US3778656A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ion source employing a microwave resonant cavity
Assignee: Commissariat à l'Énergie Atomique et Aux Énergies Alternatives
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Filing: 1972-07-26
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Granted: 1973-12-11
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Expires: 1992-07-26
Abstract
Abstract The ion source comprises a plasma source employing a microwave cavity which is excited in one of its modes of resonance and a static magnetic field adjusted to the electron cyclotron resonance, means for extracting the ions from the plasma and comprising an expansion cup pierced by an aperture which communicates with the cavity and ion-extraction electrodes brought to suitable potentials. The density of the plasma is of maximum value in the vicinity of the aperture and the static magnetic field is substantially zero in the vicinity of the extraction electrodes.
Inventors
- 👤 C Fremiot
- 👤 J Grando
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:19
CPC Classifications
H; H01; H01J; H01J27/00; H01J27/02; H01J27/16; H01J27/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
98 words
An ion source comprising : a plasma source employing a microwave cavity which is excited according to one of its modes of resonance and a static magnetic field which is adjusted to the electron cyclotron resonance, means for extracting the ions from said plasma, comprising an expansion cup pierced by an aperture which communicates with said cavity and ion-extraction electrodes brought to suitable potentials, wherein the density of said plasma is of maximum value in the vicinity of said aperture and wherein said static magnetic field is of substantially zero value in the vicinity of said extraction electrodes.
Claim 2
Dependent Claim
98 words
An ion source comprising : a plasma source employing a microwave cavity which is excited according to one of its modes of resonance and a static magnetic field which is adjusted to the electron cyclotron resonance, means for extracting the ions from said plasma, comprising an expansion cup pierced by an aperture which communicates with said cavity and ion-extraction electrodes brought to suitable potentials, wherein the density of said plasma is of maximum value in the vicinity of said aperture and wherein said static magnetic field is of substantially zero value in the vicinity of said extraction electrodes.
Claim 3
Dependent Claim
28 words
An ion source according to claim 1, wherein said static magnetic field assumes the value corresponding to cyclotron resonance only in the vicinity of said expansion cup aperture.
Claim 4
Dependent Claim
21 words
An ion source according to claim 1, wherein a high static magnetic field gradient exists in the vicinity of said aperture.
Claim 5
Dependent Claim
29 words
An ion source according to claim 3, wherein said expansion cup is fabricated from a metal having low reluctance and constitutes a magnetic shield for said static magnetic field.
Claim 6
Dependent Claim
15 words
An ion source according to claim 4, wherein said expansion cup is of soft iron.
Claim 7
Dependent Claim
69 words
An ion source according to claim 1, wherein said microwave cavity is a cylinder of revolution, said mode of resonance is transverse-electric, said static magnetic field is axial and wherein the plasma is confined within a leaktight dielectric cylinder which is coaxial with said cavity and has a small radius compared with the radius of said cavity, said expansion cup being disposed in the axis of said dielectric cylinder.
Claim 8
Dependent Claim
19 words
An ion source according to claim 6, wherein the mode of resonance of the cavity is the TE111 mode.
Claim 9
Dependent Claim
46 words
An ion source according to claim 6, wherein said mode of resonance is a mode in which the electric field has zero amplitude in certain internal zones of the cavity, the dielectric cylinder for the injection of gas being located in the vicinity of said zones.
Claim 10
Dependent Claim
18 words
An ion source according to claim 8, wherein the cavity is excited in accordance with the TE022 mode.
Claim 11
Dependent Claim
18 words
An ion source according to claim 8, wherein the cavity is excited in accordance with the TE122 mode.
Claim 12
Dependent Claim
70 words
An ion source according to claim 1, wherein said microwave cavity is formed of a cylindrical cavity along the axis of which is disposed a hollow metallic cylinder having low reluctance which is in contact with the top wall of said cylindrical cavity and opens into said cavity in the proximity of said expansion cup aperture, said cylinder being part of the magnetic circuit which guides said static magnetic field.
References Cited (Backward Citations)
US3418206A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |