A magnetometer is a device that measures the strength and direction of magnetic fields. It helps scientists and engineers understand and study magnets and Earth's magnetic field. Full definition
For these studies, NIST developed a direct - current (DC) magnetometer in which polarized light is used as a detector to measure the «spin» of rubidium atoms induced by magnetic fields. (sciencedaily.com)
Over the years, USGS has «bought a lot [of magnetometers], Narod says. (sciencemag.org)
Other researchers started asking Narod for magnetometers for their applications. (sciencemag.org)