Correction of temperature dependency of a standard; case-study - magnetic flux density standard

摘要

Temperature dependence of measuring instruments represents one of the most influential error sources in measurementof most physical quantities. There are several methods of reducing or cancelling substantial temperature influence on instruments. In this paper we are describing a calculative correction method in the field of precision magnetic flux density measurements, which involves mathematical correction of the instrument properties. For dc magnetic fields under 5 mT, nuclear magnetic resonance (NMR) measurements are both impractical and time-consuming and in some environments even impossible. To avoid complex NMR measurements, field coils as magnetic flux density transfer standards are often used. A method for correction of an air-cored field coil's coil-constant in order to take into account its temperature dependence is presented. As a result, instead of a complex NMR measurement only a simple current and temperature measurement were needed to calculate the generated magnetic flux density with relative uncertainty of 0.025percent.