Anode electrode shield for inverted magnetron cold cathode ionization gauge

摘要

A cold cathode ionization gauge (CCIG) includes an extended anode, a cathode surrounding the anode along a length of the anode, and a feedthrough insulator supporting the anode. The cathode forms a discharge space around the anode to enable formation of a plasma between the anode and the cathode and a resultant ion current flow into the cathode. The CCIG further includes a magnet applying a magnetic field through the discharge space to lengthen free electron paths to sustain the plasma. A shield is electrically isolated from the insulator and shields the insulator from electrons of the plasma. The shield may be mounted to the cathode and surrounds and is spaced from the anode. An electric controller applies voltage between the anode and the cathode to create ionization with plasma discharge between the anode and the cathode, the controller determining pressure based on measured ion current flow to the cathode.