Abstract: Methods and systems for stationary computed tomography are disclosed. The methods and systems include a gantry having alternating x-ray sources and x-ray detectors that are stationary during operation of the system. The gantry and pairs of x-ray sources and detectors substantially surrounds an object positioned inside the gantry during operation of the system. Dynamically adjustable collimators are positioned between the x-ray sources and the object. Each of the x-ray sources projects an x-ray beam through the collimators and through the object and the x-ray detectors receive the x-ray beam. The x-ray detectors include means for converting the x-ray beam to raw image data. One or more microprocessors control the x-ray sources and the process raw image data. A data storage device stores instructions, which upon execution by the microprocessor, control the x-ray sources and process the raw image data by converting the raw image data to a digital image.

Abstract: An optical device includes a light emitting device and a sensor device (light receiving element). The light emitting device includes a substrate, a plurality of light emitting elements, and a plurality of light transmission portions. The substrate has a first surface and a second surface. The second surface is opposite to the first surface. The plurality of light emitting elements is positioned at the first surface side of the substrate. Each of the plurality of light transmission portions is positioned between adjacent light emitting elements. The light emitting device is light-transmissive by the plurality of light transmission portions. Light from the plurality of light emitting elements is mainly output from the second surface of the substrate. An amount of light emitted from each of the light emitting elements and leaked to the outside of the first surface of the substrate is reduced.

Abstract: A system for improving capturing of images of a scene, and data derived from them is provided herein. The system includes a light source configured to illuminate the scene with pulsed light at a specified direction based on predefined gating parameters; two or more capturing devices configured to capture images of the scene, each one of the capturing devices from at different spatial locations, wherein at least one of the capturing is synchronized with the pulsed light, so as to result in stereoscopic fused images of the scene for the synchronized capturing; and a computer processor configured to improve the capturing by using data derived from the gated images and the gating parameters. In another embodiment, the light source is not present and at least one of the sensors' is configured to apply multiple exposures for a single readout, to yield enhanced images that are used to improve the capturing.

Abstract: A system for inspecting a sample including a detector, either a photomultiplier tube or an electron-bombarded image sensor, that is positioned to receive light from the sample. The detector includes a semiconductor photocathode and a photodiode. Notably, the photodiode includes a p-doped semiconductor layer, an n-doped semiconductor layer formed on a first surface of the p-doped semiconductor layer to form a diode, and a pure boron layer formed on a second surface of the p-doped semiconductor layer. The semiconductor photocathode includes silicon, and further includes a pure boron coating on at least one surface.

Abstract: A lighting module includes an array of light emitters, a heat pipe having a flat portion, the array of light emitters being mounted to the flat portion, a liquid inside the heat pipe, the liquid selected to vaporize upon exposure to heat from the array, and a cooling unit thermally coupled to the heat pipe configured to cool the vaporized liquid.

Abstract: An image display device is provided in which the overall brightness of an image can be varied without adversely affecting hue and contrast. The image display device includes emitters 16 connected to a cathode electrode 15, a gate electrode 13, an anode electrode 3, transistors Tr1 and Tr2, and a capacitor 12. A voltage applied to the capacitor 12 is varied to display an image. A constant voltage is applied to the gate electrode 13 to change a time ratio Du. Thus, the overall brightness of an image can be adjusted.

Abstract: An electron emitter assembly and a method for generating electron beams are provided. The electron emitter assembly includes a light source configured to emit light. The electron emitter assembly further includes a photo-responsive device operably coupled to an electron emitter device. The photo-responsive device induces the electron emitter device to emit electrons in response to receiving the light. Finally, the electron emitter assembly includes an anode receiving the emitted electrons from the electron emitter device.

Abstract: A cathode for an electron tube and a method of preparing the same are provided. The cathode includes a base metal and an electron emissive material layer attached to the base metal. A surface roughness, which is measured from the distance between a highest point and a lowest point of the surface of the electron emissive material layer, is controlled to be no greater than 8 ?m. By controlling the sizes of particles and pores constituting the electron emissive material layer to be uniform and controlling the density and porosity of the electron emissive material layer, the cathode is improved in compactness and surface evenness compared to a cathode prepared according to a spraying method. Accordingly, shrinking of the cathode during operation can be prevented, and the distance between the cathode and a G1 (first grid) electrode can be maintained uniform, so that the life of the cathode can be greatly extended, and a stable electron emission characteristic can be realized.

