Abstract: A signal processor receives random input signals from a pair of sensors such as beam sensing electrodes, antennas, microphones or optical position sensors. An estimation equation implemented by the signal processor uses weighted integration of log ratios where the weighting is adaptive and depends upon the values of signal samples being processed. The signal processor uses digital signal processing to provide an estimate of the desired parameter. Nonlinear functions such as hyperbolic tangent and logarithm are contained in programmable read only memories in order to obtain high speed operation. When the signal processor is used in conjunction with channel switching, errors due to channel mismatch are completely eliminated. In a preferred embodiment, the sensors are beam sensing electrodes and the signal processor is used for estimating the position of a scanned ion beam in a ion implantation system.

Abstract: A multiply tuned bird cage results from the combination of low pass and high pass filter elements to yield a band reject network behaving as a low pass network at a low frequency and a high pass network at a high frequency. A band pass bird cage coil is obtained by adding a parallel LC combination to each leg of a bird cage coil to create additional poles in the impedance curve z(f).

Abstract: The invention demonstrates remote tuning of an NMR probe over a length of transmission line while retaining very high efficiency relative to the equivalent locally turned coil. Fixed capacitances for partial tuning are employed at the load such that a desired range of efficiency is achievable for a selected range of capacitance values at both load and source for the intervening transmission line.

Abstract: Synchronous apparatus capable of a variety of operational states responds to a sequence of digital control words, each specifying a desired state and persistence time of the state. The control words are furnished to the apparatus from a self-clocked FIFO in accord with the persistence code. A selected sub-sequence of digital control words in ROM is placed in an auxiliary FIFO upon detection of a corresponding token in the main sequence and control is passed to the auxiliary FIFO to furnish the sub-sequence to the apparatus. At the conclusion of the sub-sequence control is returned to the main FIFO and the main sequence is resumed.

Abstract: A non-destructive ion dose monitor senses instantaneous dose increment in respect of a secondary radiation from known instantaneous coordinates of the ion beam, and a dose image distribution function of workpiece surface coordinates is accumulated in a memory. At intervals, the dose image is compared with a preselected desired dose distribution to obtain a difference distribution function of the ion beam scanning coordinates. The subsequent scanning regime is altered in accord with the difference distribution to cause the sensed dose image to converge with the desired distribution.

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: In a method for NMR excitation of a sample, an Rf pulse is applied to an irradiation coil (6) proximate the sample, in the presence of an external DC magnetic field and an adiabatic passage is performed wherein the Rf pulse is controlled such that:B.sub.1 =V A sin 2.pi..nu.t and .DELTA.H=A(cos 2.pi..nu.t+s),orB.sub.1 =v A cos 2.pi..nu.t and .DELTA.H=A(sin 2.pi..nu.t+s),where s=S/A, where S is the frequency offset of a nucleus from the center of the spectrum, and where v allows for variation of B.sub.1 throughout the sample, .DELTA.H is the resonance offset of the nuclear spins, and B.sub.1 is the rf field of a spin-lock pulse.

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: 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 correction for NMR spin echo spectral data is obtained by adjusting the time origin of an extended density data set and transforming the adjusted origin data set of original density to the frequency domain.

Abstract: A set of n NMR measurements are carried out in an inhomogeneous RF field. The set is parameterized by RF pulse amplitude or duration and for half the measurements the variation of RF pulse/duration is reversed and the RF phase inverted.

Abstract: Synchronous apparatus capable of a variety of operational states responds to a sequence of digital control words, each specifying a desired state and persistence time of the state. The control words are furnished to the apparatus from a self-clocked FIFO in accord with the persistence code. A selected sub-sequence of digital control words in ROM is placed in an auxiliary FIFO upon detection of a corresponding token in the main sequence and control is passed to the auxiliary FIFO to furnish the sub-sequence to the apparatus. At the conclusion of the sub-sequence control is returned to the main FIFO and the main sequence is resumed.

Abstract: An NMR instrument incorporating a cryogenic magnet includes a constant pressure device to maintain the pressure of cryogenic vapors at a constant value whereby a stable magnetic environment is maintained.

Abstract: A system for controlling the spin rate of a sample in an NMR spectrometer using an ON/OFF valve controlled by a digital system to regulate flow of a gas between a source and a sample spinner. A spin rate detector supplies rate information to the digital control. The digital control varies the ON/OFF valve duty cycle to control the spin rate.

Abstract: The tuned LC circuit of an NMR probe includes a coil center tapped to ground through a capacitance selected to constrain parasitic resonances to a frequency region below decoupler frequencies employed in the probe.

Abstract: An NMR spinner having a separate drive pressure and radial bearing pressure includes a differential pressure actuated valve for bleeding a portion of the radial bearing gas to the drive jets to provide for a slow rotation.

Abstract: Increased spatial sensitivity (FIGS. 4) or spatial tolerance (FIGS. 1) in selectively manipulated NMR sample analysis is excited from a spatially inhomogeneous FR field using pulse sequences which operate to exclude all spins deviating from a selected initial orientation (FIGS. 4 and 5) or to inclusively extend the applicable flip angles over a range of initial spin orientation (FIGS. 1).

Abstract: Apparatus for thermal transfer with a semiconductor wafer in a vacuum processing chamber includes a platen with a surface for supporting the wafer, a clamping ring for clamping the wafer to the platen, and passages for supplying a low pressure gas into a thermal transfer region between the wafer and the platen surface. A low compliance seal surrounds the thermal transfer region and inhibits the gas from reaching the processing chamber without overstressing the wafer. The seal includes an elastomer ring having an elongated cross-section, and a sealing groove having a first groove portion for gripping one edge of the ring and a second groove portion which receives the other edge of the ring by bending deformation thereof when a wafer is clamped to the platen. In a preferred embodiment, the ring has a parallelogram-shaped cross-section and is oriented at an acute angle to the platen surface.

Abstract: Multiple concurrent sample processing in a single spectrometer is accomplished for the respective situation of (a) samples of strongly dissimilar character and (b) samples of similar character. For the class (a) samples yielding non-superimposed line spectra are axially separated by susceptability matched delimiters in a sample tube and analyzed in a conventional spectrometer. For the class (b), resonance response from axially separated samples induce signals in respective observe coils similarly spaced along the axis of said sample tube. Plural samples disposed in non-colinear parallel alignment are also treated in this manner.

Abstract: A portion of the cornea or similar flexible membrane is flattened by urging against the cornea a footplate with a measurable force and deriving a signal proportional to the magnitude of the applanated area of the cornea when the applanating force is compared to a threshold which corresponds to a force equal to a selected reference force on the planar footplate contacting the cornea. When the selected reference force signal is reached the area of the applanated region of the cornea is transferred as a signal for scaling by another signal proportional to the force.