摘要
The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.
基金
supported by the National Key R&D Program of China(Grant No.2020YFC2200500)
the Key Laboratory of Tian Qin Project(Sun Yat-sen University),Ministry of Education
the National Natural Science Foundation of China(Grant Nos.12075325,12005308,and 11605065)
the Doctoral Research Foundation Project of Hubei University of Arts and Science(Grant No.kyqdf2059017)。
