US3767927A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron beam apparatus with beam-stabilization system
Assignee: US Philips Corp
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Filing: 1971-08-25
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Granted: 1973-10-23
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Expires: 1991-08-25
Abstract
Abstract A high-voltage electron microscope is provided with a double focussing bending magnet for stabilizing the beam velocity. The beam path between an entrance diaphragm in front of the magnet and an image produced by the bending magnet of this diaphragm on the exit side of the magnet are used as a reference for the signal to be detected on the output side of the bending magnet. Near this image, a detector device is provided which intercepts a fraction of from 1 to 10 percent of the beam from which it derives a control signal for the high voltage.
Inventors
- 👤 P Rus
- 👤 Poole J Le
- 👤 J Kramer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:27
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/24; H01J37/241; G; G01; G01T; G01T1/00; G01T1/29; H01J37/04; H01J37/147
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
111 words
An electron beam apparatus comprising a high-voltage generator having an end-electrode, an electron source for generating an electron beam, an accelerator tube for accelerating the electron beam, a beam stabilizing system and an electronoptical imaging system, said beam stabilizing system comprising a double-focussing magnetic beam bending device having a magnetic field which is directed at right angles to the electron beam for bending the electron beam which is accelerated by means of the high-voltage generator, an entrance diaphragm which defines the beam diameter preceding the bending device, and a collecting element following the bending device approximately at the location of an image of the entrance diaphragm produced by the bending device.
Claim 2
Dependent Claim
111 words
An electron beam apparatus comprising a high-voltage generator having an end-electrode, an electron source for generating an electron beam, an accelerator tube for accelerating the electron beam, a beam stabilizing system and an electronoptical imaging system, said beam stabilizing system comprising a double-focussing magnetic beam bending device having a magnetic field which is directed at right angles to the electron beam for bending the electron beam which is accelerated by means of the high-voltage generator, an entrance diaphragm which defines the beam diameter preceding the bending device, and a collecting element following the bending device approximately at the location of an image of the entrance diaphragm produced by the bending device.
Claim 3
Dependent Claim
39 words
An electron beam apparatus as claimed in claim 1, wherein the collecting element is arranged to intercept only a comparatively small part of the beam and is provided with a bounding edge which intersects the periphery of the beam.
Claim 4
Dependent Claim
21 words
An electron beam apparatus as claimed in claim 2, wherein the collecting element is a foil which scatters the intercepted electrons.
Claim 5
Dependent Claim
37 words
An electron beam apparatus as claimed in claim 2, wherein the collecting element consists of two electrically discrete parts which each have a bounding edge intersecting the beam and intercept substantially opposed periphery parts of the beam.
Claim 6
Dependent Claim
42 words
An electron beam apparatus as claimed in claim 1 wherein the largest diameter of the entrance diaphragm is at least approximately 5 Mu m smaller than the central part of the electron beam arriving there and having a substantially constant current density.
Claim 7
Dependent Claim
24 words
An electron beam apparatus as claimed in claim 1 wherein the entrance diaphragm is circular and has a diameter of approximately 50 Mu m.
Claim 8
Dependent Claim
45 words
An electron beam apparatus as claimed in claim 1 including electron-optical means between the electron source and the entrance diaphragm for directing to the idaphragm and producing a first image of the most constricted section of the electron beam which occurs near the electron source.
Claim 9
Dependent Claim
46 words
An electron beam apparatus as claimed in claim 1 wherein adjacent the collector element, which is in the form of a foil, there is disposed a detector having a signal output for detecting the electrons of the beam which have been scattered by the collecting element.
Claim 10
Dependent Claim
50 words
An electron beam apparatus as claimed in claim 8, wherein the detector is adjustable so that the angle between the axis of the beam of image-producing electrons at the area of the collecting element and a line joining the foil and the detector is adjustable between approximately 20* and 80*.
Claim 11
Dependent Claim
23 words
An electron beam apparatus as claimed in claim 8 wherein the detector is a semiconductor diode which is connected in the reverse direction.
Claim 12
Dependent Claim
58 words
An electron beam apparatus as claimed in claim 10, wherein the semiconductor diode by application of a suitable reverse voltage, produces a sufficiently thick barrier layer in order to impart a self-amplification of at least 105 to the electrons which are collected by the diode and have an energy of between approximately 3 X 105 And 106 eV.
Claim 13
Dependent Claim
28 words
An electron beam apparatus as claimed in claim 1 wherein the collecting element is a detector having an electrical signal output for the electrons intercepted from the beam.
Claim 14
Dependent Claim
40 words
An electron apparatus as claimed in claim 8 including means for controlling the potential of the electron source in accordance with the detector signal, at a constant potential of the last electrode of the accelerator tube for the electron beam.
Claim 15
Dependent Claim
39 words
An electron beam apparatus as claimed in claim 13, including a circuit between the electron source and the output electrode of the high-voltage generator comprising a variable auxiliary voltage source which is controlled in accordance with the detector signal.
Claim 16
Dependent Claim
48 words
An electron beam apparatus as claimed in claim 14, including a variable auxiliary voltage source connected between the output electrode of the high-voltage generator and a first electrode of the accelerator tube and a constant second auxiliary voltage source connected between the electron source and said first electrode.
Claim 17
Dependent Claim
30 words
An electron beam apparatus as claimed in claim 1, wherein the radius of the bend in the beam path has a length between approximately 25 cm and approximately 100 cm.
Claim 18
Dependent Claim
23 words
An electron beam apparatus as claimed in claim 1, wherein the double focussing magnetic bending device is formed by a 180* bending magnet.
Claim 19
Dependent Claim
74 words
An electron beam apparatus as claimed in claim 17, wherein the bending magnet comprises pole shoes having end surfaces which face the beam path and are situated on both sides of the beam path in planes which have a common point on the bisector of the inner bend in the beam path at a distance from the center of the beam path which is equal to twice the radius of the mean beam path.
Claim 20
Dependent Claim
87 words
An electron beam apparatus as claimed in claim 18, wherein the bending magnet includes a block of a non-ferromagnetic material which laterally embraces the beam path, the pole shoes engaging the two sides of this block which are parallel with the planes having a common point, while two wire windings extend parallel to the two sides which follow the bend of the beam path, ferromagnetic material which forms magnetic circuits being disposed against these latter sides at the outer side thereof when viewed from the beam path.
Claim 21
Dependent Claim
72 words
An electron beam apparatus as claimed in claim 19, wherein the wire windings on both sides of the beam path form part of two wire coils which are arranged substantially symmetrically with respect to a plane containing the center of the beam path in the bending magnet, the return windings of the coils following a U-shape which differs from the beam path near the ends of the bend in the beam path.
Claim 22
Dependent Claim
32 words
An electron beam apparatus as claimed in claim 17 wherein a vacuum space enveloping the beam path is formed by a bent tube of non-ferromagnetic material which laterally embraces the beam path.
References Cited (Backward Citations)
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 |