Abstract: A device for collection, digital encoding, and processing of signals from plural photo-detectors in a camera. The device includes plural digital encoding units, each digital encoding unit in the plural encoding units being associated with one individual photo-detector in the plural photo-detectors, and including a summation device and an analog-digital converter. A digital processing unit is connected to each encoding unit. Such a device may find particular application to gamma-cameras.

Abstract: 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.

Abstract: Permanent magnets for producing an intense field. A main magnetic circuit comprises two magnets (1, 1'), two pole pieces (2, 2') and a yoke (3). Two additional magnets (6, 6') of opposite magnetization reinforce the field in the air gap (5) while extending into the latter between edges (25, 25', 26, 26', 27, 27', 28, 28') of magnets (1, 1') and pole pieces (2, 2'). Application to imaging by magnetic resonance (tomography).

Abstract: Device for locating nuclear radiation and radiation image formation device incorporating such a locating device.The locating device comprises a detection head having a crystal for converting a nuclear radiation into photons and a plurality of transducers for converting the photons into electric signals.These signals are received in a position coder, which has in series a weighting circuit for supplying analog signals X.sup.+, X.sup.-, Y.sup.- (and optionally Z), a digitizing device for digitizing the analog signals and a digital computer for producing digital signals X.sub.N, Y.sub.N defining the position of a nuclear radiation exciting the crystal.

Abstract: This device comprises a liquid radioactive source which, when the patient is absent, is used for calibrating the ionizing radiation detectors of the apparatus and is located in a container which can contains the source. The device comprises a storage magazine communicating with the container by at least one pipe and means for transferring the liquid source from the storage magazine to the container and vice-versa, the container being fixed with respect to the apparatus and the magazine having a volume at least equal to that of the container.

Abstract: System of coils for producing additional fields in a magnet having pole pieces for producing images by nuclear magnetic resonance. For producing gradients Gx=(.differential.Bz/.differential.x) and Gy=(.differential.Bz/.differential.y), it comprises two layers of orthogonal windings, one on each pole piece. For producing the gradient Gz=(.differential.Bz/.differential.z), it has two systems of windings of circular symmetry and axis Oz, located on the inner facing faces of the pole pieces and traversed by currents whose direction changes between the individual pole pieces.

Abstract: The invention relates to a process for making a multidetector of X-rays forming a plane beam. This multidetector comprises a tight chamber filled with an ionizable gas and, in this chamber, at least one main multidetector assembly comprising a plane conducting plate, electrically insulated from the chamber and a plurality of flat electrodes parallel to the plate, insulated from this plate. This process is characterized in that it consists in making the electrodes, as well as main connections between these electrodes and measuring points outside the chamber enabling the currents circulating respectively in these electrodes to be sampled, on a main face of an electrically insulating plate, these main connections being electrically insulated from the chamber and passing therethrough in tight manner, opposite the source which emits the X-rays. The invention is more particularly applicable to X-ray multidetectors intended for the tomography or radiography of organs or for checking baggage.

Abstract: The present invention relates to an X-ray detector adapted to detect rays having passed through an object or an organ. This detector comprises at least one main tight chamber containing a gas ionizable by X-ray and, in this chamber, a plate for collecting the charges resulting from ionization of the gas. It comprises a secondary ionization chamber, coupled to the main chamber to compensate the scattering current.

Abstract: The present invention relates to a detector of X-rays having passed through an object or an organ. This detector comprises at least one tight ionization chamber containing a gas ionizable by the rays issuing from the object and, in this chamber, a plate for collecting the charges and a series of electrodes for collecting the charges resulting from the ionization of the gas. The ionization chamber further contains a gas capable of creating, within the mixture thus formed, a movement of gas opposite the movement of the ions.

Abstract: Conductive terminals located within a casing constituted by two separable portions and conductive terminals located outside the casing are interconnected by means of conductors which pass through the casing between the two separable portions. In particular, the invention permits interconnection of detection cells and measuring channels within an X-ray tomographic apparatus while preventing leakage currents, the connecting conductors being insulated with respect to each other and with respect to the casing.

Abstract: In the synchronous detection signals of frequency Fo immersed in a noise, an auxiliary signal is produced having a period 1/2 Fo and in the form of a rectified symmetrical wave, by rectifying a symmetrical wave of period 1/Fo. The signal to be filtered is multiplied by the auxiliary signal and synchronous filtering or synchronous detection on the frequency Fo is performed on the signal obtained after the above-mentioned multiplication. Preferably the auxiliary signal is produced in the form of a rectified sinusoidal wave and a square wave reference signal from which the above-mentioned symmetrical wave is derived, having the period 1/Fo, is also used to control the synchronous detection or the synchronous filtering.