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Nuclear magnetic resonance magnetometer

  • US 4,891,592 A
  • Filed: 06/10/1988
  • Issued: 01/02/1990
  • Est. Priority Date: 06/11/1987
  • Status: Expired due to Fees
First Claim
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1. Nuclear magnetic resonance magnetometer comprising two semi-coils for picking up and reinjecting precessional signals of the nuclear spins of two samples of a material having gyromagnetic properties, disposed in the magnetic field to be measured and energized by a VHF generator, including an oscillator comprising said two semi-coils, a capacitor connected to the terminals of the two semi-coils, and a differential amplifier connected to the terminals of the capacitor, a means for phase-shifting the output of said differential amplifier connected to the output of the differential amplifier, and means for reinjecting into each semi-coil a current controlled by the output signal from the phase-shifting means, and a frequency meter for measuring the frequency of the oscillations of said oscillator, which frequency is proportional to the magnetic field to be measured, wherein the phase-shifting means is adapted for introducing a constant phase-shift equal to 90°

  • throughout the whole frequency range of the oscillatons, and wherein the capacitor forms part of a battery of capacitors and wherein means are provided for controlling the switching of the capacitors of said battery of capacitors in response to the value of the frequency measured by the frequency meter whereby parasite phase-shifts between the signals picked up and the signals reinjected into the two semi-coils always remain less than a predefined threshold.

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