Patent US4755722A successfully refreshed from Google Patents.
US4755722A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion plasma electron gun
Assignee: RPC Industries
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Filing: 1987-03-05
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Granted: 1988-07-05
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Expires: 2007-03-05
Abstract
Abstract An ion plasma electron gun for the generation of large area electron beams with uniform electron distribution. Positive ions generated by a wire in a plasma discharge chamber are accelerated through an extraction grid into a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode causing the cathode to emit secondary electrons which form an electron beam. After passing through the extraction grid and the plasma discharge chamber, the electron beam exits from the gun by way of a second grid and a foil window supported on the second grid. The gun is constructed so that the electron beam passing through the foil window has a relatively large area and a uniform electron distribution which is substantially the same as the ion distribution of the ion beam impinging upon the cathode. Control of the generated electron beam is achieved by applying a control voltage between the wire and the grounded housing of the plasma chamber to control the density of positive ions bombarding the cathode.
Inventors
- 👤 George Wakalopulos
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:28
CPC Classifications
H; H01; H01J; H01J33/00; H01J3/00; H01J3/02; H01J3/021; H01J3/025; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/038; H01S3/09; H01S3/0955; H01S3/0959
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
292 words
An ion plasma electron gun assembly comprising: an electrically conductive evacuated housing forming first and second chambers adjacent to one another and having an opening therebetween; means for generating positive ions in said first chamber; a cathode positioned in said second chamber in spaced and insulated relationship from said housing, said cathode having a secondary electron emissive surface; means for applying a high negative voltage between said cathode and said housing to cause said cathode to draw the positive ions from said first chamber to said second chamber to impinge on said surface of said cathode and to cause said surface to emit secondary electrons; an electrically conductive electron transmissive foil extending over an opening in said housing at the end of said first chamber facing said cathode, said foil being electrically connected to the housing to constitute an anode for the secondary electrons and causing the secondary electrons to pass through the foil as an electron beam; an electrically conductive extractor grid mounted in said second chamber adjacent to the secondary electron emissive surface of said cathode and connected to said housing to create an electrostatic field at said surface to cause secondary electrons therefrom to pass through the openings in the grid and into said first chamber, said extractor grid being further characterized as possessing a variable surface depth proportional to said electrostatic field within said first chamber, such that any variations in the strength of said electrostatic field are substantially eliminated causing a substantially uniform beam of electrons to be emitted from said cathode through said foil; and an electrically conductive support grid mounted in said first chamber adjacent to said foil and connected to said foil and to said housing, said support grid serving to support said foil.
Claim 2
Dependent Claim
292 words
An ion plasma electron gun assembly comprising: an electrically conductive evacuated housing forming first and second chambers adjacent to one another and having an opening therebetween; means for generating positive ions in said first chamber; a cathode positioned in said second chamber in spaced and insulated relationship from said housing, said cathode having a secondary electron emissive surface; means for applying a high negative voltage between said cathode and said housing to cause said cathode to draw the positive ions from said first chamber to said second chamber to impinge on said surface of said cathode and to cause said surface to emit secondary electrons; an electrically conductive electron transmissive foil extending over an opening in said housing at the end of said first chamber facing said cathode, said foil being electrically connected to the housing to constitute an anode for the secondary electrons and causing the secondary electrons to pass through the foil as an electron beam; an electrically conductive extractor grid mounted in said second chamber adjacent to the secondary electron emissive surface of said cathode and connected to said housing to create an electrostatic field at said surface to cause secondary electrons therefrom to pass through the openings in the grid and into said first chamber, said extractor grid being further characterized as possessing a variable surface depth proportional to said electrostatic field within said first chamber, such that any variations in the strength of said electrostatic field are substantially eliminated causing a substantially uniform beam of electrons to be emitted from said cathode through said foil; and an electrically conductive support grid mounted in said first chamber adjacent to said foil and connected to said foil and to said housing, said support grid serving to support said foil.
Claim 3
Dependent Claim
26 words
The ion plasma electron gun defined in claim 1, in which said cathode has cooling passages therein, and means for introducing cooling fluid to said passages.
Claim 4
Dependent Claim
68 words
The ion plasma electron gun defined in claim 1, and which includes a tubular high voltage feed member extending through said housing into said second chamber, an insulating member mounted in said tubular feed member and attached to said cathode for supporting said cathode in said second chamber, and means including a cable extending through said tubular member and through said insulating member and connected to said cathode.
