Abstract: A high vacuum pump comprising an in-line connection on a single drive shaft of an axial turbomolecular compressor and a peripheral compressor where the pump provides better than 10.sup.-7 Pascal inlet when exhausting to atmosphere. The peripheral compressor has a two stage optimized Gaede design which encloses the impellers in a shroud reducing the top and bottom volume surrounding the impellers and providing a large separation pressure drop region between stages of said peripheral compressors to reduce axial leakage.

Abstract: For reduction of noise in proton resonance measurements, high voltage RF capacitors in the NMR probe comprised a fluorinated oil or grease dielectric.

Abstract: A reagent gas flow control system for use with an ion trap mass spectrometer is shown. The gas reagent gas flows from a source through a first gas flow restrictor connected to the inputs of second and third gas flow restrictors. The output of the second restrictor is connected to the ion trap where reagent gas is used, and the output of the third restrictor is connected to a vacuum pump, which may be the roughing pump used by the ion trap. At least one of the three restrictors is a variable restrictor. The configuration of the present invention allows the use of simple and inexpensive parts to provide exacting flow control.

Abstract: On-column optical detection apparatus and method for use with capillary separation columns are shown. The apparatus and method minimize the adverse effects of light scattered from the walls of the column, thereby improving detection sensitivity and providing greater dynamic range. Light from a conventional source is focussed onto a column. Spatial filter means are positioned in front of the column to prevent at least some light from striking the column wall. Another spatial filter is positioned in front of a light collecting means which gathers light emanating from the column. In a specific embodiment, a unique monolens design is shown comprising collecting and focussing lens formed as an integral unit with a bore for a capillary column.

Abstract: A high-frequency amplifier tube includes a grid that responds to an r.f. input signal to current modulate a linear electron beam derived from a cathode. A resonant structure establishes an electric field in a region between the grid and cathode. First and second resonant cavities downstream of the grid in the named order are coupled to the modulated electron beam. The first cavity responds to the r.f. signal to velocity modulate the current-modulated beam. The second cavity is coupled to the current- and velocity-modulated beam for deriving an output signal. An AC connection from a source of the input signal is established to transformer coupling in the first cavity. A phase-shift circuit adjusts the relative phase of the modulation on the beam as it passes through the first cavity and the phase of the r.f. signal as coupled to the first cavity so that fields induced in the cavity by the modulated beam are optimally phased with respect to fields established in the first cavity by the transformer coupling.

Abstract: The temperature and radiant energy emissivity of a semiconductor substrate or wafer undergoing processing are monitored by combining indications derived from an interferometer and the intensity of radiant energy emitted from the substrate. The radiant energy intensity is detected at adjacent maxima or minima in the intensity of the interference pattern.

Abstract: A narrow-band pyrometric system measures the temperature of an object (1), such as a semiconductor wafer (1), that is coated with a film (2) having an absorption band. The thermal radiation emitted by the coated object (1) passes through a lens (3) and aperture (4), and then a filter (5). The passband of this filter (5) falls within the absorption band of the film (2). The transmitted radiation is then collected by the radiation detector (6), which measures the intensity. The detected radiation is at a wavelength where the heated object (1) is substantially opaque, and the effect of uncertainties in the emissivity on the temperature measurement is minimized. Thus, a method is provided to coat the object (1) with a film (2) of material having an absorption band encompassing the filter (5) passband, and a thickness sufficiently great that the object (1) appears opaque when viewed through the filter (5).

Abstract: A method for isolating an ion in a QIT (1) employing values from a mass axis calibration chart to establish the maximum DAC value to scan to in order to scan out m(p)-1 and less during ramp up of RF trapping field while applying a specifically selected fixed supplemental frequency applied during said calibration; and employing values from the calibration curve to establish the DAC value to scan out m(p)+1 and greater during ramping down of RF trapping field, while applying a previously determined fixed broadband spectrum to the QIT end caps.

Abstract: A source for sputtering from concentric rings on the surface of a single target is shown. The source comprises a rotatable closed-loop magnet having a plurality of curved sections of different average radius interconnected by a equal number of radial sections. In the preferred embodiment the curved sections each have a shape which results in a predetermined erosion profile in the associated concentric ring of the sputter target. The relative rate of sputtering from each of the rings may be controlled by adjusting the relative lengths of the curved portions of the closed-loop magnet.

