Abstract: An apparatus for X-ray analysis by means of a focusing optical system according to the Rowland geometry. The apparatus is arranged to operate with a fixed measuring channel, the X-ray detector (14, 16) occupying a fixed position. In order to compensate for mechanical tolerances and a spread in the period of the analysis crystal (12) (a multilayer mirror), it is necessary to rotate the crystal slightly, after which the X-ray beam to be analyzed is no longer completely incident on the detector (14, 16). In accordance with the invention, the analysis crystal (12) is readjusted by coupling the rotation of the crystal to a displacement of the crystal in conformity with the Rowland geometry. The detector need not be displaced for as long as the angle of incidence of the X-rays to be analyzed on the analysis crystal remains small, for example <30°.

Abstract: An imaging optical system having a Rowland geometry can be used in a spectrometer for X-ray fluorescence. For the focusing of the X-ray beam emanating from the specimen to be analyzed use is made of a curved analyzer crystal 28 whose radius of curvature may be variable, as in the case of a crystal surface 29 in the form of a logarithmic spiral 40. If such an analyzer crystal is to be made sufficiently large so as to achieve adequate intensity in the X-ray detector, a part of the crystal would have to be given a radius of curvature which is smaller than permissible so as to avoid fracturing of the crystal. In accordance with the invention, a first part 40 of the reflective surface 29 has a radius of curvature which is dependent on the location on the crystal whereas another part 42 of the reflective surface has a constant radius of curvature 44.

Abstract: An X-ray analysis apparatus includes a scanning unit (1) with an X-ray source (3), a crystal holder (9) and an X-ray detection system (5) provided with an X-ray detector (7). The crystal holer (9) can be rectilinearly displaced in a fixed radiation pick-up direction (35) relative to the X-ray source (3). The crystal holder (9) and the X-ray detector (7) are mechanically coupled to one another via a plate (21) which can be driven by means of a motion mechanism. The X-ray source (3), the X-ray detector (7) and the crystal holder (9) remain positioned on a Rowland circle (11) during the displacement. The motion mechanism has a first guide (23) and a second guide (25). The drive direction of the first guide (23) encloses an acute angle .alpha. relative to the fixed pick-up direction (35).

Abstract: An X-ray analysis apparatus comprises an analysis crystal which is cylindrically curved in the saggital direction. As a result, a beam diffracted by the crystal is collimated in that direction, i.e. the plane of incidence of the X-ray beam, so that a substantial gain regarding radiation yield is obtained without loss of resolution.