Abstract: A photocathode manufacturing intermediary article (24) includes a substrate layer (26), and an active layer (20) that is carried by the substrate layer (26). The active layer (20) includes photoemissive alkali antimonide material that is epitaxially grown on the substrate (26).

Abstract: Apparatus and methods for providing displays based upon the principle of photoluminescent quenching are described. The invention includes a method of displaying information using photoluminescence quenching, the method comprising providing an optoelectronic display comprising a photoluminescent material between a pair of electrodes, providing illumination for the photoluminescent material to cause the photoluminescent material to photoluminescence, and biasing the electrodes to at least partially quench the photoluminescence.

Abstract: A photocathode as a source of electron beams, having a substrate of optically transmissive diamond and a photoemitter. A photocathode with a single emitting region provides a single electron beam; a photocathode with multiple emitting regions provides multiple electron beams. The photoemitter is positioned on the side of the diamond substrate opposite the surface on which the illumination is incident, and has an irradiation region at the contact with the optically transmissive diamond, and an emission region opposite the irradiation region, these regions being defined by the path of the illumination. The diamond substrate at the irradiation region/emission region interface conducts heat away from this focused region of illumination on the photocathode. Alternately, a diamond film is used for heat conduction, while another material is used as a substrate to provide structural support.

Abstract: A diamond transmission dynode and photocathode are described which include a thin layer of a crystalline semiconductive material. The semiconductive material is preferably textured with a (100) orientation. Metallic electrodes are formed on the input and output surfaces of the semiconductive material so that a bias potential can be applied to enhance electron transport through the semiconductive material. An imaging device and a photomultiplier utilizing the aforesaid transmission dynode and/or photocathode are also described.

Abstract: Strontium, calcium, strontium calcium, strontium calcium magnesium, calcium magnesium aluminates, and strontium borates activated with Pr3+ exhibit characteristics of quantum-splitting phosphors under VUV excitation. A large emission peak at about 405 nm under VUV excitation is used conveniently to identify quantum-splitting phosphors. Improvements may be achieved with addition of fluorides or boric acid as a flux during the preparation of the phosphors. It is also possible to predict improvement in quantum efficiency by observing the ratio of emission intensities at about 480 nm and about 610 nm.

Abstract: A communications system that includes one or more free space electron switches. The free space electron switch employs an array of electron emitters, where each emitter is responsive to an RF or optical input signal on an input channel. Each emitter includes a cathode that emits electrons in response to the input signal. Each emitter further includes a focussing/accelerating electrode for collecting and accelerating the emitted electrons into an electron beam. Each emitter further includes an aiming anode that directs the beam of electrons to a desired detector within an array of detectors that converts the beam of electrons to a representative RF or optical signal on an output channel. Each emitter may include a modulating electrode that generates an electric field to modulate data onto the beam of electrons. The communications systems employing the switch can be an ISDN, DSLAM networks, packet routing systems, ADSL networks, PBX systems, local exchange systems, etc.

Abstract: A free space electron switch is disclosed. The switch, which is useful in high speed telecommunications traffic, has an array of cathodes for emitting free space electrons. A grid of aiming anodes and, a focusing grid for forming electrons from the cathode into an electron beam are provided. A plurality of output ports for receiving the electron beam from each cathode is provided, the output ports having a phosphor coating facing the side of the channel remote from the cathode.

Abstract: A semiconductor cathode (11) in a semiconductor structure, in which the sturdiness of the cathode is increased by covering the emitting surface (4) with a layer of a semiconductor material (7) having a larger bandgap than the semiconductor material of the semiconductor cathode. Various measures for increasing the electron-mission efficiency are indicated.

Abstract: A photocathode device is disclosed including an active layer, a composition ramp layer and an emission layer including an emission surface. The active layer, ramp layer and emission layer each have both a predetermined material composition and a predetermined doping level for maintaining the conduction band of the device flat until the emission surface which functions to increase the photoresponse of the device.

