An X-ray analysis apparatus and method. The apparatus comprises an adjustable slit (210) between an X-ray source (4) and a sample (6); and optionally a further slit (220, 220a). A controller (17) is configured to control a width of the adjustable slit, between a first width, a larger second width, and an even larger third width. At the first and second widths: the adjustable slit (210) limits the divergence of the incident beam and thereby limits an area of the sample that is irradiated; and the further slit (220) does not limit the divergence of the incident beam. At the third width: the adjustable slit (210) does not limit the divergence of the incident beam, and the further slit (220) limits the divergence of the incident beam and thereby limits the area of the sample that is irradiated. Alternatively, at the third width, the adjustable slit (210) continues to limit the area irradiated.