Abstract: A gun for generating a multiple sheet beams 50 of electrons has a flat surfaced cathode 10 with parallel protruding ridges 12 of non-emitting material forming parallel focus electrodes for the sheet beamlets. A control grid of parallel bars 14 is aligned with the ridges 12 to reduce grid interruption. The beamlets may be focussed between support bars 54 of a foil anode 52 for passing the beam into a high-pressure volume such as a gas laser 48. The ridges are formed by inserting non-emissive bent sheets into grooves 58 in the cathode, which are dovetailed to hold them.

Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: In a radiation therapy machine it is desirable to produce irregular radiation field shapes in order to shield critical organs not invaded by the tumor. A multileaf collimator is formed of a multiplicity of heavy metal bar leaves driven relative to frames which are driven relative to jaws of a rectangular field collimator by electric motors and flexible cables.

Abstract: A power supply for helix and collector electrodes of a traveling wave tube is driven by an AC power source having a frequency of at least 500 KHz. The helix supply includes plural, stacked voltage double AC to DC modules responsive to the 500 KHz source. The collector supply includes plural AC to DC modules, each having a diode full wave rectifier bridge, connected in stacked relation. Each of the modules includes a transformer with a ferrite, toroidal core dimensioned so that it is not driven into saturation by the 500 KHz source. Each module also includes inexpensive, signal switching diodes having a recovery time of approximately 4 nanoseconds. The ratio of the collector to helix DC voltages is maintained constant by threading a common lead through the apertures of the toroidal cores of the helix and collector modules. A separate common lead threaded through the apertures of the toroidal cores in the collector modules is connected directly to the 500 KHz power source.

Abstract: A slow-wave circuit for a TWT has periodic transverse plates extending across the axial by extending vacuum envelope. An opposed pair of apertures 24, 26 in each plate 20 couple adjacent cavities 28 between plates 20. Coupling apertures 24 in alternate plates 20 are rotated transverse to apertures 26 in the other plates to provide coupling only between adjacent cavities 28. Each plate 20 has transverse ridges 30 enclosing its axial beam aperture 22. The ridges 30 are orthogonal to the coupling apertures 24, 26 to increase beam coupling and decrease capacitance for wider bandwidth and higher impedance.

Abstract: An apparatus for planarizing an aluminum layer on a semiconductor wafer includes two deposition sources. The first source applies a refractory metal silicide layer to form a barrier to oxygen. The wafer is moved to a second deposition source which is an aluminum sputter device including a heater for the wafer, R.F. bias on the wafer and a magnetic mirror behind the wafer to move the plasma away from the wafer.

Abstract: Refractory metals or ceramics are diffusion bonded or densified by assembling the workpieces to be bonded, wrapping the assembly with carbon yarn, heating the wrapped assembly, cooling the assembly and unwrapping. The expansion of the workpieces together with the shrinking of the carbon yarn produces tremendous pressures which cause bonding and densifying of the workpiece.

Abstract: The invention relates to the functionalization of particulate bonded phase chromatographic supports prepared by silanization of silica gel or controlled pore glass and containing pendant primary alkyl amine groups. Functionalization results from the activation of the amines by reaction with N,N'-carbonyldiimidazole (CDI), or a related azolide, in anhydrous organic solvent, followed by derivatization of the support. Derivatization results from reaction of the activated support with a functionalizing reagent consisting of a primary or secondary, alkyl or aryl amine in organic solvent, or from an aqueous solution of the amine or its salt. A urea linkage results through which the functionalizing reagent is covalently attached to the support. Derivatization can result from the addition of an excess of a single reagent, or as a consequence of the sequential addition of two or more functionalizing reagents.

Abstract: An NMR probe comprises a pair of capacitively coupled inductive members forming a first circuit resonant to a relatively high rf signal and also forming a portion of a second tuned circuit resonant at a relatively low rf signal, the entire circuit balanced to define a virtual ground in said circuit portions and relative isolation of low and high frequency sources achieved with transmission line elements.

Abstract: Thermal transfer between a semiconductor wafer and a platen during vacuum processing is provided through a soft, thermally-conductive polymer layer having a thin, hard surface film. The soft polymer layer, which is preferably silicone rubber containing thermally-conductive particles, conforms to surface irregularities on the wafer and has low thermal resistance. The surface film is preferably silicon dioxide in the form of a multiplicity of flat plates integrally formed on the silicone rubber. Adherence of the wafer and of foreign matter to the polymer layer is prevented by the surface film. In addition, the underlying polymer layer is protected by the surface film. A high purity polymer layer is fabricated by evacuating the mold cavity and the resin container prior to injection of resin. The mold for the polymer layer utilizes a hard, smooth mold release surface and a resilient gasket between the platen and the mold release surface.

