Abstract: To calculate a probability of an optical sensor's irregular discharge, a light detection system includes an optical sensor, an application voltage generating circuit that applies a drive pulse voltage to the optical sensor, a discharge determining portion that detects the optical sensor's discharge, a discharge probability calculating portion that calculates a discharge probability for each of first and second states in which the optical sensor is shielded from light and the drive pulse voltage's width in the second state is different from the first state, a sensitivity parameter storing portion storing the drive pulse voltage's reference pulse width as the optical sensor's sensitivity parameter, and another discharge probability calculating portion that calculates an irregular discharge's probability that occurs without depending on the optical sensor's received light quantity, based on the sensitivity parameter, and the discharge probabilities calculated and the drive pulse voltage's widths in the first and

Abstract: The present invention improves sensitivity of the ultraviolet band of a photoelectric surface. A photoelectric surface includes a window material that transmits ultraviolet rays, a conductive film that is formed on the window material and has conductivity, an intermediate film 4 that is formed on the conductive film and is formed of MgF2, and a photoelectric conversion film that is formed on the intermediate film 4 and is formed of CsTe. Since the photoelectric surface includes the intermediate film 4 formed of MgF2, the sensitivity of the ultraviolet band is improved.

Abstract: An electron source of an X-ray fluorescence analyser includes a photon source (201) and a photoelectric converter (203, 204) for converting photons into electrons. An electron multiplier (203, 204) multiplies the electrons, and a focusing element (206, 207) focuses them to a beam. A gastight casing (209) encloses the photoelectric converter and the electron multiplier (203, 204). An electron-transparent membrane (213) covers a first opening in the casing at a location where the focused electron beam is directed out of the casing.

Abstract: A lamp assembly is provided, that utilizes a light source including an LED element without cutting part of light therefrom and capable of forming a luminance distribution where the light with a maximum peak portion can be arranged substantially at (i.e., at or near) the cutoff line, thereby improving light utilization efficiency. The lamp assembly with an illumination direction can include a light source including an LED element with an emission surface, and a projection optical system for projecting an image of the light source in the illumination direction so that a desired light distribution pattern can be formed on a virtual vertical screen. The light source can have a rectangular shape having long sides and short sides, and can be configured to provide a luminance distribution on the emission surface such that a luminance peak portion is provided at or near one of the long sides.

Abstract: Disclosed herein is a PhotoMultiplier Tube (PMT) designed for use with a surface inspection system such as the Surfscan system, which operates at 266 nm wavelength. The inventive PMT is high efficiency, low noise, and low gain, a combination of features that is specific to the application and contrary to the features of PMT's in the art. The inventive PMT is designed to be tuned to a specific narrow band wavelength of incident light, thereby optimizing the QE at that wavelength. It is further designed to combine a small number of dynodes each having substantially higher secondary electron gain than typical dynodes. By designing the PMT in this way, the excess noise factor is dramatically reduced, yielding a much improved S/N, while still maintaining the overall PMT gain in the lower range suitable for use in a surface inspection system.

Abstract: A UV flame sensor for detecting a run-on condition in a flame detector tube is disclosed. The UV flame sensor comprises a pair of secondary electrodes that are enclosed in a mesotube to form a breakdown chamber in order to detect the run-on condition. These secondary electrodes are exposed to UV through an aperture in a cathode plate and are energized continuously by a lower voltage. The mesotube is expected to break down when the run-on condition occurs. The secondary electrodes can be placed in the same gas environment as the main electrodes that may take different forms, shapes and locations.

Abstract: A mesotube apparatus is disclosed which includes a header insulator in order to avoid premature breakdown at lower voltage that occurs between a cathode and an anode in a discharge assembly. A chamber can be mounted on a header base and can be located away from plasma surrounded with dielectric so that breakdown occurs outside the normal voltage operating range. A number of feed-through pins associated with the header base can be electrically isolated from the header base by a dielectric insulator. The dielectric insulator can also be placed over the header base and topside of the chamber in order to passivate from stray electrons and plasma. The header base can be thin which allows welding of the anode and the cathode to the feed-through pins with a weld tool attached to the side of the feed-through pins. The chamber can be located on the header base by tightly fitting to the feed-through pins.