Abstract: An X-ray image intensifier that includes a vacuum envelope having a metal X-ray input window and an input screen formed on the inner surface of the X-ray input window, a focusing electrode, an anode, and an output screen arranged in the vacuum envelope along the traveling direction of electrons generated from the input screen. The X-ray input window has a rough, surface-hardened layer on the side on which the input screen is formed. The input screen includes a phosphor layer adjacent to the rough, surface-hardened layer and a photocathode formed on the phosphor layer.

Abstract: The photocathode according to this invention is characterized in that an aluminium thin film is formed on a substrate, and then an antimony thin layer is deposited directly on the aluminium thin film and is activated by an alkali metal. It is especially preferable that the antimony thin layer is deposited in a thickness of 15 .mu.g/cm.sup.2 to 45 .mu.g/cm.sup.2 and is activated by an alkali metal. Such reflection-type photocathode is applicable to photomultipliers. Among functions which are considered to be done by the Al film. which is in direct contact with the Sb layer, a first one is to prevent the alloying between the Sb layer and the substrate (e.g., Ni), and a second one is to augment a reflectance of light to be detected.

Abstract: An improved photocathode (12) and image intensifier tube (10) are disclosed along with a method for making both the tube (10) and photocathode (12). The disclosed image intensifier tube (10) creates a visible light image (20) from an image emitting photons (22). The tube (10) comprises a photocathode (12) having an indium-gallium-arsenide active layer (26) and an aluminum-gallium-arsenide window layer (28). The photocathode (12) is operable to emit electrons (23) in response to the photons (22). A display apparatus is coupled to the photocathode (12) and is operable to transform the emitted electrons (23) into a visible light image (24). An embodiment of the invention is capable of detecting 1.06 .mu.m radiation.

Abstract: A cathode for photoelectric emission or a cathode for secondary electron emission comprises a thin film made of a material which emits photoelectrons by an incident light or emits secondary electrons by an electron input on a base substrate. The average particle size of the particles forming the thin film is 200 nm to 2000 nm. It is preferred that the average particle size is nearly equal to an average diffusion length of the particle of an excited electron. Further, the average particle size is preferably larger than the mean value of penetration lengths of inputted electrons or incident lights in the particles. Moreover, preferably convexities and/or concavities formed of particles each having the average particle size are formed over the surface of a plane for the incident light or electron input. Further, it is preferred that the thin film is activated by an alkali metal and is made of compounds of at least one kind of alkali metal and an antimony metal.

Abstract: A source of light in the vacuum ultraviolet (VUV) spectral region includes a reflective UV-sensitive photocathode supported in spaced parallel relationship with a mesh electrode within a rare gas at low pressure. A high positive potential applied to the mesh electrode creates an electric field which causes drifting of free electrons occurring between the electrodes and producing continuous VUV light output by electric field-driven scintillation amplification sustained by positive photon feedback mediated by photoemission from the photocathode. In one embodiment the lamp emits a narrow-band continuum peaked at 175 nm.

Abstract: A method is provided of making a photoemissive cathode including bonding an electron emissive layer to a glass faceplate at an elevated temperature and pressure to form a cathode structure and cooling the cathode structure at a rate which will maintain stress between the electron emissive layer and the faceplate at or below a predetermined level in order to avoid brush marks and crosshatchings during subsequent processing steps. The cathode is cooled from a bonding temperature to room temperature in approximately twenty minutes or less.

Abstract: A light detection and ranging (LIDAR) system uses dual detectors to provide three-dimensional imaging of underwater objects (or other objects hidden by a partially transmissive medium). One of the detectors is a low resolution, high bandwidth detector. The other is a high resolution, narrow bandwidth detector. An initial laser pulse is transmitted to known x-y coordinates of a target area. The photo signals returned from the target area from this initial pulse are directed to the low resolution, high bandwidth detector, where a preliminary determination as to the location (depth, or z coordinate) of an object in the target area is made based on the time-of-receipt of the return photo signal. A second laser pulse is then transmitted to the target area and the return photo signals from such second laser pulse are directed to the high resolution, narrow bandwidth detector.

