Microwave ion source

Abstract

A coaxial microwave ion source which provides high‐current ion beams is presented. The microwave discharge takes place in a magnetic mirror field. The intensity of this field is higher than that of the electron cyclotron resonance at 2.45 GHz over the entire discharge region. The antenna of the discharge chamber is water cooled to protect the ceramic which is used as the vacuum seal as well as the conduit for microwaves into the discharge chamber. The ion beam is extracted through a three‐stage multiaperture lens with 124 holes 3 mm in diameter. An electron suppressed Faraday cup is used to collect 200‐mA argon and 400‐mA hydrogen ion beams.