Three-dimensional microtomographic analysis system
First Claim
1. A data acquisition method for microtomographic analysis of a specimen, the specimen comprising varying phase fractions of first and second types of material, the method including the steps of:
- a. making a plurality of sets of projections of the specimen, each projection of the specimen being a measure of the incident energy (I) of a conebeam x-ray transmitted from an x-ray source through the specimen to a detector, said detector having a plurality of x-ray sensitive pixels and each set of projections including a first projection of the specimen of a selected view, wherein said x-rays used to make said first projection have a first energy spectra, and a second projection of the specimen of a selected view, wherein said x-rays used to make said second projection have a second energy spectra different from said first energy spectra, and wherein each set of projections are made of different selected views of the specimen;
b. quantifying the phase fraction of the material forming the specimen for each said selected view of the specimen by evaluating the differences in said incident x-ray energy transmitted through the specimen between said first and second projections of said specimen at each of the detector pixels for each set of projections, wherein said quantifying process for each set of projections of the specimen produces a first processed projection representative of the phase fraction of a first type of material forming the specimen and a second processed projection representative of the second type of material forming the specimen; and
c. calculating the phase fraction of the material forming the specimen at a selected point in the specimen by performing backplane analyses of said processed projections, wherein a first backplane analysis is performed of said first processed projections to obtain an indication of the phase fraction of the first type of material forming the specimen at said selected point and a second backplane analysis is performed of said second processed projections to obtain an indication of the phase fraction of said second type of material forming the specimen at said selected point.
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Accused Products
Abstract
A microtomographic system (10) for generating high-resolution, three dimensional images of a specimen (16) is disclosed. The microtomograph system includes an x-ray generator (12) that produces an x-ray beam (14), a specimen holder (18) that holds the specimen in the beam, and an x-ray detector (20) that measures the attenuation of the beam through the specimen. Two projections of each view of the specimen are made with this microtomographic system. Each projection is made with a different intensity x-ray beam. After the projections of one view of the specimen are made, the specimen is rotated on the specimen holder and another set of projections are made. The projections of each view of the specimen are analyzed together to provide a quantitative indication of the phase fraction of the material comprising the specimen. The projections of the different views are combined to provide a three-dimensional image of the specimen.
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Citations
12 Claims
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1. A data acquisition method for microtomographic analysis of a specimen, the specimen comprising varying phase fractions of first and second types of material, the method including the steps of:
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a. making a plurality of sets of projections of the specimen, each projection of the specimen being a measure of the incident energy (I) of a conebeam x-ray transmitted from an x-ray source through the specimen to a detector, said detector having a plurality of x-ray sensitive pixels and each set of projections including a first projection of the specimen of a selected view, wherein said x-rays used to make said first projection have a first energy spectra, and a second projection of the specimen of a selected view, wherein said x-rays used to make said second projection have a second energy spectra different from said first energy spectra, and wherein each set of projections are made of different selected views of the specimen; b. quantifying the phase fraction of the material forming the specimen for each said selected view of the specimen by evaluating the differences in said incident x-ray energy transmitted through the specimen between said first and second projections of said specimen at each of the detector pixels for each set of projections, wherein said quantifying process for each set of projections of the specimen produces a first processed projection representative of the phase fraction of a first type of material forming the specimen and a second processed projection representative of the second type of material forming the specimen; and c. calculating the phase fraction of the material forming the specimen at a selected point in the specimen by performing backplane analyses of said processed projections, wherein a first backplane analysis is performed of said first processed projections to obtain an indication of the phase fraction of the first type of material forming the specimen at said selected point and a second backplane analysis is performed of said second processed projections to obtain an indication of the phase fraction of said second type of material forming the specimen at said selected point. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An x-ray microtomograph for making x-ray projections of a specimen, comprising:
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a base having an interior space, an open face and a top located opening; an electron gun assembly disposed on top of said base, said electron gun assembly configured to produce a downward directed electron beam through said base top located opening and into said interior space of said base; an electron beam deflector located in said interior space of said base, said electron beam deflector positioned to deflect said downward directed electron beam away from the vertical and toward said open face of said base; a face plate secured over said open face of said base so as to have a vacuum-tight seal, said face plate including an opening, wherein said face plate opening is positioned so that said electron beam is directed toward said opening; and a target located in said face plate opening, said target being formed of a material that emits x-rays upon being struck by said electron beam so as to produce an x-ray beam directed away from said base. - View Dependent Claims (9, 10)
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11. An x-ray microtomograph for making x-ray projections of a specimen, comprising:
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a base having an interior space and an open face, said base being further formed with a top located opening; an electron gun assembly disposed on top of said base, said electron gun assembly configured to produce an electron beam directed vertically downward toward said top located opening of said base; a target mounted in said top located opening of said base, said target being formed of a material that emits x-rays in response to being struck by said electron beam, said x-rays having an incident energy; a specimen holder positioned adjacent said base for positioning the specimen in the path of said x-rays; a scintillator layer located in said base and positioned below the specimen for emitting visible light in proportion to the energy of x-rays transmitted through the specimen; a reflector disposed in said base and positioned to reflect light emitted by said scintillator layer out through said open face of said base; and a detector adjacent said base for measuring said light emitting by said scintillator layer as a measure of incident x-ray energy transmitted through the specimen. - View Dependent Claims (12)
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Specification