X-ray optics, especially for phase contrast

An x-ray or neutron beam optic configuration comprising:

• a plurality of single crystal portions formed with respective spaced x-ray or neutron reflection faces formed at predetermined asymmetry angles to a Bragg diffraction plane in the respective crystal portion;
• means to mount a sample between a first and a second of said faces, which first face is arranged to be a monochromator and collimator with respect to x-rays or neutrons of appropriate wavelength incident on said first face and reflected thereby through the sample for receipt by the second face, said second face thereby serving as an analyzer face;
• and
• means interconnecting said crystal portions whereby to allow small adjustments of the relative angle of said faces about the normal to the plane of diffraction while maintaining the normals to the Bragg planes for said first and second faces substantially in the plane of diffraction.

A method of deriving an x-ray or neutron beam image signal of a sample comprising:

• directing an x-ray or neutron beam onto a first x-ray or neutron reflection face for reflection from that face through the sample to a second x-ray or neutron reflection face and thence to x-ray detection means,
• said reflection faces being interconnected such that a beam Bragg diffracted by the first face is at or near the correct angle for Bragg diffraction by the second face,
• said reflection faces being formed in respective single crystal portions at predetermined asymmetry angles to a Bragg diffraction plane in the respective crystal portion, wherein said first face is arranged to be a monochromator and collimator with respect to x-rays or neutrons of appropriate wavelength incident on said first face and reflected thereby through the sample for receipt by the second face, said second face thereby serving as an analyzer face;
• and
• said reflection faces being inter-connected so as to allow small adjustments of the relative angle of said reflection faces about the normal to the plane of diffraction while maintaining the normals to the Bragg planes for said first and second reflection faces substantially in the plane of diffraction.

A method of deriving an x-ray or neutron beam image signal of a sample comprising:

• directing an x-ray or neutron beam onto a first x-ray or neutron reflection face for reflection from that face through the sample to a second x-ray or neutron reflection face and thence to x-ray detection means,
• said reflection faces being interconnected such that a beam Bragg diffracted by the first face is at or near the correct angle for Bragg diffraction by the second face,
• said reflection faces being formed in respective single crystal portions at predetermined asymmetry angles to a Bragg diffraction plane in the respective crystal portion, wherein said first face is arranged to be a monochromator and collimator with respect to x-rays or neutrons of appropriate wavelength incident on said first face and reflected thereby through the sample for receipt by the second face said second face thereby serving as an analyzer face;
• and
• wherein the second face is well matched in angular acceptance to the angular divergence of the beam from the first face, or is of higher angular resolution.

A method of deriving an x-ray or neutron beam image signal of a sample comprising:

• directing an x-ray or neutron beam onto a first x-ray or neutron reflection face for reflection from that face through the sample to a second x-ray or neutron reflection face and thence to x-ray detection means,
• said reflection faces being interconnected such that a beam Bragg diffracted by the first face is at or near the correct angle for Bragg diffraction by the second face,
• said reflection faces being formed in respective single crystal portions at predetermined asymmetry angles to a Bragg diffraction plane in the respective crystal portion, wherein said first face is arranged to be a monochromator and collimator with respect to x-rays or neutrons of appropriate wavelength incident on said first face and reflected thereby through the sample for receipt by the second face, said second face thereby serving as an analyzer face;
• wherein said single crystal portions are respective segments of a monolithic perfect or near-perfect single crystal shaped by initial growth or subsequent modification to define the respective reflection faces, which crystal thereby interconnects said crystal faces, and
• wherein said reflection faces are formed at predetermined asymmetry angles to a common Bragg diffraction plane in the crystal.

An x-ray or neutron optic configuration comprising:

• a plurality of single crystal portions formed with respective spaced x-ray or neutron reflection faces formed at predetermined asymmetry angles to a Bragg diffraction plane in the respective crystal portion;
• and
• means to allow small adjustments of the relative angle of said faces about the normal to the plane of diffraction while maintaining the normals to the Bragg planes for said first and second faces substantially in the plane of diffraction;
• wherein said means allows maintenance and/or selection of an angular setting of the second face which is well matched in angular acceptance to the angular divergence of the beam from the first face, or is of higher angular resolution.