X-ray fluorescence analysis of multilayered samples

The invention refers to a device for measurement of the thickness of a first layer, comprising one or more sublayers, on a second layer of a metal sheet by X-ray fluorescence analysis comprising means for generating and directing a beam of polychromatic primary X-rays, said beam being able to penetrate into the first and second layers for converting primary X-rays into chemical element specific fluorescent X-rays by means of absorption of primary X-rays and re-emission of fluorescent X-rays by the chemical element, and further comprising means for detecting element specific fluorescent X-rays and determining an intensity thereof. The means for detection have been placed at an angle with respect to the primary beam of X-rays in dependence of the chemical element from which the fluorescent X-rays are to be detected. Herewith an improvement of the efficiency of detection is achieved, and the measurement time is reduced accordingly. Hence, a device is provided with which alloys with a low concentration of fluorescent elements can now be analysed, for determining the thickness of a cladding.