Removable discharge initiating means for cold cathode discharge ionization gauge
AssigneeMKS Instruments, Inc.
InventorsRoy N. Peacock, Neil T. Peacock
Life of this patent
Estimating the term…
Abstract
A cold cathode gauge including a glow lamp or the like disposed within the vacuum space of the gauge for initiating the gauge discharge, the lamp emitting UV or blue light directly at at least the cathode of the gauge where the energy of the light is sufficient to release photoelectrons from the cathode to thus initiate the discharge. A member is also provided for removably positioning the glow lamp within the vacuum space whereby the lamp can be removed during bake out and then subsequent thereto, be inserted within the vacuum space to thus enhance longevity of the lamp.
Claims24
A cold cathode gauge for measuring the pressure of a vacuum within a system where the system is in direct communication with a vacuum space within the gauge, said gauge comprising:
- an anode disposed within the vacuum space of the gauge;
- a cathode disposed within the vacuum space of the gauge;
- magnet means to produce a magnetic field substantially perpendicular to an electric field between the anode and cathode whereby a discharge may be established between the anode and cathode;
- means for initiating the discharge, said discharge initiating means being disposed within the vacuum space and emitting electromagnetic radiation directly at at least the cathode where the energy of the electromagnetic radiation is sufficient to release photoelectrons from the cathode to thus initiate the electrical discharge;
- and
- positioning means for removably positioning the discharge initiating means within the vacuum space whereby in the removed position of the discharge initiating means, the gauge is subjected to high temperatures required for bake out, and subsequent thereto, the discharge initiating means is positioned within the vacuum space to effect said discharge whereby the longevity of the discharge initiating means is enhanced due to the removability thereof.
An accessory for use with a cold cathode gauge where the gauge measures the pressure of a vacuum within a system and where the system is in direct communication with a vacuum space within the gauge, said gauge including a port adapted for connection to the system, an anode disposed within the vacuum space of the gauge, a cathode disposed within the vacuum space of the gauge, and magnet means to produce a magnetic field substantially perpendicular to an electric field between the anode and cathode whereby a discharge may be established between the anode and cathode, said accessory comprising:
- a first member removably attachable to the gauge at said port;
- means for initiating the discharge, said discharge initiating means being so supported by the member that, when the member is attached to the gauge, the discharge initiating means is so disposed within the vacuum space of the gauge that it emits electromagnetic radiation directly at at least the cathode where the energy of the electromagnetic radiation is sufficient to release photoelectrons from the cathode to thus initiate the electrical discharge;
- and
- positioning means for removably positioning the discharge initiating means within the vacuum space whereby in the removed position of the discharge initiating means, the gauge is subjected to high temperatures required for bake out, and subsequent thereto, the discharge initiating means is positioned within the vacuum space to effect said discharge whereby the longevity of the discharge initiating means is enhanced due to the removability thereof.
Dependencies are inferred from the claim text.