核磁共振陀螺仪中共振磁场强度优化研究

Research on Optimal Amplitude of Resonance Magnetic Field in Nuclear Magnetic Resonance Gyroscope

核磁共振陀螺中,共振磁场的幅值直接影响原子核自旋磁矩进动信号的强度,进而影响陀螺信号的信噪比。基于核磁共振陀螺Bloch方程,从理论和实验两方面研究了共振磁场幅值对宏观原子核自旋磁矩的影响。结果表明,随着共振磁场幅值的增加,宏观核自旋磁矩进动信号的强度先增大后减小,进动信号的强度与共振磁场的幅值呈色散关系。共振磁场幅度值存在最优值,且最优值的取值与惰性气体原子的旋磁比、纵向弛豫时间和横向弛豫时间有关。

In the Nuclear Magnetic Resonance Gyroscope(NMRG),the amplitude of the resonance magnetic field affects the intensity of the precession signal generated by the nuclear spin precession and the signal to noise ratio of the NMRG.In this paper,based on the Bloch equation,the influence of the amplitude of the resonance magnetic field on the net nuclear spin magnetic moment is studied theoretically and experimentally.The results show that with the amplitude of the resonance magnetic field increasing,the intensity of the precession signal climbs up and then declines,which presents a dispersion relationship.This means that there is an optimal value for the amplitude of the resonance magnetic field.The optimal value is related to the gyromagnetic ratio,longitudinal spin lifetime and transverse spin lifetime.