Abstract: A microwave powered electron cyclotron resonance reactor employing a low pressure, high electron density plasma for rapid oxide etching using hydrogen and argon incorporates an alumina-coated quartz dielectric microwave window to couple microwave energy into an etch chamber while preventing oxygen in the window from contaminating the etch chamber or its contents. The etch chamber side of the dielectric microwave window is coated with alumina.

Abstract: Turbomolecular vacuum pumps having structures which provide increased pumping speed, increased discharge pressure and decreased operating power in comparison with prior art turbomolecular vacuum pumps. In a first embodiment, the staters of one or more axial flow vacuum pumping stages in proximity to the exhaust port of the vacuum pump have progressively lower conductance so that the bulk velocity of the gas being pumped is increased. In a second embodiment, one or more stages near the inlet port of the vacuum pump are provided with a peripheral channel to utilize the centrifugal component of the gas being pumped. In a third embodiment, one or more stages in the vacuum pump are molecular drag stages, each including a disk rotor. One or more pumping channels in the stator adjacent to the upper surface of the disk are connected in series with one or more pumping channels adjacent to the lower surface of the disk.

Abstract: A charge measuring system for determining implantation dose in a PI.sup.3 system with means to compensate for current in the charge sensor which does not arise from positive ions arriving on the wafer.

Abstract: A time-of-flight mass spectrometer includes an ion beam source having a quadrupole ion trap. To form a parallel ion beam, the ions are simultaneously sucked and pulsed out of an interaction region of the trap through an opening in a front end cap electrode of the trap by applying different polarity voltage pulses at the same time to the front end cap electrode and a back end cap electrode of the trap.

Abstract: The present invention relates to improving the sensitivity of an NMR system for electrically conductive (polar) NMR samples. Many NMR samples use water or a salt solution of water or other electrically conductive liquid as a solvent for biologically active materials. When such a sample is placed in the probe coil of an NMR spectrometer, electrical losses in the conductive material lowers the Q of the receiving circuit and thereby reduces the sensitivity of the spectrometer. These electrical losses can be greatly reduced by breaking up the current paths within the sample. This can be achieved by a special sample cell that compartmentalizes the sample with electrical insulating material reducing the electrical current paths.

Abstract: The volume magnetic susceptibility of an NMR probe is established and maintained at a desired value, such as a value characterizing other components of the probe, by a linear combination of partial pressures of respective fluids introduced into the sensitive volume of the probe.

Abstract: Turbomolecular vacuum pumps having structures which provide increased pumping speed, increased discharge pressure and decreased operating power in comparison with prior art turbomolecular vacuum pumps. In a first embodiment, the stators of one or more axial flow vacuum pumping stages in proximity to the exhaust port of the vacuum pump have progressively lower conductance so that the bulk velocity of the gas being pumped is increased. In a second embodiment, one or more stages near the inlet port of the vacuum pump are provided with a peripheral channel to utilize the centrifugal component of the gas being pumped. In a third embodiment, one or more stages in the vacuum pump are molecular drag stages, each including a disk rotor. One or more pumping channels in the stator adjacent to the upper surface of the disk are connected in series with one or more pumping channels adjacent to the lower surface of the disk.

Abstract: Turbomolecular vacuum pumps having structures which provide increased pumping speed, increased discharge pressure and decreased operating power in comparison with prior art turbomolecular vacuum pumps. In a first embodiment, the stators of one or more axial flow vacuum pumping stages in proximity to the exhaust port of the vacuum pump have progressively lower conductance so that the bulk velocity of the gas being pumped is increased. In a second embodiment, one or more stages near the inlet port of the vacuum pump are provided with a peripheral channel to utilize the centrifugal component of the gas being pumped. In a third embodiment, one or more stages in the vacuum pump are molecular drag stages, each including a disk rotor. One or more pumping channels in the stator adjacent to the upper surface of the disk are connected in series with one or more pumping channels adjacent to the lower surface of the disk.

Abstract: A method for automatically controlling a collimated sputtering source that is controllable by a computer to compensate for the build-up of sputtered material on the collimator. The method involves providing software for the computer including a formula to calculate a multiplier as a function of the age of the collimator, sequentially depositing film on a series of substrates using the sputtering source, monitoring the age of the collimator, and using the software to periodically adjust the value of a controllable sputtering parameter as a function of the multiplier. The sputtering parameter is automatically adjusted by the software such that a property of the film deposited by the source on the series of substrates does not substantially vary among the substrates as sputtered material builds up on the collimator.

Abstract: An improved ECD employing an ECD cell having a third electrode, i.e. guard positioned between the ECD cell field electrodes. The guard electrode is physically interposed between said field electrodes to divert all leakage current in the support insulators which flow between the field electrodes. The guard electrode ECD cell provides improved linear dynamic range as well as avoiding deterioration from handling during manufacture or repair.

Abstract: A method of using a quadrupole ion trap mass spectrometer for high resolution mass spectroscopy is disclose. In the preferred embodiment, the space charge in the ion trap is controlled with high accuracy. The mass spectrum to be analyzed is divided into a plurality of contiguous mass segments and each of the segments is separately scanned. To control space charge, a broadband supplemental waveform is applied to the ion trap during the ionization period for each segment, the broadband signal being construct to eliminate all unwanted ions from the ion trap by resonance ejection such that only those ions having masses within the desired mass segment remain in the ion trap. Preferably, the ionization of each mass segment is performed under identical trapping conditions, and the ionization parameters for each segment is adjusted to optimize the space charge in the trap for that particular segment.

