics. Van de Graaff developed an interest in accelerating atomic particles to very high speeds for use in disintegrating the nuclei of atoms, a process that would enable scientists to study the nature of individual atoms. He then conceived of a process to deposit electrical charges on a moving belt and then accumulate those charges inside a hollow metal sphere. In 1929, Van de Graaff, now a National Research Fellow at the Palmer Physics Laboratory at Princeton University in New Jersey, began developing a device for this purpose with the assistance of fellow scientist Nicholas Burke. Now known as the Van de Graaff generator, it consists of a long vertical hollow column with a moving belt inside and a dumbbell-shaped sphere at the top of the column that holds the electrical charge from the belt. His first electrostatic generator produced 80,000 volts. In 1931, he became a research associate at the Massachusetts Institute of Technology (MIT) and an associate professor three years later. That November, at the first meeting of the American Physical Society, he demonstrated a model that produced more than one million volts.

Working with John G. Trump and William W. Buechner, both of MIT, Van de Graaff improved his device to obtain higher voltages, more consistent particle beams, and a smaller design. In 1932, he built a larger version consisting of two polished aluminum spheres mounted on insulating columns. In 1935, Van de Graaff, Karl T. Compton, and MIT vice president Vannevar Bush patented the design. His continuing work led to later generators that could produce particles with more than five million volts. Van de Graaff married Catherine Boyden in 1936, and they had two sons.

Van de Graaff contemplated a number of applications for his machine, particularly bombarding heavy atoms, like uranium and thorium, with protons. He thought that by doing so, these already unstable atoms might disintegrate into smaller atomic particles or might transform into new manmade elements (those with atomic numbers higher than 92) if their nuclei captured protons. In 1937, the Harvard Medical School first used his machine to produce X-rays for irradiating cancer tumors. Later in his career, Van de Graaff developed methods to accelerate uranium atoms and then use them to bombard other uranium atoms, creating uranium ions with up to 50 electrons fewer than those of a normal uranium atom for use in highly accurate calculations of atomic properties.

During World War II, Van de Graaff directed the High Voltage Radiographic Project, sponsored by the federal Office of Scientific Research and Development. In this position, he adapted his electrostatic generator for precision radiographic examination of U.S. Navy ordnance. During the 1950s, he invented the insulating-core transformer, which produced high-voltage direct current, using magnetic fields to accelerate particles instead of electrostatic charging. In 1946, Van de Graaff, Trump, and British engineering professor Denis M. Robinson established the High Voltage Engineering Corporation (HVEC), where he served as the company's chief physicist and as later chief scientist. The following year, the company began its manufacturing operations and became a leading supplier of particle accelerator systems used in cancer therapy, radiography, and nuclear structure studies. He resigned from MIT in 1960 but continued his research in nuclear physics at HVEC until his death in Boston, Massachusetts, on January 16, 1967. By this time, there were more than 500 Van de Graaff particle accelerators in more than 30 countries.

During his professional life, Van de Graaff published numerous scientific papers and received seven patents. In 1935, he was elected a Fellow of the American Academy of Arts and Sciences. He received several honorary degrees and awards, including the 1947 Duddel Memorial Medal of the Physical Society of Great Britain and the 1966 Tom W. Bonner prize of the American Physical Society.

His boyhood home in Tuscaloosa, known as the Jemison-Van de Graaff Mansion, was constructed between 1859 and 1862 by state senator Robert Jemison Jr., a great grandfather on his mother's side. The home is notable for its Italianate architecture and was documented by the Historical American Buildings Survey in the 1930s and added to the National Register of Historic Places in 1972.

• Reference: Ancestry Genealogy - SmartCopy: Dec 28 2018, 18:32:33 UTC
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