Abstract: A wafer of neutron transmutation doped silicon having a p-n junction between extended opposite surfaces is formed with bevelled edges. A single or plurality of reverse biased signal contacts is disposed on one surface to provide a single or integrated array of avalanche photodiodes. In addition, an avalanche photodetector (APD) capable of detecting a single photoelectron or imaging multiple photoelectrons comprises a light sensitive photocathode, similar to that in a photomultiplier tube, acting as a converter to produce photoelectrons, which are then accelerated to an anode. The anode comprises a single avalanche photodiode (AP) for detecting or an array (APA) for imaging photoelectrons. The energetic photoelectrons striking the AP or the APA serve as the AP or APA's input signal, respectively.

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 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 method of forming a variable sensitivity transmission mode negative eleon affinity (NEA) photocathode in which the sensitivity of the photocathode to white or monochromatic light can be varied by varying the backsurface recombination velocity of the photoemitting material with an electric field. The basic structure of the photocathode is comprised of a Group III-V element photoemitter on a larger bandgap Group III-V element window substrate.

Abstract: An X-ray image tube has a vacuum envelope, a photocathode arranged at an input side in the vacuum envelope and having a curved surface open to an output side thereof, and a phosphor screen arranged at an output side in the vacuum envelope and having a surface on which electrons emitted from the photocathode are electrooptically focused. The photocathode consists of a central surface region with a diameter which is 1/2 to 4/5 of the diameter of the photocathode and a peripheral surface region. The central surface region has a profile such that an increment of the meridional curvature radius from the center to a peripheral portion thereof is larger than a constant derived from a linearity between the increment and a distance from the axis of the photocathode.

Abstract: In a pick-up unit, a tube base for a camera tube is integrated with a coil former having a system of coils. As a result, the length of the pickup unit is small so that it is possible to manufacture portable cameras of small dimensions. The radial position of the tube with respect to the coil former is fixed by centering means provided in the tube base and in a sealing cap engaging the coil former. The axial position of the tube relative to the coil former is fixed by urging the tube against an abutting face of the sealing cap by means of a spring. The coil former is surrounded by a .mu.-metal screening sleeve consisting of two portions. The two portions of the screening sleeve are coupled together by means of a clamping ring.

Abstract: A method of forming a variable sensitivity transmission mode negative eleon affinity (NEA) photocathode in which the sensitivity of the photocathode to white or monochromatic light can be varied by varying the backsurface recombination velocity of the photoemitting material with an electric field. The basic structure of the photocathode is comprised of a Group III-V element photoemitter on a larger bandgap Group III-V element window substrate.

Abstract: An improved color filter array comprises a transparent heat-transfer dye-receiving layer containing an array of filter elements wherein the dye-receiving layer is a certain polyester wherein at least 30 mole percent of the recurring units contain a saturated gem-bivalent radical having a saturated polycyclic three-dimensional structure that includes a saturated bicyclic atomic bridge hydrocarbon ring member. The improved dye-receiving layers provide filter elements with excellent edge sharpness. The improved color filter arrays are useful in color imaging devices, such as solid-state video cameras.

Abstract: A photocathode is formed by depositing a film of tellurium on a conductive base and then sensitizing the tellurium with at least two different alkali metals such as cesium and potassium or sodium and potassium. The photocathode has high sensitivity in the ultraviolet region and is substantially insensitive to solar radiation through the earth's atmosphere. Such a photocathode is useful in "solar-blind" detectors.

Abstract: An epitaxial layer of a quaternary III-V alloy of Ga, In, As, and P has its constituents proportioned for lattice matching to a substrate having a lattice constant falling within the range of 5.45 to 6.05 A. In addition, the constituents of the alloy are proportioned to provide a selected bandgap energy falling within the range of 2.23 to 0.35 electron volts; this corresponds to wavelengths of 0.55 to 3.5 microns. Near perfect lattice matched heterojunctions are provided between the epitaxial layer and the lattice matched substrate; these are useful for providing improved photocathodes and lasers, particularly in the infrared range of wavelengths between 0.8 and 2.0 microns.

Abstract: The invention relates to an X- and Gamma-ray sensitive image intensification tube for use in a so-called gamma camera or the like, which tube preferably has a single crystal input phosphor.