Room temperature three sensor magnetic field gradiometer

We have constructed a portable magnetic field gradiometer from fluxgate magnetometers using a novel common-mode rejection method. The sensor, known as a room temperature Three Sensor Gradiometer (rtTSG), is, as far as we know, the first hand-held gradiometer that can measure all components of the magnetic field gradient tensor. The rtTSG can measure these components in motion at a noise level of about 1.4×10-10 T/m√Hz at 1 Hz. Real time tracking of magnetic dipoles while the gradiometer is in motion has been demonstrated. © 1996 American Institute of Physics.