摘要:
A method for making an NMR probe coil (90) comprises:
(a) depositing a conductive film on a substrate; (b) patterning the film to form a coil having an inductive element and a capacitive element wherein the coil has an expected resonant frequency less than a desired resonant frequency of the coil; (c) coupling RF power to the coil at or near the expected resonant frequency; (d) measuring a first observed resonant frequency of the coil; (e) increasing the RF power to the coil at or near its observed resonant frequency; (f) observing the coil for a change in the resonant frequency to a new observed resonant frequency; (g) repeating the increasing the RF power to the coil at or near the observed resonant frequency until a desired power to the coil is reached; and (h) tuning the coil by removing a portion of the capacitive element.
This provides a method for making a thin-film oxide superconductor NMR probe coil resistant to frequency shifts due to conductor burn out at operating currents.
摘要:
A capacitor for use in RF probes, especially for use with a thin-film oxide superconductor NMR probe coil is provided. Further objects of the invention are to reduce the effect of the HTS coil on the uniformity of the polarizing field throughout the sample volume, to provide a capacitor for use with an NMR coil with increased RF current-carrying capability of the coils and/or with reduced electric fields from the coil which fringe into the sample volume and hence less noise. These and other objects of the invention are met by providing a capacitor comprising a thin film of conductive material on a planar substrate, the film comprising a first elongate tapered finger and a second elongate tapered finger, each finger (50) having a wide end and a narrow end; the wide end of the first finger being proximately disposed to the narrow end of the second finger and the narrow end of the first finger being proximately disposed to the wide end of the second finger, adjacent fingers forming a uniform gap (52) therebetween, whereby a capacitive element is formed between the first and the second finger.
摘要:
It is an object of the invention to reduce the effect of the HTS coil on the uniformity of the polarizing field throughout the sample volume, to provide an NMR coil with increased RF current-carrying capability of the coils, to provide an NMR coil with reduced electric fields from the coil which fringe into the sample volume and hence less noise and to provide an NMR coil resistant to frequency shifts due to conductor burn out at operating currents. These and other objects of the invention are met by providing an RF coil (90) for magnetic resonance spectroscopy or microscopy made of a thin film of conductive material deposited on a planar substrate comprising a capacitive element and an inductive element, wherein the inductive element comprises three nested coplanar loops interrupted by gaps, the central loop comprising two fingers of width w and the inner and outer loops each comprising two fingers of width about w/2 whereby a capacitive element is formed between adjacent pairs of fingers.