X-ray interferometer for phase contrast imaging

1. An interferometer for x-rays for obtaining quantitative x-ray images from an object, comprising:

a) an x-ray source;

b) a diffractive beam splitter grating other than a Bragg crystal;

c) a position-sensitive detector with spatially modulated detection sensitivity having a plurality of individual pixels;

d) a recording device for recording images from said detector; and

e) an evaluating device for evaluating respective intensities for each pixel in a series of the images in order to identify a characteristic of the object for each individual pixel as an absorption-dominated pixel and/or a differential phase contrast-dominated pixel and/or an x-ray scattering-dominated pixel;

f) means for generating display data for displaying the evaluated images of the object, wherein an encoding approach is used for differentiating an individual contribution to each individual pixel, and wherein:

a value of a differential absorption signal dA(m,n)/dx or an absorption signal dA(m,n) or an absolute value of any of the differential absorption signal or the absorption signal dA(m,n) is assigned to a first codification;

a value of a differential phase contrast signal dφ(m,n)/dx or an integrated phase signal φ(m,n) or an absolute value of any of the differential phase contrast signal dφ(m,n)/dx or the integrated phase signal φ(m,n) is assigned to a second codification; and

a value of a differential scattering signal dS(m,n)/dx or a scattering signal S(m,n) or an absolute value of any of the differential scattering signal dS(m,n)/dx or the scattering signal S(m,n) is assigned to a third codification.

2. The interferometer according to claim 1 , wherein said x-ray source is a standard polychromatic x-ray source.

3. The interferometer according to claim 1 , wherein said beam splitter grating is in transmission geometry.

4. The interferometer according to claim 1 , wherein said evaluating device comprises calculation means for analyzing a course of detected intensities for each pixel of the detector, wherein the course of the detected intensities is yielded by a predetermined number of the images recorded in step d).

5. The interferometer according to claim 4 , wherein said calculation means includes a memory for storing the images without an object being placed in an x-ray beam line.

6. The interferometer according to claim 1 , which comprises an analyzer grating for generating the spatially modulated detection sensitivity, said analyzer grating having absorbing lines at a same periodicity and orientation as a set of fringes generated by said diffractive beam splitter grating, and wherein said analyzer grating is placed in a plane of said detector.

7. The interferometer according to claim 6 , wherein said analyzer grating is placed immediately in front of said detector.

8. The interferometer according to claim 6 , wherein the phase-stepping approach is achieved by scanning at least one of said gratings relative to the object in a direction substantially perpendicular to the orientation of the lines in said at least one of said gratings.

9. The interferometer according to claim 1 , wherein said means for generating display data are programmed to calculate a superimposed image containing all three values being superimposed according to a respective codification thereof.

10. The interferometer according to claim 1 , wherein said means for generating display data are configured to display an individual image for each of the three codifications.

11. The interferometer according to claim 1 , wherein each of the three codifications comprises an individual signal type selected from the group consisting of an individual letter, a symbol, and/or a color.

12. The interferometer according to claim 1 , wherein a superimposed image comprises an array of M×N pixels, each of the pixels having a color representing a type of contribution of individual signal types in a superposition of the three absolute values.

13. The interferometer according to claim 1 , configured for processing hard x-rays.

14. An interferometer for x-rays for obtaining quantitative x-ray images from an object, comprising:

a) a slit mask having a given number of slits arranged between an X-ray source and a beam splitter grating, allowing the object to be disposed between said slit mask and said beam splitter grating;

b) at least one analyzer grating disposed between said beam splitter grating and a detector, wherein said beam splitter grating and each of said at least one analyzer grating have a grating structure associated with the given number of slits in said slit mask;

c) wherein said detector is configured as an array of individual line detectors each having a number of pixels, and wherein a number of said line detectors corresponds to the given number of slits in said slit mask;

d) means for moving the object along a scan direction oriented perpendicular to an orientation of the gratings in said grating structure;

e) means for recording the images from said detector in a continuous scanning approach; and

f) means for evaluating intensities for each pixel in a series of the images representing a phase stepping scan for at least a part of the object being moved along the scan direction;

wherein the grating structure in said at least one analyzer grating comprises a number of sub-gratings having a shift perpendicular to grating lines by an integer multiple of p 2 /n, wherein p 2 is a period of said at least one analyzer grating and n is a given number of said line detectors.

15. The interferometer according to claim 14 , configured for processing hard x-rays.

16. An interferometer for x-rays for obtaining quantitative x-ray images from an object, comprising:

a) a slit mask having a given number of slits arranged between an X-ray source and a beam splitter grating, allowing the object to be disposed between said slit mask and said beam splitter grating;

b) at least one analyzer grating disposed between said beam splitter grating and a detector, wherein said beam splitter grating and each of said at least one analyzer grating have a grating structure associated with the given number of slits in said slit mask;

c) wherein said detector is configured as an array of individual line detectors each having a number of pixels, and wherein a number of said line detectors corresponds to the given number of slits in said slit mask;

d) means for moving the object along a scan direction oriented perpendicular to an orientation of the gratings in said grating structure;

e) means for recording the images from said detector in a continuous scanning approach; and

f) means for evaluating the intensities for each pixel in a series of the images representing a phase stepping scan for at least a part of the object being moved along the scan direction;

wherein sub-gratings are disposed equidistantly from said x-ray source, and wherein conveyor means are provided for moving the object along a deflected trajectory following a shape defined by a position of said sub-gratings.