Magnetic environment and magnetic field standards at NPL for the calibration of low noise magnetometers and gradiometers for cleanliness studies

The magnetic field standards, facilities and capabilities available at NPL for the calibration of magnetometers and gradiometers and the measurement of the magnetic moment and relative magnetic permeability of materials will be presented. This work is performed in the NPL low magnetic field facility. The details of this facility will be explained, how the noise floor is being reduced and how the facility enables magnetic cleanliness measurement will be presented. This will include the discussion of a gradient field coil for the calibration of gradiometers. Methods to check that the materials used in space projects are not unduly magnetic will be discussed.