The exact determination of the magnetic flux density of a homogeneous magnetic field is the basis of all calibrations in international magnetic bureaus of standards, as for example the PTB (Physikalisch Technische Bundesanstalt) in Braunschweig or the NPL (National Physical Laboratory) in London. Also BROCKHAUS uses this technology to calibrate with a very high accuracy magnetic properties like flux density and field strength as well as measuring instruments and coil systems. The nuclear magnetic resonance instrument (NMR) measures the frequency of a precision movement magnetic moments of protons produce, if they are exposed to a magnetic field.
This frequency is measured over a resonance circuit. As this frequency is coupled strictly linear to the strength of the magnetic field, the magnetic flux density or field strength can be determined with an accuracy of 10-6 T using this method.
| Test Method | Measuring coil | Material | Field Strength | Standard |
| Material testing of hard magnets in an electromagnet |
Compensated surrounding coils | Ferrite AlNiCo Rare Earth |
max. 2500 KA/m | IEC 404-5 |
| Pole coils | Ferrite | max. 2500 KA/m | ||
| Calibration of hard magnetic measuring equipment | Compensated surrounding coils | Ferrite AlNiCo Rare Earth |
max. 2500 KA/m | IEC 404-5 |
| Pole coils | Ferrite | max. 2500 KA/m | ||
| Calibration of reference samples |
Compensated surrounding coils | Nickel | max. 1500 KA/m | |
| Test Method | Measuring coil | Properties | Field Strength | Standard |
| Calibration of magnetic measuring instruments |
Fluxmeter | Magnetic flux | max. 1500 KA/m Kernspin- resonanz |
Nuclear magnetic resonance (NMR) |
| Gaussmeter | Field strength H Flux density B Polarisation J |
max. 1500 KA/m Kernspin- resonanz |
NMR | |
| Hall sensors | Field strength H Flux density B Polarisation J |
max. 1500 KA/m Kernspin- resonanz |
NMR | |
| Helmholtz coils | Coil constant k | Reference magnet/ NMR |
||
| Field coils | Coil area A | max. 1500 KA/m Kernspin- resonanz |
NMR |