Bruker Biospin Gmbh

Varian, Inc.

Agilent Technologies, Inc.

Robert E Nast

Richard Stacy Withers

Weston A Anderson

Martin Hofmann

Manfred Spraul

Damon Leslie Harris

RF electric fields produced by electric potential differences in NMR probe coil windings may penetrate the NMR sample and sample tube causing sensitivity loss and noise in NMR spectroscopy. Counter-wound spiral coils placed on the opposite surfaces of a planar substrate or on two adjacent planar substrates produce electric potentials that minimize the electric field over the sample region, thereby increasing the sensitivity of the NMR probe. Alternatively counter-wound spiral coils placed adjacent to each other on the outer surface of two concentric cylindrical surfaces that surround the NMR sample minimize the electric field over the sample region. The electric potential of the spiral coils is reduced by adjusting a length of at least one coil.

NMR spiral RF probe coil pair with low external electric field

Improved superconducting coils for a nuclear magnetic resonance probe use capacitive elements that are located in regions further from an active sample volume than magnetic field generating elements to which they are electrically connected. The sample volume is a substantially oblong shape, and the magnetic field generating elements run substantially parallel to the major axis of the shape, while the capacitor elements run perpendicular to the major axis. Gaps between the capacitor elements, and the width of the elements themselves, may increase toward the outside of the coil to minimize electrical discharge. The variation may be according to a monotonic, possibly linear, function. Discharge may also be minimized by using a dielectric cover that, together with a coil substrate, encloses the coil.

Planar NMR coils with localized field-generating and capacitive elements

A nuclear magnetic resonance (NMR) spectroscopy probe has a sample cell into and out of which a room temperature liquid sample may be directed. The cell is surrounded by a radio frequency coil that is used to perform NMR measurements of the liquid sample, and which is maintained at cryogenic temperatures. The coil is separated from the sample cell by a thermally insulative boundary, such as a vacuum. The sample may enter the cell through an input path, and may exit through an output path. The input path, output path and sample cell may be surrounded by a sheath through which flows room temperature gas. The ends of the sample cell may be tapered to promote thorough flow through the cell, and flow diverters may be included in the sample cell adjacent to the input and output paths to force flow to the outer wall of the sample cell.

Flow-through cryogenic NMR probe

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Saratoga, CA, United States of America

Robert E Nast