| 摘要 |
PURPOSE:To perform easy adjustment of the intensity of an electron beam and reduce the capacity of a power supply connected to a cathode, by providing a magnetic field generating device for generating a magnetic field parallel to the longitudinal direction of a wire placed in an ionization chamber. CONSTITUTION:When a pulsive voltage is applied between an anode wire 1 provided in an ionization chamber 3 and the wall 4 of the ionization chamber, and also applying the same voltage to a magnetic field generating device 20 synchronously, a gas in the ionization chamber 3 is ionized by a pulsive discharge to generate electrons and the resulting electrons move in spiral motion in the longitudinal direction of the anode wire 1. As the result, collisions with gas atoms are so promoted that ionization efficiency is increased as well as a plasma density. Thus, even if the same electron beam intensity is required as in a conventional device, ionic current can be increased by generating a magnetic field parallel to the longitudinal direction of the anode wire 1 by the magnetic field generating device 20. Consequently a negative biasing voltage V applied to a cathode 7 and a pulsive voltage applied to the anode wire 1 can be reduced so that a power supply capacity can be reduced. |
