Squid detected NMR and MRI at ultralow fields
AssigneeThe Regents of th University of California
InventorsJohn Clarke, Robert McDermott, Alexander Pines, Andreas Heinz Trabesinger
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Abstract
Nuclear magnetic resonance (NMR) signals are detected in microtesla fields. Prepolarization in millitesla fields is followed by detection with an untuned dc superconducting quantum interference device (SQUID) magnetometer. Because the sensitivity of the SQUID is frequency independent, both signal-to-noise ratio (SNR) and spectral resolution are enhanced by detecting the NMR signal in extremely low magnetic fields, where the NMR lines become very narrow even for grossly inhomogeneous measurement fields. MRI in ultralow magnetic field is based on the NMR at ultralow fields. Gradient magnetic fields are applied, and images are constructed from the detected NMR signals.
Claims20
A method for nuclear magnetic resonance (NMR) of a sample, comprising:
- prepolarizing nuclear spins in the sample in a millitesla magnetic field;
- detecting nuclear magnetic resonance (NMR) signals from the sample in a microtesla magnetic field with an untuned low critical temperature (Tc) superconducting quantum interference device (SQUID) magnetometer.
Apparatus for nuclear magnetic resonance (NMR) of a sample, comprising:
- prepolarization coils for providing a millitesla magnetic field for prepolarizing nuclear spins in the sample;
- measurement coils for providing a microtesla magnetic field for detecting nuclear magnetic resonance (NMR) signals from the sample;
- an untuned low critical temperature (Tc) superconducting quantum interference device (SQUID) magnetometer for detecting nuclear magnetic resonance (NMR) signals from the sample.
Dependencies are inferred from the claim text.