Method and arrangement for identifying crystalline and polycrystalline materials

An arrangement for identifying crystalline and polycrystalline material in an object, comprising:

• an x-ray source including a diaphragm for projecting a central x-ray beam having a polychromatic energy distribution in a fan plane into an examination region containing the object for irradiating a cross section of the object, the x-rays being diffracted by individual subregions of the object along the cross section in dependence of the presence of at least one of crystalline and polycrystalline material in a respective one of the individual subregions;
• collimators arranged beyond the examination region relative to the x-ray source, the collimators being arranged in at least one row symmetrically around the axis of the central x-ray beam in a plane extending perpendicularly to the fan plane of the central x-ray beam and including collimating windows extending in parallel with respect to one another and respectively at a fixed angle .alpha. with respect to the axis of the central x-ray beam, each collimating window covering a fixed, predetermined subregion of the examination region and extracting at least one diffracted plane fan beam from the respective individual subregion of the object;
• and
• detectors each arranged at a respective one of the collimating windows of the collimators in the plane of the respectively collimated fan beam for capturing energy spectra of the diffracted x-ray plane fan beam exiting a respective one of the collimating windows and converting the energy spectra into signals for subsequent use in a data processing arrangement, wherein the detectors each comprises a silicon photodiode including an end face having an area of 1 mm.sup.2 to 5 mm.sup.2 behind a respective one of the collimating windows so that each diffracted x-ray plane fan beam exiting a respective one of the collimating windows is incident on a respective one of the end faces of the silicon photodiodes.