Plasma spraying of conversion screens

DETAILED DESCRIPTION What is claimed is: 1.
An X-ray image intensifier tube having an entrance screen comprising a first phosphor layer deposited upon a first carrier, an exit screen comprising a second phosphor layer deposited upon a second carrier and sides connecting said two screens, characterized in that said phosphor layers are dense homogeneous layers consisting of phosphor material provided on said carriers by forming a dispersion of a self-adhering powder of said phosphor material in a gas stream, passing said dispersion through a heated zone capable of melting said powder to thereby melt said powder and then causing said molten powder to impact upon a carrier maintained at a temperature below the melting point of said powder.
2.
The X-ray image intensifier tube of claim 1 wherein the carrier of the exit screen is an optical fiber window.
3.
An X-ray image intensifier tube of claim 1 wherein the second phosphor layer is a cesium iodide layer.
4.
The X-ray image intensifier tube of claim 3 wherein the carrier of the exit screen is an optical fiber window.




Description:
The invention relates to a method of manufacturing conversion screens in which a conversion material is deposited on a carrier, to conversion screens manufactured by means of this method and to products comprising such a screen.
A conversion screen usually comprises a carrier on which or in which there is provided a radiation-conversion material.
The carrier is adapted to the nature of the screen; for example, it will have a low absorption for radiation to be detected when employed in an entrance screen or an intensifier screen, it will be suitably transparent for the luminescent light developed in the conversion layer when employed in an exit screen, and it will exhibit an adapted electrical conductivity in the case of conversion screens in which a charge pattern is built up by incident radiation, for example, in photoconductive screens.
The choice of the carrier is thus determined to a high degree by the nature and the energy of the radiation to be measured, by the nature of the conversion product to be formed in the conversion layer, and by the method of detection or reading of the conversion product