Abstract: An x-ray image detector suitable for radiology has an active matrix substrate with scanning and read-out circuits. Over this active matrix substrate, which can be a two dimensional array of TFTs associated with a storage capacitance, there is deposited a photoreceptor made of a thin layer of amorphous selenium based multilayer structure. The photoreceptor is covered with a light-transparent electrode on top of which there is provided a scintillator. The indices of refraction of the scintillator and of the selenium based multilayer may be matched with the use of the biasing electrode.

Abstract: The invention provides a direct conversion flat panel X-ray detector with automatic cancellation of ghost images due to charge trapping. The detector includes a direct X-ray to charge converter, a readout thin film transistor array supported by a glass substrate and on the rear side of the glass substrate, a layer of luminophor which automatically and instantly suppresses the ghosting effect.

Abstract: The invention provides a direct conversion flat panel X-ray detector with automatic cancellation of ghost images due to charge trapping. The detector includes a direct X-ray to charge converter, a readout thin film transistor array supported by a glass substrate and on the rear side of the glass substrate, a layer of luminophor which automatically and instantly suppresses the ghosting effect.

Abstract: An input screen scintillator for an X-ray image intensifier tube. The tube includes light conductive cesium iodide needles formed on an electrically conductive substrate. Each needle is entirely coated with a material such as a metal or a semiconductor which reflects the light travelling within the needle toward the inside of the needle. This coating can enhance the efficiency and resolution of the image intensifier tube.

Abstract: The invention concerns an input screen scintillator for an X-ray image intensifier tube. This tube comprises light-conductive cesium iodide needles formed on an electrically conductive substrate. According to the invention, each needle is entirely coated with a material such as a metal or a semiconductor which reflects the light travelling within the needles and allows an identical potential level in the coating material as in the substrate towards the inside of said needles. The coating can enhance the efficiency and resolution of image intensifier tubes. The invention has applications in the field of X-ray imagery.

Abstract: Before being introduced within the intensifier, the grid which is nearest the anode is coated with a layer of electrically conductive material having the property of oxidizing alkali metals. This has the effect of elininating any parasitic illumination of the viewing screen caused by alkali metals unintentionally deposited on the grid at the time of formation of the photocathode.

Abstract: The present invention provides an input screen scintillator for a radiological image intensifier tube in which the cesium iodide needles of the scintillator are coated with a refractory, transparent of reflecting, material having an optical index close to or less than that of the cesium iodide. Different methods may be used for coating, such as chemical vapor phase deposition, activated by thermal excitation, plasma excitation or photonic excitation; or such as diffusion deposition of a colloidal solution; or such as polymerization of a polymer resin. After coating, is realized the heat treatment which ensures the luminescence of the screen.

Abstract: A large-format photosensitive device for detection of radiographic images comprises a semiconductor substrate of lightly n-doped hydrogenated amorphous silicon. On one face of the substrate are supported rectangular picture frame-like pads disposed in a matrix array, each having a central opening and formed of material which provides a rectifying junction with the semiconductor substrate, a layer of insulating material, and a control grid capacitively coupled to the pads. On the other face of the substrate are supported an array of drain electrodes located opposite the central openings of the pads, ladder-type source electrodes which circumscribe the drains, a layer of insulating material, and a conductive pattern for interconnecting all of the drains in a common row of all the columns in the array.

Abstract: The present invention provides a vacuum envelope for a radiation image intensifying tube and a process for manufacturing same. In a vacuum envelope of the type comprising a central body, an input window made from aluminum or an aluminum alloy at one end of said central body and a transparent output window at the other end of the body, said input window comprises a peripheral skirt fitting over a ring having the same section as said skirt, and made from iron or an iron alloy, integral with the end of the body, said skirt being welded to the ring by magnetic induction welding so as to be vacuum tight.

Abstract: A variable gain R.I.I. target is obtained by using an optical fibre board, whose face on the R.I.I. side has blind holes containing two types of granular luminescent materials having different luminous efficiencies and which are separated by a barrier layer. The electron beam from the R.I.I. photocathode is subject to two different accelerating voltages, the lower accelerating voltage exciting the luminescent material with the lower luminous efficiency and the higher accelerating voltage exciting the luminescent material with the higher luminous efficiency. Application to image intensifier tubes, used more specifically in radiology and fluoroscopy.

Abstract: The invention relates to a radiological image intensifier tube with a video output. The tube has in the same vacuum envelope an image section and an analysis section having a common face occupied by target. An electrical image corresponding to the incident X-ray image is formed in the image section and this image is read in the analysis section by an electron beam scanning the target point by point. This target has in the tubes according to the invention a structure making it possible to limit the X photon-video signal gain and to regulate it between two predetermined values. On its face which receives the photoelectrons e.sup.31 it has a metal barrier layer 1 covering a luminescent layer 2, in contact with a semitransparent layer 3 covering the actual target 4.

Abstract: A display apparatus having a matrix (4) of semiconductor parts (42) acting both as memories and as amplifiers, and which is driven by two grids of electrodes that are parallel respectively to the lines (L) and to the columns (C) of the matrix (4). Actuation means (6, 7, 8) permits one line of the matrix to be selectively actuated to receive the information to be entered in each part on that line. Electrical signal from each semiconductor part (42) of the given line represents the information that is stored and that signal is displayed in an electroluminescent layer of diodes (3) in the apparatus. The apparatus may be used to display television images.

Abstract: A semiconductor body contains microscopic passages in which multiplication of the free electrons appearing at the entrances to said passages, under the effect of the incident (arrow) ionizing radiation, takes place. In the drawing, the reference 2 signifies the conductive film forming a surface barrier in conjunction with the semiconductor body which is endowed with the property of secondary emission with an emission coefficient better than unity; V.sub.o signifies the voltage applied to the terminals of said barrier; 5 and 6 designate the electron collector.

Abstract: The invention relates to a semiconductor detector for detecting ionizing radiation. The surface barrier required for the formation of field zones in the semiconductor body (1) is created by contact between the semiconductor body (1) and an electrolyte (3) in which it is immersed. In addition, the body is cut out, in the form of a comb in the example, in such a way as to increase its active surface as much as possible. The source (8) maintains the potential difference V.sub.o between the contact (5) on the body (1) and the cathode (7). The output signal s is extracted at (6).

Abstract: A solid detector for detecting the presence of ionizing radiation in the noise of the detector crystal. For this purpose, the device provides for the generation, at the moment of each of pulses of the ionizing radiation, of signals which open a gate towards a level selector. The device comprises a semiconductor, provided with microchannels where electrons are multiplied by means of secondary emission, and a collector of the electrons generated in the microchannels. The signals which open the gate are generated by the secondary electrons issuing from the microchannels and picked up by the collector.

Abstract: In scintigraphic cameras according to the invention, the treatment of the signals generated by each point of the image in the observation elements is carried out in two steps: a first device with a relatively short delay (0.55.mu.s) roughly localises the point and, at the same time, eliminates the signals outside a given energy band and corrects any inequalities of gain from one point to another of the image; a second device with a longer delay (3.mu.s), which receives the same signals, with a delay equal to that of the first device, and the results of the treatment effected in the latter, defines the precise position of each point.

Abstract: An image converter or intensifier which supplies a visual image from incident radiation. It comprises a metallic grid, a detector layer formed by a mosaic of semiconductor elements disposed in the meshes of the grid, a layer which is sensitive to the incident radiation and which supplies photons to the semiconductor elements, means for biasing the grid and semiconductor elements, and means for visualizing the spatial distribution of electrical charges thus obtained.