Varian Associates, Inc.

Albert P Zens

Howard D Hill

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.

Double tuned circuit for distributed lumped capacitance observe coils

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.

Spurious resonance control for NMR observe coils

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.

Concurrent NMR analysis of multiple samples

It is desired to promote magnetic homogeneity of materials, including structural elements, present in the sensitive volume of a gyromagnetic analysis apparatus. Where the sample is rotated along an axis transverse to the field the requirement reduces to establishing axial homogeneity. Plugs which match the solvent magnetic susceptibility are employed to constrain a sample within the central region of an RF probe coil thereby appearing relatively invisible in the magnetic sense to the instrument. The susceptibility of materials can be tailored to achieve a desired value to suppress magnetic perturbation without introducing extraneous signals.

Controlled susceptibility plugs

An RF probe for a gyromagnetic resonance spectrometer includes a coil cage for supporting the probe coil preferably within the cage formed of a number of rod-like members displaced parallel to the coil axis and spaced apart from the axis at a constant distance. Access to the coil through an axial continuous slot 46 or equivalent eliminates axial discontinuity in susceptibility due to discrete holes in the coil form.

NMR Probe coil form structure

A saddle coil for operation in the probe of an NMR spectrometer is formed from coil portions of opposite helicities disposed on a flexible insulating material, the outer windings of said portions connected by a linking conductor disposed on said insulating medium, which medium is then deformed to form a cylindrical body.

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Fremont, CA, United States of America

Albert P Zens