Ionization gauge with emission current and bias potential control

摘要

An ionization gauge that measures pressure has an electron source that emits electrons, and an anode that defines an ionization space. The gauge also includes a collector electrode to collect ions formed by an impact between the electrons and a gas and to measure pressure based on the collected ions. The electron source is dynamically varied in emission current between a plurality of emission levels dependent on pressure and a second parameter other than pressure. The ionization gauge may also vary various operating parameters of the gauge components according to parameters stored in a non-volatile memory and selected by a user.

主权项

1. An ionization gauge to measure pressure comprising:
an electron source cathode that emits electrons; an anode that defines an ionization space; a collector electrode to collect ions formed by an impact between the electrons and gas in the ionization space; and a controller that actively controls emission current from the electron source cathode to an optimal emission current level by heating the electron source cathode, the optimal emission current level being determined from a stored profile of emission current relative to pressure, the controller responding to sensed temperature of the electron source cathode to limit the cathode temperature by reducing the emission current level to less than the optimal emission current level with reduced sensitivity of the gauge.