US5365070A
Expired / Lapsed
US
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Negative ion beam injection apparatus with magnetic shield and electron removal means
Assignee: University of California
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Filing: 1992-04-29
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Granted: 1994-11-15
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Expires: 2012-04-29
Abstract
Abstract A negative ion source is constructed to produce H - ions without using Cesium. A high percentage of secondary electrons that typically accompany the extracted H - are trapped and eliminated from the beam by permanent magnets in the initial stage of acceleration. Penetration of the magnetic field from the permanent magnets into the ion source is minimized. This reduces the destructive effect the magnetic field could have on negative ion production and extraction from the source. A beam expansion section in the extractor results in a strongly converged final beam.
Inventors
- 👤 Oscar A. Anderson
- 👤 Chun F. Chan
- 👤 Ka-Ngo Leung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:01
CPC Classifications
H; H01; H01J; H01J27/00; H01J27/02; H01J27/022; H01J27/028
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
60 words
A negative ion beam injection apparatus, comprising: a. a negative ion generating means with an exit aperture of sufficient diameter to allow negative particles to exit the ion generating means, b. a negatively-charged particle extracting means, c. an electron removal means located exterior to the ion generating means, d. a magnetic field shielding means, and e. a beam transport means.
Claim 2
Dependent Claim
60 words
A negative ion beam injection apparatus, comprising: a. a negative ion generating means with an exit aperture of sufficient diameter to allow negative particles to exit the ion generating means, b. a negatively-charged particle extracting means, c. an electron removal means located exterior to the ion generating means, d. a magnetic field shielding means, and e. a beam transport means.
Claim 3
Dependent Claim
18 words
The negative ion beam injection apparatus of claim 1, wherein the negative ion generating means generates hydrogen ions.
Claim 4
Dependent Claim
18 words
The negative ion beam injection apparatus of claim 1, wherein the negative ion generating means comprises a filament.
Claim 5
Dependent Claim
20 words
The negative ion beam injection apparatus of claim 1, wherein the negative ion generating means comprises a radio frequency antenna.
Claim 6
Dependent Claim
13 words
The apparatus of claim 4, wherein the radio frequency antenna is glass coated.
Claim 7
Dependent Claim
13 words
The apparatus of claim 4, wherein the radio frequency antenna is ceramic coated.
Claim 8
Dependent Claim
33 words
The negative ion beam injection apparatus of claim 1, wherein the negatively-charged particle extracting means comprises an extracting electrode having an electric potential that is positive with respect to the ion generating volume.
Claim 9
Dependent Claim
13 words
The apparatus of claim 7 wherein the extracting electrode comprises a copper electrode.
Claim 10
Dependent Claim
14 words
The apparatus of claim 7 wherein the extracting electrode comprises an oxygen-free copper electrode.
Claim 11
Dependent Claim
23 words
The apparatus of claim 1, wherein the exit aperture includes the magnetic-field shielding means comprising material of magnetic permeability greater than 100 gauss/oersted.
Claim 12
Dependent Claim
24 words
The apparatus of claim 1 wherein the magnetic-field shielding means comprises a material of magnetic permeability between about 10 2 and 10 7 gauss/oersted.
Claim 13
Dependent Claim
24 words
The apparatus of claim 11 wherein the magnetic-field shielding means comprises a material of magnetic permeability between about 10 3 and 10 6 gauss/oersted.
Claim 14
Dependent Claim
24 words
The apparatus of claim 12 wherein the magnetic-field shielding means comprises a material of magnetic permeability between about 10 3 and 10 5 gauss/oersted.
Claim 15
Dependent Claim
24 words
The apparatus of claim 13 wherein the magnetic-field shielding means comprises a material of magnetic permeability between about 10 3 and 10 4 gauss/oersted.
Claim 16
Dependent Claim
17 words
The apparatus of claim 1 wherein the magnetic-field shielding means comprises a material of carbon steel composition.
Claim 17
Dependent Claim
27 words
The apparatus of claim 15 wherein the magnetic-field shielding means comprises a material of carbon steel composition, designated by any SAE Number from 1006 to 1095, inclusively.
Claim 18
Dependent Claim
21 words
The apparatus of claim 1 wherein the magnetic-field shielding means comprises a machinable material of magnetic permeability greater than 100 gauss/oersted.
Claim 19
Dependent Claim
60 words
The negative ion beam injection apparatus of claim 1, wherein the electron removal means comprises: a. a magnet so aligned that a component of the field of induction is perpendicular to the electric field of the beam path, b. the magnetic field shielding means comprising shielding material of magnetic permeability greater than 100 gauss/oersted, and c. an electron collecting electrode.
Claim 20
Dependent Claim
12 words
The apparatus of claim 18, wherein the magnet is a permanent magnet.
Claim 21
Dependent Claim
13 words
The apparatus of claim 19, wherein the magnet is a SmCo permanent magnet.
Claim 22
Dependent Claim
11 words
The apparatus of claim 18, wherein the magnet is an electromagnet.
Claim 23
Dependent Claim
17 words
The apparatus of claim 18, wherein the magnet produces a magnetic field between 300 and 1000 gauss.
Claim 24
Dependent Claim
17 words
The apparatus of claim 22, wherein the magnet produces a magnetic field between 350 and 750 gauss.
