U.S. Philips Corporation

Gerardus Van Aller

Ulrich Schiebel

Engelbertus Rongen

Walter H Kuhl

Jan Wieldraaijer

Guido T Mulder

A proximity-type image intensifier tube has an entrance screen which includes a photocathode which is substantially insensitive to light of wavelengths above 500 nm, and an exit screen having a phosphor layer having a substantial emissivity of notably red light having a wavelength of at least 550 nm. Consequently, optical radiation produced by the exit screen does not produce disturbing feedback radiation from the photocathode. This avoids the need for a reflecting metallic layer on the phosphor layer, as has heretofore been required in order to prevent feedback radiation.

Image intensifier tube with entrance screen photocathode which is

An X-ray image amplifier tube designed with an input screen having a photocathode and with a detection screen which is opposite the latter and a short distance away for detection of a photo-electron beam which is generated by X-ray input image signals and is amplified in the tube. The detection screen is provided with a conversion coating for converting an image-carrying photo-electron beam into a potential excursion and to this end contains, for example, an amorphous selenium coating or a porous KCl coating. A variable potential can be applied both over the vacuum gap between the photocathode and the conversion coating and over the conversion coating itself and, as a result of this, high image brightness dynamics can be achieved without image disruption.

X-ray detector with charge pattern read-out by TFT switching matrix

An X-ray image intensifier tube includes an entrance screen with a photocathode and, opposite thereto and at a slight distance therefrom, is a detection screen for detecting entrance image signals intensified by the proximity tube. The detection screen comprises a phosphor layer and an integrated matrix of detection elements within the tube envelope. The detection screen can be read in a location-sensitive manner and produces signals which can be directly electrically processed. The detection screen may be provided with a metal layer enabling brightness control and be mounted completely or partly outside the tube. The tube is assembled using low-temperature thermocompression seals wherever desired. The latter is applicable to the tube seal, so that the risk of deactivation of the photocathode is avoided.

Proximity X-ray image intensifier tube

Via the shape of the photocathode surface and the geometry and potential distribution of electrodes of the electron-optical system, an X-ray image intensifier tube is optimized for reduction of the transit time variance for photoelectrons from the photocathode surface to a photoelectron detector. The photoelectron detector, on which an image need not be formed in this case, has, for example, a comparatively small entrance surface and is arranged in or near a cross-over of the photoelectrons.

Radiation detector for elementary particles

In an image intensifier tube the input screen has a profile which is determined by a higher degree polynomial of which the constant term and the first order term are both zero. As a result of this the profile shows no local inhomogeneities and the profile may be adapted to an optical imaging by the electron-optical system of the photocathode on the output screen.

Image intensifier tube with input screen having a profile which

A detector for the detection of, for example, Cerenkov radiation includes an entrance screen (5) which may cover more than half of an envelope (1); the majority of the envelope is preferably spherical. A photo-electron detecting exit screen (11) is proportioned and arranged inside the envelope (1) so that a small decay time and a high sensitivity are achieved. A scintillant exit screen (11), which is mounted on an indentation (15) in the envelope (1), can thus produce, in conjunction with a photomultiplier tube (17) mounted inside the indentation (15), a photoelectric intensification by a factor 100.

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Heerlen, Netherlands

Gerardus Van Aller