Abstract: A photoelectric emission surface which is excellent in stability and reproducibility of photoelectric conversion characteristics and has a structure capable of obtaining a high photosensitivity is provided. A predetermined voltage is applied between an upper surface electrode and a lower surface electrode by a battery. Upon application of this voltage, a p-n junction formed between a contact layer and an electron emission layer is reversely biased. A depletion layer extends from the p-n junction into the photoelectric emission surface, and an electric field is formed in the electron emission layer and a light absorbing layer in a direction for accelerating photoelectrons. When incident light is absorbed in the light absorbing layer to excite photoelectrons, the photoelectrons are accelerated by the electric field toward the emission surface.

Abstract: Disclosed is a method for the use of an X-ray image amplifier tube comprising a succession of electrodes, among them a photocathode. This X-ray image intensifier tube may have, alternately, an off state and an operating state. The method consists of the application, to the photocathode, of an operating voltage that is a substantially zero voltage when the X-ray image intensifier tube is in an operating state and a positive turning-off voltage greater than the operating voltage so that the X-ray image intensifier tube is in the off state. Application is notably to X-ray image intensifier tubes used in sets that work alternately.

Abstract: This invention relates to an improvement of a reflection mode alkali photocathode which relies on controlling a deposition weight of antimony. The reflection mode alkali photocathode according to this invention includes a thin layer of antimony directly deposited on a base substrate and activated by alkali metals. The thin film of antimony is deposited in a thickness of below 100 .mu.g/cm.sup.2. This reflection mode photocathode is suitably usable in photomultipliers. As the base substrate, nickel, aluminium and stainless, etc. are used. As the alkali metals, cesium, potassium, sodium and rubidium are usable.

Abstract: This invention relates to an improvement of a reflection mode alkali photocathode which relies on controlling a deposition weight of antimony. The reflection mode alkali photocathode according to this invention includes a thin layer of antimony directly deposited on a base substrate and activated by alkali metals. The thin film of antimony is deposited in a thickness of below 100 .mu.g/cm.sup.2. This reflection mode photocathode is suitably usable in photomultipliers. As the base substrate, nickel, aluminium and stainless, etc. are used. As the alkali metals, cesium, potassium, sodium and rubidium are usable.

Abstract: A segmented photomultiplier tube having an electrode which, in its higher part acts as a focusing electrode for distributing photo-electrons on both sides of an axial plane, while in its lower part forming a collection cage, the photo-electrons undergo a first multiplication at the portions of the lateral walls, which are folded towards the axial plane. Apertures in a median plate of the electrode are covered by a highly transparent grid. The electrode is completed by a central partition which extends along the median plate just to the proximity of an input dynode of a laminated multiplier. A bar having a small cross-section may be provided, centered on the axial plane and receiving a potential near the potential across the photocathode. A plurality of these tubes can be arranged in a mosaic pattern for mapping luminous events.

Abstract: A transparent photocathode comprises a silver layer formed on a transparent substrate, comprising silver particles having an average diameter of 80 to 200 nm, and a silver oxide layer, potassium layer, and a cesium layer. As a result of the silver layer comprising silver particles having dispersive diameters, the transparent photocathode can selectively achieve high sensitivity to an infrared region of near 1.5 .mu.m wavelength.

Abstract: There is provided a photomultiplier in which a transmittance of an incident light and a photosensitivity is high and a hysteresis characteristic is excellent. Therefore, in the present invention, a photocathode 16, dynodes 17a to 17c and an anode 18 are supported between insulating material substrates 12a and 12b provided in a glass bulb 11. A transparent conductive film 19 is formed on an inside wall surface of a light entrance portion 15. The transparent conductive film 19 electrically contacts with a pad 20 which is led through a terminal 14 to the outside. The same potential as the photocathode 12 is applied through the pad 20 to the transparent conductive film 19. The incident light directly impinges on the photocathode 16 through the glass bulb 11 and the transparent conductive film 19 at a place corresponding to the light entrance portion 15. As a result, the incident light reaches the photocathode 12 with not being interfered at all, and the transmittance of the incident light is improved.

