Thomson-csf

Thomson Tubes Electroniques

Guy Roziere

Bernard Munier

Henri Rougeot

Paul Petit

An image detector using arrays of photodiodes, and in particular to a radiological image detector. In the image detector, all the photodiodes of one and the same array are linked to adapter amplifiers embodied in the form of at least one integrated circuit. In each integrated circuit, an adapter amplifier, to which no photodiode is linked, delivers a voltage serving as a reference to define a bias voltage to be applied to the photodiodes. This arrangement makes it possible in particular to associate photosensitive arrays with amplifiers exhibiting different voltage thresholds.

Image sensor with integrated amplifiers for data acquisition

In order to solve an analogue/digital conversion dynamic swing problem encountered with detectors, especially solid-state detectors, of a tomodensitometer, there is provision to operate converters at a greater frequency, that is to say more often. In doing this, the converters used need not have as large a conversion dynamic swing. It is shown that instead of a 20-bit conversion, one can make do with a 14-bit conversion. The various conversions are added together to construct the signal. The measurement is thereafter switched, by way of improvement, as a function of the level of the signal received. This measurement is performed according to one mode of use or another, in which modes this acceleration of the rate of analogue/digital conversion is or is not effected.

Method for acquiring measurements and scanner implementing said method

To solve a control complexity problem encountered with very numerous detectors of a tomodensitometer, there is provision to group the detectors into groups and to subject all the detectors of a group to the same processing. By way of improvement, the determination of the mode of processing is performed during a view, and the processing is applied to the signals detected during a subsequent view.

Method for acquiring measurements and scanner with sensor groups

A process for the development of a corrective term, process which can be applied during the acquisition of signals of analog measurements (S1 to Sn) of a radiation detector (21) by an acquisition device (22). Measuring signals (S1 to Sn) are corrected then transmitted to acquisition device (22) in digital form. According to the invention, the measuring signals (S1 to Sn) are corrected analogically before transmitting them to acquisition device (22) by a main analog-to-digital converter (31). This makes it possible to reduce the number of bits required for analog-to-digital converter (31). The process of the invention applies in particular in correcting measuring signals (S1 to Sn) as a function of the dark current.

Process of correction of signals from a linear radiation detector and

Disclosed are detectors, of the type comprising scintillators, enabling the detection of radiation with different energy levels. The scintillator used in the case of a double energy X-ray detector consists of two materials, one sensitive to high-energy radiation and the other sensitive to low-energy radiation, the former emitting green radiation and the latter emitting red radiation. These radiations are spatially separated by green and red filters before being measured by photodiodes.

Multiple-radiation detector particularly for X-rays with two energy

The present invention relates to a film for correcting gain irregularities occurring between the different points of optical images. The film applied to the image is split into elementary areas of constant transparency. Within each of these areas, the transparency is adjusted by opaque parts separated by transparent parts. The product of the gain of the image by the transparency of the film is maintained constant over the whole of the area of the image. In the example, these elementary areas are squares and the opaque parts are strips of fixed width. Application is to the image intensifier tubes of scintillography circuits.

Film for correcting spatial irregularity in the gain of optical images

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.

Solid-state device for detecting and locating the points of impact of

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.

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Voreppe, France

Guy Roziere