A dc high-current low-energy electron beam gun

Abstract

A dc high-current and low-energy electron beam gun has been developed. The maximum electron beam current is 63 A for an accelerating energy of 140 eV. The maximum ratio of the beam current to the discharge current is 78%. The ion current, which is extracted from the helium plasma produced by the electron beam, is 12.3 A. This value corresponds to the current density of about 7 A/cm2, which is the highest value among the ion sources in steady operation. The electron density of the plasma is estimated from the ion saturation current to be about 4.6×1013 cm−3, which corresponds to the degree of ionization of 21%. This gun will open the way for many electron beam applications.