Round Hill generator

The Round Hill generator is an experimental high-voltage Van de Graaff generator built at Round Hill, Massachusetts. When constructed in 1933, it was designed as the world's most powerful particle accelerator. The generator is now used at the Boston Museum of Science for educational demonstrations.

The instrument was constructed by a Massachusetts Institute of Technology (MIT) team led by physicist Robert J. Van de Graaff, who hoped to be the first scientist to artificially split the atom. They completed construction a year after John Cockroft and Ernest Walton accomplished the feat in 1932. The machine was the forerunner of high-voltage electrostatic particle accelerators built by the High Voltage Engineering Corporation, which Van de Graaff and his student John G. Trump introduced to cancer clinics and nuclear physics labs around the world.

Too large to fit in a research lab, the 43-foot-tall generator was assembled in Round Hill's airship hangar. Originally, a technician ran the machine from within one of its metal terminals, which acted as a Faraday cage. It was first demonstrated to the public in November 1933 and dubbed an "electrical Niagara" by the New York Times because of its copious electrical discharges. Coverage in Time, Science, and a review by Nikola Tesla in Scientific American brought fame to its inventor. Designed to reach potentials of 10 megavolts, challenges with air insulation limited the accelerator to 5.1 megavolts.

When the research program at Round Hill ended in 1936, the generator was overhauled and installed on MIT's campus in Cambridge, Massachusetts. After two decades of research use at MIT, the Round Hill generator was moved to the Boston Museum of Science in 1955, where it remains operational in the "Theater of Electricity" exhibition.