Abstract: A photocathode which is responsive to ultraviolet light to release photoelectrons includes a supportive window layer of sapphire and a single-crystal active layer of AlGaN. Interposed between the window layer and the active layer is an interface layer which insures a low population density of crystalline defects at the interface of the interface layer with the active layer and in the active layer itself. Consequently, the photocathode is an effective emitter of photoelectrons in the transmission mode.

Abstract: There is disclosed a photocathode comprising:a photoelectric conversion layer for internally exciting photoelectrons in response to incident photons; a semiconductor layer having a photoelectron emission surface for emitting the photoelectrons generated and accelerated in the photoelectric conversion layer from the photoelectron emission surface; an upper surface electrode formed on the photoelectron emission surface of the semiconductor layer; and a lower surface electrode formed on the semiconductor layer so that the lower surface electrode is opposite to the upper surface electrode through the semiconductor layer, the upper surface electrode being divided so as to provide a plurality of pixel electrodes which are electrically insulated from each other, the plurality of pixel electrodes being respectively connected to a plurarity of bias application wires.

Abstract: There is disclosed a process for forming a photocathode having high quantum yield which comprises the first step of making a number of fine concavities and convexities in a surface of a substrate finished substantially in a mirror; the second step of blunting the fine concavities and convexities; and the third step of coating a photoelectron emissive material on the surface of the substrate.

Abstract: In an X-ray image intensifier tube an entrance section is optimized in respect of image quality, optical aberrations and efficiency. To achieve this, notably in order to avoid photocathode charging phenomena, a separating layer having an adapted electrical transverse conduction is provided. In order to reduce scattered radiation, an edge portion of the entrance screen is deactivated for relevant examinations. In order to increase efficiency, use is made of a double phosphor layer having different X-ray absorption properties. In order to compensate for vignetting a radial variation of the thickness or of the radiation properties of a separating layer or of the luminescent layer itself is used.

Abstract: This invention relates to a semiconductor photo-electron-emitting device for emitting photoelectrons excited from the valence band to the conduction band by incident photons on a semiconductor layer. The device includes a Schottky electrode formed on the emitting surface on a surface of the semiconductor layer, and a conductor layer formed on a surface opposite to the emitting surface. A set bias voltage is applied between the Schottky electrode and the conductor layer to accelerate photoelectrons generated by the excitation of incident photons to the emitting surface and to transfer the accelerated photoelectrons from an energy band of a smaller effective mass to an energy band of a larger effective mass.

Abstract: A high performance reflection type photocathode for use in a photomultiplier tube is formed by sequentially depositing three layers on a substrate made of nickel. The first layer is made of either one of chromium, manganese and magnesium as a major component and is deposited over the substrate. The second layer is made of aluminum as a major component and is deposited over the first layer. The third layer is made of antimony and at least one kind of alkaline metals and is deposited over the second layer.

Abstract: A multiple section photomultiplier tube. The tube is constructed essentially as a matrix of several independent tubes in one envelope. The photocathode of each individual section of the tube is formed into an independent surface, and the photocathode to dynode spacings are isolated by a configuration built with separator electrodes which connect to photocathode boundary dividers formed in the faceplate. The boundary dividers also isolate the independent photocathode regions. The boundary dividers can be either slots into which the separator electrodes fit or ribs with which the separator electrodes are engaged.

Abstract: An interference photocathode includes a reflective substrate and interference layers disposed on said reflective substrate for selectively enhancing a first photoelectric yield of said photocathode when irradiated by radiation having a first wavelength relative to a second photoelectric yield of said photocathode when irradiated by radiation having a second wavelength. In one embodiment, the interference layers include a dielectric layer having a wavelength dependent effective thickness disposed on said reflective substrate such that said effective thickness for radiation having said first wavelength is an odd multiple of a quarter of said first wavelength and said effective thickness for radiation having said second wavelength is an even multiple of a quarter of said second wavelength. In another embodiment, the dielectric layer includes a layer of electrically conductive material and a dielectric material disposed between said layer of electrically conductive material and said reflective substrate.

