Design and test of a liquid helium cryogenic system for the cooling of a superconductive single-flux-quantum circuit chip

摘要

A small-scale mobile liquid helium cryogenic system has been designed for the cooling of a superconductive single-flux-quantum circuit. The system includes a unique double inner cylinder, a "zigzag" cold energy recovery structure for the coaxial line and a special magnetic shielding structure. Experiments were conducted to test the thermal performance and the magnetic shielding efficiency of the liquid helium cryogenic system. The results show that the storage time of the liquid helium is about 5 h with a heat load of 2 W and the magnetic flux density at the chip location is about 5 nT at the temperature of 4.2 K.