Patent US3306321A successfully refreshed from Google Patents.
US3767952A
Expired / Lapsed
US
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Ion source with reduced emittance
Assignee: Atomic Energy of Canada Ltd AECL
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Filing: 1972-10-24
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Granted: 1973-10-23
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Expires: 1992-10-24
Abstract
Abstract An ion source modified by an additional electrode, designated as a scraper electrode, positioned between the anode and extractor electrode, having an aperture slightly less than the source plasma aperture, and adapted to carry a pre-determined voltage in reference to the anode. It has been found that the scraper electrode intercepts and removes ions at the periphery of the beam cross-sectional area and this is the region that contains ions that contribute most greatly to the increased emittance. The central, non-intercepted cross-sectional area therefore has a much reduced emittance. The voltage on the scraper electrode should be such as to not disturb or distract the electric field between anode and extractor electrode.
Inventors
- 👤 J Ormrod
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:43
CPC Classifications
H; H01; H01J; H01J27/00; H01J27/02; H01J27/022; H01J27/08; H01J27/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
114 words
An ion source of the type having a chamber for containing an ionized gas plasma, an aperture in a wall of said chamber, and extractor electrode positioned external to said aperture and adapted to carry an electrical potential such that ions are extracted from the plasma and formed into an ion beam, the improvement comprising a scraper electrode positioned adjacent the said chamber aperture and in spaced relationship towards the extractor electrode, said scraper electrode containing an aperture whose diameter is slightly less than the aperture in the chamber wall and effective to intercept and remove the outer portion of the ions in the said beam and thus reduce the emittance of the beam.
Claim 2
Dependent Claim
114 words
An ion source of the type having a chamber for containing an ionized gas plasma, an aperture in a wall of said chamber, and extractor electrode positioned external to said aperture and adapted to carry an electrical potential such that ions are extracted from the plasma and formed into an ion beam, the improvement comprising a scraper electrode positioned adjacent the said chamber aperture and in spaced relationship towards the extractor electrode, said scraper electrode containing an aperture whose diameter is slightly less than the aperture in the chamber wall and effective to intercept and remove the outer portion of the ions in the said beam and thus reduce the emittance of the beam.
Claim 3
Dependent Claim
57 words
An ion source as in claim 1 wherein the scraper electrode is adapted to carry a potential in relation to that of the chamber and the extractor electrode such that the electric field distribution in the region between extractor and chamber is not greatly different to that which would occur if the scraper electrode were not present.
Claim 4
Dependent Claim
129 words
An ion source having reduced emittance comprising: a. an ionization chamber, b. means in said chamber for ionizing gas therein, c. a plasma forming chamber connected to the ionization chamber, d. an anode, e. an extractor electrode for extracting ions from the plasma via an aperture in a plasma aperture plate associated with said anode and forming an ion beam therewith, and f. a scraper electrode positioned adjacent the plasma aperture plate towards the extractor electrode, said scraper electrode containing an aperture whose diameter is slightly less than that of the plasma aperture plate and effective to intercept and remove the outer portion of the ions in the said beam, said ions being those that have transverse momentum components that give rise to the satellite peaks in the emittance.
Claim 5
Dependent Claim
129 words
An ion source having reduced emittance comprising: a. an ionization chamber, b. means in said chamber for ionizing gas therein, c. a plasma forming chamber connected to the ionization chamber, d. an anode, e. an extractor electrode for extracting ions from the plasma via an aperture in a plasma aperture plate associated with said anode and forming an ion beam therewith, and f. a scraper electrode positioned adjacent the plasma aperture plate towards the extractor electrode, said scraper electrode containing an aperture whose diameter is slightly less than that of the plasma aperture plate and effective to intercept and remove the outer portion of the ions in the said beam, said ions being those that have transverse momentum components that give rise to the satellite peaks in the emittance.
Claim 6
Dependent Claim
56 words
An ion source as in claim 1 wherein the scraper electrode is adapted to carry a potential in relation to that of the anode and extractor electrode such that the electric field distribution in the region between anode and extractor is not greatly different to that which would occur if the scraper electrode were not present.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-22 | 1977-04-23 | 1977-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-22 | 1981-04-23 | 1981-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-22 | 1985-04-23 | 1985-10-23 | $7700.00 | Window Closed / Lapsed |