摘要:
A photocathode is formed on a monocrystalline silicon substrate having opposing illuminated (top) and output (bottom) surfaces. To prevent oxidation of the silicon, a thin (e.g., 1-5 nm) boron layer is disposed directly on the output surface using a process that minimizes oxidation and defects. An optional second boron layer is formed on the illuminated (top) surface, and an optional anti-reflective material layer is formed on the second boron layer to enhance entry of photons into the silicon substrate. An optional external potential is generated between the opposing illuminated (top) and output (bottom) surfaces. The photocathode forms part of novel electron-bombarded charge-coupled device (EBCCD) sensors and inspection systems.
摘要:
The object of the present invention is to provide a radioactive-ray image tube having less deformations, such as the twist of an input substrate, less aberration over the entire regions of an output image, excellent resolution and good brightness uniformity and contrast characteristics. This radioactive-ray image tube 1a comprises an input window 10 formed on one side surface of a vacuum vessel 2a and allowing radioactive-rays to enter the vacuum vessel 2a, an input screen 5 for converting the radioactive-rays incident on the input window 10 into a fluorescent image or a photoelectric image, and an input substrate 4a holding the input screen 5, is characterized in that the input substrate 4a comprises of a clad material 13 having an aluminum alloy material 11 on the radioactive-ray incidence side and a pure aluminum material 12 on the input screen 5 side provided integrally with each other.
摘要:
The present invention assures a satisfactory adhesiveness of an input screen 13 of an X-ray image intensifier, high resolution of an output image and brightness uniformity as required, by configuring an aluminum or aluminum alloy substrate 21 so to have a concave surface with minute irregularities of the substrate material removed by burnishing, excepting gentle irregularities 21c without directivity which are caused by pressing. The gentle irregularities 21c of the substrate 21 preferably have an average length L in a range of 50 &mgr;m to 300 &mgr;m between the neighboring bottoms and an average height H in a range of 0.3 &mgr;m to 4.0 &mgr;m from peaks to bottoms. The invention improves resolution with light on the substrate surface suppressed from being scattered, and decreases image noises which are caused by the minute irregularities.
摘要:
In an image intensifier comprising an entrance faceplate, made of a material transparent to light, having a photoelectric surface, formed on a surface opposite to a light entrance surface, for photoelectrically converting incident light into an electron; and an optical fiber block, constituted by a plurality of optical fibers bundled together, having a phosphor face at an end face of each optical fiber on the light entrance side, for emitting light in response to the electron incident thereon; the photoelectric surface of the entrance faceplate and the phosphor face of the optical fiber block opposing each other, while a vacuum atmosphere being formed therebetween; the optical fiber block is provided with a pit in which an end face of a core portion of each optical fiber is recessed from an end face of a cladding portion thereof, the bottom of the pit is filled with a phosphor, the surface of this phosphor is provided with a metal back layer, the cladding portion projects from the surface of the phosphor toward the entrance surface by a predetermined height, and the projecting surface of the cladding portion is provided with a metal film.
摘要:
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.
摘要:
A buffer assembly for a gamma-insensitive gas avalanche focal plane array operating in the ultra-violet/visible/infrared energy wavelengths and using a photocathode and an avalanche gas located in a gap between an anode and the photocathode. The buffer assembly functions to eliminate chemical compatibility between the gas composition and the materials of the photocathode. The buffer assembly in the described embodiment is composed of two sections, a first section constructed of glass honeycomb under vacuum and a second section defining a thin barrier film or membrane constructed, for example, of Al and Be, which is attached to and supported by the honeycomb. The honeycomb section, in turn, is supported by and adjacent to the photocathode.
摘要:
A multistage, proximity type, radiation image intensifier tube having improved performance characteristics and more rugged construction is provided. A scintillator assembly is comprised of a first ceramic, cellular substrate defining an array of hexagonally shaped cells. The cell walls taper to an edge and are coated with a conductive material such as aluminum. The cells are filled with a scintillation material such as cesium iodide. A first flat photocathode is provided adjacent the first substrate. An intermediate assembly spaced from the scintillator assembly is provided comprised of a second ceramic, cellular substrate similar to the first. The cell walls are coated with a conductive material such as aluminum. A support layer is mounted to the substrate on an end opposite the scintillator assembly. A first flat phosphor display screen is mounted to the support layer on a side internal the second substrate. A second photocathode is provided adjacent the second substrate. An output assembly spaced from the intermediate assembly is provided and is comprised of a third ceramic cellular substrate which is similar to the first nd second substrate. The cell walls are coated with a conductive material such as aluminum. A second flat phosphor display screen is mounted to the third substrate on an end opposite the second substrate. An output window mounted to the tube envelope and adjacent the second display screen is provided. Means are provided for applying separate electrostatic potentials between the various substrates.
摘要:
An X-ray image intensifier comprises a vacuum envelope having an input window, through which X-rays are incident on said vacuum envelope, an input fluorescent screen for converting the X-rays into light rays, a photoelectric layer for converting the light rays into electrons, an anode and a focusing electrode forming an electron lens for accelerating and focusing the electrons and an output fluorescent screen for converting the electrons accelerated and focused by the electron lens into a visible image. The input fluorescent screen includes a first phosphor layer having a first density and a second phosphor layer having a second density higher than the first density. The second phosphor layer is placed on that side of the first phosphor layer which faces the photoelectric layer. The thickness of the second phosphor layer is greater at the peripheral areas than the central part of the input fluorescent screen.
摘要:
A system comprising an X-ray source (1), an elongate detector tube (3) including at least one cathode (5) extending in the longitudinal direction of the tube and at least one anode (6) located opposite to the cathode, a slit diaphragm (2), and a filter (4) mounted in the path between the X-ray source (1) and the detector tube (3). The filter (4) blocks relatively low energy X-radiation in a portion of the beam emitted by the source (1). The cathode (5) is provided with an X-ray detection layer consisting of two strips (8',8") extending in the longitudinal direction of the tube (3). One strip (8") receives the radiation passed by the filter (4) and the other strip (8') receives the unfiltered radiation. The one strip (8") is of considerably greater thickness than the other strip (8').
摘要:
The present invention provides an input screen scintillator for a radiological image intensifier tube in which the cesium iodide needles of the scintillator are coated with a refractory, transparent of reflecting, material having an optical index close to or less than that of the cesium iodide. Different methods may be used for coating, such as chemical vapor phase deposition, activated by thermal excitation, plasma excitation or photonic excitation; or such as diffusion deposition of a colloidal solution; or such as polymerization of a polymer resin. After coating, is realized the heat treatment which ensures the luminescence of the screen.