Title :
Maintenance and dissemination of the magnetic field unit at PTB
Author_Institution :
Phys. Tech. Bundesanstalt, Braunschweig, Germany
fDate :
4/1/2001 12:00:00 AM
Abstract :
The different methods which are used at PTB to disseminate the unit of flux density are presented and compared with respect to their uncertainties. A DC flux density range from 10 μT to 2 T is covered with the lowest relative uncertainty of 10-6 at fields of 1 mT to 2 mT. In case of AC fields, field coils are used as standards, the frequency response of which is checked by means of a simple but very reliable inductive measuring technique. A relative uncertainty of 3·10-3 or even less is typically achieved for frequencies below 30 kHz
Keywords :
calibration; coils; frequency response; gyromagnetic ratio; magnetic field measurement; measurement uncertainty; nuclear magnetic resonance; transfer standards; units (measurement); 10 muT to 2 T; AC fields; DC flux density range; NMR based setups; dissemination; field coils; flux density unit; free precession; frequency response; magnetic field standard; magnetic field unit; maintenance; transfer standards; uncertainties; Calibration; Coils; Frequency measurement; Instruments; Magnetic field measurement; Magnetic fields; Measurement standards; NIST; Nuclear magnetic resonance; Uncertainty;
Journal_Title :
Instrumentation and Measurement, IEEE Transactions on