Abstract: A direct conversion X-ray photo-electron cathode has specially designed secondary electron emission layers which provides high efficiency, low noise, high speed and broad band X-ray photon detection. The X-ray photocathode is integrated with a micro channel plate and an output phosphor display screen to form a panel type X-ray intensifier. The X-ray intensifier is combined with a micro-focus X-ray source to provide projection type X-ray microscope for use in X-ray microscopic diagnostic applications.

Abstract: Contact device (10) for the photocathode (11) of photoelectric tubes is produced by a metallic deposit on a substrate (12) intended to receive the photocathode. According to the invention, the contact device (10) is formed by narrow conductive contacts (20) deposited on the useful area (21) of the substrate (12).

Abstract: Apparatus for high speed analog data recording utilizing a new tube design (referred to herein as a photonic cathode ray tube) is presented. The photonic cathode ray tube includes a flat photocathode, a small aperture electron lensing system, a set of deflection plates and a phosphor screen.

Abstract: A junction, such as a Schottky junction, is formed between a conductive electrode and a semiconductor. A bias voltage is applied between the conductive electrode and an outward-emission-side electrode formed on the semiconductor at the side opposite to the junction. Upon illumination, photoelectrons are internally emitted in the conductive electrode into the semiconductor, transported through the semiconductor, and emitted outward from the semiconductor surface, which has been so treated as to reduce the surface barrier height. The semiconductor is semi-insulating, or a p-n junction is formed therein.

Abstract: A photo cathode used for an electron image projection apparatus has a silver layer as a photo electric material and a layer of an alkali metal or alkaline earth metal, such as cesium, coated on the silver layer. The cesium is as thick as several atomic layers, and reduces the work function of the photo cathode. The silver layer may be coated all over a substrate, and portions other than the cathode may be masked by a non photoelectric metal, or non transparent metal, such as platinum. Or, the silver layer may be patterned on the layer of a non photoelectric metal coated on the substrate. An excitation light to the photo cathode may be irradiated onto the surface of the silver, or onto the back of the silver layer through a transparent substrate. After depositing the cesium layer on the silver, the layers are heated in a vacuum at 50.degree. to 200.degree. C., thus a contrast ratio, i.e. ratio of electron current from the cathode and from the non cathode portion, is achieved as high as 20.

Abstract: Provided is a means for triggering certain high voltage electronic, gas discharge switches that are a novel type of high power thyratron. Triggering of switches of the so-called "backlighted thyratron" type (a type of cold cathode thyratron) is enhanced by the inclusion of a very small, photoemissive cathode, separate and isolated from the main switch electrodes, to initiate the triggering discharge. The trigger cathode is protected from destruction by the main discharge current through the switch by mechanically and electrically isolating it from further participation in the discharge once the triggering process has been initiated. Alternatively, photosensitive material is coated on the backside of one of the main switch electrodes. A light source located externally of the switch directs light through a sealed aperture into the interior of the switch where it is incident on the photosensitive material generating electrons which in turn trigger the main switch discharge.

Abstract: Contact device for the photocathode of photoelectric tubes includes a metallic deposit of narrow conductive contacts on the photocathode substrate. The device is useful in image intensifier tubes and fast slot scanning cameras.

Abstract: A proximity focused direct view, microdischarge electro-optical converter for converting a target scene into an enhanced visible image, whereby an optical target scene impinging on the input surface of a detector converts the photons of the optical scene into electrons, where upon an electrostatic lens focusses and enhances the resulting electron equivalent image onto a phosphor screen for effecting a direct view optically enhanced image.

Abstract: This disclosure identifies dielectric liquids for use as opening and closing switching media in pulsed power technology, and describes a dielectric-liquid-pulsed-power switch empolying flashlamps.

Abstract: A new method and apparatus for providing a stable, temporally controllable high current density electron beam from a photocathode has been developed. A low level of cesium and, possibly a stabilizing gas, is supplied to the photoemitting surface while the electron beam is being generated, thereby replenishing cesium and possibly other ions lost from the emitting surface on a continual basis.

