Peltier Current Lead Experiments with a Thermoelectric Semiconductor near 77 K

TL;DR

This paper experimentally verifies the effectiveness of Peltier current leads in reducing heat leak in cryogenic systems and proposes a novel semiconductor-HTS hybrid current lead design for improved performance.

Contribution

It confirms the heat leak reduction of Peltier leads and introduces a new FGM-based semiconductor-HTS current lead system for cryogenic applications.

Findings

Heat leak reduced by 30% with Peltier leads in helium systems.

Heat leak reduced by 40% with Peltier leads in nitrogen systems.

Proposed semiconductor-HTS hybrid system potentially offers higher current capacity and stability.

Abstract

Peltier current lead was proposed to reduce heat leak from the current lead. The temperature of the hot side of semiconductors was kept to be room temperature and the liquid nitrogen was used to cool the system in the experiment. The experiment confirmed the principle of the Peltier current lead, and the reduction of the heat leak is calculated to be 30 % for the liquid helium system and 40 % for the liquid nitrogen system. We also proposed a new current lead system which is composed of semiconductors and high temperature superconducting material (HTS). This idea bases on the functionally gradient material (FGM), and the HTS is connected to the semiconductor directly. The temperature of the hot side of semiconductor is kept to be the liquid nitrogen temperature, the temperature of HTS can be expected to be lower than 77 K. Therefore, we can expect high current capacity of the HTS and/or high stability of the HTS. We use BiSb as a N-type semiconductor and BiTe as a P-type semiconductor in the experiment, and the temperature of the cold side of the semiconductor is 73 K in this experiment.