A standard system for low magnetic fields has been developed at the Korea Research Institute of Standards and Science. The system consists of a precision solenoid, He-Cs atomic magnetic resonance magnetometer, and apparatus for three-axis compensation of the Earth's magnetic field. The variations of the Earth's magnetic field are automatically compensated within 0.1 nT/h by a Cs atomic magnetic resonance field controller. The solenoid reproduces a dc field that is uniform at better than 3×10~(-7) within ±2 cm around the center. The experimentally measured coil constant and temperature coefficient of the solenoid are 1.231 0596×10~(-3) T/A (25℃) and 3.8×10~(-7)/℃, respectively. The standard serves for the calibration of magnetometers and uniform field coils, and also supports experiments related to research in magnetic fields in the range of (0.02-1.2) mT with (2-10)×10~(-6) uncertainty.
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