Abstract: The present invention provides a photocathode which is formed on a substrate consisting of polycrystalline members, and which mainly consists of a semimetal, manganese or silver, and one or a plurality of alkaline metals, characterized in that the photocathode is formed on an alkaline metal oxide layer formed on the substrate, and a composition ratio of the semimetal, manganese or silver, and the one or a plurality of alkaline metals is stoichiometric or almost stoichiometric. The photocathode of the present invention has high sensitivity and can stably maintain the sensitivity for a long period of time.

Abstract: A femtosecond sampling oscilloscope includes a femtosecond laser for generating a pulse of light in the femtosecond range and a beam splitter for splitting the pulse of light into pulses traveling along first and second beam paths. A photoconductive switch disposed along the first beam path is used to produce an electrical stimulus output at a first output port, an electrical pulse output at a second output port and an optical output at a third output port. A photomultiplier tube having a strip line photocathode receives the pulse of light traveling along the first beam path. An input port is coupled to the photocathode. In use, the output signal at one of the output ports is connected to a test device producing a test voltage signal which is applied to the input port. When the test voltage signal and the light pulse traveling along the second path intersect on the photocathode in space and time, an electrical signal output is produced at the photomultiplier tube.

Abstract: A photoelectron beam converting device including a semiconductor substrate having a p-n junction formed between an n-type region and a p-type region and an opening portion formed on the side of the semiconductor substrate. An electron beam is generated by a light which enters from the opening portion and by a reverse voltage to be applied to the p-n junction.

Abstract: A device for the multiplication of charge carriers of a given type by an avalanche phenomenon includes:a semiconductor material of homogeneous composition, placed in an electrical field.Perpendicular to the working field, plane and parallel layers which are thin as compared with the thickness of the material separating them, are made in this material and are n-doped or p-doped depending on the type of charge carrier, the said layers forming reservoirs where charge carriers of the said type are confined. The injection of at least one charge carrier of the said type in the charge carrier multiplying device sets off the multiplication of charge carriers through a process of impact ionization. This charge carrier is accelerated by the working field and thus acquires energy sufficient to make it capable of ejecting a charge carrier of the said type from the doped layer. The charge carriers obtained are guided by the working field.

Abstract: An improved ion detection system and method for detection of low or high mass ions. A target having a low work function, photoemissive surface layer is employed to fragment the incident ions and produce secondary negative ions and electrons. The target surface preferably is formed of a thin layer of an alkali antimonide compound, bialkali antimonide compound, multi-alkali antimonide compound, cesiated III - V semiconductor compound, or other photoemissive material having a relatively low band gap energy and electron affinity. Additionally, the photoemissive material should have a low thermionic emission level at room temperature to reduce noise levels in the detector. The secondary ions and electrons may be detected by a conventional electron multiplier detector. The potential difference between the target surface and electron multiplier detector is chosen to accelerate the secondary ions and electrons to the electron multiplier detector with an energy corresponding to high detection efficiency.

Abstract: An apparatus continous imaging apparatus comprising a camera portion and an image receiving portion, Specifically, the image pickup portion comprises an image pickup tube that deflects and scans electron beams and allows electron signals correponding to one pixel or a one-dimensional array of pixels to be converted successively and continuously to time-series light signals. The image receiving portion comprises means that converts to electron beams the time-series light signals transmitted from the pickup tube through at least one optical fiber and which reproduces an image by deflecting the electron beams in synchronism with the camera portion.

Abstract: A photomultiplier tube which may be used in time resolving a luminiscence profile emitted from a sample with picosecond resolution using short (picosecond) electrical pulses as a probe and in time resolving an electrical pulse profile produced by fast electronic or optoelectronic devices with femtosecond resolution, using short (femtosecond) laser pulses as the probe is disclosed.

Abstract: According to the invention, under glancing incidence a first radiation (6) in the infrared range and which is linearly polarized is supplied to a target (2) made from a non-electrically insulating material and simultaneously to said target is supplied under a non-glancing incidence a second radiation (8) in the visible or ultraviolet range, in such a way that a same zone of the target is reached by the first and second radiations, the polarizing plane of the first radiation also being such that it contains a perpendicular to said zone, which then produces electrons.Application to the production of free electron lasers.

