Dilution Refrigerator for Nuclear Refrigeration and Cryogenic Thermometry Studies
Dilution Refrigerator for Nuclear Refrigeration and Cryogenic Thermometry Studies
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用于核制冷和低温测温研究的稀释制冷机
DOI：
10.1007/s10765-014-1670-9
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发表时间：
2014
影响因子：
2.2
通讯作者：
Tohru Hata
中科院分区：
文献类型：
--
作者：
Hisashi Nakagawa;Tohru Hata
本研究探讨了超低温设施的设计和建造，以实现日本从0.9 mK到1 K的临时低温标度（PLTS-2000），通过校准服务推广其使用，并研究低于1 K的低温下的温度测量。为此，在内部构建了稀释制冷机，其具有四个烧结银离散热交换器，用作铜核退磁阶段的预冷却阶段。连接在混合室法兰上的融化曲线温度计可以使用冰箱连续冷却至4.0 mK。最低温度对循环速率的依赖性可以通过基于完美连续逆流换热器模型的Frossati公式的计算来解释，假设Kapitza阻力具有温度依赖性。估计泄漏到混合室的残余热约为86 nW。我们正在构建一个具有含有效量铜（9 T磁场中为51 mol）的核级的核退磁低温恒温器，目前将开始实现PLTS-2000的工作。本文介绍了稀释制冷机的设计和性能。
This study explores the design and construction of an ultra-low temperature facility in order to realize the Provisional low-temperature scale from 0.9 mK to 1 K (PLTS-2000) in Japan, to disseminate its use through calibration services, and to study thermometry at low temperatures below 1 K. To this end, a dilution refrigerator was constructed in-house that has four sintered silver discrete heat exchangers for use as a precooling stage of a copper nuclear demagnetization stage. Amelting curve thermometer attached to the mixing chamber flange could be cooled continuously to 4.0 mK using the refrigerator. The dependence of minimum temperatures on circulation rates can be explained by the calculation of Frossati’s formula based on a perfect continuous counterflow heat exchanger model, assuming that the Kapitza resistance has atemperature dependence. Residual heat leakage to the mixing chamber was estimated to be around 86 nW. A nuclear demagnetization cryostat with a nuclear stage containing an effective amount of copper (51 mol in a 9 T magnetic field) is under construction, and we will presently start to work toward the realization of the PLTS-2000. In this article, the design and performance of the dilution refrigerator are reported.