Polatomic is the world leader in laser-pumped helium magnetometers. The company has developed three major innovations in magnetometer instrumentation:
- Omni-directional magnetic field measurement with a single laser pump source.
- An order of magnitude improvement in sensitivity compared to lamp-pumped helium magnetometers in both the MAD band-pass and ELF band-pass meaning sensitivity in the sub-picotesla range from almost DC to 200+ hertz.
- The option to extract both vector components and scalar field magnitude from a single optically pumped sensor.
- Demonstrated sensor sensitivity on the order of 50 Femto-Tesla
These design innovations are
made possible by the use of a proprietary diode laser pump source,
which is covered by U.S. Patent #5,036,278, “Radiation Source for
Helium Magnetometers”, issued to Polatomic July 30, 1991. This patent
covers the use of diode lasers to optically pump resonance
magnetometers utilizing any isotope of helium as a resonance element.
Operation
The
patented laser-pumped helium magnetometer sensing element used in
Polatomic systems is capable of operating in either vector or scalar
mode. In vector mode three output voltages are generated, which are
proportional to the three mutually orthogonal magnetic field vector
components. In scalar mode the Larmor precession frequency, which is
proportional to the absolute magnetic field, is measured. The vector
fields are measured to an accuracy of better than 0.1%; in scalar mode
the field magnitude is measured to an absolute accuracy of better than
0.001%. Because of the modular designs developed by Polatomic, the
laser-pumped vector and scalar helium magnetometers have a large amount
of commonality, both in the sensor and in the electronics.
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Advantages
The
free precession magnetometer, as well as other nuclear magnetometers,
are typically used for scalar geomagnetic measurements on the earth’s
surface. Measurements of vector components of the magnetic field are
made with a single-axis and tri-axial fluxgate magnetometers. Current
airborne magnetic surveys and airborne ASW missions are conducted using
lamp-pumped magnetometers. The optically pumped magnetometers have an
order of magnitude better sensitivity than the proton or fluxgate
magnetometers. Polatomic’s Laser Magnetometer technology offers an
order of magnitude improvement in sensitivity and accuracy over the
best of previous instruments, including the AN/ASQ-81 MAD set, used by
the U.S. Navy for airborne detection of submarines.
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