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.

中文翻译：

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用于冷却超导单通量量子电路芯片的液氦低温系统的设计和测试

设计了一种小型移动式液态氦低温系统，用于冷却超导单通量量子回路。该系统包括一个独特的双内筒，一个用于同轴线的“之字形”冷能回收结构以及一个特殊的磁屏蔽结构。进行实验以测试液氦低温系统的热性能和磁屏蔽效率。结果表明，在2 W的热负荷下，液氦的存储时间约为5 h，在温度为4.2 K时，芯片位置的磁通密度约为5 nT。