Pulsed Nuclear Magnetic Resonance Instrument for Soil-water Content Measurement: Sensor Configurations1

Nuclear Magnetic Resonance Imaging of Water Content in the Subsurface

“…These parameters are measured by nuclear magnetic resonance. Paetzold et al (1987) conclude from their laboratory experiments that the NMR signal is a linear function of volumetric water content and is not affected by clay mineralogy, soil organic matter, or texture within the ranges studied. They concluded that the NMR signal is indeed uniquely related to liquid water in soils and other rocks.…”

Nuclear magnetic resonance imaging of water content in the subsurface

“…These parameters are measured by nuclear magnetic resonsnce. Paetzold et al (1987) conclude from their laboratory experiments that the NMR signal is a linear function of volumetric water content and is not afkcted by clay mineralogy,soil orgauic matter, or texture within the ranges studied. They concluded that the NMR signal is indeed uniquely related to liquid water in soilsã nd other rocks.…”

Unilateral MRI using a rastered projection

“…Jackson developed the inside-out magnet geometry [2][3][4] for borehole logging [5,6]. Others have utilized a U-shaped, twopole [7][8][9]15] or split U-shaped, four-pole [10,11] magnets where B o is parallel to the surface of the probe. Paetzold et al, developed an NMR system pulled behind a tractor to detect soil moisture for remote sensing ground truth [15].…”

“…Others have utilized a U-shaped, twopole [7][8][9]15] or split U-shaped, four-pole [10,11] magnets where B o is parallel to the surface of the probe. Paetzold et al, developed an NMR system pulled behind a tractor to detect soil moisture for remote sensing ground truth [15]. This system, a modified version of their earlier nonunilateral system [18], produced B o parallel and B 1 perpendicular to the surface of the Earth.…”

“…Many of these unilateral systems have been used to perform one-dimensional imaging by moving the coil, magnet, or both coil and magnet [8,11] relative to the sample; changing the resonant frequency of the RF coil [13,15]; or utilizing the gradient in the applied static B o field [12]. Two-dimensional imaging has also been performed with phase and frequency encoding by applying pulsed field gradients in B o [16].…”