A detection method for extremely weak magnetic materials

Abstract

The invention discloses a detection method of extremely weak magnetic materials. The method mainly comprises following steps of winding a to-be-tested material in a center position of a sample tube surface wall detection region; setting an inclined three-dimensional gradient echo pulse sequence; acquiring gradient echo sample data; based on above data, processing to acquire a two-dimensional columnar rotation image; and based on the image information, estimating the magnetism of radio frequency coil materials. According to the invention, by use of the nuclear magnetic resonance three-dimensional gradient imaging principle, images for representing additional magnetic field change caused by magnetization of the materials can be acquired; the resolution ratio of space pixel points can be reduced to be 10-10; on one hand, the detection precision of the magnetism of the extremely weak materials is remarkably improved; and particularly when the extremely weak materials are applied to the field of radio frequency coils, real effects of the radio frequency coil materials on the strict experiment environment about the homogeneity of the static magnetic field in the magnet can be really considered.

Description

technical field [0001] The invention belongs to the technical field of nuclear magnetic resonance probes, in particular to a method for detecting extremely weak magnetic materials. Background technique [0002] The influence of the material itself on the uniformity of the static magnetic field is determined by the magnetic susceptibility (magnetic susceptibility) χ. Any material may be magnetized under the action of a strong magnetic field and generate magnetism, thereby inducing the vector field of the dipole magnetic moment, namely additional magnetic field. In order to minimize the interference to the main magnetic field, paramagnetic substances (χ>0,|χ|≈10 -5 ~10 -6 ) and diamagnetic substances (χ<0,|χ|≈10 -5 ~10 -6 ) is used in the development of probes, especially components such as radio frequency coils are too close to the sample detection area, which puts forward high requirements on structure, uniformity and preparation process. In the prior art, copper ...

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Problems solved by technology

However, on the one hand, because MRI equipment does not have high requirements on the uniformity of the magnetic field, the spatial resolution of the magnetic field can only reach 10 -5 ~10 -6 , which cannot meet the detection accuracy of the magnetic susceptibility of the probe material itself; on the other hand, the conventional three-dimensional gradient imaging technology needs to be equipped with gradient coils in the three directions of Z\X\Y and generate a very high Z\X\Y gradient field. Machine (including hardware, software) performance level and instrument cost put forward very high requirements

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