Abstract: The disclosure concerns radio-therapy machines and installations. The precise position of a patient is verified by means of a device mounted on the movable arm of a mount with isocentric motion. This device includes a system for scanning by a light beam. The position of the source of this light beam corresponds to the position of radiation source. The device further has a system for the optical detection of the point of impact of the light beam on the patient. These two systems enable the position of the point of impact to be determined by means of a data-processing system.

Abstract: The invention relates to detectors of ionizing radiation which use a photoconductor as the detecting element. The invention lies in an electrode moving in a direction OX through a photoconductive medium disposed between two grids of electrodes extending parallel to OX. During the irradiation time, the grid electrodes of one grid are raised to a positive potential relative to the electrodes of the other grid and electrons and positive ions are created in the photoconductor. The electrons are removed by maintaining the positive potential on the electrodes of said one grid for a period of time longer than the irradiation. During displacement of said moving electrode, only the positive ions give rise to current in the electrodes. The invention is applicable to radiotherapy and radiography.

Abstract: Problems related to acquistion time with reconstructed image type tomographs are resolved by causing step by step rotations of the X-ray tube/multiple detector set of this tomograph and, at each step, by causing a translational movement of this set in order to scan the entire region to be examined of a body under examination. It is shown that, by using a multiple row multidetector, it is possible, at equal speeds, to improve the quality of the images produced or, at equal quality, to increase the acquisition speed. Furthermore, this mode of operation is especially well suited to the monitoring of radiotherapy action where the practitioner, when acquiring images, needs to be able to touch the patient.

Abstract: The invention concerns an X-ray stand permitting isocentric movements and intended particularly for radio diagnosis. Stand includes a base supporting a binding clip having a first and second arm supporting respectively an X-ray source and receiver. According to a feature of the invention, binding clip includes a foot by which it is supported by the base by means of devices to move foot in a circular movement centered on an isocenter point.

Abstract: The device can be used for the displacement of light lines above determined zones of a surface and for the optical identification of these zones. It comprises one or more lateral diffusion light guides arranged parallel to the surface, coupled by one end to a light source and to controlling means in order to selectively illuminate each zone of the surface by means of at least one light guide.

Abstract: A radiological scanning apparatus for forming an image of an object on a film by scanning said object with a flat fan shaped beam. The film is conformed so as to form a surface of revolution. The surface of revolution is, on the one hand, moved in the same movement as the scanning movement of said beam, and on the other hand it is rotated about its axis of revolution so as to renew a surface exposed to said beam in order to reduce the dimension of said film considered in the direction of said scanning movement.

Abstract: Image sensor with memory and, more especially, image sensor with reading by thermal effect.This sensor comprises mainly a layer of a photoconductive material and a layer of a transparent material, the impedance of which varies with the temperature, these two layers being comprised between two electrodes. Furthermore, a voltage generator can be connected to the electrodes during the recording when the device is illuminated. Finally, a charge amplifier can be used to detect a current when the unit is heated.

Abstract: The present invention concerns an X-ray examination apparatus allowing to produce images of an object through the scanning of the object by at least two fan-shaped beams having different energy spectra, and obtained from a single X-ray source, thereby allowing to obtain simultaneously images of the object adapted to contain different informations.

Abstract: The device according to the invention comprises a source and an electronic optical system permitting the projection of the beam onto a target plane. According to the invention, a diaphragm for the angular limitation of the beam is positioned between the source and the electronic optical system, the useful current of the beam at the target plane being more than one thousandth of the current emitted by the source.

Abstract: A sample on which pre-established patterns are to be defined is rigidly fixed to a moving object-holder and subjected to bombardment with a beam of charged particles by means of a microlithographic system. This system comprises an array of elements placed in one plane in a predetermined spatial configuration and an imaging system having a magnification which is considerably less than unity, the elements being each capable of assuming two distinct states. A narrow beam of charged particles which emerges from each element is on-off modulated according to the state assumed by the element under the control of logic circuits.The plane of the sample is adapted to correspond to the plane of the elements with respect to the imaging system and the elements are disposed at the intersections of the lines and columns of a matrix.

Abstract: The invention relates to the alignment of designs in two near planes, whereby one (the mask) carries a design which is to be reproduced on the second (the pattern).The invention relates to a method for the optical alignment of these two planes using a pair of marks formed by a lens (4) having linear Fresnel zones inscribed on the mask (1) and a reflecting grating (3) of appropriate width inscribed on the pattern (2). The illumination by a parallel beam of monochromatic light of the lens with Fresnel zones produces on the pattern a substantially rectangular illumination spot which, when made to coincide with the line inscribed on the pattern is reflected or transmitted, and supplies a detected intensity maximum or minimum depending on whether the lines reflects more or less than the remainder of the pattern. The invention also relates to an optical alignment apparatus for performing this method.

Abstract: A device to effect the programmed tracing of figures which have different shapes comprises two electron-optical systems respectively associated with two diaphragms. The first system forms the image of the first diaphragm at a fixed magnification, on the second diaphragm. The first electrically controlled deflection system makes it possible to displace said image in said plane. A second system forms an image of the thus defined diaphragm, in the object plane. A second deflection system makes it possible to displace said latter image in the object plane.

Abstract: A device is provided for adjusting electron-optical apparatus. The specimen to be scanned is equipped with a marker emitting back-scattered electrons. A transducer, in response to these electrons, emits a signal which unblocks the modulating electrode of a cathode ray tube used for the display purpose. The tube screen has long persistance characteristics; the beam and the object holder being displaced in four mutually perpendicular directions by theoretically corresponding quantities, the adjusting errors are visible immediately.

Abstract: The present invention relates to a device designed to automatically trace designs at a very small scale. The device comprises an electron-optical system forming an elementary image of extremely small dimensions, of a diaphragm. A scanning system makes it possible to display said image, line by line over the surface which is to be printed, in a first direction, while a mechanical system displaces the surface in a direction perpendicular to the first direction. The arrangement is controlled by a logic system supplying code numbers which indicate the programme to be followed in respect of each line. The invention applies to microelectronics.

Abstract: An apparatus with an increased efficiency, for ion bombardment machining operations at voltages not exceeding some few thousands of volts, is provided. It comprises an ion source whose plasma is extracted across grids forming cylinders of revolution about one and the same axis, for example a vertical axis. The specimens for machining are arranged in a ring around the ion source. The ion beam, of radial type, is highly uniform within a cylindrical space defined between two parallel planes, for example horizontal planes. It is possible to limit the apertural angle of the beam by the use of a mask arranged against one of the grids.

Abstract: A device for the accurate positioning of an object holder in relation to the elements of a particle-type optical system, for example an electron-optical system, comprises for each direction of displacement a comparator which compares the position required by a computer, with the number recorded by a counter counting the fringes in an interferometer. The comparator is connected to a three-output logic circuit which can adopt each of two logic levels. The states of the outputs represent the direction of displacement to be produced, and its amplitude. A stepping motor receives the pulses from a clock which adopts two preset frequencies that are controlled by said three outputs.