Bruker Instruments, Inc.

Joel T Lewandowski

David G Cory

Werner E Maas

A gradient magnetic field generator is provided for generating a spatially varying gradient magnetic field for use with a nuclear magnetic resonance spectroscopy probe having a rotatable sample container. The gradient field generator has a plurality of straight line conductive segments which lie parallel to one another and perpendicular to a plane within which lies a rotation axis about which the sample container rotates. The straight line conductive segments each conduct a current which generates a component of the overall gradient magnetic field. The conductive segments preferably lie in a cylindrical distribution about a stator within which the sample container is rotated. The appropriate currents for the conductive segments may be determined by finding a solution for the Jacobian which defines the magnetic field variations in the three-dimensional space of the stator. Finding an appropriate solution is simplified by presuming the cylindrical distribution of conductive segments and allowing restriction due to the size and shape of the stator, and the physical space between the stator and an inner surface of the probe housing.

Apparatus and method for the generation of gradient magnetic fields for

A nuclear magnetic resonance cross polarization probe uses a dual-coil arrangement in which a single-turn inner coil is surrounded by a solenoid coil. The inner coil is tuned to the frequency of a relatively high Larmor frequency nuclei type, such as proton. The solenoid coil is tuned to a lower Larmor frequency nuclei type. An inner sample region surrounded by the inner coil has a first magnetic field component induced by an electrical signal at the relatively high frequency in the inner coil. An electrical signal at the lower frequency is input to the solenoid coil and results in the generation of a magnetic field alternating at the lower frequency. This field induces a current in the inner coil at the lower frequency that, in turn, induces a magnetic field component in the inner region at the lower frequency. Because the structure of the relatively high magnetic field component and the lower magnetic field component in the inner region are both dictated by the shape of the inner coil, a good spatial matching of the fields is obtained resulting in a good Hartman-Hahn match across the sample volume.

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Oxford, MA, United States of America

Joel T Lewandowski