U.S. Philips Corporation

Johan W Stolk

Maarten A Van Andel

Johannes Van Der Borst

Maurice J Lambers

Alphonsius D Klessens

A focal spot having an annular shape is often formed on the an (4) of an X-ray tube for analytic purposes. For the cooling of an anode it is known to force the cooling water to impinge on the anode with a flow profile having the same shape as the focal spot. In order to achieve this effect in the case of an annular focal spot, a circular delivery opening (36) is provided. In order to break up the steady boundary layer on the surface to be cooled, the impinging cooling water is forcibly split so as to flow into two directions. This is achieved by making the water flow via a distribution member 30 in which the circular delivery opening 36 is provided and by discharging the water via a discharge opening 40 which is situated within the circular delivery opening 40 and also via a return opening which is defined by the outer surface 42 of the distribution member 30 and the inner side of the discharge tube 16.

X-ray tube having a cooling profile adapted to the shape of the focal

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.

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Heerlen, Netherlands

Johan W Stolk