DC breakdown in low-pressure CF4

Abstract

This paper reports the results of studying dc breakdown in low-pressure CF4 gas. We measured the breakdown curves over a broad range of values of CF4 pressure and interelectrode distance L. Two breakdown modes were observed at different CF4 pressures. When the values of the product of gas pressure and gap width are moderate, pL < 2 Torr cm, a balance is achieved between molecular ionization through electron impact and electron escape to the anode and tube walls due to the drift in the electric field and diffusion, respectively, whereas the attachment of free electrons to CF4 molecules does not play any role. At large values, pL > 2 Torr cm, the rate of growth of breakdown voltage with pressure essentially increases because a considerable number of electrons may be attached to gas molecules.