Claim 5
Dependent Claim
25 words
The ion plasma electron gun defined in claim 3, in which said insulating member has cooling passages therein for supplying cooling fluid to the cathode.
Claim 6
Dependent Claim
28 words
The ion plasma electron gun defined in claim 3, and which includes a resistor mounted in said tubular feed member serially connected between said cable and said cathode.
Claim 7
Dependent Claim
33 words
The ion plasma electron gun defined in claim 1, and which includes a wire mounted in said first chamber in insulated relationship with said housing to supply electric current for positive ion generating.
Claim 8
Dependent Claim
25 words
The ion plasma electron gun defined in claim 6, and which includes a direct current voltage source for providing a direct current through said wire.
Claim 9
Dependent Claim
25 words
The ion plasma electron gun defined in claim 6, and which includes a radio frequency voltage source for providing radio frequency current through said wire.
Claim 10
Dependent Claim
39 words
The ion plasma electron gun defined in claim 1, and which includes a frame member mounted on said housing adjacent to said foil and having a gas manifold therein for directing cooling gas to the surface of said foil.
Claim 11
Dependent Claim
29 words
The ion plasma electron gun defined in claim 1, in which the extractor grid and support grid each has a passage therein for carrying cooling fluid for the grids.
Claim 12
Dependent Claim
27 words
The ion plasma electron gun defined in claim 10, in which said foil is brazed to said support grid to provide for efficient cooling of said foil.
Claim 13
Dependent Claim
54 words
The ion plasma electron gun defined in claim 1, in which said first chamber comprises a plurality of adjacent sections, and which includes a corresponding plurality of wires respectively extending through said sections, and said support grid has a corresponding plurality of adjacent sections respectively disposed in the adjacent sections of said first chamber.
Claim 14
Dependent Claim
108 words
The ion plasma electron gun defined in claim 6, and which includes a source of pressurized ionizable gas, conduit means coupling said source to the interior of said first chamber, a valve mounted in said conduit means for controlling the pressure of the ionizable gas in said first chamber, monitor means connected to said first chamber for generating an electric signal which is a function of the instantaneous quiescent gas pressure in said first chamber, and controller means for said valve responsive to said electric signal from said monitor means for adjusting said valve to maintain a predetermined operating pressure of said ionizable gas in said first chamber.
Claim 15
Dependent Claim
42 words
The ion plasma electron gun defined in claim 35, and which includes a current source connected to said wire and to said monitor means and responsive to the electrical signal from said monitor means for controlling the current flow through said wire.
Claim 16
Dependent Claim
269 words
An ion plasma electron gun assembly comprising: an electrically conductive evacuated housing forming first and second chambers adjacent to one another and having an opening therebetween; means for generating positive ions in said first chamber; a cathode positioned in said second chamber in spaced and insulated relationship from said housing, said cathode having a secondary electron emissive surface; means for applying a high negative voltage between said cathode and said housing to cause said cathode to draw the positive ions from said first chamber to said second chamber to impinge on said surface of said cathode and to cause said surface to emit secondary electrons; an electrically conductive electron transmissive foil extending over an opening in said housing at the end of said first chamber facing said cathode, said foil being electrically connected to the housing to constitute an anode for the secondary electrons and causing the secondary electrons to pass through the foil as an electron beam; an electrically conductive extractor grid mounted in said second chamber adjacent to the secondary electron emissive surface of said cathode and connected to said housing to create an electrostatic field at said surface to cause secondary electrons therefrom to pass through the openings in the grid and into said first chamber; and an electrically conductive support grid mounted in said first chamber adjacent to said foil and connected to said foil and to said housing, said support grid serving to support said foil and having openings therein aligned with the openings in said extractor grid to act in conjunction with said extractor grid to accelerate the secondary electrons to the foil.
