Overhauser Geomagnetic Sensor Based on the Dynamic Nuclear Polarization Effect for Magnetic Prospecting

Based on the dynamic nuclear polarization (DNP) effect, an alternative design of an Overhauser geomagnetic sensor is presented that enhances the proton polarization and increases the amplitude of the free induction decay (FID) signal. The short-pulse method is adopted to rotate the enhanced proton magnetization into the plane of precession to create an FID signal. To reduce the negative effect of the powerful electromagnetic interference, the design of the anti-interference of the pick-up coil is studied. Furthermore, the radio frequency polarization method based on the capacitive-loaded coaxial cavity is proposed to improve the quality factor of the resonant circuit. In addition, a special test instrument is designed that enables the simultaneous testing of the classical proton precession and the Overhauser sensor. Overall, comparison experiments with and without the free radical of the Overhauser sensors show that the DNP effect does effectively improve the amplitude and quality of the FID signal, and the magnetic sensitivity, resolution and range reach to 10 pT/Hz1/2@1 Hz, 0.0023 nT and 20–100 μT, respectively.

[1]  Reinhard Meusinger Nuclear Overhauser effect challenge , 2011, Analytical and bioanalytical chemistry.

[2]  Mioara Mandea,et al.  Geomagnetic Observations and Models , 2011 .

[3]  Ulrich Amsel,et al.  Encyclopedia Of Solid Earth Geophysics , 2016 .

[4]  Hideo Utsumi,et al.  Dynamic nuclear polarization properties of nitroxyl radicals used in Overhauser-enhanced MRI for simultaneous molecular imaging. , 2006, Journal of magnetic resonance.

[5]  Werner Heil,et al.  Ultrasensitive 3He magnetometer for measurements of high magnetic fields , 2014 .

[6]  Brandon D Armstrong,et al.  A new model for Overhauser enhanced nuclear magnetic resonance using nitroxide radicals. , 2007, The Journal of chemical physics.

[7]  Ding Yaogen,et al.  Research on parameters of higher-order transverse magnetic modes in cylindrical coaxial cavity resonator , 2005 .

[8]  J. Belfi,et al.  Dual channel self-oscillating optical magnetometer , 2008, 0812.1160.

[9]  N. Kernevez,et al.  Description of a high sensitivity CW scalar DNP-NMR magnetometer , 1991 .

[10]  Fritz Primdahl,et al.  Internal field of homogeneously magnetized toroid sensor for proton free precession magnetometer , 2005 .

[11]  A. Abragam,et al.  OVERHAUSER EFFECT IN NONMETALS , 1955 .

[12]  Noël Djongyang,et al.  A review of geophysical methods for geothermal exploration , 2015 .

[13]  M. Nabighian,et al.  The historical development of the magnetic method in exploration , 2005 .

[14]  E. Riis Optical Magnetometry , 2013 .

[15]  S. Glaser,et al.  Dynamic nuclear polarization at high magnetic fields in liquids. , 2012, Progress in nuclear magnetic resonance spectroscopy.

[16]  Tao Wang,et al.  Optimizations of spin-exchange relaxation-free magnetometer based on potassium and rubidium hybrid optical pumping. , 2014, The Review of scientific instruments.

[17]  A. Overhauser Polarization of Nuclei in Metals , 1953 .

[18]  Karl F. Warnick,et al.  Problems Solving in Electromagnetics, Microwave Circuit and Antenna Design for Communications Engineering , 2003 .

[19]  Brian D Ross,et al.  Continuous flow Overhauser dynamic nuclear polarization of water in the fringe field of a clinical magnetic resonance imaging system for authentic image contrast. , 2010, Journal of magnetic resonance.

[20]  Peter Russer,et al.  Electromagnetics, Microwave Circuit, And Antenna Design for Communications Engineering, Second Edition (Artech House Antennas and Propagation Library) , 2006 .

[21]  D. Duret,et al.  Performances of the OVH magnetometer for the Danish Oersted satellite , 1996 .

[22]  D. Budker,et al.  Optical magnetometry - eScholarship , 2006, physics/0611246.

[23]  Songi Han,et al.  Dynamic nuclear polarization of 13C in aqueous solutions under ambient conditions. , 2009, Journal of magnetic resonance.

[24]  董玉和 Dong Yuhe,et al.  Transmission characteristics of microwave rectangular waveguide , 2013 .

[25]  N. Kernevez,et al.  Weak field NMR and EPR spectrometers and magnetometers , 1992, 1992. Digests of Intermag. International Magnetics Conference.

[26]  Hideo Utsumi,et al.  Dynamic nuclear polarization properties of nitroxyl radical in high viscous liquid using Overhauser-enhanced Magnetic Resonance Imaging (OMRI). , 2015, Journal of magnetic resonance.

[27]  H. S. Wolff,et al.  iRun: Horizontal and Vertical Shape of a Region-Based Graph Compression , 2022, Sensors.