Abstract: The present invention is directed to an arrangement for switching high electric currents by way of a gas discharge at high voltages or for generating gas discharge plasma emitting EUV radiation. It is the object of the invention to find a novel possibility for generating a hollow cathode plasma that permits a longer life of the cathodes of short wavelength-emitting gas discharge radiation sources and pseudospark switches, also in high-power operation. This object is met in that the metal wall between the hollow cathode space and the discharge space has a thickness on the order of the centimeter range so that the openings of the metal wall change into relatively long channels and in that substantially radially extending cooling channels are introduced in the metal wall to reduce the ion erosion of the metal wall of the hollow cathode through efficient cooling.

Abstract: A metal halide fill for forming an ionizable fill comprises at least one inert gas, mercury and metal halides, the fill comprising the constituents V halide, Cs halide, Tl halide and halides of the rare earths. This fill may in particular be contained in the discharge vessel of a metal halide lamp.

Abstract: A UV flame sensor for detecting a run-on condition in a flame detector tube is disclosed. The UV flame sensor comprises a pair of secondary electrodes that are enclosed in a mesotube to form a breakdown chamber in order to detect the run-on condition. These secondary electrodes are exposed to UV through an aperture in a cathode plate and are energized continuously by a lower voltage. The mesotube is expected to break down when the run-on condition occurs. The secondary electrodes can be placed in the same gas environment as the main electrodes that may take different forms, shapes and locations.

Abstract: An electron beam column comprises a thermal field emission electron source to generate an electron beam, an electron beam blanker, a beam shaping module, and electron beam optics comprising a plurality of electron beam lenses. In one version, the optical parameters of the electron beam blanker, beam shaping module, and electron beam optics are set to achieve an acceptance semi-angle ? of from about ¼ to about 3 mrads, where the acceptance semi-angle ? is half the angle subtended by the electron beam at the writing plane. The beam-shaping module can also operate as a single lens using upper and lower projection lenses. A multifunction module for an electron beam column is also described.

Abstract: An electron beam lithography system has an electron gun including at least one laser that is operable in a first mode to generate electrons for lithography. The electron beam lithography system is operable in a second mode to regenerate the photocathode of the electron gun by application of the laser. The photocathode includes a layer of cesium telluride.

Abstract: A flame detector and burner fuel valve control has an ultraviolet sensitive, cold cathode, gas discharge tube in a DC quench circuit. In the presence of a flame, the circuit generates a pulse signal at a frequency related to the intensity of radiation from the flame. The pulse signal from a contaminated tube is at a higher frequency. A frequency discriminator circuit distinguishes between a flame responsive signal and a contaminated tube signal and controls the burner fuel valve.

Abstract: A semiconductor source of emission electrons which uses a target of a wide bandgap semiconductor having a target thickness measured from an illumination surface to an emission surface. The semiconductor source is equipped with an arrangement for producing and directing a beam of seed electrons at the illumination surface and a mechanism for controlling the energy of the seed electrons such that the energy of the seed electrons is sufficient to generate electron-hole pairs in the target. A fraction of these electron-hole pairs supply the emission electrons. Furthermore, the target thickness and the energy of the seed electrons are optimized such that the emission electrons at the emission surface are substantially thermalized. The emission of electrons is further facilitated by generating negative electron affinity at the emission surface. The source of the invention can take advantage of diamond, AlN, BN, Ga1-yAlyN and (AlN)x(SiC)1-x, wherein 0?y?1 and 0.2?x?1 and other wide bandgap semiconductors.

Abstract: A solar energy converter includes: a light-concentrating instrument; an electron emitter in an insulated vacuum vessel, emitting electrons in a vacuum as a temperature rises by sunlight; an electron accelerator within the light-concentrating instrument; a cathode on a surface of the electron emitter opposite to a surface which is irradiated by sunlight, and electrically connected with the electron emitter; an electric field supplier having a positive terminal and a negative terminal; and an electron collector in the vacuum vessel, collecting the emitted electrons flying from the electron emitter toward the electron accelerator; wherein the electron accelerator is connected with the positive terminal and the cathode is connected with the negative terminal to generate an electric field, and the electron collector is used as a negative generator electrode and the cathode is used as a positive generator electrode in which the collected electrons migrate to the electron emitter to generate electricity.

