Experimental Energy Loss Analysis of the SMB-Based Rotation Mechanism Below 10 K

We present the experimental characterization of energy loss in a rotation mechanism using a superconducting magnetic bearing (SMB), designed for the polarimeter of a cosmic microwave background polarization experiment. The design specification aims to achieve mW-level heat dissipation at 5 K with a rotation speed of 46 rpm. We estimated the heat dissipation from the SMB-based rotation mechanism, constructed a loss-mechanism model, and narrowed down the causes of the loss. The results indicate that the loss is predominantly caused by eddy currents in the drive mechanism.