Precise standard system for low dc magnetic field reproduction

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 °C) and 3.8×10−7/°C, 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.