Abstract: The present invention relates to a flame detector for detection of the presence of a flame or spark in front of the detector comprising a UV sensitive photocathode (12; 21) and an anode (14; 22), respectively, wherein the UV sensitive photocathode is oriented such that UV light from a flame present in front of the detector can strike the photocathode; a voltage supply unit (18; 23) connected to the UV sensitive photocathode and to the anode to force photoelectrons emitted from the UV sensitive photocathode when struck by UV light from a flame present in front of the detector to move towards the anode; and a readout arrangement (15-17; 24) adapted to detect charges induced by electrons moving towards the anode to thereby detect the presence of a flame in front of the detector. The flame detector can be combined with an alarm unit (33) to form an automatic alarm (31).

Abstract: Provided is a small-sized less expensive light-intensity measuring apparatus for measuring a xenon excimer lamp that radiates a light beam having a central wavelength of 172 nm for an intensity. The light-intensity measuring apparatus of the present invention comprises a photoelectric converting means 23, preferably a photodiode, having photosensitivity in the range of from 800 to 1,000 nm, an operating means 25 for relatively determining the intensity of a light beam having a central wavelength of 172 nm depending upon an output of the photoelectric converting means 23 and a transmitting means 26 for transmitting the light intensity determined with the operating means 25.

Abstract: The solar energy converter comprises an electron emitter and an electron collector. They are provided separate from each other in a vacuum vessel. Solar energy in a wide range of sunlight spectrum can be efficiently converted into electric energy by moving electrons from the electron emitter to the electron collector.

Abstract: A method and apparatus for increasing the quantum efficiency of a photomultiplier tube by providing a photocathode with an increased surface-to-volume ratio. The photocathode includes a transparent substrate, upon one major side of which is formed one or more large aspect-ratio structures, such as needles, cones, fibers, prisms, or pyramids. The large aspect-ratio structures are at least partially composed of a photoelectron emitting material, i.e., a material that emits a photoelectron upon absorption of an optical photon. The large aspect-ratio structures may be substantially composed of the photoelectron emitting material (i.e., formed as such upon the surface of a relatively flat substrate) or be only partially composed of a photoelectron emitting material (i.e., the photoelectron emitting material is coated over large aspect-ratio structures formed from the substrate material itself.

Abstract: In one aspect, the present invention is a technique of, and a system and sensor for sensing an aerial image produced by, for example, optical lithographic equipment used in semiconductor fabrication. In one embodiment, the apparatus includes a negative electron affinity photo-electron emission device for projecting the aerial image thereon. In response, the photo-electron emission device emits electrons with a very tight energy spread in a pattern corresponding to the light intensity distribution produced by the aerial image. Electron optics is provided for guiding and projecting the electrons to form an enlarged pattern of the pattern in which the electrons are emitted. A sensing unit senses the enlarged pattern and supplies it to a device for capturing and digitizing the enlarged pattern to obtain therefrom a digitized aerial image. The resolution increase is achieved through the enlargement of the pattern by the electron optics.

Abstract: The present invention relates to a flame detector for detection of the presence of a flame or spark in front of the detector comprising a UV sensitive photocathode (12; 21) and an anode (14; 22), respectively, wherein the UV sensitive photocathode is oriented such that UV light from a flame present in front of the detector can strike the photocathode; a voltage supply unit (18; 23) connected to the UV sensitive photocathode and to the anode to force photoelectrons emitted from the UV sensitive photocathode when struck by UV light from a flame present in front of the detector to move towards the anode; and a readout arrangement (15-17; 24) adapted to detect charges induced by electrons moving towards the anode to thereby detect the presence of a flame in front of the detector. The flame detector can be combined with an alarm unit (33) to form an automatic alarm (31).