Claim 17
Dependent Claim
269 words
An ion plasma electron gun assembly comprising: an electrically conductive evacuated housing forming first and second chambers adjacent to one another and having an opening therebetween; means for generating positive ions in said first chamber; a cathode positioned in said second chamber in spaced and insulated relationship from said housing, said cathode having a secondary electron emissive surface; means for applying a high negative voltage between said cathode and said housing to cause said cathode to draw the positive ions from said first chamber to said second chamber to impinge on said surface of said cathode and to cause said surface to emit secondary electrons; an electrically conductive electron transmissive foil extending over an opening in said housing at the end of said first chamber facing said cathode, said foil being electrically connected to the housing to constitute an anode for the secondary electrons and causing the secondary electrons to pass through the foil as an electron beam; an electrically conductive extractor grid mounted in said second chamber adjacent to the secondary electron emissive surface of said cathode and connected to said housing to create an electrostatic field at said surface to cause secondary electrons therefrom to pass through the openings in the grid and into said first chamber; and an electrically conductive support grid mounted in said first chamber adjacent to said foil and connected to said foil and to said housing, said support grid serving to support said foil and having openings therein aligned with the openings in said extractor grid to act in conjunction with said extractor grid to accelerate the secondary electrons to the foil.
Claim 18
Dependent Claim
26 words
The ion plasma electron gun defined in claim 15, in which said cathode has cooling passages therein, and means for introducing cooling fluid to said passages.
Claim 19
Dependent Claim
68 words
The ion plasma electron gun defined in claim 15, and which includes a tubular high voltage feed member extending through said housing into said second chamber, an insulating member mounted in said tubular feed member and attached to said cathode for supporting said cathode in said second chamber, and means including a cable extending through said tubular member and through said insulating member and connected to said cathode.
Claim 20
Dependent Claim
25 words
The ion plasma electron gun defined in claim 17, in which said insulating member has cooling passages therein for supplying cooling fluid to the cathode.
Claim 21
Dependent Claim
28 words
The ion plasma electron gun defined in claim 17, and which includes a resistor mounted in said tubular feed member serially connected between said cable and said cathode.
Claim 22
Dependent Claim
33 words
The ion plasma electron gun defined in claim 15, and which includes a wire mounted in said first chamber in insulated relationship with said housing to supply electric current for positive ion generating.
Claim 23
Dependent Claim
25 words
The ion plasma electron gun defined in claim 20, and which includes a direct current voltage source for providing a direct current through said wire.
Claim 24
Dependent Claim
25 words
The ion plasma electron gun defined in claim 20, and which includes a radio frequency voltage source for providing radio frequency current through said wire.
Claim 25
Dependent Claim
39 words
the ion plasma electron gun defined in claim 15, and which includes a frame member mounted on said housing adjacent to said foil and having a gas manifold therein for directing cooling gas to the surface of said foil.
Claim 26
Dependent Claim
29 words
the ion plasma electron gun defined in claim 15, in which the extractor grid and support grid each has a passage therein for carrying cooling fluid for the grids.
Claim 27
Dependent Claim
27 words
The ion plasma electron gun defined in claim 24, in which said foil is brazed to said support grid to provide for efficient cooling of said foil.
Claim 28
Dependent Claim
54 words
The ion plasma electron gun defined in claim 15, in which said first chamber comprises a plurality of adjacent sections, and which includes a corresponding plurality of wires respectively extending through said sections, and said support grid has a corresponding plurality of adjacent sections respectively disposed in the adjacent sections of said first chamber.
Claim 29
Dependent Claim
108 words
The ion plasma electron gun defined in claim 20, and which includes a source of pressurized ionizable gas, conduit means coupling said source to the interior of said first chamber, a valve mounted in said conduit means for controlling the pressure of the ionizable gas in said first chamber, monitor means connected to said first chamber for generating an electric signal which is a function of the instantaneous quiescent gas pressure in said first chamber, and controller means for said valve responsive to said electric signal from said monitor means for adjusting said valve to maintain a predetermined operating pressure of said ionizable gas in said first chamber.
Claim 30
Dependent Claim
42 words
The ion plasma electron gun defined in claim 27, and which includes a current source connected to said wire and to said monitor means and responsive to the electrical signal from said monitor means for controlling the current flow through said wire.
References Cited (Backward Citations)
US3411035A
Cited
US3903891A
Cited
US3619684A
Cited
US3866089A
Cited
US3863163A
Cited
US3970892A
Cited
US4061944A
Cited
US4025818A
Cited
US4088926A
Cited
US4143272A
Cited
US4335297A
Cited
US4359667A
Cited
US4450031A
Cited
US4559477A
Cited
US4596945A
Cited
US4642522A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-07-05 | 1992-01-04 | 1992-07-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-07-05 | 1996-01-04 | 1996-07-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-07-05 | 2000-01-04 | 2000-07-05 | $7700.00 | Window Closed / Lapsed |