Abstract: The filament for the emission of the electrons in an X-ray tube inevitably evaporates gradually during operation of the tube. Depending on the location of the filament in the tube, the metal vapor thus released is deposited on the X-ray window of the tube. Consequently, the transmission of the X-ray tube window gradually decreases in the course of the service life of the tube. In order to counteract the deposition of filament material, an edge structure is provided on the inner side of the window; this structure comprises edges which extend perpendicularly to the window surface, and is preferably a honeycomb structure with hexagonal cells. The height of the edges is chosen so that, viewed from the filament, the edge structure forms a shadow zone for the entire X-ray window, so that the metal vapor is deposited on the structure instead of on the window.

Abstract: An X-ray collimator in an X-ray analysis apparatus, consisting of plates of X-ray absorbing material, for example tungsten, which are arranged transversely of the X-ray beam. The plates are identical and provided with a pattern of rows and columns of rectangular openings 40, 42 which have a vertical period p.sub.1 and a horizontal period p.sub.2. The openings take up an opening fraction t.sub.1 and t.sub.2 of the periods p.sub.1 and p.sub.2, respectively. The plates are arranged in the collimator in a series in which the ratio between two successive distances (d.sub.i, d.sub.i+1) between the plates of the series is equal to the given opening fractions t.sub.1 and t.sub.2 of the periods p.sub.1 and p.sub.2, respectively. It has been found that all directions in the X-ray beam are then intercepted except for the direction to be collimated. Moreover, this configuration also enables transverse collimation.

Abstract: An X-ray window for an X-ray component such as an X-ray detector. Windows of this kind must be as thin as possible so as to minimize X-ray absorption. The known material polypropylene is not available in the desired thickness of the order of 1 .mu.m, and stretching of this material so as to reduce the thickness causes an inadmissible spread in thickness. The material polyethylene naphthalate (PEN) in accordance with the invention is available in the desired thickness and with a much smaller spread in thickness. Furthermore, the window material should exhibit suitable mechanical properties (such as strength, rigidity and tightness) which are not allowed to degrade significantly under the influence of continuously varying circumstances in respect of pressure, temperature and X-rays. In comparison with the known polyethylene terephtalate (PET), PEN in this respect has better properties which satisfy the mechanical requirements.

Abstract: The anode connections in a gas-filled X-ray detector are mounted so as to extend transversely of the anode wire so that a substantial saving as regards space is achieved. In order to reduce field inhomogeneities in the ionization space, there may be provided a field profile bush which partly encloses the anode wire and field bushes may be arranged around the anode connection pins.