Pressurised-helium breakdown at very low temperatures

Abstract

An extensive investigation of the electrical-breakdown behaviour of helium at very low temperatures has been carried out to assist the design and development of superconducting power cables. At very high densities, both liquid and gaseous helium showed an encouraging enhancement in electric strength when pressurised to a few atmospheres; conditioned values of breakdown fields then varied between 30 and 45 MV/m. Breakdown processes occurring over a wide range of helium densitites are briefly discussed.