低场核磁共振（low-field NMR）谱仪常采用钕铁硼（NdFeB）永磁体提供静磁场.NdFeB对温度非常敏感，磁体温度变化会引起磁场漂移，影响NMR实验的可靠性.为提高低场磁共振谱仪的稳定性，本文提出了一种基于双回路控制算法的磁共振永磁体精密温度控制方案，并在0.06 T磁共振谱仪上进行验证.结果表明：24 h内控温精度达到±0.005℃；相比无温控时，质子共振频率0.5 h内漂移量由255 Hz减小至15 Hz，24 h内漂移量由4 950 Hz减小至145 Hz，有效提高了低场磁共振谱仪永磁体的稳定性.
杨畅
,
陈俊飞
,
陈黎
,
张志
,
冯继文
,
陈方
,
刘朝阳
. NMR永磁体精密温度控制器的设计与实现[J]. 波谱学杂志, 2018
, 35(3)
: 294
-302
.
DOI: 10.11938/cjmr20182632
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.
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