Fluxmeter

In addition to NMR, Metrolab is historically known for its integrators, primarily in the world of accelerators.

The many applications and intricacies of this powerful technology require much more than a single web page, but we aim to provide at least an overview of some basics.

Induced Voltage by Movement in a Magnetic Field

The movement of a coil in a magnetic field induces a voltage proportional to the change in flux observed by the coil. Similarly, a varying field induces a voltage on a stationary coil.

These principles have been understood and exploited since the 19th century for precise measurement, for example, of the Earth’s magnetic field.

Fluxmeters also continue to play an important role in measuring the hysteresis of magnetic materials and in magnetic design, for example, to determine losses in a magnetic circuit.

One Application: One Coil but an Integrator for All Coils

Although coils come in all shapes and sizes, a few standard configurations cover many applications:

Mobile coils are moved from the measurement location to another location, typically a zero-field zone. The voltage integral is proportional to the total change in flux, regardless of the exact path taken by the coil. Moving wires are used to map magnets in very narrow spaces, by measuring voltage changes in a wire swept through space.

Tilting coils rotate in place to measure the field at a particular point. As the coil returns exactly to its starting point, the change in flux is known to be zero, allowing for very precise drift correction.

Static coils are used to measure varying fields. Periodic sampling of the voltage integral provides the exact shape of the field ramp.

Rotating coils and moving wires are used for field mapping.