Plasma cleaning device
OwnerJames C. administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Roger L. Shannon +1inventors
InventorsJames C. administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, Roger L. Shannon, Roger B. Gillette
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Abstract
Apparatus for cleaning contaminated surfaces such as hydro-carbon contaminant films in high vacuum environments including a plasma discharge housing for allowing a plasma to be generated in an environment having a higher pressure than the surface which is to be cleaned. A ground electrode and a radio frequency electrode partially surround a quartz plasma tube, for the introduction of an ionizable gas therein. These electrodes ionize the gas and help generate the plasma. This plasma flows through a non-constrictive aperture, through the plasma discharge housing and then on to the contaminated surface.
Claims7
A method for cleaning contaminated surfaces in a high vacuum environment using a cold plasma discharge apparatus having an outer shield separating the interior of the discharge apparatus from the high vacuum environment, said method comprising the steps of:
- introducing an ionizable gas into a conduit disposed within the outer shield of the plasma discharge apparatus, said conduit partially encircled by two radio frequency electrodes;
- generating a radio frequency field within the conduit thereby ionizing the gas contained therein to create a cold plasma within said conduit between said first and second electrodes as well as between a non-constrictive nozzle and said second electrode;
- ejecting the plasma at a low flow rate from the plasma discharge apparatus through said non-constrictive nozzle and aperture into the high vacuum environment while directing the plasma toward the contaminated surface.
A plasma cleaning device for cleaning contaminated surfaces present in a high vacuum environment comprising:
- a substantially hollow housing member having an outer wall, and an end wall containing an aperture, said outer and end walls separating a higher pressure region within the interior of said housing from the high vacuum environment outside of said housing;
- a hollow conduit, having an admitting end section and an emitting end section disposed within said housing member;
- supply means connected to the admitting end section of said conduit for supplying highly ionizable gas therethrough;
- first and second electrodes, each electrode partially encircling said conduit, said first electrode intermediate of said gas supply means and said second electrode;
- a non-constrictive nozzle connected to the emitting end section of said conduit and disposed adjacent to said aperture;
- and
- a radio frequency generator connected to said first and second electrodes generating a cold plasma between said electrodes as well as between said second electrode and said non-constrictive nozzle, said plasma flowing into the high vacuum environment through said non-constrictive nozzle means and said aperture.
Dependencies are inferred from the claim text.