ON THE ACCURACY OF FLUX - GATE MAGNETOMETERS - Calibration Experiment

We examined the efficiency of the flux-gate magnetometers, MB-160 and MB-162, Shimadzu, which we use for variation observation at the Kakioka Magnetic Observatory. We also examined our method and the equipment for the calibration of the installed calibration apparatus in the flux-gate magnetometer. On the basis of examinations, we obtained the following conclusions: 1. Using our equipment for the calibration at Kakioka, which is composed of mainly one set of 3-axial Helmholtz coil, we can calibrate the installed calibration apparatus within an accuracy of 0.1%. 2. When we use the flux-gate magnetometer with the resolution of 0.1 nT, we can extend the range of the observation from ±500 nT to ±600 nT with a sufficient linearity. 3. The output signal for the calibration which is generated by the installed apparatus in the flux-gate magnetometer is stable. With the use of this installed apparatus, therefore, we are able to calibrate the scale value during the observation.