RT-FPS: Relaxation Time of Free Precession Signal Measurement Method for Bell-Bloom Magnetometer

The Bell-Bloom magnetometer is an instrument for measuring weak magnetic fields that are widely used in geophysical exploration, earthquake monitoring, natural disaster monitoring, and other fields. In geophysical exploration, the magnetometer can detect changes in underground materials; and in magnetic field monitoring, it can accurately detect magnetic field anomalies caused by earthquakes. Relaxation is a crucial characteristic of the Bell-Bloom magnetometer, and unclear relaxation information can hinder the design and improvement of the Bell-Bloom magnetometer, thereby affecting its potential applications. This study proposes an intelligent algorithm called relaxation time of free precession signal (RT-FPS) for measuring the relaxation time of the Bell-Bloom magnetometer parameters to address these issues. Experimental results demonstrate the algorithm's superior convergence efficiency, fitting accuracy, and noise robustness. Moreover, the algorithm exhibits rapid convergence and high computational accuracy with a minimum sum of squared residuals 1.8386x10(-11) s(2) . The algorithm is robust against different types of noise and is minimally affected by data quality, with minimum errors of 0.1 ms and 0.71 mu s for T-1 and T-2 , respectively. This study can enhance the performance of the Bell-Bloom magnetometer and its potential applications in magnetic anomaly detection and geomagnetic field monitoring. Our shareable code and data sources are available at https://github.com/baicaidezhenshi/RT-FPS-DATA.git .