Varian, Inc.

Thomas De Swiet

Thomas M Barbara

Marco A Romo

Wai Ha Wong

Knut G Mehr

James Finnigan

Sean T Burns

Nancy Winward

The NMR device with a magnet utilizes a composition exhibiting a desired value of magnetic susceptibility, wherein the composition comprises a metal ion selected from the group consisting of Gd, Feand Mnand an amorphous material using a ligand or chelating agent to solubilize the metal ion throughout the amorphous material, wherein the magnetic susceptibility of the composition exhibits a desired value at cryogenic temperatures such as nearly zero susceptibility at temperatures at or below 77 K.

Low temperature susceptibility compensation

An composition exhibiting a desired value of magnetic susceptibility, which can be used to fabricate components in an NMR device, and method thereof, wherein the composition comprises a metal ion selected from the group consisting of Gd, Feand Mnand an amorphous material using a ligand or chelating agent to solubilize the metal ion throughout the marphous material, wherein the magnetic susceptibility of the composition exhibits a desired value at cryogenic temperatures such as nearly zero susceptibility at temperatures at or below 77&#xb0; K.

Nuclear magnetic resonance (NMR) systems and methods employing squashed (transversely-elongated) sample vessels (sample tubes or flow cells) for holding liquid NMR samples, and matching squashed saddle-shaped RF coils allow reducing sample and/or coil losses and increasing the RF circuit quality factors (Q). In a present implementation, the RF coils and sample vessels have rectangular cross-sections. Rounded (e.g. ellipsoidal) or other squashed cross-sections may also be used. The coil corresponding to the highest sample losses is positioned such that the magnetic field generated by the coil is along the major axis of the sample vessel. Squashed sample vessels may also be used with conventional circular coils, particularly for low-temperature measurements where sample losses dominate.

Squashed liquid NMR sample tubes and RF coils

An NMR probe comprises a resonator formed of two separate conducting loops disposed on opposite sides of the sample, where one loop is driven and the other floats in a preferred operating mode. Slotted shields are disposed coaxially within said loops and outside the sample with slots aligned with gaps between the loops.

Radio frequency NMR resonator with split axial shields

A birdcage resonator has a pair of conductor rings separated from each other along a central axis and a plural number of axially disposed conductor rungs, which extend between the rings and are evenly spaced around the central axis. Each of the rungs has a sectional shape with thickness or a radial extension comparable to or greater than its width or its azimuthal extension. Measures of the width and thickness of the rungs may be determined by using them as parameters to calculate the values of Q factor from an analytical procedure to locate parameter value ranges corresponding to maximal Q. Geometric calculations for filling factor yield ranges of parameters providing for compromise parameter values. Saddle coils have been found to exhibit similar enhancement of Q with radially oriented conductor cross section.

NMR resonators optimized for high Q factor

A radio-frequency (RF) coil for a nuclear magnetic resonance (NMR) probe includes rounded longitudinal conductors connecting end rings formed by sheets. The rounded conductors can be formed by curled sheets or wires. The rounded conductors allow reduced RF losses at the coil window edges, and thus allow increased coil sensitivities. The rounded conductors also allow increased coil sensitivities for an orthogonal coil, by allowing increased transparency to the magnetic field generated by the orthogonal coil. A curled-sheet RF coil can be generated from a single etched sheet by curling longitudinal sections of the sheet into tubular longitudinal conductors. To make such a coil, each longitudinal section is inserted into a longitudinal slot of a sheet-curling member, and the member is rotated about its longitudinal axis. As the curling member is rotated, the longitudinal sheet section wraps around the curling member and becomes curled. The curling member can be provided as part of a sheet-curling tool including two transverse plates for securing the coil into place between the plates, and a set of guides allowing the longitudinal motion of one plate relative to the other.

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Redwood City, CA, United States of America

Thomas De Swiet