Field frequency interlocking system and method of permanent-magnetic low-field mini NMR spectrometer

Abstract

The invention relates to a field frequency interlocking system and method of a permanent-magnetic low-field mini NMR spectrometer. The system comprises a magnetic field intensity measurement unit, anadjustable temperature detection control unit and a data processing and display unit; the magnetic field intensity measurement unit is provided with a support, a triaxial orthogonal positioning slideunit and a magnetic field intensity detector, and the magnetic field intensity detector detects the magnetic field intensity of magnet to-be-detected area; the adjustable temperature detection controlunit is provided with a temperature control box, a multipoint temperature detection sensor and an adjustable temperature control circuit, the temperature control box provides a temperature constant environment for a magnet via a PWM method during calibration, and the instant temperature of the magnet is detected during measurement; and the data processing and display unit is provided with a temperature fitting module, a magnetic field intensity fitting module, a resonance frequency fitting module and a display module, and objective functions of temperature in the magnet cavity, magnetic intensity distribution and relation of the resonance frequency and internal cavity temperature are obtained via fitting algorithms. During measurement, a frequency source of the NMR spectrometer receives resonance frequency data and carries out RF excitation on a sample, and a spectral line is corrected automatically. The system and method can be applied to different permanent-magnetic mini NMR instruments.

Description

technical field [0001] The invention relates to the technical field of nuclear magnetic resonance (Nuclear Magnetic Resonance, NMR) field-frequency interlocking technology, in particular to a field-frequency interlocking system and method for a permanent magnet low-field miniaturized nuclear magnetic resonance spectrometer. Background technique [0002] Magnetic field stability is one of the necessary conditions for obtaining high-quality NMR signals. The most important factor affecting the stability of the magnetic field of a permanent magnet is the temperature of the magnet. Despite a good heat insulation treatment, the open permanent magnet is still greatly affected by the temperature change of the surrounding environment. Compared with high-field superconducting magnets, low-field NMR permanent magnets are more sensitive to temperature, and the magnetic field strength is more likely to drift. On the other hand, since the shim coil is installed on the surface of the inne...

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Problems solved by technology

[0006] The main purpose of the present invention is to overcome the problem in the prior art that the NMR spectrum experimental spectral line shifts under the influence of the small drift of the internal temperature of the NMR permanent magnet cavity, and propose a simple and effective permanent magnet low-field miniaturized nuclear magnetic resonance spectrum Instrument field frequency interlocking system and method

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