Real-Time Transverse Relaxation Time Measurement Method for Spin-Exchange Optical Pumped Noble Gas Nuclei in Nuclear Magnetic Resonance Rotation Sensors

The transverse relaxation time of the spin-exchange optical pumped noble gas nuclei is a fundamental parameter to evaluate the performance of a nuclear magnetic resonance (NMR) rotation sensor. In practical tests and applications, measuring the transverse relaxation time in real-time is challenging. Due to the conflict with feedback loops, the traditional methods are unsuitable for real-time measurement. To address this limitation, this paper proposes a real-time method based on parameter identification to measure the transverse relaxation time. In the proposed method, a step signal is added to the oscillation magnetic field to excite nuclear spins, and the phase response generated is collected for identification. An NMR rotation sensor prototype is developed for the proof of concept. The experimental results verify the effectiveness and the feasibility of the proposed method.