Abstract: In a stator assembly for a turbomolecular pump, each stator is assembled from two semicircular portions mutually aligned and secured in place by tongue and grooves means, each such stator including a plurality of radially directed blades connecting an inner circular edge and outer circular edge of the stator, such edges occupying respective parallel displaced planes. The outer edge of each stator includes regularly outward projected tabs which bear between spacer rings to maintain axial alignment.

Abstract: An improved metal center rotating anode x-ray tube is shown. The improved x-ray tube includes means for preventing the build-up of charge on the anode glass portion of the tube envelope where the glass flares by constraining the equipotential lines of the electric field in the vicinity of th eflare to parallel the flare surface. Parallelism may be achieved by (1) controlling the angle of the flare and sealing the flare directly to the metal section, (2) modifying the anode rotor to include a flare conforming to the glass flare, and (3) including a ground plane screen in the tube housing.

Abstract: Methods and apparatus for neutralization of a workpiece such as a semiconductor wafer in a system wherein a beam of positive ions is applied to the workpiece. The apparatus includes an electron source for generating an electron beam and a magnetic assembly for generating a magnetic field for guiding the electron beam to the workpiece. The electron beam path preferably includes a first section between the electron source and the ion beam and a second section which is coincident with the ion beam. The magnetic assembly generates an axial component of magnetic field along the electron beam path. The magnetic assembly also generates a transverse component of the magnetic field in an elbow region between the first and second sections of the electron beam path. The electron source preferably includes a large area lanthanum hexaboride cathode and an extraction grid positioned in close proximity to the cathode.

Abstract: Remote measurement of temperature of a process chamber provided with a substrate exhibiting a temperature dependent band gap which substrate is illuminated by a source of continuous spectrum light with a spectrum which overlaps the band gap edge of the substrate. The light which exits the substrate is focused by a lens and is picked up by a fiber optic which takes it to a spectrometer where the spectrum is analyzed to ascertain the intensity versus wavelength histograph for exit rays in the wavelength region of the equivalent band gap of the substrate. The wavelength at the point of infection in the region of band gap edge of the substrate in the histograph of the wavelength versus intensity characteristic of exit rays determines the real time substrate temperature from predetermined calibration data which correlates the wavelength at the point of inflection to actual temperature of the substrates.

Abstract: The detector of the present invention is suitable for use in a radiation therapy simulator machine. The detector comprises an X-ray image intensifier tube to convert X-rays into photons, a linear array of photodiodes to convert the photons to electrical signals, optical means for coupling the photons to the linear array of photodiodes, and electronic signal processing means for conditioning the signals from the photodiodes. The conditioning includes the use of low noise, phaselocked sampling electronics, implementation of a dual sampling technique for increasing dynamic range, implementation of a linearizing technique for increasing the accuracy of the measurements, and implementation of techniques for adjusting the measurements for point spread and background noise effects.

Abstract: The method for improving sample concentration in capillary electrophoresis by extracting the sample buffer from the capillary column using the electro-osmotic flow while the sample components are stacked into the support buffer utilizes a system for this technique. The system has a separation column 11, sample introduction means 16 for injecting the sample solution, an injection detector means 20 for detecting the volume of injected sample solution, a separation detector means 21 for detecting the sample components, power supply means 17 for applying a high voltage along the separation column 11 for reversing the direction of the electro-osmotic flow thereby causing extraction of the sample buffer from the separation column and afterward providing the separation sample into its components.

Abstract: A matrix modifier of finely-divided metallic palladium dispersed to contact a metal constituent to improve analysis of the constituent during graphite furnace atomic absorption spectroscopy. The palladium interacts with a variety of metals in a sample to increase the vaporization temperatures of the metals. One way of contacting palladium with the metal analyte is to introduce it as a salt in solution with the sample into the graphite furnace along with a surfactant. A finely-divided metallic palladium having high surface area is produced in the furnace by introduction of hydrogen gas, which acts as a reducing agent, to reduce and maintain palladium in its metallic form at an early point in the temperature program, prior to evaporation of the surfactant.

Abstract: A wafer handler arm conveys a wafer from a horizontal orientation to a vertical orientation for wafer processing. The arm includes a wafer holding member which is rigidly attached to a first shaft. The first shaft is rotatable about its longitudinal axis and the first shaft is rotatable about a second axis perpendicular to the first axis.

Abstract: A receiver protector device includes a sealed discharge chamber containing one or more pairs of spaced-apart, conical electrodes and an ionizable gas. A field emission array is mounted in the discharge chamber to provide a source of free electrons which assist in initiating a discharge when an RF input signal exceeds a desired threshold power level. The field emission array includes a substrate, a plurality of generally conical emitters distributed on the substrate, a conductive gate layer for extracting electrons from the emitters and a dielectric layer between the gate layer and the substrate. When a bias voltage is applied to the gate layer, electrons are extracted from the emitters. The field emission array can be mounted adjacent to the electrodes or in a recess in one of the electrodes. The bias voltage can be supplied by a battery mounted on the receiver protector device external to the discharge chamber.

Abstract: An improved electroinjection method of introducing a sample having positive and negative ions into a capillary column for CE or CZE process by introducing a short plug of a low concentration buffer before introducing the sample into the column which results in increasing amount of charged ions of the sample introduced in the capillary column due to increasing the electric field at the injection point. A method for efficiently introducing both positive and negative ions is also shown.

