X ray apparatus includes a sample stage (4) for supporting a sample (6), an X-ray source (2) and an energy dispersive X-ray detector (8). A conical X-ray collimator (10) is provided either between the sample and the X-ray source or between the sample and the energy-dispersive X-ray detector, the conical X-ray collimator including a plurality of truncated cones arranged concentrically around a central axis, the truncated cones having a common apex defining a central measurement spot on the sample.