Abstract: A photomultiplier tube having an ion suppression electrode positioned between a photocathode and an electron multiplying device in the photomultiplier tube is disclosed. The ion suppression electrode includes a grid that is configured to provide sufficient rigidity to avoid deformation during operation of the photomultiplier tube. The photomultiplier tube also includes a source of electric potential connected to the electron multiplying device and to the ion suppression electrode to provide a first voltage to the second electrode and a second voltage to the suppression grid electrode wherein the second voltage has a magnitude equal to or greater than the magnitude of the first voltage. A method of making the photomultiplier and a method of using it are also disclosed.

Abstract: A reflectron lens for a time-of-flight mass spectrometer and a method of making same are disclosed. The reflectron lens includes a glass tube having a conductive surface along the length of the tube. The conductive surface has an electrical resistance gradient along its length. The electrical resistance gradient provides an electric field interior to the tube that varies in strength along the length of the tube when an electric potential is applied to opposing ends of the tube. A mass spectrometer incorporating the reflectron lens, a method of making the reflectron lens, and an apparatus for removing lead from the surface of a lead silicate glass tube are also disclosed.

Abstract: An arrangement for a MALDI sample plate for ion mass spectroscopy is disclosed. The sample is configured to shape the hypersonic explosion which creates the ions generated in a MALDI-type time-of-flight mass spectrometer. The MALDI sample plate includes a glass wafer formed from a plurality of clad glass fibers and has a first planar surface. The plate also has a plurality of micro-wells formed in the glass wafer. The micro-wells extend to a depth that is less than the thickness of the glass wafer and act to hold a spot sample in a manner that prevents spreading, maximizes the formation of ions, and shapes the resulting ion cloud to improve ion migration.

Abstract: A microchannel plate and a method of making same are disclosed. The microchannel plate has an active area and at least one solid glass pad. The active area has a plurality of microchannels formed therein. The solid glass pad or pads are formed within the active area, and preferably at peripheral locations, for mounting the microchannel plate. With this arrangement, shrinkage of the microchannel plate during fabrication and hydration induced swelling of the active area after fabrication of the microchannel plate do not result in catastrophic warping or cracking of the microchannel plate.

Abstract: A reflectron lens and method are provided. The reflectron lens comprises a tube having a continuous conductive surface along the length of the tube for providing an electric field interior to the tube that varies in strength along the length of the tube. The tube may comprise glass, and in particular, a glass comprising metal ions, such as lead, which may be reduced to form the conductive surface. The method includes a step of introducing a beam of ions into a first end of a dielectric tube having a continuous conductive surface along the length of the tube. The method further includes a step of applying an electric potential across the tube to create an electric field gradient that varies in strength along the length of the tube so the electric field deflects the ions to cause the ions to exit the tube through the first end of the tube.

Abstract: An apparatus and method for video imaging the spatial response of radiation-responsive devices, such as photomultiplier tubes. The apparatus probes the device under-test with an array of radiation emitting elements, such as light-emitting diodes, programmed with a scanning sequence such that the device under-test output response, e.g., the anode current of a photomultiplier tube, may serve as a video signal to a video display device such as a television or monitor. A video image so produced provides a map of the spatial response of the radiation-responsive device which may indicate perturbances, flaws, and inhomogeneities in the spatial responsivity of the device.

Abstract: Photomultiplier tubes with improved collection of incident radiation, especially from the periphery of the front face of the tube, and that more efficiently couple the collected radiation to the photocathode, and moreover have higher packing densities when assembled into arrays, resulting in enhanced imaging characteristics. The improvements in radiation collection and photomultiplier tube packing density are gained by a combination of several features including: tapering the edges of the faceplate so that the faceplate subtends an area as large or larger than any other cross-sectional area of the photomultiplier tube; forming the junction between the faceplate and metal tube on the underside of the faceplate, and in such a manner as to avoid obscuring the optical path between the incident radiation and photocathode; and utilizing the tapered edge of the faceplate as a reflector to couple radiation incident on the periphery of the faceplate to the photocathode.

Abstract: A detector for a coaxial bipolar time-of-flight mass spectrometer is described. The detector includes a microchannel plate, a scintillator disposed in parallel relation to said microchannel plate, and a mirror oriented at an angle relative to said scintillator. The angle of the mirror is selected to reflect photons given off by the scintillator in a direction substantially orthogonal to the scintillator. The microchannel plate, the scintillator, and the mirror each have an opening formed centrally therein. The detector according to this aspect of the invention also includes a transparent tube extending through the central openings formed in each of the microchannel plate, the scintillator, and the mirror. A photomultiplier tube is coupled to the detector for receiving photons reflected by the mirror. A coaxial bipolar time-of-flight mass spectrometer incorporating the detector is also described.

Abstract: A gating circuit switches the responsivity of a photomultiplier tube between ON and OFF states by modulating the voltage bias of the one or more of its electrodes. The gating circuit capacitively couples a voltage pulse to the photocathode or other electrode of the photomultiplier tube in response to a low-voltage gating triggering signal. The voltage divider network and high-voltage power supply used to statically bias the photomultiplier tube also power the gating circuitry and source the gating voltage pulse, thus circumventing the need for a separate high-voltage power supply. The gating circuit represents a near-inconsequential burden on the power supply, as it draws practically negligible current from the voltage divider network. The electrode gating pulse characteristics, including rise- and fall-times, voltage swing amplitude and duration, can be modified by adjusting resistor and capacitor values and Zener diode characteristics of the gating circuit and voltage divider network.

