Brooks Automation Gmbh

Richard A Knott

Paul C Arnold

Michael Dale Borenstein

Larry K Carmichael

Stephen C Blouch

Gerardo A Brucker

Shields for feedthrough pin insulators of a hot cathode ionization gauge are provided to increase the operational lifetime of the ionization gauge in harmful process environments. Various shield materials, designs, and configurations may be employed depending on the gauge design and other factors. In one embodiment, the shields may include apertures through which to insert feedthrough pins and spacers to provide an optimal distance between the shields and the feedthrough pin insulators before the shields are attached to the gauge. The shields may further include tabs used to attach the shields to components of the gauge, such as the gauge's feedthrough pins. Through use of example embodiments of the insulator shields, the life of the ionization gauge is extended by preventing gaseous products from a process in a vacuum chamber or material sputtered from the ionization gauge from depositing on the feedthrough pin insulators and causing electrical leakage from the gauge's electrodes.

Method and apparatus for shielding feedthrough pin insulators in an ionization gauge operating in harsh environments

An ionization gauge that eliminates a hot cathode or filament, but maintains a level of precision of gas density measurements approaching that of a hot cathode ionization gauge. The ionization gauge includes a collector electrode disposed in an ionization volume, an electron source without a heated cathode, and an electrostatic shutter that regulates the flow of electrons between the electron source and the ionization volume. The electrostatic shutter controls the flow of electrons based on feedback from an anode defining the ionization volume. The electron source can be a Penning or glow discharge ionization gauge.

Ionization gauge with a cold electron source

A method and apparatus for operating a multi-hot-cathode ionization gauge is provided to increase the operational lifetime of the ionization gauge in gaseous process environments. In example embodiments, the life of a spare cathode is extended by heating the spare cathode to a temperature that is insufficient to emit electrons but that is sufficient to decrease the amount of material that deposits on its surface or is optimized to decrease the chemical interaction between a process gas and a material of the at least one spare cathode. The spare cathode may be constantly or periodically heated. In other embodiments, after a process pressure passes a given pressure threshold, plural cathodes may be heated to a non-emitting temperature, plural cathodes may be heated to a lower emitting temperature, or an emitting cathode may be heated to a temperature that decreases the electron emission current.

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Broomfield, CO, United States of America

Richard A Knott