High Voltage Insulators for Particle Accelerators

In modern high energy particle accelerators there are many component parts and devices which operate at high voltages in vacuum, e.g., injectors, inflectors, beam choppers and velocity separators. Since the surface voltage stress attainable across insulators is generally lower than across plane gaps, the physical size of the apparatus is governed by the high voltage performance of the support insulators in vacuum. In this paper the author discusses the various factors affecting the insulator performance, in the light of his experience with NIMROD, the 7 BeV proton synchrotron and the design of a D. C. injector for an intense neutron generator machine which was under study at Chalk River, Canada.