Nuclear Magnetic Resonance Instruments for Geotechnical and Geophysical Investigations

We propose the development of a compact high-sensitivity Surface Nuclear Magnetic Resonance (SNMR) instrument that is tailored for characterization of the uppermost 2 meters of the subsurface. Through the proposed research and development effort, we will demonstrate an approach that applies new compact Atomic Magnetic (AM) sensors integrated with an advanced high-power transmitter and control system. The SNMR high power transmitter design will be optimized for the top 2 meters of the subsurface with variable pulse moments enabling moisture content layering. The SNMR receiver will specifically utilize a tunable RF magnetometer in the Spin-Exchange Relaxation-Free (SERF) regime. The fundamental sensitivity of the magnetometer in the SERF mode using a 10x10x10 cm vapor cell is 0.001 fT/vHz. The proposed instrument will be light and portable, facilitating easy deployment and enabling personnel to achieve rapid high resolution moisture content information from the top 2 meters.