US4303864A
Expired / Lapsed
US
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Sextupole system for the correction of spherical aberration
Assignee: United States Department of Energy
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Filing: 1979-10-25
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Granted: 1981-12-01
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Expires: 1999-10-25
Abstract
Abstract A means is provided for compensating for spherical aberration in charged particle beam devices. The means includes a sextupole positioned between two focusing lenses.
Inventors
- 👤 Albert V. Crewe
- 👤 David A. Kopf
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:32
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/153; B; B82; B82Y; B82Y15/00; H01J3/00; H01J3/12
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
78 words
In an electron beam device having a source of electrons, the improvement in the device for correcting spherical aberration, comprising: a first lens for focusing the beam to a point, a sextupole for focusing a beam in an image plane having a third order, spherical aberration, the point being at the center of said sextupole, and a second lens positioned at the image plane of said sextupole for focusing the beam to a point in an image plane.
Claim 2
Dependent Claim
78 words
In an electron beam device having a source of electrons, the improvement in the device for correcting spherical aberration, comprising: a first lens for focusing the beam to a point, a sextupole for focusing a beam in an image plane having a third order, spherical aberration, the point being at the center of said sextupole, and a second lens positioned at the image plane of said sextupole for focusing the beam to a point in an image plane.
Claim 3
Dependent Claim
20 words
The device of claim 1 further including steering means for aligning said beam along the optical axis of the device.
Claim 4
Dependent Claim
33 words
The device of claim 2 wherein said steering means includes two pairs of steering coils with one coil positioned on either side of said sextupole between said sextupole and one of said lenses.
Claim 5
Dependent Claim
59 words
The device of claim 3 wherein said second lens has a focal length of 1 mm, a value of spherical aberration constant of 0.4 mm, the source produces 50,000 volt electrons, said sextupole is electrical of length 10 cm, drift space 5 cm, and width 0.15 cm and current in each wire from said electrical sextupole of 7.78 amperes.
References Cited (Backward Citations)
US3753034A
Cited
US3781732A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-11-30 | 1985-06-01 | 1985-12-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-30 | 1989-06-01 | 1989-12-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-30 | 1993-06-01 | 1993-12-01 | $7700.00 | Window Closed / Lapsed |