Advanced Nmr Systems, Inc.

American Superconductor Corporation

Thermo Iec, Inc.

Robert R Evans, Iii

Michael L Rohan

Dara McMahon

A method and apparatus for controlling a centrifuge system, the centrifuge system including a rotor and a motor operatively coupled to the rotor, the apparatus including an accelerometer coupled to the centrifuge system so as to measure an acceleration of at least a portion of the centrifuge system during operation of the centrifuge system to provide an acceleration signal, a filter that receives the acceleration signal and provides a filtered acceleration signal, and a controller that receives the displacement signal and controls the centrifuge system in response to the displacement signal.

Method and apparatus for detecting and controlling imbalance conditions in a centrifuge system

An electronic circuit that comprises a MOSFET device includes source, drain and gate terminals and operates at cryogenic temperatures. The circuit includes a snubber that is connected between the source and drain terminals of the MOSFET and that has capacitance but substantially no resistance. A control element, which is coupled to at least the gate terminal of the MOSFET device, turns the device 'on' (i.e., it effects conduction in the MOSFET) by selectively applying a voltage to the gate terminal that is positive with respect to the source terminal and with respect to ground. The circuit further includes a resistive load, e.g., a resistor, that is coupled in series between the control element and the gate terminal. The control element selectively applies negative-going voltage to the gate terminal, e.g., when the MOSFET is not on.

Apparatus for improved operation of MOSFET devices in cryogenic

In a magnetic resonance imaging system in which the read and phase directions are rotated with respect to the orthogonal gradient coil directions, a gradient coil is driven to generate a gradient waveform having a segment, either sinusoidal or linear, that approximates the sum of the simultaneous non-zero components of the read and phase gradient waveforms in the direction of the gradient coil. Resonant circuits, each including a gradient coil, generate simultaneous periodic gradient coil waveforms in which the integral over each waveform period is non-zero. First and second capacitive elements in the resonant power supply are electrically connected to the gradient coil through a switch and a bridged network, respectively. The bridged network selectively provides current flow paths between the coil and either of the terminals of the second capacitive element.

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Framingham, MA, United States of America

Robert R Evans, Iii