An improved magnetic properties measurement scheme using a torsion pendulum

Magnetic disturbance, originating arising from the interaction between the environmental magnetic field and the test mass (TM) properties, is a significant source of the high-precision inertial sensor noise in the space-borne gravitational wave detection missions, which puts forward an extremely stringent requirement on the TM magnetic cleanliness. Therefore, a torsion pendulum for on-ground testing is required to characterize the magnetic properties of a TM. We report an improved magnetic properties measurement scheme using a torsion pendulum with an electrostatically controlled block. In this novel scheme, four magnetometers are set near the TM for real-time monitoring the magnetic field, and a magnetic field correction method is proposed to improve the magnetic properties calculation precision. The results showed that the relative error of our method, compared with that of the traditional method, decreased from 35.40% to 2.38% for the component of the remnant magnetic moment my and from 8.65% to 6.75% for the magnetic susceptibility χ. •Magnetometer is used in the torsion pendulum to monitor the magnetic field.•Improving the calculation precision by using a corrected magnetic field.•Suitable for measurement under weak applied coil magnetic field.•Reconstructing the background magnetic field by multipole expansion.