Abstract: A photocathode having internal amplification includes a first electrode adapted for receiving a first voltage, and for transmitting received photons. An absorption layer is disposed adjacent the first electrode and comprises a P-type semiconductor material having a forbidden band of sufficiently small width to cause photons received through said first electrode to be converted into electron-hole pairs. At least one ionization-induced electron multiplication layer is disposed adjacent the absorption layer. Each such multiplication layer comprises two layers of N-type semiconductor material having respectively two different compositions at an interface therebetween. The two different compositions at the interface cause the multiplication layer, when biased, to accelerate the electrons received from the absorption layer to a degree greater than the acceleration provided to the holes received from the absorption layer.

Abstract: A multilinear charge transfer array is provided formed by N lines of P photosensitie detectors. Each photosensitive detector is connected directly by a connection to a demultiplexing and reading system, the signals obtained at the output of the array being fed to a processing device external to the array.The demultiplexing system comprises a charge transfer shift register with N.times.P stages, the connections between each detector and the corresponding input of the register being provided so that the detectors of the same rank are connected to contiguous inputs.

Abstract: A method and a device for analyzing a pyroelectric target in an evacuated envelope. The target with two opposite faces has a first face disposed towards a zone of the envelope which is transparent to an incident radiation. The second face is orientated towards an electron gun generating device which operates at least one electron beam. A first scanning of the pyroelectric target with a high intensity low resolution electron beam allows a stage of neutralization of the electron charges induced in the target by the incident radiation. The stage of neutralization is to be considered as effecting a storage of the signal recorded on the target. A second scanning of the pyroelectric target with an electron beam of high resolution and low intensity corresponds to a stage of read-out proper of the target.

Abstract: In camera using resistive targets wherein a recording tube of which the target (100) made of a pyroelectric material in the example and read by a beam of electrons, permanently receives a flow of ions formed in the tube by the collision between the electrons of the beam and the atoms of a gaseous mass of which the pressure in the tube is determined by the temperature of a reservoir, the invention provides means for controlling the temperature of the reservoir (filament 03) in dependence upon the average target current which is proportional to the flow of ions in question.

Abstract: A target for ultrasonic camera comprising, applied to a substrate, a pyroelectric retina covered, in the present example, with a layer which absorbs incident ultrasonic waves; the temperature rise due to said absorption produces in the retina a charge relief read out by means which depend upon the selected device, for example an electron beam as in the case of the known pyroelectric targets.