A Line Cathode Electron Gun of the Pierce-Type Design

Abstract
An electron gun of the Pierce-type configuration with a line cathode of the same size as the electron beam required has been developed. A line-shaped beam measuring 1.1 mm×6.0 mm with a current efficiency of more than 99% was obtained. The electron gun was designed by computer simulation based on the electrolytic-tank method. Calculation within the gun revealed that a negatively biased focus electrode and a line cathode with a rectangular cross section are appropriate to obtain a line-shaped electron beam. Beam uniformity along the line is within ±6% in the middle part 5.0 mm long. The influence of the magnetic field due to the cathode heating current on the beam uniformity was investigated by beam trajectory tracing.