Relaxation time measurement in liquids using compact NMR

This study investigates the influence of experimental parameters on the accurate determination of longitudinal and transverse relaxation times in liquids using compact nuclear magnetic resonance relaxometry. Water and glycerin were selected as representative samples due to their contrasting viscosities and relaxation behaviors. The primary objective was to evaluate how repetition time, echo time, number of data points, and time step affect the precision of T₁ and T₂ measurements. Longitudinal relaxation times were determined using a variable repetition time method, while transverse relaxation times were measured via a multi-echo spin sequence. Exponential fitting algorithms were employed to extract relaxation parameters from recorded signal amplitudes. For water, the relaxation times were found to be approximately 3.0 s for T₁ and 1.423 s for T₂. In contrast, glycerin exhibited significantly shorter relaxation times, with T₁ estimated at 0.126 s and T₂ at 0.094 s. The results demonstrated that accurate estimation of relaxation times requires carefully optimized acquisition settings. Specifically, repetition time must exceed three times the T₁ value to ensure full longitudinal recovery, while short echo times and a high number of echoes are essential for reliable T₂ determination. The findings address a critical methodological gap in relaxometry protocols and offer practical recommendations for enhancing measurement accuracy in simple liquids.