Abstract: Apparatus equipped for both megavoltage radiotherapy and a diagnostic X-ray source for portal imaging. Both the high energy therapeutic and low energy diagnostic source of radiation are physically located at the same point in apparatus space, and utilize a single moveable target converter that is physically positioned according to the desired use, either therapy or diagnostics.

Abstract: The present invention refers to a pumping stage particularly designed for turbomolecular pumps, having increased compression ratio, and capable of extending the operating range of the turbomolecular pump towards high pressure. The new pumping stage comprises a casing housing, a rotor disk, and a substantially coplanar stator ring. The stator ring consists of two plates connected with each other along their circumferential periphery, thereby defining a region of close tolerance with the opposite surfaces of the rotor. The rotor and stator cooperate to define a tapered, free annular channel having a suction port and a discharge port at the opposite ends of this channel. The channel tapers in a functional, predetermined fashion, having the largest cross-sectional area near the suction port, and converging, according to the rotational direction of the rotor, at the discharge port.

Abstract: A power efficient selective mass range trap filling process in which the RF trapping voltage connected to the ring electrode is slowly modulated simultaneously with: (1) e-beam ionization bombardment and (2) application of a broadband supplemental waveform containing selected secular frequencies to the QIT end caps. The modulation permits the reduction of the number of frequency components required in the broadband supplemental waveform and permits elimination of absorption by ions of energy from more than one supplemental frequency component at any one time.

Abstract: Apparatus for electrostatic clamping of a semiconductor wafer in a vacuum processing chamber wherein an ion beam is applied to the wafer. In a first embodiment, the apparatus includes an electrically conductive platen, a resilient, thermally-conductive dielectric layer affixed to the platen and one or more conductive wires positioned on the clamping surface. A clamping voltage is applied between the wires and the platen to firmly clamp the wafer against the clamping surface and depress the wires into the resilient dielectric layer. In a second embodiment, a three-phase wafer clamping apparatus includes a platen divided into three electrically isolated sections. One phase of a three-phase clamping voltage is connected to each of the platen sections. In the three-phase configuration, the wafer charging current is very small, and the clamping force is essentially constant. In a third embodiment, a six phase wafer clamping apparatus includes a platen having six symmetrically located electrodes.

Abstract: A spark sampling microparticle generator device and method providing means to first ionize a gap and then to switch a stabilized and controllable current into and out of said ionized gap to provide extremely high, selectable current density in a sample material in said gap with very fast rise and fall times to ablate said material to form microparticles. A plurality of identical modular circuits containing high frequency power transistors are selectably switchably connected in parallel simultaneously to the gap to achieve current densities which are higher than achievable with a single transistor, thereby obtaining the benefits of the high frequency response without being limited by the current limitations of the available transistors.

Abstract: The present invention relates to turbomolecular pumps comprising one or more tangential flow pumping stages in addition to axial flow pumping stages, so as to raise the pump exhaust pressure up to the atmospheric pressure, wherein at least one tangential flow pumping stage having a tangential flow pumping channel of improved design. The channel is located between the lateral surface of the rotor disk and the annular inner wall of stator and comprises an upper closure plate provided with suction port and a lower closure plate provided with diskharge port wherein these ports operably coupled to the tangential flow pumping channel. The cross-section area of the channel is enlarged from its periphery portion defined by the lateral surface of the rotor disk to a central portion defined by the upper and lower closure plates.

Abstract: An improved waveguide window (10) for use in high power waveguide applications. The window (10) preferably includes a thin sheet (12) of dielectric material having a first planar face (14), a second (16) face, and a support structure (18) attached to the first face (14) to provide mechanical support for the sheet (12). The support structure (18) preferably includes a plurality of parallel conductive support bars (20), each bar having an inner portion (22) attached to the first face (14) and an outer portion (24) extending away from the sheet (12), the outer portion (24) being tapered to minimize wave reflection. At least one bar (20) also has a channel (28) bored therethrough to allow a coolant to flow through the bar (20) to remove heat generated within the dielectric sheet (12). Together, the sheet (12) and the support structure (18) form a waveguide window (10) which may be used to environmentally separate one waveguide section (32) from another (34).

Abstract: An improved FT NMR system capable of faster computations by eliminating the time required to operate a shift register for the scaling in signal averaging. The system employs a combinational circuit which provides the commanded various scaled outputs in 50-80 nanoseconds of a 16 bit data word.

Abstract: A method of using a quadrupole ion trap mass spectrometer for high resolution mass spectroscopy is disclosed. In the preferred embodiment, the space charge in the ion trap is controlled to high accuracy. This is done by using a prescan of the trap before each analytical scan, where the ionization parameters used in the prescan are not fixed, but rather are based on the previous analytical scan. The method is especially useful in connection with performance of high resolution MS/MS experiments of the type described in the inventor's prior U.S. Pat. No. 5,198,665.