Commissariat a L'energie Atomique

Gaetan Pleyber

Robert Allemand

Martine Drouet

Edmond Tournier

Philippe Gerard

Jean-Jacques Gagelin

Jean-Paul Bonnefoy

Jacques Bergeri

Paul Perroud

Henri Guers

Jean-Louis Violet

Jean-Louis Allera

Radioluminescent screen with an improved quality factor and spatial resolution for X or gamma photon imaging having a transparent plate (2) made from a scintillating material cooperating with an image sensor (16) transforming the light photons produced in the scintillating plate (2) by X or gamma photons into currents supplying a video system, characterized in that the scintillating plate (2) has in its volume light deflecting lines (4) distributed in a direction perpendicular to the plane of the plate, in accordance with spacings equal to or smaller than those of the image points of the said plate.

Radioluminescent screen with an improved quality factor and spatial

A detection array for ionizing radiation tomography for obtaining the image of at least one section of an object or organ. The array has at least one chamber (1) provided with a radiation-transparent entrance window (2) and in the chamber a detection stack (E1) incorporating a conductive polarizing plate (3) parallel to the sectional plane and a series of identical electrodes (5) parallel to the sectional plane. An insulating spacer (9) is placed between the electrodes (2) and the plate (5) and has, facing the window, at least one radiation-opaque intermediate plate (14) parallel to the sectional plane. This intermediate plate (14), the electrodes (5) and the polarizing plate (3) are disturbing elements which, separated by a distance d, make it possible to eliminate the artefacts for linear or quasi-linear inclusions in the object.

Detection array for ionizing radiation tomography

The invention concerns an X-ray tomographic detector. This detector comprises a sealed chamber (4) containing a gas able to be ionized by X-rays having traversed a device or an object. This chamber comprises on a front face an X-ray inlet gate (5) and contains an X-ray detection unit (11). Connections means (27, 28, 29, 32, 33) traversing a rear face of the chamber (9) to link the detection means to measuring (14) and feed (15, 16) means outside the chamber. The detection means comprise electrodes (19) and a polarization plate (18) separated by an insulating brace (3) transparent to X-rays. According to the invention, this brace has the shape of frame. This frame rests firstly on the polarization plate (18) and secondly on conductive strips (22, 24) brought to the same potential reference (16) as that of the electrodes. Application for X-ray tomography.

X-ray tomographic detector

A process for the examination of the flat radiograph of an object irradiated with the aid of an ionizing radiation source is disclosed. In an ionization chamber is detected the latent image of the object formed by the different electrical charges produced in the volume of the chamber under the influence of the impact of the radiation flux which has traversed the object. As this irradiation is continuous, the object to be examined is moved relative to the ionization chamber in the direction and at the migration speed of the ions formed in the electrical field thereof.

Process for examining a flat radiograph of an object and ionization

The invention relates to a process and apparatus for detecting the presence of a physical phenomenon. The apparatus comprises a sensor which is sensitive to a characteristic quantity of the phenomenon to be studied and supplies a signal which is representative of the phenomenon. An amplifier is connected to the output of the sensor and an indicator for indicating passing beyond the threshold is connected to the amplifier. A differentiating circuit differentiates the amplified signal, while a comparator compares the differentiated signal as soon as a reference potential is exceeded. A time sampling circuit fixes prealert periods as soon as the reference potential is exceeded. The invention is applicable to the detection of pollution by combustible gaseous vapors, oil slicks, firedamp, thunderstorms, defects in surface states, etc.

Process and apparatus for detecting the presence of a physical phenomenon

The method consists in causing objects to pass in front of a background having a distinctly different brightness, in aligning a collimator by means of a sighting telescope in a direction of observation such that the path of the objects intersects a line defining the direction of observation of the collimator, in eliminating light from all directions other than the direction of observation, in detecting the variation of light intensity corresponding to the passage of the object by means of an electrical signal which is delivered by a photoreceiver and is a function of the luminous flux picked up by the photo-receiver and in differentiating the signal with respect to time by means of an electronic circuit so as to obtain an output signal which is a function of the variations of luminous flux on the photoreceiver.

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Domene, France

Gaetan Pleyber