Patent ID: 7023954

Claim:
Apparatus for X-ray analysis of a sample, comprising: an X-ray excitation source, which is arranged to irradiate a spot on the sample with an X-ray beam along a beam axis; one or more X-ray detectors, which are arranged so as to define a ring around the spot, the ring having a gap therein at a location that is radially displaced from the beam axis, and wherein the one or more X-ray detectors are adapted to receive X-ray photons from the spot on the sample and to generate a first signal in response to the photons that is indicative of a characteristic of the sample; an optical radiation source, which is aligned with the X-ray excitation source so as to illuminate the spot on the sample with optical radiation; and an optical detector, which is positioned in the gap in the ring so as to receive the optical radiation that is reflected from the sample, and to generate a second signal that is indicative of an alignment of the spot with a target area of the sample.