Abstract: A vacuum diode with a high saturation current density and a rapid response time for the detection of electromagnetic radiation. This diode comprises a grid (6) in the shape of a cylinder and a photo-cathode (4) which extends along the axis (X) of the cylinder. The photo-cathode includes a part of the internal conductor of a coaxial cable (8), the external conductor and the electrically insulating material of the coaxial cable being removed opposite this part, and the grid is electrically connected to the external conductor of this coaxial cable, the internal and external conductors being coaxial. Application to the detection of visible, infra-red, ultra-violet and X radiation.

Abstract: A lamp device comprises a UV intermediate pressure lamp tube (1), arranged in an outer globe (2) mounted in a socket (4). Sealing means (5, 6, 7, 8, 9) enclose the outer globe (2) in order to ensure mutual vacuum-tight mounting of socket (4) and outer globe (2). The lamp device is suitable for application in a UV system for photochemical water purification. A control system comprises device for temperature measurement of an inactive gas in the outer globe and device for regulating the tube voltage of the lamp tube. Controlling the tube voltage of the lamp tube increases service life of the lamp and ensures uniformity in the electromagnetic radiation (UV light) emitted by the lamp. The UV lamp is replaceable in the remaining part of the lamp device.

Abstract: An ultraviolet detector comprises a metal tubular member which hermetically encloses an anode and a cathode therein and is filled with a discharged gas introduced therein from a metal exhaust tube. After the anode and the cathode are enclosed within the tubular member, the ultraviolet detector can be made without being subjected to any glass fusing process. Accordingly, the inside of the sealed vessel V1 can be prevented from being contaminated with fluorine, whereby the ultraviolet detector with stable characteristics can be provided.

Abstract: A photocathode includes a first layer of polycrystalline diamond or a material mainly composed of polycrystalline diamond. The first layer of polycrystalline diamond may be terminated with hydrogen, or oxygen, and a second layer of an alkali metal or compound of an alkali metal, may be provided on the first layer of polycrystalline diamond whose surface is terminated with hydrogen or oxygen. The photocathode can be use for both reflection and transmission electron tubes and can yield a quantum efficiency higher than that in a monocrystal diamond thin film.

Abstract: The ultraviolet detector in accordance with the present invention comprises a sealed vessel enclosing a discharged gas therein, and a metal anode and a metal cathode which are disposed close to each other within the sealed vessel so as to generate therebetween discharge in response to ultraviolet radiation entering the sealed vessel. The anode and cathode are independently secured to the sealed vessel with a plurality (at least three pieces each) of anode pins and cathode pins, respectively. An electrically-insulating spacer is disposed between the anode and cathode so as to fix their relative positions with respect to each other, thereby defining a discharging gap, by which discharge is stably generated between these electrodes. The current resulting from the discharge is observed so as to detect the incidence of ultraviolet radiation.

Abstract: An electron source includes a negative electron affinity photocathode on a light-transmissive substrate and a light beam generator for directing a light beam through the substrate at the photocathode for exciting electrons into the conduction band. The photocathode has at least one active area for emission of electrons with dimensions of less than about two micrometers. The electron source further includes electron optics for forming the electrons into an electron beam and a vacuum enclosure for maintaining the photocathode at high vacuum. The photocathode is patterned to define emission areas. A patterned mask may be located on the emission surface of the active layer, may be buried within the active layer or may be located between the active layer and the substrate.

Abstract: An electron beam source includes a cathode having an electron emission surface including an active area for emission of electrons and a cathode shield assembly including a conductive shield disposed in proximity to the electron emission surface of the cathode. The shield has an opening aligned with the active area. The electron beam source further includes a device for stimulating emission of electrons from the active area of the cathode, electron optics for forming the electrons into an electron beam and a vacuum enclosure for maintaining the cathode at high vacuum. The cathode may be a negative electron affinity photocathode formed on a light-transmissive substrate. The shield protects non-emitting areas of the emission surface from contamination and inhibits cathode materials from contaminating components of the electron beam source. The cathode may be moved relative to the opening in the shield so as to align an new active area with the opening.