Claim 25
Dependent Claim
17 words
The apparatus of claim 23, wherein the magnet produces a magnetic field between 400 and 600 gauss.
Claim 26
Dependent Claim
61 words
The negative ion beam injection apparatus of claim 1, wherein the beam transport means comprises: a. an extractor electrode, b. the magnetic-field shielding means comprising shielding material of magnetic permeability greater than 100 gauss/oersted, c. magnets exterior to the negative ion generating means and downstream from the shielding means, d. an acceleration and electron collecting electrode, and e. a focusing electrode.
Claim 27
Dependent Claim
45 words
The negative ion beam injection apparatus of claim 1, wherein the beam transport means comprises: a. an extractor electrode, b. a magnet containing electrode at the same electric potential as the extractor electrode, c. an acceleration and electron collecting electrode, and d. a focusing electrode.
Claim 28
Dependent Claim
19 words
The negative ion beam injection apparatus of claim 25 wherein the beam transport means additionally comprises a deceleration electrode.
Claim 29
Dependent Claim
19 words
The negative ion beam injection apparatus of claim 26 wherein the beam transport means additionally comprises a deceleration electrode.
Claim 30
Dependent Claim
22 words
The apparatus of claim 16 wherein the magnetic-field shielding means comprises a material of carbon steel composition designated by SAE Number 1018.
Claim 31
Dependent Claim
17 words
The apparatus of claim 18 wherein the magnetic field shielding means is used as an extraction electrode.
Claim 32
Dependent Claim
14 words
The apparatus of claim 18, wherein the electron collecting electrode is a focusing electrode.
Claim 33
Dependent Claim
19 words
The apparatus of claim 10 wherein the exit aperture includes the magnetic field shielding means and electron deflecting magnets.
Claim 34
Dependent Claim
25 words
The apparatus of claim 32 wherein the exit aperture additionally comprises electrically-conducting, nonmagnetic metal inserts placed between the magnets and around exit the aperture opening.
Claim 35
Dependent Claim
14 words
The apparatus of claim 33 wherein the metal inserts comprise copper or oxygen-free copper.
Claim 36
Dependent Claim
16 words
The apparatus of claim 1 wherein the exit aperture is comprised of the magnetic-field shielding means.
Claim 37
Dependent Claim
13 words
The apparatus of claim 1 wherein the exit aperture comprises an extraction electrode.
Claim 38
Dependent Claim
26 words
The apparatus of claim 27, wherein the acceleration, electron collecting, and deceleration electrodes are made of one of copper, oxygen-free copper, molybdenum, graphite, and alloys thereof.
Claim 39
Dependent Claim
26 words
The apparatus of claim 28, wherein the acceleration, electron collecting, and deceleration electrodes are made of one of copper, oxygen-free copper, molybdenum, graphite, and alloys thereof.
Claim 40
Independent Claim
120 words
A method of removing electrons from a negative ion beam produced in an ion beam injection apparatus comprising: a. extracting negatively charged particles from an ion source through an exit aperture of sufficient diameter to allow negative particles to exit the ion source volume by use of an extraction electrode having an electric potential that is positive with respect to the ion generating volume; b. diverting electrons immediately after they traverse the exit aperture with magnets located adjacent to the exit aperture, c. shielding the ion source volume from the magnetic field of said magnets by surrounding the exit aperture with high magnetic permeability material and d. collecting the diverted electrons on a second electrode in the ion beam path.
Claim 41
Independent Claim
120 words
A method of removing electrons from a negative ion beam produced in an ion beam injection apparatus comprising: a. extracting negatively charged particles from an ion source through an exit aperture of sufficient diameter to allow negative particles to exit the ion source volume by use of an extraction electrode having an electric potential that is positive with respect to the ion generating volume; b. diverting electrons immediately after they traverse the exit aperture with magnets located adjacent to the exit aperture, c. shielding the ion source volume from the magnetic field of said magnets by surrounding the exit aperture with high magnetic permeability material and d. collecting the diverted electrons on a second electrode in the ion beam path.
Claim 42
Dependent Claim
96 words
A producing a negative ion beam comprising: a. extracting ions from a plasma ion source by a positive extraction electrode, b. removing electrons from the extracted beam using a magnetic field perpendicular to the beam path, c. shielding the plasma ion source from the magnetic field with a magnetic-field shield d. controlling the trajectory of the beam by the electrostatic potential of circular focusing electrodes located along the beam path, and e. imparting energy to the beam by electrodes so that the beam energy meets the injection requirements of a next stage of the ion accelerator.
Claim 43
Dependent Claim
96 words
A producing a negative ion beam comprising: a. extracting ions from a plasma ion source by a positive extraction electrode, b. removing electrons from the extracted beam using a magnetic field perpendicular to the beam path, c. shielding the plasma ion source from the magnetic field with a magnetic-field shield d. controlling the trajectory of the beam by the electrostatic potential of circular focusing electrodes located along the beam path, and e. imparting energy to the beam by electrodes so that the beam energy meets the injection requirements of a next stage of the ion accelerator.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-11-14 | 1998-05-16 | 1998-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-14 | 2002-05-16 | 2002-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-14 | 2006-05-16 | 2006-11-15 | $7700.00 | Window Closed / Lapsed |