Development of electron guns for excimer light sources in the vacuum UV

Two types of electron guns for ultraviolet (UV) and vacuum UV light sources are presented. The first type is a very compact electron gun which produces a highly collimated beam with a beam diameter of about 0.6 mm. This gun is designed for operation in continuous and pulsed modes with beam currents from 2 /spl mu/A to 20 mA. The second electron gun is a high current gun with rectangular beam profile. The transverse dimensions of the beam are 0.6 by 40 mm. The maximum peak current in pulsed mode produced by the gun is on the order of 5 A. A ceramic membrane (300 nm thick) separates the vacuum part of the gun from the cell which contains a target gas. The membrane is attached to the gun with a new brazing technique. This technique produces complete vacuum-tight sealing and allows operation of the gun without any external pumping. The other advantage of the technique is inertness of the brazing material in respect to aggressive gases and short wavelength radiation. Permeability measurements of argon, neon and helium through the membrane were performed at different temperatures and electron beam currents.