Experimental and numerical characteristics of Peltier current lead for direct current mode

For the reduction of heat leakage via the current leads to superconducting magnets, several researches of the Peltier Current Lead (PCL) were performed, and demonstrate the principle of the PCL to reduce the heat leakage experimentally and numerically. The shape dependences were evaluated by using the ratios of the length and the cross section (L/A) both for the copper and thermoelectric (TE) semiconductor parts. The calculation results indicate that the L/A of the TE semiconductor is much smaller than that of the copper lead. This is due to the fact that the thermal and electric conductivities of the bismuth telluride alloy, which is used as the TE semiconductor, are much smaller than that of copper. Moreover, the heat leakage of the PCL is not sensitive to the L/A of the copper like the conventional current lead (CCL)s´. The characteristics of the PCL were evaluated and compared with that of the CCL experimentally. The heat leakages of both the PCL and the CCL increased with the increase of the current. In the comparison of the heat leakage of the both leads, it was found that the heat leakage of the PCL was always smaller than that of the CCL experimentally. In this work, the experimental results are compared and analyzed by the numerical calculation for direct current mode, and we discuss the assumption of the calculation.