Patent US4288716A successfully refreshed from Google Patents.
US4288716A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion source having improved cathode
Assignee: International Business Machines Corp
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Filing: 1979-12-03
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Granted: 1981-09-08
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Expires: 1999-12-03
Abstract
Abstract A direct heated rod-shaped cathode for an ion source is provided with a region of reduced cross-section adjacent its negative end to maximize the path length of electron movement within the discharge chamber and to provide effective control of the cathode resistance in a region that is relatively free of sputtering erosion during use.
Inventors
- 👤 Holger Hinkel
- 👤 Georg Kraus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:02
CPC Classifications
H; H01; H01J; H01J27/00; H01J27/02; H01J27/08; H01J27/14; H01J37/00; H01J37/02; H01J37/04; H01J37/08
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
99 words
An ion generator having a housing forming a chamber, means for supporting a cathode within the housing, means for establishing an electrostatic field between the cathode and the housing, positive and negative terminals for applying a DC voltage across opposite ends of the cathode to induce a heating current therein, and means for supplying a source of ionizable molecules into said chamber, wherein the improvement comprises: the cathode having a region of reduced cross-section with respect to the cross-section of the remainder of the cathode, said reduced cross-section region being located nearer said negative terminal than said positive terminal.
Claim 2
Dependent Claim
99 words
An ion generator having a housing forming a chamber, means for supporting a cathode within the housing, means for establishing an electrostatic field between the cathode and the housing, positive and negative terminals for applying a DC voltage across opposite ends of the cathode to induce a heating current therein, and means for supplying a source of ionizable molecules into said chamber, wherein the improvement comprises: the cathode having a region of reduced cross-section with respect to the cross-section of the remainder of the cathode, said reduced cross-section region being located nearer said negative terminal than said positive terminal.
Claim 3
Dependent Claim
22 words
An ion generator as defined in claim 1 wherein said reduced cross-section region is located immediately adjacent one end of the chamber.
Claim 4
Dependent Claim
41 words
An ion source as defined in claim 1 wherein the difference in cross-section of said reduced cross-section region and the remainder of said cathode is such that the electrical resistance of the cathode is essentially determined by said reduced cross-section region.
References Cited (Backward Citations)
GB792042A
Cited
US3364355A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-09-07 | 1985-03-09 | 1985-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-07 | 1989-03-09 | 1989-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-07 | 1993-03-09 | 1993-09-08 | $7700.00 | Window Closed / Lapsed |