U.S. Philips Corporation

Johannes K Colditz

August L Simons

Johnny W Van Der Velden

Tiemen Poorter

Henricus M De Vrieze

Willem H Diemer

Engelbertus Rongen

Martinus A Ligtenberg

Johannes W Scheuermann

Theodorus F Van Bergen

Henricus F Diebels

Laurens H Jonk

Franciscus M Dreesen

Pieter J T Hoen

Caspard H Creusen

An X-ray image intensifier tube (1) includes an entrance section (2) for converting high-energy X-rays of from 100 keV to 120 keV into an electron beam (10). The entrance section (2) had a conversion layer (3) with a filter layer (5) for absorbing a part of comparatively low energy (from 60 keV to 80 keV) of the X-rays and a conversion layer for converting the high-energy X-rays of approximately from 100 keV to 120 keV into radiation whereto the photocathode is sensitive.

X-ray detector having an entrance section including a low energy x-ray

In order to increase the sensitivity of an image intensifier tube, the efficiency with which an electron image is formed from radiation of a first wavelength is increased. Radiation of the first wavelength is converted into radiation of a second wavelength by means of a conversion screen provided with a scintillation layer, and radiation of the second wavelength releases electrons from a photocathode which is sensitive to the second wavelength. Loss of radiation of a second wavelength, incurred because a part of this radiation does not reach the photocathode, is reduced. Radiation of the second wavelength which is not emitted in the direction of the photocathode is recaptured by providing the conversion screen with a metallic reflecting intermediate layer.

Image intensifier tube

In an X-ray image intensifier tube an entrance section is optimized in respect of image quality, optical aberrations and efficiency. To achieve this, notably in order to avoid photocathode charging phenomena, a separating layer having an adapted electrical transverse conduction is provided. In order to reduce scattered radiation, an edge portion of the entrance screen is deactivated for relevant examinations. In order to increase efficiency, use is made of a double phosphor layer having different X-ray absorption properties. In order to compensate for vignetting a radial variation of the thickness or of the radiation properties of a separating layer or of the luminescent layer itself is used.

X-ray image intensifier tube with improved entrance section

An exit section of an X-ray image intensifier tube, including an the exit phosphor screen, exit window and basic optical system, is optimized so as to achieve a high light yield, low optical aberration and a high resolution. The exit window notably has a pre-compensation geometry for curvature of the image plane of the basic optical system, or the exit window an interference filter, or the exit phosphor layer contains a layer of a comparatively slow phosphor in addition to a layer of a customary phosphor in order to achieve noise-suppressing image integration.

X-ray examination apparatus including an X-ray image intensifier having

The entrance screen in an X-ray image intensifier includes an intermediate layer of a material which selectively absorbs photon energy. As a result, the speed of the photo-electrons is substantially reduced, thus improving the imaging. By introducing a radial variation of the absorption in the intermediate layer, vignetting-compensation can also be realized without substantial loss of sensitivity and resolution for the central portion of the tube. The resolution at the periphery of the tube can thus be substantially improved.

X-ray image intensifier tube comprising a selective filter

An X-ray image intensifier tube comprises an entrance window which is composed of a carbon fibre reinforced plastics foil which is covered with a metal layer. The plastics foil has a comparatively low absorption and the metal layers can be constructed so as to be sufficiently thin and from suitable materials such that only a low absorption occurs therein. The metal layers ensure that the entrance window is suitably vacuumtight and allow for simple vacuumtight connection of the entrance window to the further envelope.

X-ray image intensifier tube with carbon-reinforced plastic foil

A neutron generator having a target which is hit by a beam of hydrogen ions. The target comprises a metal layer having a large coefficient of absorption for hydrogen, which is provided on a carrier layer of a metal having small coefficients of absorption and diffusion for hydrogen and a large coefficient of thermal conductivity, and a first intermediate layer of another metal having a large coefficient of thermal conductivity and a low sputtering ratio between the metal and the carrier layer. Between the carrier layer and the first intermediate layer a second intermediate layer of a metal, having a coefficient of linear expansion of a value which is between the coefficients of linear expansion of the carrier layer and the first intermediate layer, is present. Such a target is suitable for being used in a neutron generator which is to provide a high neutron yield.

Neutron generator having a target

The portion of the shield of a neutron radiation apparatus which is situated nearest to the neutron source is made of tungsten. As a result, a commonly used outer shielding layer consisting of a heavy metal can be dispensed with, so that improved shielding and a substantial saving as regards weight are combined.

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Heerlen, Netherlands

Johannes K Colditz