The coupling effect of temperature and Rb-Xe in NMR sensor

The nuclear magnetic resonance (NMR) sensor is the atomic sensor which has the advantages of high accuracy, high sensitivity, small size, etc., and has broad application prospects in the field of inertial navigation. Temperature is one of the important parameters that determine the ultimate performance of NMR sensor including temperature fluctuations, temperature gradients, and temperature uniformity. Among them, temperature fluctuations give rise to the resonance frequency detuning, which not only shifts the carrier frequency, but also affects the alkali metal magnetic field perceived by the Xe nuclei. The accuracy and sensitivity of NMR sensor were limited as consequence of temperature fluctuations on account of its temperature sensitivity. In this paper, we have demonstrated a model of the coupling effect of temperature and Rb-Xe to analyze the influence of temperature fluctuations on the resonance frequency detuning of Xe nuclei. On the one hand, this model has analyzed the resonance frequency detuning caused by the Rb-Xe coupling effect in the NMR sensor demodulation system, whose fitting degree between theoretical analysis and experimental results is achieved 99.78%. On the other hand, it has analyzed the resonance frequency detuning caused by the magnetic field generated by the alkali metal atoms, which is associated with temperature fluctuations and experienced by Xe nuclei. The fitting degree of theoretical model of the coupling effect of temperature and Rb-Xe is achieved 99.87%. These works have provided a valuable scheme for enhancing the ultimate performance of NMR sensor and future applications.