An X-ray analysis apparatus comprising: an X-ray source configured to generate X-rays; a sample stage configured to support a sample, the X-ray source and the sample stage being arranged so that X-rays generated by the X-ray source define an incident beam that irradiates the sample; an X-ray detector, arranged to receive X-rays from the sample; an adjustable slit between the X-ray source and the sample; a further slit, between the X-ray source and the adjustable slit, or between the adjustable slit and the sample; and a controller configured to control a width of the adjustable slit, wherein the controller is configured to vary the width of the adjustable slit between a first width, a second width, and a third width, the third width being greater than the second width, the second width being greater than the first width, wherein at the first width: the adjustable slit limits the divergence of the incident beam to a first divergence angle and thereby limits an area of the sample that is irradiated, at the second width: the adjustable slit limits the divergence of the incident beam to a second divergence angle and thereby limits the area of the sample that is irradiated, and characterised in that at the third width: the adjustable slit does not limit the divergence of the incident beam; and the further slit limits the divergence of the incident beam to a third divergence angle and thereby limits the area of the sample that is irradiated, wherein the third divergence angle is greater than the second divergence angle, and the second divergence angle is greater than the first divergence angle. an X-ray source configured to generate X-rays; a sample stage configured to support a sample, the X-ray source and the sample stage being arranged so that X-rays generated by the X-ray source define an incident beam that irradiates the sample; an X-ray detector, arranged to receive X-rays from the sample; an adjustable slit between the X-ray source and the sample; a further slit, between the X-ray source and the adjustable slit, or between the adjustable slit and the sample; and a controller configured to control a width of the adjustable slit, wherein the controller is configured to vary the width of the adjustable slit between a first width, a second width, and a third width, the third width being greater than the second width, the second width being greater than the first width, wherein at the first width: the adjustable slit limits the divergence of the incident beam to a first divergence angle and thereby limits an area of the sample that is irradiated, at the second width: the adjustable slit limits the divergence of the incident beam to a second divergence angle and thereby limits the area of the sample that is irradiated, and characterised in that at the third width: the adjustable slit does not limit the divergence of the incident beam; and the further slit limits the divergence of the incident beam to a third divergence angle and thereby limits the area of the sample that is irradiated, the adjustable slit does not limit the divergence of the incident beam; and the further slit limits the divergence of the incident beam to a third divergence angle and thereby limits the area of the sample that is irradiated, wherein the third divergence angle is greater than the second divergence angle, and the second divergence angle is greater than the first divergence angle.