The present invention refers to a method for determining a position of a divergent radiation source (1), comprising Irradiating a pixel detector (2) with a predetermined intensity distribution of radiation with wavelength λ originated from the radiation source (1), wherein the pixel detector (2) comprises a plurality of pixels with pixel coordinates (xi, yi, zi); Detecting, for each of the plurality of pixels, an intensity of the incident radiation (10); Determining, for each of the plurality of pixels, an incidence direction of the incident radiation using information on an orientation of an internal periodic structure at the pixel and the predetermined intensity distribution, wavelength λ and the detected intensity; and Determining the position (xp, yp, zp) of the radiation source (1) using the pixel coordinates (xi, yi, zi) and the incidence direction for each of the plurality of pixels. The invention further refers to a system, a computer-related product and a sample (8) for performing such method and to the use of a pixel detector (2) for determining a position of a divergent radiation source (1).