US5044001A
Expired / Lapsed
US
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Method and apparatus for investigating materials with X-rays
Assignee: Nanod Ynamics Inc
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Filing: 1990-06-20
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Granted: 1991-08-27
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Expires: 2010-06-20
Abstract
Abstract A method of investigating materials, especially biological specimens, utilizes a focused accelerated beam of electrons within an evacuated chamber, striking a metal foil within the chamber and exposing a specimen outside the evacuated chamber to x-rays generated in the metal foil. The apparatus of the invention functions as an x-ray microscope and in a preferred embodiment, as a scanning x-ray microscope.
Inventors
- 👤 Chia-Gee Wang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:28
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/252; H01J37/256; G; G01; G01N; G01N23/00; G01N23/02; G01N23/22; G01N23/223; G21; G21K; G21K7/00; H01J35/00; H01J35/02; H01J35/14; G01N2223/00; G01N2223/07; G01N2223/076; H01J35/04; H01J35/08; H01J35/112; H01J35/116
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
156 words
A method of investigating materials by the use of x-rays which comprises focusing an accelerated beam of electrons in an evacuated space on a metal foil facing said evacuated space, wherein the metal foil has a thickness of less than about 0.1 μm, the electron beam focused on said metal foil having a beam diameter of less than about 1000 Å incident on the metal foil, said metal foil being supported on a first surface of a support substrate which is substantially transparent to x-rays and has a second surface outside said evacuated space, said focused electron beam generating x-rays in said metal foil, placing a specimen of a material to be investigated adjacent to said second surface of said substrate in a position exposed to the x-rays generated in said metal foil, and selectively detecting from said specimen only x-rays selected from those having a peak energy or an energy close to the peak energy.
Claim 2
Independent Claim
156 words
A method of investigating materials by the use of x-rays which comprises focusing an accelerated beam of electrons in an evacuated space on a metal foil facing said evacuated space, wherein the metal foil has a thickness of less than about 0.1 μm, the electron beam focused on said metal foil having a beam diameter of less than about 1000 Å incident on the metal foil, said metal foil being supported on a first surface of a support substrate which is substantially transparent to x-rays and has a second surface outside said evacuated space, said focused electron beam generating x-rays in said metal foil, placing a specimen of a material to be investigated adjacent to said second surface of said substrate in a position exposed to the x-rays generated in said metal foil, and selectively detecting from said specimen only x-rays selected from those having a peak energy or an energy close to the peak energy.
Claim 3
Dependent Claim
28 words
A method according to claim 1, wherein the beam of electrons is focused to a beam diameter of less than about 500 Å incident on the metal foil.
Claim 4
Dependent Claim
28 words
A method according to claim 1, wherein the beam of electrons is focused to a beam diameter of less than about 100 Å incident on the metal foil.
Claim 5
Dependent Claim
28 words
A method according to claim 1, wherein the beam of electrons is focused to a beam diameter of less than about 10 Å incident on the metal foil.
Claim 6
Dependent Claim
18 words
A method according to claim 1, wherein the metal foil is a coating of metal on said substrate.
Claim 7
Dependent Claim
59 words
A method according to claim 1, wherein a first signal from x-rays detected from said specimen, a second signal is obtained from x-rays detected from the metal foil and substrate in the absence of said specimen, and said second signal is digitally subtracted from said first signal, thereby obtaining a digitally encoded image of a region of the specimen.
Claim 8
Dependent Claim
70 words
A method according to claim 13, wherein an area of the metal foil is scanned by the beam of electrons, and a digitally encoded image of a region of the specimen is amplified and displayed by an electron beam in a cathode ray tube, said electron beam in the said cathode ray tube being scanned in synchronization with the scanning of the beam of electrons directed to the metal foil.
Claim 9
Dependent Claim
16 words
A method according to claim 1, wherein fluorescent x-rays emitted from said specimen are selectively detected.
Claim 10
Dependent Claim
36 words
A method according to claim 8, wherein fluorescent x-rays characteristic of a specific chemical element are detected and a signal is produced which is representative of the concentration of said specific chemical element in said specimen.
Claim 11
Dependent Claim
32 words
A method according to claim 9, wherein the energy of the accelerated beam of electrons is substantially the same as the energy of the fluorescent x-rays characteristic of said specific chemical element.
Claim 12
Dependent Claim
54 words
A method according to claim 10, wherein the energy of the accelerated beam of electrons is sequentially changed to provide a series of different energies corresponding to different energies of fluorescent x-rays characteristic of different chemical elements, and signals are produced which represent the concentration of a plurality of chemical elements in said specimen.
Claim 13
Dependent Claim
27 words
A method according to claim 11, wherein over a period of time different signals are produced representing changing concentrations of said different chemical elements in said specimen.
Claim 14
Dependent Claim
42 words
A method according to claim 11, wherein an area of 370 the metal foil is scanned by the accelerated beam of electrons and signals are produced representative of the concentrations of a plurality of different elements throughout a region of said specimen.