Abstract: In inductively coupled plasma spectroscopy, the use of an induction coil assembly comprising at least two helical coils which are arranged in overlapping relationship. In one practical form, the overlap is achieved by interlacing of the coils so that at least one turn of one coil is interposed between two adjacent turns of the other coil. For that purpose, the two coils will ideally be of the same diameter and will be coaxial. A tubular part of a plasma torch is contained within the space surrounded by the coil assembly, and a RF energy source is connected to an end of each coil. The other ends of the coils may be connected to ground.

Abstract: Parasitic excitation of an NMR sample is minimized by providing shielding of the sample against RF pick-up from coil leads or like proximate conductive structure in the interior region of the RF coil.

Abstract: A process for manufacturing impellers of turbine pumps provides for subjecting disks corresponding to the impeller to be obtained to electrical discharge machining, using tools in form of plates provided with radial slits extending along at least an arc of circumference and opening into hollow areas. A combined motion of rotation and translation is imparted to the disks, thus generating twisted blades having a profile with defined geometric characteristics. A one-piece rotor can be manufactured employing open tools with slits formed along a semicircumference, and two passages in succession of the workpiece through the tools, moving the workpiece with a combined motion of rotation and translation. An advantageous application of the articles manufactured by this process is for rotors of turbomolecular pumps, since the compression ratio and the pumping speed are optimized and a considerable structural sturdiness of the article is obtained.

Abstract: In a gyrotron having an annular collector for an expanded e-beam and a gyrotron output waveguide with an annular gap for passing the expanded e-beam is provided with a mode converter between the resonator and the gap to shift more energy to the waveguide central axis to decrease EM field leakage coupling through said gap.

Abstract: A gyrotron microwave output window made of a pair of centrally coupled dielectric disks in which the displacement between the windows is tunable by adjusting means external to the waveguide and in which the window central coupling automatically compensates for such adjustments and for coolant pressure changes.

Abstract: The cross polarization condition for hetero-coupled NMR spectroscopic investigations for a sample spinning at rate .omega..sub.R is improved by causing at least one of the RF excitation channels to emit pulses in synchronous relationship to the sample spinner during the cross polarization contact whereby dependence of the NMR signal on mechanical spin rate .omega..sub.R is reduced.

Abstract: Disclosed is a method for improving the dynamic resolution of an imaging system. The method employs a dual sampling or exposure technique which samples light from an image intensifier over a long and a short sample interval. When the resulting measurement for the long sample interval exceeds a threshold level, the short sample interval measurement is used, multiplied by a scaling factor. Below the threshold the long sample interval is used.

Abstract: An NMR probe employs an adjustable RF voltage divider (C.sub.1, C.sub.2 ') comprising a single capacitive impedance switched into or out of the divider by a single 2-pole switch (SP1', SP2').

Abstract: A high voltage high power DC source includes a magnetic flux pole structure responsive to a high frequency, relatively low voltage source inductively coupled to the pole. Multiple AC to DC converters inductively coupled to the pole are connected in series, stacked relationship with each other, to derive the high voltage, high power DC output. Each stage includes a pair of oppositely wound planar coils on opposite sides of a printed circuit board. The printed circuits of the different stages are displaced from each other and a coil driven by the high frequency source.

Abstract: A multileaf collimator for use in therapeutic radiology treatment systems for producing irregular shaped radiation fields in order to shield normal tissue or critical organs. A multileaf collimator following the present invention includes leaves designed such that the collimator exhibits penumbra which is minimized and generally uniform for positions that are equidistant from the central axis of the radiation field. The shape of each leaf end includes an asymmetric central portion and a flat portion on either side of the central portion. The central portion is designed such that geometric penumbra and transmission penumbra are equalized. The flat portions on either side of the central portion are coincident with a tangent drawn from the edge of the radiation source to a reference plane when the leaf is in the fully retracted or fully extended positions.

Abstract: A rotatable vacuum flange includes a flange ring having a recess, an insert mounted in the recess in the flange ring, the insert including a seal portion and being adapted for vacuum-tight attachment to a vacuum conduit, and a wire spring positioned between the flange ring and the insert. The wire spring retains the insert in the recess in the flange ring and permits rotation of the insert relative to the flange ring. The flange ring and the insert include grooves located in opposing alignment to receive the wire spring.