A method for inspection of a sample includes directing a beam of X-rays toward a sample and configuring an array of detector elements to capture the X-rays scattered from the sample. The sample is shifted in a direction parallel to the axis of the array between at least first and second positions, which positions are separated one from another by an increment that is not an integer multiple of the pitch of the array. At least first and second signals are generated by the detector elements responsively to the X-rays captured thereby while the sample is in at least the first and second positions, respectively. The first and second signals are combined so as to determine an X-ray scattering profile of the sample as a function of position along the axis.