LARGE-AREA SECONDARY EMISSION ELECTRON GUN

摘要

A high current electron beam processor, using secondary emission electrons from a cold cathode by striking helium ions, has been developed for industrial applications. The helium ions are extracted, through a honeycomb partition, from 10 x 70 cm of a discharge chamber where the plasma is generated by a glow-discharge using the wire-anode of 74 cm length and are accelerated toward a cathode biased at -250 kV. The secondary electrons emitted from the cathode are accelerated in the inverse direction to ions and pass through the plasma chamber. It was demonstrated that a current of 200 mA was extracted into the air through a thin window foil and irradiated running products. The dose uniformity on the products was +/-5% over the 65 cm width of the beam area. Processing capacities were up to about 500 Mrad . m/min. The characteristics of this gun will be discussed. Copyright (C) 1996 Published by Elsevier Science Ltd. [References: 10]