Emitter (3) and target (7) are arranged so as to face each other in vacuum chamber (1), and guard electrode (5) is provided at outer circumferential side of electron generating portion (31) of emitter (3). Guard electrode (5) is supported movably in directions of both ends of vacuum chamber (1) by guard electrode supporting unit (6). To perform regeneration process of guard electrode (5), guard electrode (5) is moved to opening (22) side (to separate position) by operating guard electrode supporting unit (6), and a state in which field emission of electron generating portion (31) is suppressed is set, then by applying voltage across guard electrode (5), discharge is repeated. After performing regeneration process, by operating guard electrode supporting unit (6) again, guard electrode (5) is moved to opening (21) side (to emitter position), and a state in which field emission of electron generating portion (31) is possible is set.

Disclosed are methods and devices suitable for producing an electron beam.

A semiconductor structure includes a thin-film device layer, an optoelectronic device disposed in the thin-film device layer, and a surrogate substrate permanently attached to the thin film device layer. The optoelectronic device is excitable by light at an application wavelength. The surrogate substrate is optically transparent and has a thermal conductivity of at least 300 W/m-K. The surrogate substrate has a volume of substrate removed therefrom to form a via. Light passes through the via and at least some of the surrogate substrate prior to reaching the optoelectronic device.

In an embodiment, a system is provided that includes an electron gun, a focusing system, and a housing. The electron gun can include a cold cathode electron source and an extraction electrode. The focusing system can be configured to focus a beam of electrons extracted from the electron gun to a focal region. The housing can include the electron gun and extend along a housing axis in the direction of the electron beam. The cold cathode source is configured to emit electrons at a first operating pressure that is higher than a second operating pressure at the focal region of the electron beam.

An electron beam apparatus which can stably achieve high spatial resolution also during low acceleration observation using CeB.sub.6 for the CFE electron source is provided. In an electron beam apparatus having a CFE electron source, the emitter of the electron beam of the CFE electron source is Ce hexaboride or a hexaboride of a lanthanoid metal heavier than Ce, the hexaboride emits the electron beam from the {310} plane, and the number of the atoms of the lanthanoid metal on the {310} plane is larger than the number of boron molecules comprising six boron atoms on the {310} plane.

Provided is a high-brightness, high-current electron source including a wire-like member. The wire-like member has an electron emission plane at the tip of the wire-like member. The electron emission plane has a projectingly curved surface. At least the surface of the electron emission plane is formed of an amorphous material.

Flash tubes for photographic use, in particular, a flash tube is adapted to provide a light output adapted to FP-sync, Flat Peak. The flash tube includes a length of glass tubing enclosing a gas for use in the flash tube, a cathode inside a first end part of glass tubing and an anode inside a second end part of glass tubing. The cathode includes an element that helps to ionize the gas that is wound around the cathode, such that a spark stream starts from the upper part of the cathode and is prevented from spreading down wards on the cathode and changing the arc length during the light output adapted to FP-sync.

Flash tubes for photographic use, in particular, a flash tube is adapted to provide a light output adapted to FP-sync, Flat Peak. The flash tube includes a length of glass tubing enclosing a gas for use in the flash tube, a cathode inside a first end part of glass tubing and an anode inside a second end part of glass tubing. The cathode includes an element that helps to ionize the gas that is wound around the cathode, such that a spark stream starts from the upper part of the cathode and is prevented from spreading down wards on the cathode and changing the arc length during the light output adapted to FP-sync.

A semiconductor structure includes a thin-film device layer, an optoelectronic device disposed in the thin-film device layer, and a surrogate substrate permanently attached to the thin film device layer. The optoelectronic device is excitable by light at an application wavelength. The surrogate substrate is optically transparent and has a thermal conductivity of at least 300 W/m-K. The surrogate substrate has a volume of substrate removed therefrom to form a via. Light passes through the via and at least some of the surrogate substrate prior to reaching the optoelectronic device.

A semiconductor structure includes a thin-film device layer, an optoelectronic device disposed in the thin-film device layer, and a surrogate substrate permanently attached to the thin film device layer. The surrogate substrate is optically transparent and has a thermal conductivity of at least 300 W/m-K. The optoelectronic device excitable by visible light transmitted through the surrogate substrate.