Abstract: A method for producing an ion beam for ion implantation by chemically enhanced bombardment of solids. The method is carried out in a reaction chamber having an anode and cathode and a cathode liner rich in a selected element, namely boron, arsenic, phosphorus or antimony. A non-poisonous feed gas is introduced into the reaction chamber and energy is supplied to the feed gas to generate a plasma in the reaction chamber. The constituents of the plasma react chemically with the selected element in the cathode liner and an electrical potential is established between the anode and the cathode so that ions in the plasma bombard the cathode liner. The chemical reaction and bombardment together generate an ion species in the plasma containing the selected element. A beam of ions containing the selected species is then extracted from the plasma.

Abstract: A photoionization detector for detecting effluents from a gas chromatographic column has a microwave induced helium plasma as the photon source. Since the source plasma may be at atmospheric pressure and need not be sealed, energy loss due to transmission of photons through a window can be eliminated. Use of alternating electromagnetic fields instead of a direct current discharge obviates the problems of anode sputtering.

Abstract: A pulse forming network or capacitor load is charged to a precise voltage from an energy storing device with a circuit including a transformer having a primary connected in series with a switch and storage device and a secondary connected in series with the load and a monitor circuit. The monitor circuit develops an output signal indicative of the load voltage and current. In response to the output signal increasing to a predetermined value the switch is opened. The transformer, having a substantial leakage inductance, releases its stored energy when the switch is opened. The transformer stored energy is coupled to the load and to a capacitor connected to the primary. Charge stored in the capacitor after the load requirements have been satisfied is transferred back to the energy storage device.

Abstract: A spectroscopic plasma torch suitable for use at atmospheric pressure is disclosed. The torch utilizes a microwave induced helium plasma confined in a plasma discharge tube. The plasma is suspended and stabilized by a vortex flow of helium. The torch includes a high velocity gas jet for introducing sample materials into the plasma. The design avoids the formation of carbon deposits in the plasma discharge tube caused by the premature pyrolysis of organic materials outside the plasma and prevents other sample materials from being adsorbed on the surface of the plasma tube. Because of these characteristics, the torch is particularly well suited for use as a component in a gas chromatography detector which employs helium as the plasma support gas.

Abstract: An apparatus and method for switching unpolarized light are provided. The apparatus includes GaInAs/GaAs optical switching devices which can be fabricated using conventional processes on a single wafer in matrix arrangement to provide an n.times.m cross bar switch. Switching is accomplished by shifting the band gap of the GaInAs material of a device using electrical or optical power to heat the material. Each switching device may comprise two-polarity (n/p) or single polarity (n or p) semiconductor materials.

Abstract: Information on radiation dosage from segmented ionization chambers can be incomplete due to the existence of insensitive regions of the chamber. By measuring the total current to the high voltage power supply, the total ionization current including that in the insensitive areas can be estimated, thereby providing a measure of the dosage to the insensitive areas.

Abstract: A liquid nitrogen Dewar includes a spun can for the liquid nitrogen, which spun can is surrounded by an exterior shell. Between the exterior shell and the can is an evacuated space containing a second shell that functions as a radiation shield. The can and both shells are formed of an aluminum alloy having a very high percentage of aluminum. The exterior can surface, interior surface of the exterior shell, and both surfaces of the second shell have clean, non-pitted, smooth, matted, smut free and etched appearances free from discoloration and stains so that these surfaces have low radiation emissivity properties and there is a minimum amount of radiant energy transmitted from the exterior shell to the can and reduced heating of the liquid nitrogen in the can. Each of the surfaces is initially polished, either mechanically, electrochemically or chemically, and then chemically treated with an etchant of nitric acid and hydrofluoric acid for a sufficient duration to achieve the desired appearance.

Abstract: A band selector for a klystron includes a cam carrier and a plurality of cam followers. The cam carrier includes a plurality of cams with the cams being arranged in a plurality of rows. Each of the cam followers has a first end adapted to be mounted to a respective one of the plungers in the klystron and a second end. The cam carrier is positionable so that a selected one of the rows aligns with the cam followers. The cam followers are normally biased so that the second end of the cam followers abuts a respective one of the cams. The band selector further includes a first member movable between a first position and a second position. When the first member is in the first position, it is non-interactive with the cam followers. When the first member is moved to its second position, it becomes engageable with the first end of each of the cam followers to remove the second end of the cam followers from abutment with the respective one of the cams.

Abstract: A device for releaseably holding a workpiece includes a resilient collet which is attached to a base by an elastomeric member. Typically, the collet is an annular ring. Several fingers for holding the workpiece extend from the collet. The fingers are pivoted by actuating a member which elastically deforms the collet and causes the fingers to pivot from a position for engaging the workpiece to a position for releasing the workpiece and vice-versa. In one application, the base is a platen for supporting a wafer in a semiconductor processing system, and a plurality of the holding devices are arranged around the periphery of a rotating disk. A counterweight ring is attached to the collet to counterbalance the moment generated by the centrifugal force of the wafer pressing against the fingers as the disk is rotated.

Abstract: The collector in a linear-beam electron tube is insulated from its heat sink so that it can be operated at a depressed potential. The insulation comprises two bands of dielectric sequentially in contact between the collector and heat sink. The intervening space is sealed off and preferably filled with a dielectric fluid to improve heat transfer and inhibit voltage breakdown. Gaps in one band are preferably aligned with solid parts of the other to reduce electric leakage.