Abstract :
An aging process, which applies a high frequency (HF) magnetic field on the electron gun during the aging process, is
introduced to solve the unbalanced I-cathode emission slump. The effect is that the scanning electron beam and the HF magnetic
field heat up the gun parts by electron bombarding and eddy current heating. In this way, the grids are effectively degassed.A part
of the desorbed gases is pumped by the Ba-getter in the tube, whereas another part is ionized by electron collision. These ionized
gas molecules, notably Ar+, are partially trapped in gun parts. Therefore, a lower residual gas pressure and emission slump can
be achieved
