Abstract: A method of increasing ion source lifetime in an ion implantation system uses the introduction of an inert gas, such as argon or xenon, into the halide-containing source gas. Inert gas constituents have a cleansing effect in the plasma ambient by enhancing sputtering.

Abstract: An apparatus and method of forming a radioactive stent having a radioactive layer. A solution containing a radioactive isotope depositing substance in solution is provided and placed into contact with the stent or any other substrate material capable of receiving the radioactive isotope. The radioactive isotope is deposited on the stent or substrate material. Preferably a phosphorous isotope is used and the solution is polymerized forming polymer chains containing the radioactive isotope. In this embodiment, the phosphorous is bonded with the substrate material in a phosphorous-oxygen-phosphorous network.

Abstract: An inversion pulse for wideband application is obtained from a simple nonlinear amplitude modulation wherein the amplitude is modulated in accord with A(t)=A.sub.0 {1-.vertline. sin .beta.t.vertline..sup.n } and the entire pulse is frequency modulated such that the phase varies as .phi.(t)=.phi..sub.0 +1/2 kt.sup.2.

Abstract: Longitudinally collapsible apparatus for compacting packing material within a tubular liquid chromatography column. The apparatus includes a first support member, a second support member and a movable support member. The movable support member is releasably connectable to the second support member for support thereby. When released from the second support member, the movable member is adapted to ride on guide members extending between the first and second support members. A compression mechanism is supported on the movable support member to move therewith to a longitudinally collapsed position for the apparatus. The compression mechanism comprises a reversible drive for an axially movable rod carrying a movable piston. With the movable support member secured to the second support member, the piston of the compression mechanism is movable in an end of the tubular column when the column is supported on the first support member.

Abstract: The present invention relates to a rotor of a vacuum pump comprising a rotatable shaft and a plurality of spaced apart parallel rotor disks secured to said rotatable shaft, such rotor being provided with a corrosion-resistant protective coating formed by a layer of polymeric material.

Abstract: A signal sampling circuit for performing correlated double sampling (CDS) of an input signal with a pipelined sample and hold architecture includes a time multiplexed integrating amplifier circuit in which the output circuit is a pipelined sample and hold circuit which provides time multiplexed input signal samples and the feedback integration capacitor is discharged between samples. At all times, one of the channels of the pipelined sample and hold circuit is providing one of the time multiplexed input signal samples while the other channel continues tracking the input signal. The feedback integration capacitor acts as a clamp to null out residual reset noise received as part of the input signal to be sampled. Hence, with the exception of that very brief period of time necessary for switching between the two pipelined sample and hold circuit channels, one of the two pipelined sample and hold circuit channels is always available for signal acquisition.

Abstract: A gas flow distribution system accumulates a sample from a sample bearing carrier gas in a micro-accumulator, delivers it using a carrier gas to a gas chromatography column, and supplies a carrier gas to the gas chromatography column to facilitate separation of the sample into sample components and transport the sample components to a mass spectrometer for trace vapor detection and analysis or testing in real time. The system is made of inert components and configured to have low dead volume for improved performance and accuracy of detection. External valves are employed for easy management and balance of the flow in the system to minimize operation time and facilitate continuous accumulation, delivery, and testing of the sample. The delivery of the sample to the gas chromatography column using an electrically heated cold trap as the micro-accumulator can be performed extremely fast.

Abstract: Observation of transient phenomena in an oversampled regime is implemented with a time correction obtained by prepending one or more pseudo datums to the oversampled data to constitute an effective negative delay for the oversampled data set including the pseudo datums. For an oversampling factor N and oversampling rate .omega..sub.s, a digital filter furnishes downsampled data uniformly spaced in time by N/.omega..sub.s and positioned at n (N/.omega..sub.s) where n is the discrete downsampled time coordinate.

Abstract: A three-piece NMR detection cell comprises an inlet tube having a conically, tapered outlet nozzle, leading to an analysis tube, in turn leading to an outlet tube having a conically tapered inlet nozzle. The inlet and outlet tubes are inserted into the analysis tube at a distance from their inserted ends and sealed in a manner appropriate to their composition. When the detection cell is used in a coupled HPLC-NMR apparatus, increased NMR sensitivity and improved lineshape are obtained at low injection volumes while maintaining a low level of chromatographic band broadening and a high level of magnetic field homogeneity.

Abstract: A fluid handling apparatus, particularly a vacuum pump, has as a first stage a high volumetric displacement rate scroll pump of multiple nested interacting pairs of fixed and movable spiral-shaped blades supported in a housing between an inlet and an outlet. Each adjacent blade pair closes one inter-blade pocket in each cycle of operation. For very low base pressure vacuum applications, the adjacent blades extend about two revolutions to produce plural pockets in series. A second scroll pump mounted in the housing has its inlet fed directly from the first scroll outlet. The second scroll has a single pair of co-acting fixed and movable blades with multiple revolutions. A central drive shaft rotating in main bearings has an eccentric portion coupled to a plate that carries the movable blades of both scroll pumps. Synchronization cranks constrain the plate to orbit, not rotate. A purge gas flows over the crank bearings to sweep away and/or dilute corrosive fluids.

