Abstract
In order to measure the pressure at extremely high vacuum practically, a new design of ionization gauge is studied with the computer simulation. The new gauge has simple structure, and is operated so that electrons reciprocate many times. To avoid the undesirable effect due to the space-charge formed by the electrons, this oscillation is periodically stopped by modulating the potential of the filament. Then, the sensitivity of this gauge shall be about several-tens times higher than that of the usual B-A gauge, and the pressure at extremely high vacuum can be measured rather easily.
