Compact SNMR sensors: a sensitivity study

Abstract

Extending surface nuclear magnetic resonance (SNMR) with prepolarization (PP) enables mobile compact SNMR layouts, that are promising for soil moisture investigations. The prepolarization introduces additional parameters into the SNMR experiment, and therefore predicting the resolution performance of a specific PP SNMR layout becomes more complicated. In this paper, we use the numerical integral over the diagonal elements of the resolution matrix in the target depth range to evaluate the resolution performance of a large number of possible PP SNMR layouts. We also apply this approach to the recently proposed concentric figure of eight (cFOE) layout, which, due to intrinsic cancellation of external noise, enables measurements in high noise environments. We identify conditions under which good resolution performance is achieved. To verify our approach, we also perform inversions of synthetic data for selected layouts.