Study of a low-energy collimated beam electron source and its application in a stable ionisation gauge

Abstract

Stable ionisation vacuum gauges obtain stable sensitivity by controlling both the well-defined electron trajectory and electron energy in the ionisation volume. To achieve this goal, a collimated electron beam and large ionisation cross-section are required as the electrons enter the ionisation volume. In this paper, a low-energy electron source based on carbon nanotubes is designed to realise a collimated electron beam by the addition of specialised deceleration and focus electrodes. The experimental transmission is approximately 25%, which is in good agreement with the simulation results. Furthermore, a simulation study is carried out combining the electron source with the components of a novel stable ionisation gauge. The numerical simulation results show a sensitivity of 0.250 Pa-1. It provides an important reference for the development of stable ionisation gauge based on the field emission cathode.