Optimization of thermal link for a conduction-cooled superconducting magnet system

The thermal link between the second stage of cryocooler and the superconducting magnet has a significant influence on the initial cooldown time of conduction-cooled superconducting magnet. In this paper, a numerical investigation is carried out on the initial cooldown characteristics of a superconducting magnet system used flexible copper strap as the thermal link. The optimal shape ratio (cross-sectional area to length) of the copper strap is obtained to minimize the cooldown time. The results show that optimal shape ratio decreases with increasing the length. In addition, the effect of copper purity on the cooldown time is little at the optimal shape ratio or at RRR (Residual Resistive Ratio) > 100.