Experimental estimation of the accuracy of modern scalar quantum magnetometers in measurements of the Earth's magnetic field

The results of calibration of proton, cesium, potassium and helium–cesium scalar magnetometers in the range 20–100 μT are discussed. The calibration made it possible to estimate errors and to apply corrections to reduce the uncertainty of measurements.Experimental data have been obtained using a standard calibration system designed in the Russian Mendeleyev Metrology Institute (VNIIM). The systematic uncertainty in the reproduction of the magnetic flux density is estimated to be 1.8 × 10−7, the random standard deviation being 0.001 nT.The experimental data can be used for the proper selection of measuring instruments and prediction of their uncertainty when studying the Earth's magnetic field.