Abstract: A device adapted for examining and detecting foreign objects in a flat plate-shaped material comprises a transport device for transporting a flat plate-shaped material to be examined through the device in a transport direction. The device comprising a first X-ray source and a second X-ray source adapted for, in operation, emitting a first X-ray beam and a second X-ray beam. The device comprising a first sensor unit and a second sensor unit arranged to detect the first and second X-ray beam. The first and second sensor unit being adapted for detecting data indicative of the presence and the indirect or direct position in the transport direction of a foreign object in a flat plate-shaped material. The first and second sensor unit comprise or are connected to a data processing unit adapted for processing the detected data to determine the presence of a foreign object in the flat plate-shaped material.

Abstract: System for measuring layer thicknesses of a multi-layer pipe by measuring with a detector array (2) the attenuation of an X-ray transmitted though the pipe. According to the invention the detector array (2) comprises an array of detector elements D1, D2, D3, D4 with a collimator for defining the field of radiation in front of each detector element. The collimator has a narrow diaphragm aperture setting the resolution when the position of the pipe walls is to be determined. The defined field of radiation has an extent sufficient to radiate the four detector elements D1, D2, D3, D4 in parallel. In a suitable signal processing of the output signals from the detector elements D1, D2, D3, D4, eg by using the method of least squares, the thicknesses of the different layers may be fairly accurately determined.