Abstract: In a photomultiplier tube, antimony layers of a photocathode are prepared on a nickel substrate by providing a barrier layer of aluminum oxide between the substrate and antimony layers. The photocathode is subsequently exposed to the vapors of at least one alkali metal to sensitize the antimony layers. The aluminum oxide layer prevents alloying of the nickel with the antimony at processing temperatures in the range from 260.degree. C. to 285.degree. C. and provides a source of oxygen to oxidize the photocathode for increased photosensitivity, the oxidation time being a function of the thickness of the aluminum oxide layer. The photocathode is then exposed to cesium and may be superficially oxidized until substantially maximum photosensitivity is achieved.

Abstract: A photoconductor body for a camera tube includes a semiconductor body including an overlayer of a material selected from a granular metal-insulator system. Suitable semiconductor materials are limited to those materials capable of providing Schottky barrier heights in excess of 0.9 eV. when fabricated with such overlayers and those having bandgaps greater than about 1.4 eV. A method of fabricating such photoconductive bodies is disclosed wherein a cadmium selenide semiconductor material is thermally treated to modify the Schottky barrier heights to a desired value in excess of about 0.9 eV.

Abstract: A substantially flat body of a photoconductive semiconductor material is coated on one surface with an electrically conductive layer. A layer of a solid insulator material is on another surface of the semiconductor material. The insulator material is of the type having mobile deep lying carriers and forms a blocking junction with the semiconductor material. The insulator material may be an electronically conductive glass, an ionically conductive glass, or a cermet composition. The photoconductor can be used as a target for a camera tube, or as an electrophotographic plate.

Abstract: A low dark current vidicon is disclosed having a target comprising a thallium doped layer of hexagonal, or trigonal, polycrystalline selenium. A mechanically stable blocking contact for holes is also provided by a transparent tin oxide electrode in intimate proximity to the layer along a major surface of a faceplate in contact with the target.

Abstract: An evacuated tube has a face plate and a tubular body with at least a portion of the body having a circular cross section. In the evacuated tube is an electron emissive electrode adapted to release electrons in response to impinging photons or photoelectrons, means for collecting the electrons and an anode. The electron emissive electrode is cup shaped, having an approximate circular top opening through which photons or photoelectrons enter to impinge on the electrode, a circular rim around the periphery of the top opening, and a side opening through which the electrons pass to exit from the electrode. The inside of the electrode is lined with electron emissive material.

Abstract: An electron discharge tube comprising a plenum having therein a photocathode, an anode, a plurality of spaced apart dynodes, each having an input aperture and an output aperture, the dynodes arranged so as to concatenate electron emissions from the photocathode to the anode, and a conductive mesh overlying each input aperture, is improved by providing non-uniform openings in the mesh whereby relatively greater electrostatic shielding is provided for the dynode surface proximate to the output aperture of a preceding dynode.

Abstract: 1. A photoconductive target for a pickup tube comprising a layer of porous lead telluride on a transparent conductive layer, said porous lead telluride having a resistivity of approximately 10.sup.-11 ohm cm when maintained at a temperature substantially equal to liquid nitrogen temperature.

Abstract: Photocathode having a transparent conductive undercoating to provide a radial voltage distribution across the cathode surface. The conductive undercoating is in the form of radially spaced rings made of chromium deposited on a glass substrate. Over the substrate and the conducting undercoating is provided a resistive layer comprising chromium having a thickness of about 50 Angstroms. Over the resistive chromium layer is deposited a photoemissive layer of antimony, potassium, sodium and cesium. The radially spaced conductive rings are connected to sources of different voltage to produce a desired voltage distribution across the resistive chromium layer.

Abstract: The method comprises the steps of providing a camera tube having an evacuated envelope, a photoconductive layer primarily of lead monoxide, an activated getter and an unactivated getter within the envelope. After a period of operation or storage the tube exhibits a deterioration in spectral photosensitivity of the layer. The characteristic ratio of blue light photosensitivity is measured and when the ratio is less than about 80% the unactivated getter is activated to regenerate the tube.

Abstract: A nickel oxide surface layer of a nickel mesh supporting structure is coated with a layer of chromium. The nickel oxide layer has a thickness of between about 500 to 750A. The layer chromium is at least about 100A thick. The chromium coated nickel oxide-nickel mesh is particularly suitable for use in vidicon tubes.

Abstract: A phototube includes a cup-shaped apertured electrode interposed between a substantially flat cathode and an electron collection electrode. Anapertured electrode is coaxially secured within the recess of the cup-shaped electrode in parallel spaced-apart facing relation to the cathode.