Abstract: A photoconductive member is provided with increased sensitivity to radiation incident thereupon and with increased photo-yield in response thereto by means of a multi-layered, sandwich-type construction based upon the provision of successive layers of sensitizing material over corresponding successive layers of conducting material. The photoconductive member comprises at least two composite layers formed one above the other on an insulating substrate, each composite layer comprising a first layer of material capable of conducting charge and a second layer of material comprising polar molecules disposed upon the charge-conducting material layer in such a manner that successive layers of polar molecules are adsorbed and retained in an oriented fashion on successive layers of the charge-conducting material.

Abstract: A scanned electron beam system employs an electron beam source using an NEA activated photo-emitter as the cathode. The activated photo-emitter cathode produces a pre-shaped electron beam having a relatively small spot focussed on a target plane. The beam is selectively deflected to scan the beam spot along the target plane to expose desired patterns on that plane. The distance between the cathode and anode can be made large enough to accommodate in situ replenishment of cathode material, such as Cesium, without obstructing the electron optical path. The system includes two vacuum chambers which are differentially pumped through respective ports. The first chamber, in which the anode and cathode are located, is utilized for establishing the required electrostatic field. The second chamber is employed to produce the necessary focussing and selective beam deflection.

Abstract: A streak tube comprising an envelope having therein a photocathode surface, a mesh electrode, a focusing electrode, an aperture electrode, a deflection electrode and a phosphor screen positioned along the longitudinal axis of the envelope in the given order. The axis connects the photocathode surface and the phosphor screen which face each other. The photocathode is formed on a concave surface at one end of the envelope, the distance between the photocathode surface and the mesh electrode being greatest at the axis of the envelope and gradually decreasing toward its periphery. Electrons emitted from any position on the photocathode surface at a given instant enter simultaneously into the deflection field formed by the deflection electrode.

Abstract: A photocathode including a first silver layer formed on a transparent substrate by vacuum deposition, a silver oxide layer formed in such a manner that oxygen gas is introduced and electric discharge is caused in the oxygen gas thus introduced to oxide the surface of the first silver layer, a potassium layer formed on the silver oxide layer in such a manner that the substrate and the first silver layer are heated and potassium is vacuum-deposited on the silver oxide layer, a sodium layer formed on the potassium layer by vacuum-depositing sodium with the potassium layer heated, a second silver layer formed on the sodium layer by vacuum-depositing silver, a cesium layer formed on the second silver layer by vacuum-depositing cesium, and a third silver layer formed on the cesium layer by vacuum-depositing silver.

Abstract: An x-ray image intensifier including an input screen 3 having a radiation transparent support 7 on which is applied a fluorescence layer 8 of CsI, a translucent conductive barrier layer 9 which replenishes the photocathode 10 with electrons but tends to reflect incident light especially when made of metal, e.g. of aluminum 7 nm thick which reflects about 50% of the incident fluorescence. The improvement adds first and second intermediate layers 21, 22 of metal oxide e.g. respectively TiO.sub.2, MnO, which are semiconductive. The thickness of the first layer 21 adjusts the reflection amplitude to equal that at the photocathode-vacuum interface, and that of the second layer adjusts the relative phase so that the reflections cancel. The first and second layers can be non-conductors such as Al.sub.2 O.sub.3, however the second layer is then made thin enough, e.g. 25 nm or less, to allow electron conduction by tunnelling to occur.

Abstract: A color separation filter arrangement for an image intensifier having separate blue, green and red filters which respectively have pass bands for visible blue light and its second order wavelengths, visible green light and its second order wavelengths, and visible red light. The blue, green and red filters are interposed individually in succession in the path of incident visible light and infrared energy to the photocathode of the image intensifier. Use of this color separation filter produces a relatively high signal-to-noise ratio at the output of the image intensifier when it is used under night sky illumination.

Abstract: A method of producing a transparent photocathode comprises applying a multi-layer wafer to a carrier service so that the wafer projects beyond the carrier on all sides, effecting a chemical denudation on the substrate and after the chemical denudation on the substrate removing at least the overhanging parts of the multi-layer wafer mechanically. Chemical denudations are advantageously made by etching. The substrate comprises a gallium arsenide. The subsequent layers in the active photocathode semiconductor layer are applied by an epitaxial process.