Abstract: Improved solvent suppression in NMR data is achieved using pulse sequences wherein each of a series of selective excitation pulses are followed by a magnetic gradient pulse and a delay, where the magnetic gradient pulse amplitudes monotonically decrease by a selected fraction of the preceeding gradient pulse. Decoupling a second nucleus during selective excitation pulses has been shown to be efficacious for suppression of organic solvents.

Abstract: A method and apparatus for superimposing a plurality of electron beams at a desired location after X-ray tube manufacturing processes are generally complete. The method is embodied in providing mechanical and electrical means which are internal to the X-ray tube which provide means for adjustment of a focal point of a plurality of electron beams being emitted from a cathode assembly to thereby provide precise control of where the plurality of electron beams achieve superimposition on a target anode.

Abstract: An inductively coupled plasma spectrometer including shielding/sampling means (1) located between a plasma torch (3) and an optical system (4) of the spectrometer, wherein said shielding/sampling (1) means is associated with an enclosure (9) for the plasma torch such that a relatively high independance path (10, 11) is established for limiting flow of electrical current between said shielding/sampling means (1) and said enclosure (9).

Abstract: A rotatable assembly for supporting the rotor of a vacuum pump with a plurality of gas pumping stages formed by cooperating rotor discs secured to the rotor and stator rings integral with a body, comprising rotatable means for supporting the shaft of the rotor that are housed within this shaft.

Abstract: A gas flow distribution system accumulates a sample from a sample bearing carrier gas in a micro-accumulator, delivers it using a carrier gas to a gas chromatography column, and supplies a carrier gas to the gas chromatography column to facilitate separation of the sample into sample components and transport the sample components to a mass spectrometer for trace vapor detection and analysis or testing in real time. The system is made of inert components and configured to have low dead volume for improved performance and accuracy of detection. External valves are employed for easy management and balance of the flow in the system to minimize operation time and facilitate continuous accumulation, delivery, and testing of the sample. The delivery of the sample to the gas chromatography column using an electrically heated cold trap as the micro-accumulator can be performed extremely fast.

Abstract: A rotating anode X-ray target has a matrix structure such as a carbon-carbon matrix and a high Z material imbedded inside this matrix structure. The high Z material may be a refractory metal with atomic number at least 72, its alloy or carbide and may be imbedded in the matrix either as discrete particles or as a non-discrete layer. Such a target can be made by any of a number of known methods such as chemical vapor deposition and chemical vapor infiltration. Without a TZM layer or a braze required for holding together an x-ray-producing surface layer and a carbon heat storage material, the target can be made lighter and can be operated at higher temperatures.

Abstract: A flat workpiece is placed in contact with a flat platen in a vacuum chamber, and is held by a uniformly-distributed force while a small mass flow of gas is introduced along a contour to form a uniform pressure region between the flat workpiece and the platen. Separation of the two surfaces due to aplanarity or surface roughness is less than the gas mean free path, and high rates of heat transfer are obtained uniformly over the area of the workpiece. A scavenging port, located outwardly of the gas introduction contour is differentially pumped to reduce the rate of gas leakage into the chamber. Preferably, pressure is provided by an electrostatic clamp (for non-insulating substrates) or other clamping arrangement which does not occlude the front surface of the workpiece. In the electrostatic clamp, the voltage activation sequence prevents workpiece vibration, while a clamping current sensor immediately detects degree of contact, e.g., due to debris on the platen, and initiates a suitable warning or control.

Abstract: A symmetric RF coil for use in a probe for NMR apparatus comprises an odd number of turns having generally straight portions and arc-shaped portions wound alternately in series on the curved surface of a cylindrical sample region. An additional pair of arc-shaped segments connect to the outermost turn to form continuous end rings, and to split the current on the outermost turn to the continuous end rings. Such an RF probe coil possesses material symmetry provided by the additional arc-shaped segments and RF symmetry as a result of the symmetry in current flow generated by the split in current of the outermost turn to the continuous end rings. The symmetric odd-turn RF coil achieves NMR performance at the same level of even-turn coils with high RF homogeneity, and is suitable for high resolution NMR applications. The coil inductance of the present invention bridges the gap between even-turn coils, and facilitates improved optimization of the resonance circuits over the entire operating range.

Abstract: A mass spectrometer system for performing a separation of ions from neutrals and mass analyzing ions comprising a inductively coupled plasma ion generating source with an ion introducing system, a radio-frequently ion guide and a mass analyzer disposed within a vacuum chamber. The space between the radio-frequency ion guide and the ion introduction system defined an aerodynamic jet region which is used for directing a sample containing ions to be analyzed to the entrance of a radio-frequency ion guide and the via the radio-frequency ion guide to the mass analyzer.

Abstract: An accessory has a fixed member and a rotatably supported and eccentrically mounted disk which are each inserted into a corresponding one of a pair of crescent-shaped indentations formed on a panel of a couch top. As the disk is rotated, its center moves towards the fixed member, causing the disk to press against the inner wall of the indentation and locking the accessory to the panel securely and repeatably.