Abstract: Apparatus (10, 30, 60) and a method for generating low energy electrons (26, 46) for neutralizing charges (16, 36, 66) accumulated on a wafer (14, 34, 64) is provided. The apparatus includes a photocathode (24, 44, 67) located within a predetermined distance from the wafer (14, 34, 64), and a light source (20, 40, 70, 76, 86) operable to emit a light (22, 42, 72, 78, 88) striking the photocathode (24, 44, 67), the photocathode (24, 44, 67) generating a cloud of low energy electrons (26, 46) with a narrow energy distribution near the wafer (14, 34, 64).

Abstract: An electron source includes a negative electron affinity photocathode on a light-transmissive substrate and a light beam generator for directing a light beam through the substrate at the photocathode for exciting electrons into the conduction band. The photocathode has at least one active area for emission of electrons with dimensions of less than about two micrometers. The electron source further includes electron optics for forming the electrons into an electron beam and a vacuum enclosure for maintaining the photocathode at high vacuum. In one embodiment, the active emission area of the photocathode is defined by the light beam that is incident on the photocathode. In another embodiment, the active emission area of the photocathode is predefined by surface modification of the photocathode. The source provides very high brightness from an ultra-small active emission area of the photocathode.

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: A cold cathode (3) in the form of a solid thin film component is the basis for electron-optical terminal image devices. The thin-film structure is made up of a base electrode (5), e.g., in the form of a bundle of parallel strips, an insulating film (6), a semiconductor film (7) and a covering electrode (8), e.g., also a bundle of parallel strips but running perpendicularly to the base electrode (5) bundle. This set of layers borne on a substrate plate (4), is in an evacuated casing (2) and is opposite a fluorescent screen (12) or a light emitter (15), the metalized coating (11) of which forms the counter-pole for the electron acceleration chamber (9). The main applications of such electron-optical terminal image devices are embodiments as matrix-addressed flat displays, image converters or write/read lines.

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 compact pulsed optical source of near to ultraviolet wavelength energy adapted to be connected to an external power source. The optical source includes a device for emitting photons, apparatus for transforming photons into photoelectrons, apparatus for multiplying the photoelectrons, a lens, a phosphor coated anode, circuit apparatus for providing a pulsed electric signal and first and second biasing apparatus. The emitting device impinges photons on the photon transforming apparatus which accelerates electrons to the multiplying apparatus as pulses are received from the circuit apparatus which relates the multiplying apparatus to the transforming apparatus. With each pulse, a cloud of electrons is emitted from the multiplying apparatus and excites the phosphor coated anode thereby causing optical emission.

Abstract: A photomultiplier with plural photocathodes comprising a rectangular end face plate, plural photocathodes arranged on the end face plates at predetermined intervals in the longitudinal direction of the end face plate, plural focusing electrodes assigned to the photocathodes respectively, plural dynodes provided in common for all of the photocathodes, and plural anode electrodes assigned to the photocathodes respectively, each of the dynodes having plural electron emitting parts for emitting secondary electrons and insulating parts for preventing the secondary electrons emitted from any one of the electron emitting parts from straying into the other electron emitting parts.

Abstract: A so-called "solar-blind" photomultiplier tube includes an envelope having a sidewall and an input faceplate formed from an ultraviolet transmitting filter. A photoemissive cathode is disposed within the envelope for providing photoelectrons in response to radiation incident thereon. The cathode has an intrinsic responsivity extending from the near-ultraviolet portion through the visible portion of the electromagnetic spectrum; however, the filter faceplate transmits only the ultraviolet portion of the spectrum to the photoemissive cathode. The combination of the filter faceplate and the photoemissive cathode therefore limits the tube to a responsivity within the wavelength range of about 300 to less than 400 nanometers.

Abstract: The photosensitivity of a photomultiplier dynode to white light or infrared radiation is greatly reduced by coating the dynode with a layer of an alkali halide material having good secondary electron emission characteristics. A method of applying the coating to the dynode is also described.

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: An ultraviolet detector comprises a metal tubular member which hermetically encloses an anode and a cathode therein and is filled with a discharged gas introduced therein from a metal exhaust tube. After the anode and the cathode are enclosed within the tubular member, the ultraviolet detector can be made without being subjected to any glass fusing process. Accordingly, the inside of the sealed vessel V1 can be prevented from being contaminated with fluorine, whereby the ultraviolet detector with stable characteristics can be provided.