Abstract: A non-phase-matchable nonlinear plate such as amorphous zinc sulfide or zinc selenide is inserted in front of a conventional streak image generator with high sensitivity to visible radiation to produce an infrared streak camera arrangement with improved sensitivity and decreased cost.

Abstract: A non-evacuated photodiode for detecting far-uv radiation. The photocathode is a cylindrical element surrounded by an annular anode. The photocathode is constructed of a metal (e.g., nickel) that emits electrons only in response to far-uv radiation of 140 nanometer or shorter wavelengths. A window (e.g., magnesium fluoride) is positioned at the entrance to the photodiode, to filter out far-uv radiation with wavelengths shorter than about 100 nanometers. The window and photocathode material serve to make the photodiode sensitive to radiation in a wavelength range to greater than 100 to 140 nanometers. A high-temperature perfluoroethylene material is used as an insulating layer for spacing the window from the anode and for spacing the anode from the photocathode. The photodiode is used in a gas chromatography detector.

Abstract: A multi-layered photoconductive material which comprises first layers containing at least one VIb chalcogen element chosen from S, Se and Te and second layers containing at least one IIb element chosen from Zn, Cd and Hg and acting as electric potential barriers, said first layers and said second layers being alternatively arranged and the total number of said first layers and said second layers being not less than 5 and has a high response speed and an excellent sensitivity to long wavelength light with a great dark resistance.

Abstract: A photocathode arrangement comprises a body of semiconductor material, such as gallium arsenide which is bonded to a fiber optic face plate. A thin anti-reflection coating of silicon nitride is positioned between the body and the plate and forms an integral part of the bond. The properties of the glasses from which the fiber optic face plate is made are carefully chosen to minimize crystal dislocations which can be introduced into the body of gallium arsenide when it is bonded to the face plate. Such crystal dislocations can seriously impair the performance of the photocathode. It has been found that it is advantageous to use a glass having an annealing temperature of about 575.degree. C. or less. Because of high temperature processing steps, its softening temperature must be about 680.degree. C. or greater. The photocathode arrangement so formed is intended to constitute the input port of an image intensifier.

Abstract: The photoresist film 12 on the surface of a wafer 11 is exposed through the shadow pattern which is generated by a transmission mask 13 arranged a short distance therefrom when the mask is subjected to a large-area electron beam. The source of the electron beam is an unstructured photocathode 16 on an ultraviolet transparent carrier such as, quartz glass 17 which is subjected to UV radiation from the backside. The electrons exiting from layer 16 are accelerated by a homogeneous electric field 14 towards the mask 13 and shaped to form a homogeneous collimated electron beam. By means of laterally positioned electrostatic deflecting electrodes 19a, 19b, the entire electron beam can be tilted relative to the wafer for adjusting the mask pattern.

Abstract: An electron emitting device including an active semiconductor layer having a surface from which electrons are emitted. The layer is doped with impurity atoms at a density which decreases with distance from the surface.

Abstract: An electron beam generator particularly adapted for direct-write semiconductor lithography applications is disclosed which includes a photoemissive cathode, a modulable laser for illuminating the photoemissive cathode, and light optics to create an optical pattern on the cathode. The photoemissive cathode is composed of a light transmissive substrate onto which is deposited an optically semitransparent, electrically conductive film. This film in turn is coated with a thin layer of a photoemissive substance such as cesium antimonide so that the photoemissive cathode emits an intense and substantially monochromatic beam of electrons upon laser light illumination. The emitted electron beam is configured in accordance with the optical pattern created on the cathode, and in passing through successive electron optical devices is further shaped and sized for use, for example, in lithographically generating very large scale integrated (VLSI) circuits on semiconductors.

Abstract: An improved photodetector arrangement comprises positioning a photodetector having at least one semitransparent cathode so that the light beam striking the cathode passes through it at least twice before exiting from the photodetector. In another embodiment of the invention, a second photodetector is positioned relative to a first photodetector so that the light beam, after striking the first photodetector, strikes the second photodetector. Where the two photodetectors are employed, they may be electrically connected in parallel.