Patent Number: 
Section: claims

1. An X-ray imaging spectrometer with a well-defined spectral resolution for each wavelength in a spectral range of interest, said X-ray imaging spectrometer comprising:an X-ray detector;an X-ray source;a glass substrate machined to a multi-cone form;a crystal slab attached to the glass substrate, wherein said multi-cone form is generated by superimposing a plurality of cones with different aperture angles on a common nodal line,wherein said multi-cone form provides a rotational symmetry of a ray pattern,wherein said crystal slab reflects X-rays onto said X-ray detector,wherein said reflected X-rays intersects a corresponding cone axis. 2. The X-ray imaging spectrometer of claim 1, wherein the X-ray detector comprises a streak camera. 3. The X-ray imaging spectrometer of claim 1, wherein the X-ray detector comprises a gated strip detector. 4. The X-ray imaging spectrometer of claim 1, wherein said substrate comprises a 3D printed material having a multi-cone form. 5. A method for imaging each wavelength in a spectral range of interest of small X-ray sources employing an X-ray imaging spectrometer;the X-ray imaging spectrometer comprising:a glass substrate machined to a multi-cone form;a thin crystal slab attached to the glass substrate; anda point-like X-ray source,the method comprising:calculating a multi-cone geometry, wherein said multi-cone geometry is determined by superimposing a plurality of cones with different aperture angles on a common nodal line, wherein said plurality of cones includes a cone for each Bragg angle;machining said glass substrate to have said multi-cone geometry;providing a rotational symmetry of a ray pattern; andimaging each wavelength in a spectral range of interest. 6. The method of claim 5, wherein the thin crystal slab provides a well-defined and very large spectral resolution. 7. The method of claim 5, further comprising assessing large Bragg angles >50°. 8. The method of claim 5, further comprising using a crystal that increases ray throughput. 9. A method for an X-ray imaging spectrometer employing multi-cone focusing crystal geometry, said method comprising:attaching a thin crystal slab to a substrate;machining at least said substrate to have a multi-cone geometry, wherein said multi-cone geometry is determined by superimposing a plurality of cones with different aperture angles on a common nodal line, wherein said plurality of cones includes a cone for each Bragg angle;providing an X-ray imaging spectrometer, wherein said X-ray imaging spectrometer includes said thin crystal slab having multi-cone geometry and an X-ray detector;exposing said X-ray imaging spectrometer to an X-ray source, wherein said X-ray source comprises a point-like X-ray source;thereby providing a rotational symmetry of a ray pattern and imaging each wavelength in a spectral range of interest at a high resolution.