DC CONDUCTIVITY OF RF ABSORBING MATERIALS

Several of the typical RF absorbing materials utilized in particle accelerator environments have DC electrical conductivities that decrease significantly when cooled to cryogenic temperatures. If such RF absorbers are in close proximity to a beamline, they are prone to collecting static charge and may deflect the particle beam. The DC electrical conductivities of two types of ferrite and a ceramic are measured at various temperatures, showing that the electrical conductivities indeed decrease, often to unacceptably low levels in regard to static charge accumulation.