用于亚开温区的极低温绝热去磁制冷机  

Ultra-low temperature adiabatic demagnetization refrigerator for sub-Kelvin region

作　　者：王昌 李珂[1] 沈俊[1,2,3] †戴巍 王亚男 罗二仓 沈保根[3,4] 周远 Wang Chang;Li Ke;Shen Jun;Dai Wei;Wang Ya-Nan;Luo Er-Cang;Shen Bao-Gen;Zhou Yuan(Key Laboratory of Cryogenic Engineering,Technical Institute of Physical and Chemistry,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100190,China;Ganjiang Innovation Academy,Chinese Academy of Sciences,Ganzhou 341000,China;State Key Laboratory of Magnetism,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]中国科学院理化技术研究所,低温工程学重点实验室,北京100190 [2]中国科学院大学,北京100190 [3]中国科学院赣江创新研究院,赣州341000 [4]中国科学院物理研究所,磁学国家重点实验室,北京100190

出　　处：《物理学报》2021年第9期257-263,共7页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51925605);中国科学院科研仪器设备研制项目(批准号:GJJSTD20190001)资助的课题。

摘　　要：随着空间观测、量子技术等前沿科研领域的发展,亚开温区的极低温制冷需求日益增加.本文设计并研制了一台极低温单级绝热去磁制冷机.该制冷机由GM型制冷机提供约3 K热沉,以钆镓石榴石为磁热工质,由超导线圈提供最大为4 T的磁场,通过绝热去磁,实验最低温度可达470 mK.在恒温控制模式下,可在1 K下提供2.7 J冷量,温度波动小于0.5 mK,绝热去磁制冷的第二热力学效率为57%;在0.8 K下,制冷量为1.2 J.该制冷机将作为50 mK温区三级绝热去磁制冷系统中的第一级,在1 K下提供0.7 mW制冷功率.本研究为进一步开展极低温多级连续绝热去磁制冷奠定了基础.With the development of space observation,quantum technology and other frontier scientific research fields,the demand for ultra-low temperature refrigeration in sub-Kelvin region is increasing.Compared with dilution refrigeration and sorption refrigeration,adiabatic demagnetization refrigeration(ADR)has the outstanding advantages of high efficiency,compact,gravity independence and accessibility of working materials,which make ADR a promising technology for sub-Kelvin cooling.A single-stage ultro-low temperature adiabatic demagnetization refrigerator is designed and developed.The thermodynamic principle and quantitative analysis are presented,from the macroscopic and microcosmic view,and operating results show good agreement with the theoretical value.This refrigerator is precooled to 3 K by a GM-type refrigerator,with 252 g gadolinium gallium garnet(monocrystalline)used as a working medium.The maximum magnetic field of 4 T is provided by a superconducting coil.Flexible heat connection is used between the pre-cooler and ADR,so heat generated by vibration decreases.From(3 K,4 T),the lowest temperature can reach 0.47 K by adiabatic demagnetization,which is consistent with the result drawn from the entropy data.In a constant-temperature-control mode,the demagnetization rate is controlled by a feedback loop,so the temperature can be held in the presence of a load.A cooling capacity of 2.7 J is provided at 1 K,with temperature fluctuation being lower than 0.5 mK,and the second thermodynamic efficiency of adiabatic demagnetization refrigeration is 57%.at 0.8 K,the cooling capacity is 1.2 J.Future work on improving the performance includes the improving of the on-off ratio of the heat switch,so,the irreversible loss caused by the heat transfer temperature difference in conduction state can be reduced.Improving the heat transfer performance of the salt pill,the heat can be ejected in a shorter period.This refrigerating machine is the first Chinese adiabatic demagnetization refrigeration system that can be operated in circ

关 键 词：亚开温区制冷 极低温 绝热去磁 

分 类 号：TB651[一般工业技术—制冷工程]