The Pelletron Accelerator

A review is given of early development work at the University of Wisconsin on electrostatic accelerators insulated by high pressure gas. This work started in 1933 and led in 1940 to a 4.5MeV accelerator. Starting in 1946 development work was initiated along three lines: 1) Bakeable high strength metal to ceramic bonding, 2) Organic-free pumping, 3) Metal charge carrying devices. In 1951 construction was started at the University of Wisconsin on an accelerator utilizing results of these three development programs. In 1965 much development work was transferred to the National Electrostatics Corp. where the charging chain was developed. It consists of metal cylinders joined by links of solid insulating material. A 1MV column support unit was perfected which is used to construct column modules. A bakeable all metal and ceramic tube, free of organic vapors was developed. It consists of short sections bolted together with three sections per column module. A three-stage accelerator was built and was tested with a beam up to energies of 22MeV. A two-stage accelerator to provide 28MeV protons (14MV on terminal) is under construction. A two-stage accelerator to give 40MeV protons (20MV on terminal) has been designed.