Gradient coil for NMR spectrometer

Abstract

The invention discloses a gradient coil of a nuclear magnetic resonance spectrometer. The gradient coil is composed of a main coil and a shielding coil coaxially arranged outside the gradient coil, wherein several groups of the main coil are symmetrically distributed up and down in the axial direction of the coil. Two sets of coil windings, the upper two sets of coils are opposite to the lower two sets of coils, the shielding coil is two sets of upper and lower symmetrically distributed coil windings with opposite winding directions, all winding coils are connected in series, the shielding coil and the main coil A distance of 4.3-5.3 mm is preferably maintained between them, and a heat insulating component is also provided in the inner space of the main coil. The gradient coil realized according to the present invention obviously improves the coil efficiency, and a gradient magnetic field with a strength greater than 50Gs / cm@10A and a linear error less than 0.5Gs@10A can be obtained with a simple algorithm and process, and it can ensure that the gradient field is stable when the temperature changes stability in the experiment.

Description

technical field [0001] The invention belongs to the field of nuclear magnetic resonance spectrometers, and more specifically relates to a gradient coil. Background technique [0002] When the NMR spectrometer performs gradient shimming and two-dimensional gradient experiments, a strong longitudinal gradient field needs to be generated in the main magnetic field, and its strength is generally required to be above 50Gs / cm@10A. Therefore, it is necessary to add a gradient coil to the NMR spectrometer probe, which generates a gradient field driven by an external pulse gradient current. The stronger the gradient field, the better. However, when the gradient coil generates a gradient field, the metal conductor near it The stronger the gradient field, the easier it is to generate eddy current. The eddy current will generate a magnetic field opposite to the original gradient field, which will reduce the efficiency of the gradient coil and the stability of the magnetic field, affecti...

AI Technical Summary

Problems solved by technology

Therefore, it is necessary to add a gradient coil to the NMR spectrometer probe, which generates a gradient field driven by an external pulse gradient current. The stronger the gradient field, the better. However, when the gradient coil generates a gradient field, the metal conductor near it The stronger the gradient field, the easier it is to generate eddy current. The eddy current will generate a magnetic field opposite to the original gradient field, which will reduce the efficiency of the gradient coil and the stability of the magnetic field, which will affect the normal operation of the NMR spectrometer.

[0003] In the prior art, the method of flow function and target field is used to solve the problem. However, the space for placing the gradient coil in the NMR spectrometer probe is very limited. The gradient coil must meet the requirements of small size, small inductance, and strong gradient field. When the field method requires high field strength and the coil volume is strictly limited, it is difficult to obtain a reasonable gradient coil scheme by this design method, and it leads to processing difficulties and cannot be used for actual production

[0004] At present, there is a mainstream method of using self-shielding coils to solve the eddy current problem, but the shielding coil will generate a reverse magnetic field in the target area, which will cancel almost half of the gradient field of the main coil, so in order to obtain a strong enough gradient field, it has to be increased The number of coil windings, but in the case of increasing the number of windings, the inductance and resistance of the coil are increased, which affects the gradient field switching speed of the coil and significantly increases the power consumption of the coil

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