Design and Implementation of NMR Permanent Magnet Precision Temperature Controller

doi:10.11938/cjmr20182632

Abstract

Abstract: Neodymium-iron-boron (NdFeB) permanent magnets always used to generate a static magnetic field in low field NMR spectrometers has poor temperature stability. Temperature fluctuations will affect the reliability of NMR experiments. In order to improve the stability of low-field magnetic resonance spectrometer, a precise temperature control scheme of permanent magnet based on dual-loop control algorithm was proposed and verified on 0.06 T NMR spectrometer. The results show that the 24 h temperature control accuracy is better than ±0.005℃. And the drift in ¹H resonance frequency decreases from 255 Hz to 15 Hz within 0.5 h, and from 4 950 Hz to 145 Hz within 24 h, compared to that without temperature control. That improves the stability of low-field NMR spectrometer with permanent magnet effectively.

Key words: low-field NMR, precision temperature controller, double-loop control algorithm, permanent magnet

CLC Number:

O482.53

YANG Chang, CHEN Jun-fei, CHEN Li, ZHANG Zhi, FENG Ji-wen, CHEN Fang, LIU Chao-yang. Design and Implementation of NMR Permanent Magnet Precision Temperature Controller[J]. Chinese Journal of Magnetic Resonance, 2018, 35(3): 294-302.

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