Abstract: A DC power supply for a traveling wave tube having cathode, collector and helix electrodes responds to a DC power source and a high frequency switching source. A switch controlled by the switching source is opened and closed at a fixed frequency and variable duty cycle determined by the helix-cathode voltage. A flyback choke is connected to the switch and DC power supply so current flows between the power source via the choke to the switch and a series resonant circuit while the switch is closed. First and second capacitors in separate branch circuits of the resonant circuit are respectively connected to first and second AC to DC converter and voltage multiplier stacks; each multiplier in the stacks includes a pair of branches with oppositely poled plural signal switching diodes and a capacitor. The cathode and helix are respectively connected to output terminals of the first and second stacks, while the collector is connected to a terminal between the first and second stacks.

Abstract: A device for releaseably holding a workpiece includes a resilient collet which is pivotally attached to a base. 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 such platens and a corresponding plurality of the holding devices are arranged around the periphery of the disk. A counterweight ring is attached to the ring-shaped collet to counter-balance the moment generated by the centrifugal force of the wafer pressing against the fingers as the disk is rotated.

Abstract: A light source with appropriate optics focusses light on the wafer surface during deposition, while a nearby collector is biased to collect photoemitted electrons from the growing surface. A pico ammeter can be used to convert the small oscillatory current detected to a substantial voltage signal which can be recorded or processed by computer or other sutiable device. The light must contain wavelengths at energies close to or greater than the energy of the photoemission threshold. The detected photoemitted electron signal has an oscillatory component occurring due to the growth of epitaxial layers. This oscillation has frequency 1/.tau., where .tau. is the monolayer accumulation time.

Abstract: A pair of coupled surface coils are arranged to provide active detuning whereby the shape of the RF field due to the RF current in one coil is modified in a calibrated fashion by the RF current in the second coil whereby a selected fraction of the RF field of one coil may be selectively added or substracted from the RF field of the one other coil thereby shaping the RF field.

Abstract: A method of mapping implanted ion dose uniformity is disclosed in which wafers of polysilicon-on-silicon or polysilicon-on-oxidized-silicon are implanted with the ion dose to be mapped and then scanned in a spectrophotmeter using monochromatic radiation. An interference spectral technique is used to achieve improved sensitivity while preserving thermal and electrical properties close to those of actual devices.

Abstract: An NMR sample spinner comprises first rotational torque means to impart a first rotation to a sample rotor and a second rotational torque means for applying a rotational torque of selected magnitude opposite that applied by said first rotational torque means, whereby positive rotational rate control is more precisely and rapidly realized, sense of rotation is controlled, and undesired rotational torque may be compensated.

Abstract: A method and apparatus for exciting slices of an object in an NMR device in a specific order. N slices are indexed from 0 to (N-1). An integer X relatively prime to N is selected and the finite sequence I.sub.0 +kX, k+0, . . . , (N-1) is generated where I.sub.0 is a selected integer. The least positive residue r.sub.k satisfying r.sub.k .ident.I.sub.0 +kX(Mod N) is calculated and then the slice S.sub.r.sbsb.k is excited before the slice S.sub.r.sbsb.(k+1) for k=0, . . . , (N-2). The method and apparatus disclosed ensures that slices are excited in an order which reduces the resonant signal contamination present in a slice from the excitation of previously excited slices.

Abstract: In a chemical vapor deposition apparatus for coating semiconductor wafers, the wafer is held face down in the reaction chamber. A radiant heat source above the wafer and outside the reaction chamber. The wafer is held on a ring chuck by means of a retractable clamp heats the wafer from its backside to a temperature in excess of 1000.degree. C. rapidly. The radiant heat source includes cylindrical lamps placed in a radial pattern to improve heating uniformity. In the selective tungsten process the temperature of the wafer is raised from ambient to about 600.degree. C. while flowing process gases. At the upper temperature range the heating source can be rapidly cycled on and off to improve the uniformity of coating.

Abstract: A high-intensity X-ray source generates significant heat at the anode. To help dissipate this heat, the anode is often rotated in the vacuum. Heat must still be radiated from the anode to the exterior walls. An improved X-ray source incorporates the anode in the walls of the vacuum chamber and rotates the entire chamber. The heat is then easily conducted to the exterior where it may be dissipated by connection or forced air cooling.

Abstract: The invention is a method of manufacture of a cylndrical electrode such as a thermionic cathode comprising an array of helical filaments. The method comprises the step of placing the array, attached to its support electrodes which are fixedly mounted to a common subassembly support, inside a close-fitting refractory dielectric cylinder and heating the filament assembly by passing current through the filaments. The filament assembly expands to contact the form. On further heating it is plastically deformed to form a perfect cylindrical shape. After cooling and shrinking, it is removed from the form.