Abstract:
The image contrast in an image display tube having a channel plate electron multiplier (2) is improved by preventing secondary electrons emitted from the face of an input dynode (26) from straying to channels located at a relatively large distance from their origin. This is done by disposing a grid (24) at a short distance from the input dynode (26). If the grid (24) is held at a positive voltage relative to the input dynode (26), stray secondary electrons will be attracted toward the grid (24). Alternatively, if the grid (24) is held at a negative voltage relative to that of the input dynode (26), the secondary electrons will be induced to enter channels close to their origin.
Abstract:
A photomultiplier tube includes an evacuated envelope having therein a photocathode, an anode and an electron multiplier disposed between the cathode and the anode for propagating and concatenating electrons along a path therebetween. The electron multiplier and the anode are supported by a pair of oppositely-disposed support plates. At least one aperture which extends along at least a portion of the electron path is formed in each plate. A pair of focusing shields may be spaced from the exterior surface of each of the support plates. The focusing shields are disposed adjacent to the apertures in the support plates and extend longitudinally along the electron path to provide a transverse focusing field which prevents substantially all of the electrons from impinging on the interior surface of the support plates.
Abstract:
A photomultiplier tube comprises an evacuated envelope having therein a photocathode, an anode and a high speed electron multiplier. The electron multiplier includes a primary dynode having a substantially parallel electron permeable member spaced from the primary dynode and disposed between the photocathode and the primary dynode. The electron permeable member also extends between the primary dynode and a plurality of secondary dynodes and accelerates secondary electrons from the primary dynode towards an input secondary dynode. Steering means disposed between the electron permeable member and the secondary dynodes direct the secondary electrons toward the input secondary dynode. Optional electron permeable second members, spaced from and disposed parallel to the secondary dynodes are operated at a potential midway between the adjacent dynode and the next succeeding dynode to accelerate the secondary electrons towards the anode.
Abstract:
An electron emissive surface portion on one of a series of electrodes includes a cross-sectional contour substantially characterized by a superimposed undulating line of curvature which includes a plurality of interconnected arcuate regions.
Abstract:
The faceplate of a light detector tube is provided with an internal photocathode having wedge-shaped projections and external lenses to concentrate the light from a source onto the projecting photosensitive surface areas. An accelerating grid having a corresponding configuration is spaced closely to the photocathode to increase the emission of electrons from the photosensitive surface. A potential source establishes an electric field between the photocathode and an anode, with the anode collecting the electrons.
Abstract:
A gas electron multiplier (GEM), used to track cosmic ray muons, can have readout electrodes oriented in a helical pattern so that it can fit inside a narrow aperture borehole. The helical orientation of the readout electrodes provides for high spatial resolution and yet is cost effective to manufacture. The GEM can have an insulation layer, a plurality of conduction layers and an inner layer comprising a plurality of helical conductive stripes extending between two ends of the GEM.
Abstract:
A magnetic sensor that generates a signal based on inverse spin Hall effect. The sensor includes a magnetic free layer and a non-magnetic, electrically conductive spin Hall layer located adjacent to the magnetic free layer. Circuitry is configured to supply an electrical current that travels through the magnetic free layer and the spin Hall layer in a direction that is generally perpendicular to the plane of the layers or perpendicular to a plane defined by an interface between the magnetic free layer and the spin Hall layer. The inverse spin Hall effect causes an electrical voltage in the spin Hall layer as a result of the current, and the voltage changes relative to the orientation of magnetization of the magnetic free layer. Circuitry is provided for measuring the voltage in the spin Hall layer in a direction that is generally perpendicular to the direction of the electrical current.
Abstract:
A scalable vacuum photosensor configured to simplify mass production with a housing having an evacuated first side at an ultrahigh vacuum and a second side which does not require high vacuum. The first side of the device is sealed to a base plate, having a central electron readout element, using an oxide-free sealing technique, with the deposited sealing areas serving as high voltage throughputs from the first to second sides. A conductive photocathode layer on the transparent first side converts photons to photoelectrons and concentrates the photoelectrons upon the readout. The first and second sides together form an electrostatic lens for accelerating and focusing photoelectrons upon the readout, preferably having a scintillator which generates secondary light measured by an optical detector in the second side of the housing.
Abstract:
Disclosed are devices, systems, and methods are disclosed that include: (a) a first material layer positioned on a first surface of a support structure and configured to generate secondary electrons in response to incident charged particles that strike the first layer, the first layer including an aperture configured to permit a portion of the incident charged particles to pass through the aperture; and (b) a second material layer positioned on a second surface of the support structure and separated from the first layer by a distance of 0.5 cm or more, the second layer being configured to generate secondary electrons in response to charged particles that pass through the aperture and strike the second layer, where the device is a charged particle detector.