Abstract: An ion mobility spectrometer is described in which the reaction-ionization chamber and/or the ion drift chamber are constructed with one or more single-piece glass tubes. The inner surface of the tube is rendered electrically conductive by thermal and/or chemical treatment thereof. The glass tube(s) are used in place of the stack assemblies of metal and ceramic annular components that typically used in such devices. The use of the glass tube(s) provides a significant reduction in the number of parts used in such spectrometers, simplification in their manufacture, and improvements in their performance and reliability.

Abstract: A means of neutralizing the excess charge on workpieces, such as semiconductor wafers, that results from ion-implantation processes, wherein the excess positive charge on a small area of the workpiece surface is locally sensed, and in response, an appropriate dose of charge-compensating electrons is delivered from an electron emission source to the area of excess charge on the workpiece. A charge-sensing probe and a voltage-controlled electron generator array are configurationally and operatively coupled in a closed feedback loop, and are made to scan the surface of the workpiece, in close but non-contacting proximity to the workpiece. Arrays of charge-sensing probes and electron generator arrays can be configured for rapid coverage of the implanted areas of the workpiece. The present invention has significant advantages over other methods, such as plasma and electron showers and plasma flood systems, for neutralizing the excess charge due to ion implantation.

Abstract: A replaceable, electronically-isolated, MCP-based spectrometer detector cartridge with enhanced sensitivity is disclosed. A coating on the MCP that enhances the secondary electron emissivity characteristics of the MCP is selected from aluminum oxide (Al2O3), magnesium oxide (MgO), tin oxide (SnO2), quartz (SiO2), barium flouride (BaF2), rubidium tin (Rb3Sn), berrylium oxide (BeO), diamond and combinations thereof. A mass detector is electro-optically isolated the from a charge collector with a method of detecting a particle including accelerating the particle with a voltage, converting the particle into a multiplicity of electrons and converting the multiplicity of electrons into a multiplicity of photons. The photons then are converted back into electrons which are summed into a charge pulse. A detector also is provided.

Abstract: A voltage divider network in combination with a voltage multiplier circuit voltage biases the electrodes of a photomultiplier tubes or related device. The circuit exploits the several voltage levels produced at successive stages of a voltage multiplier circuit in order to optimize the voltage divider network with respect to power consumption, current draw from the power supply, operating stability, and linear operation of the photomultiplier tube.

Abstract: A replaceable, electronically-isolated, MCP-based spectrometer detector cartridge with enhanced sensitivity is disclosed. A mass detector is electro-optically isolated from a charge collector with an electron multiplier for converting a charged particle into a multiplicity of electrons and a scintillator for converting the multiplicity of electrons into a multiplicity of photons. A light sensor is provided to convert the multiplicity of photons back into electrons which are summed into a charge pulse. The light sensor is realized by any of a plurality of photo-responsive devices.

Abstract: An electron-emitting photocathode includes a base and a large number of projecting elements such as microscopic wires projecting from a surface of the base. The photocathode has high quantum efficiency, and hence can be used as the emitting element in a sensitive phototube.

Abstract: An electron-emitting photocathode includes a base and a large number of projecting elements such as microscopic wires projecting from a surface of the base. The photocathode has high quantum efficiency, and hence can be used as the emitting element in a sensitive phototube.

Abstract: A replaceable, electronically-isolated, MCP-based spectrometer detector cartridge with enhanced sensitivity is disclosed. A coating on the MCP that enhances the secondary electron emissivity characteristics of the MCP is selected from aluminum oxide (Al2O3), magnesium oxide (MgO), tin oxide (SnO2), quartz (SiO2), barium fluoride (BaF2), rubidium tin (Rb3Sn), beryllium oxide (BeO), diamond and combinations thereof A mass detector is electro-optically isolated the from a charge collector with a method of detecting a particle including accelerating the particle with a voltage, converting the particle into a multiplicity of electrons and converting the multiplicity of electrons into a multiplicity of photons. The photons then are converted back into electrons which are summed into a charge pulse. A detector also is provided.

Abstract: An electron-emitting photocathode includes a base and a large number of projecting elements such as microscopic wires projecting from a surface of the base. The photocathode has high quantum efficiency, and hence can be used as the emitting element in a sensitive phototube.

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: An electron flux amplifier is provided wherein a microchannel plate (MCP) is monolithically formed with, or bonded to, a semiconductor amplifier. In a preferred embodiment, microchannels are formed to extend into a semiconductor substrate to a predetermined depth from the surface, and a collection diode is formed in the substrate beneath the channels. The collection diode may comprise a single planar diode, or a plurality of electrically isolated diodes to provide for imaging of the electron flux. The electron flux amplifier may be used as a detector in a photomultiplier tube (PMT) having a photoelectronically responsive input surface and one or more accelerating electrodes for directing a photoelectron flux toward the electron flux amplifier.