Claim 15
Dependent Claim
38 words
A method according to claim 12, wherein an area of the metal foil is scanned by the accelerated beam of electrons and signals are produced representative of changing concentrations of different elements throughout of region of the specimen.
Claim 16
Dependent Claim
31 words
A method according to claim 1, wherein the specimen is a biological specimen which is investigated under ambient conditions of the environment without being subjected to high radiation dosage or evacuation.
Claim 17
Independent Claim
175 words
An apparatus for investigating materials by the use of x-rays, which comprises: a chamber for being maintained under vacuum; said chamber having a wall which has an aperture in which is mounted a support substrate composed of a material substantially transparent to x-rays, said support substrate having a first surface facing the interior of said chamber and a second surface outside said chamber, said first surface of the support substrate having thereon a metal foil, said metal foil having a thickness of less than about 0.1 μm, exposed to the interior of the chamber; means for focusing a beam of electrons within said chamber on said metal foil to a beam diameter of less than about 1000 Å incident on the metal foil; means for positioning a specimen outside said chamber adjacent to said second surface of the support substrate; and at least one x-ray detector positioned to detect x-rays leaving said specimen, said x-ray detector being an energy dispersive x-ray detector capable of selecting and recording peak energy and energies close to peak energy.
Claim 18
Independent Claim
175 words
An apparatus for investigating materials by the use of x-rays, which comprises: a chamber for being maintained under vacuum; said chamber having a wall which has an aperture in which is mounted a support substrate composed of a material substantially transparent to x-rays, said support substrate having a first surface facing the interior of said chamber and a second surface outside said chamber, said first surface of the support substrate having thereon a metal foil, said metal foil having a thickness of less than about 0.1 μm, exposed to the interior of the chamber; means for focusing a beam of electrons within said chamber on said metal foil to a beam diameter of less than about 1000 Å incident on the metal foil; means for positioning a specimen outside said chamber adjacent to said second surface of the support substrate; and at least one x-ray detector positioned to detect x-rays leaving said specimen, said x-ray detector being an energy dispersive x-ray detector capable of selecting and recording peak energy and energies close to peak energy.
Claim 19
Dependent Claim
25 words
An apparatus according to claim 16, which further comprises means for producing and accelerating a beam of electrons within said chamber along a beam path.
Claim 20
Dependent Claim
75 words
An apparatus according claim 17, wherein said chamber is an elongated hollow body having first and second end walls, with said means for producing and accelerating said beam of electrons being adjacent to said first end wall, and said support substrate being mounted in said second end wall, said beam path extending along a lengthwise axis in a downstream direction, from said means for producing and accelerating said beam of electrons to said metal foil.
Claim 21
Dependent Claim
47 words
An apparatus according to claim 18, wherein an x-ray detector is positioned downstream from said means for positioning a specimen, in the path of x-rays transmitted from said specimen, and said means for positioning a specimen and said x-ray detector are disposed in alignment with said axis.
Claim 22
Dependent Claim
41 words
An apparatus according to claim 19, having another x-ray detector which is positioned out of alignment with said axis, substantially out of the path of x-rays transmitted through said specimen and in the path of fluorescent x-rays emitted from said specimen.
Claim 23
Dependent Claim
40 words
An apparatus according to claim 18, wherein an x-ray detector is positioned out of alignment with said axis, substantially out of the path of x-rays transmitted through said specimen and in the path of fluorescent x-rays emitted from said specimen.
Claim 24
Dependent Claim
56 words
An apparatus according to claim 16, further comprising an axial symmetric diffractor for directing x-rays having energies close to peak energies towards said x-ray detector while blocking the passage of lower energy x-rays, said diffractor being located between said means for positioning a specimen and said x-ray detector and being axially in alignment with said axis.
Claim 25
Dependent Claim
16 words
An apparatus according to claim 16, wherein said energy dispersive x-ray detector is a charge-coupled device.
Claim 26
Dependent Claim
80 words
An apparatus according to claim 18, further comprising: means for scanning said beam of electrons over an area of the metal foil, means for amplifying a signal representative of detected x-rays; means for converting the amplified signal into a digitally encoded image of a scanned area; means for amplifying and displaying said image, said means for amplifying and displaying comprising a cathode ray tube for being scanned by an electron beam, in synchronization with the scanning of the metal foil.
Claim 27
Dependent Claim
29 words
An apparatus according to claim 21, wherein the means for producing and accelerating said beam of electrons includes means for dynamically scanning the energy of said beam of electrons.
Claim 28
Dependent Claim
28 words
An apparatus according to claim 20, wherein the x-ray detector is an energy dispersive and energy discriminating detector for selectively detecting fluorescent x-rays characterisitic of specific chemical elements.
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) | 1994-08-26 | 1995-02-25 | 1995-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-08-26 | 1999-02-25 | 1999-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-08-26 | 2003-02-25 | 2003-08-27 | $7700.00 | Window Closed / Lapsed |