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Helmholtz Coil Systems and Test Equipment

Bartington Instruments supplies a range of Helmholtz coil systems for creating stable homogeneous magnetic fields. These systems consist of an assembly of up to three pairs of coils, each generating a field along a specific axis. They may be connected to a PA1 (power amplifier), and CU1 (control unit), which interfaces with a National Instruments™ acquisition card. They are supplied with a mounting table to hold the test item during operation.

The CU2 comprises a control module and reference magnetometer, allowing for active compensation of DC magnetic field variations, and attenuation of AC magnetic fields up to mains frequencies. This can be fitted easily onto existing systems, or as part of a new system. This module greatly facilitates the setup of a complete Helmholtz coil system.

These systems are used for calibration and testing of magnetic field sensors, and for producing stable magnetic environments in a laboratory.

HC1 This has a coil diameter of 500mm, and can produce a 0.1% homogeneous field in a volume of 260cm3. This coil is available as a single, two or three-axis unit. It can generate fields up to 500μT at DC, and 100μT at 3kHz.

HC2 This is designed for testing larger items. It has a coil diameter of 1m, and produces a homogeneous field to less than 1% error in a volume of 14000cm3, and less than 0.1% error in a volume of 2500cm3. For ease of shipping and installation, the HC2 comes in flat-pack form for customer assembly.

HC9 This small Helmholtz coil has a nominal coil diameter of just 350mm, and is built on aluminium coil formers. It can generate a homogeneous magnetic field of up to 1mT from DC to 440Hz, and over 100μT at 5kHz. It produces a homogeneous field to less than 0.1% error in a volume of 175cm3, and less than 1% error in a volume of 1150cm3.

HC16 This coil has the same specification as the HC9, but is built on non-conductive coil formers, which avoids the possibility of creating eddy currents.

Ferronato™ Coils For testing large objects, we can supply Helmholtz coils manufactured by Serviciencia S.L.. These coils are compatible with the Bartington PA1 power amplifier and CU1 control unit. The coils are available in diameters of 1.3m (BH1300) and 2m (BHC2000).

Helmholtz Coil Control System This includes the PA1 power amplifier, CU1 control unit, and CU2 closed-loop module. It enables generation and control of the current to be applied to the Helmholtz coils.

Test Equipment

Bartington Instruments also produces systems for equipment testing.

Degaussing Wand This is a handheld instrument that produces an alternating field. The wand offers a convenient way to remove remanent magnetisation accumulated in equipment such as magnetic shields.

Magnetic Shields These cylindrical chambers made of mumetal (a nickel-iron soft ferromagnetic alloy) attenuate the Earth’s magnetic field of ~50,000nT to a level of ~1nT. They can be supplied open-ended, or with capped ends to reduce noise.