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Development of liquid He free dilution refrigerator with Gifford-McMahon refrigerator.

开发液氦自由稀释制冷机和吉福德-麦克马洪制冷机。

基本信息

批准号：
10554014
负责人：
FUKASE Tetsuo
金额：
$ 8.26万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

A ^3He-^4He dilution refrigerator is developed to operate without using liquid helium. A commercial two-stage Gifford-McMahon refrigerator(SRDK-408DA, Sumitomo Heavy Industries, ltd.)is used to cool the dilution unit and the radiation shield of shield of the cryostat. A Joule-Thomson cycle for condensation of the ^3He-^4He gas mixture into the dilution unit is designed to built in the dilution refrigeration process.1. The GM refrigerator can cool the DR unit down to 3.05K.This low temperature is enough to operate Joule-Thomson cycle and the dilution refrigeration process.2. A dilution unit with a standard tube-in-tube type heat exchanger and a counter flow type heat exchanger for Joule-Thomson expansion has been made and passed on the helium leak test.3. Automatic circulation ^3He-^4He gas control system has been made and tested.4. The dilution unit has been combined with the GM refrigerator. Leak test with helium gas has been passed on several connection parts to the gas control system.5. Thermometers and electrical heaters are attached to the dilution unit.6. A condensation process of the mixture gas in a Joule-Thomson cycle is under examination. Final refrigeration test is planed soon just after the condensation test.

研制了一台不使用液氦的^3He-^4He稀释制冷机。将商用两级Gifford-McMahon制冷机（SRDK-408 DA，Sumitomo Heavy Industries，ltd.）用于冷却低温恒温器的稀释单元和辐射屏蔽。在稀释制冷过程中设计了一个用于冷凝^3He-^4He混合气体进入稀释单元的焦耳-汤姆逊循环。GM制冷机可以将DR单元冷却到3.05K，这个低温足以运行焦耳-汤姆逊循环和稀释制冷过程.研制了一套具有标准管中管式换热器和对流式焦耳-汤姆逊膨胀换热器的稀释装置，并通过了氦泄漏试验.研制了自动循环^3He-^4He气体控制系统，并进行了试验.稀释装置已与GM冰箱结合。气体控制系统的几个连接部件已通过氦气泄漏测试。温度计和电加热器连接到稀释单元。6.研究了混合气体在焦耳-汤姆逊循环中的冷凝过程。最终制冷试验计划在冷凝试验后不久进行。