proton-precession magnetometer

measurement instrument

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July 13, 2026

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A proton-precession magnetometer is an instrument used to measure the strength of magnetic fields. It works by utilizing the magnetic and gyroscopic properties of protons, which are found in fluids like gasoline or water.12

The process involves aligning the magnetic moments of protons using a strong external magnetic field. Once this field is removed, the protons attempt to realign with the ambient magnetic field, such as Earth's. Because the protons are spinning, they precess around the magnetic field at a frequency directly related to the field's magnitude. This precession induces a weak voltage in an external coil, which is then electronically measured to determine the magnetic field's strength with high sensitivity. This method is particularly useful for magnetic surveys because it doesn't require precise alignment.1

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geomagnetic field
Measurement of the field
One such method involves the proton-precession magnetometer, which makes use of the magnetic and gyroscopic properties of protons in a fluid such as gasoline. In this method the magnetic moments of protons are first aligned by a strong magnetic field produced by an external coil. The magnetic field is then…
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One such method involves the proton-precession magnetometer, which makes use of the magnetic and gyroscopic properties of protons in a fluid such as gasoline. In this method the magnetic moments of protons are first aligned by a strong magnetic field produced by an external coil. The magnetic field is then…
Read More

magnetometer
…modern absolute instrument is the proton-precession magnetometer. It measures a voltage induced in a coil by the reorientation (precession) of magnetically polarized protons in ordinary water.
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…modern absolute instrument is the proton-precession magnetometer. It measures a voltage induced in a coil by the reorientation (precession) of magnetically polarized protons in ordinary water.
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Earth exploration
Magnetic methods
…magnetic surveys are made with proton-precession or optical-pumping magnetometers, which are appreciably more accurate. The proton magnetometer measures a radio-frequency voltage induced in a coil by the reorientation (precession) of magnetically polarized protons in a container of ordinary water. The optical-pumping magnetometer makes use of the principles of nuclear resonance…
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…magnetic surveys are made with proton-precession or optical-pumping magnetometers, which are appreciably more accurate. The proton magnetometer measures a radio-frequency voltage induced in a coil by the reorientation (precession) of magnetically polarized protons in a container of ordinary water. The optical-pumping magnetometer makes use of the principles of nuclear resonance…
Read More