Van de Graaff´s generator

The development by Robert J. Van de Graaff of the generator that bears his name is recounted. A memorandum he produced in 1933 reveals his first major insight: he could accelerate ions and electrons to enormous energies by generating a high voltage in a vacuum. Actual experimental work had to wait until September 1929, when the new Ph.D. arrived at Princeton University in New Jersey to work under physicist Karl T. Compton. A month later, Van de Graaff was able to show Compton the first model of his electrostatic generator. Its operating principle was explained formally the following March in a report. The electrostatic machine was easy to build. Operated in the open air, the first model reached a potential of 80000 V. A few months later, Van de Graaff generated over 1,000,000 V between two 60 cm-diameter spheres on Pyrex columns 180 cm high. Van de Graaff followed Compton to MIT in November and devoted the rest of his life to building more powerful and sophisticated electrostatic accelerators for industrial, scientific, and medical applications.<>