In the past few years, small-scale (2 m) prepolarized surface nuclear magnetic resonance (SNMR) has gained increasing interest in the research community. As recent studies demonstrated, the application of a strong prepolarization field enhances the SNMR signal of coils with a footprint <1 m² up to a level that even enables investigations in urban areas. In particular, it is expected that this noninvasive method provides the soil moisture distribution in the upper 2 m of the subsurface in the near future. However, until now all field experiments have been carried out on water reservoirs only, in an approach to test and implement this rather new technique into the field of SNMR applications. We present the first prepolarized SNMR measurement on a real soil and demonstrate the general feasibility of this technique to qualitatively and quantitatively detect soil moisture in the upper first 0.5 m. Our soil moisture measurements are validated by independent time domain reflectometry data. To complement the field experiments with numerical simulations, we adapted the underlying SNMR spin dynamics simulations and account for prepolarization switch-off effects in the forward modeling of the SNMR excitation.

中文翻译：

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用于土壤水分测量的预极化表面核磁共振的可行性研究

在过去的几年中，小规模 (2 m) 预极化表面核磁共振 (SNMR) 越来越受到研究界的关注。正如最近的研究表明的那样，强预极化场的应用增强了占地面积 <1 m ²的线圈的 SNMR 信号甚至可以在城市地区进行调查。特别是，预计这种非侵入性方法在不久的将来会提供地下上部 2 m 的土壤水分分布。然而，到目前为止，所有现场实验都只在水库上进行，以测试这种相当新的技术并将其应用于 SNMR 应用领域。我们在真实土壤上进行了第一次预极化 SNMR 测量，并证明了该技术在定性和定量检测上部前 0.5 m 土壤水分方面的一般可行性。我们的土壤湿度测量值通过独立的时域反射计数据进行验证。为了用数值模拟补充现场实验，