Patent ID: 8513616

Claim:
A gas avalanche detector for detecting and locating X-ray or gamma ray ionizing radiation in radiographic imaging, the detector comprising: a gas enclosure provided with an admission window for admitting a beam of incident X-ray photons; an intermediate plane electrode placed in said gas enclosure between two end plane electrodes and held parallel to the two end plane electrodes; a configuration of the end plane electrodes and of the intermediate plane electrode forming an amplification space, the amplification space also constituting a conversion space in which the incident X-ray photons are convertible into electrical charges, the electrical charges being made up of primary electrons and of corresponding ions; the intermediate plane electrode being operable to be at an electrical potential relative to electrical potentials of the end plane electrodes suitable for generating an electric field that causes the primary electrons to be multiplied by an avalanche phenomenon in the amplification space in a vicinity of the intermediate plane electrode; one of the end plane electrodes being configured as a collector electrode for picking up electrical signals induced by the ions; and said admission window being placed level with the amplification space between the intermediate plane electrode and said collector electrode for admission of said beam of incident X-ray photons between the intermediate plane electrode and said collector electrode.