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Development of Simple Diolution Refrigerators free from Cryogen refilling

开发无需充注冷冻剂的简单稀释冰箱

基本信息

批准号：
07559016
负责人：
KUBOTA Minoru
金额：
$ 2.11万
依托单位：
Institute for Solid State Physics, the University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07559016/
关键词：
dilution refrigerator(DR)cryogen free refrigerators milli Kelvins continuous operation pulse tube refrigerator below 4K ultra low temp.low vibration level World first Pulse tube refrigerator precoold DR

项目摘要

Dilution refrigerator is the very low temperature refrigerator continuously operable down to much below 1K and in the extreme case to 2 milli Kelvin [1]. The complication of the machine and the operation often limits the versatility of such a refrigerator covering the wide temperature range over a factor of a few hundred or so, which is essential for basic research in many fields [2].The first simplification of the refrigerator was brought about by the extinction of the pumped He bath for the condensation of the circulating 3He, instead the enthalpy of the 3He pumped out from the still is utilized in the JT precooling heat exchanger [3]. We have been using a number of JT precooled Dilution Refrigerators and One of them is being used for experiments under world fastest rotation for the fundamental study of physics of quantized vortices for years because of the reliability and the simplicity of the refrigerator [4].The second important simplification is achieved by the elimination of the cryogen usage. The development of the Cryocoolers enables us to operate a dilution refrigerator without cryogen [5], yet the viblation limits the ultimate low temperature as well as type of experiments.We have achieved continuously operating dilution refrigeraor which runs over many weeks without reffiling the cryogen while keeping the temperature below 40mK.This was made possible by combination of the hybrid He refrigerator, consists of Gifford McMahon cycle with solid displacer as the 1st stage and a double inlet pulse tube refrigerator as the second with a JT precooled dilution refrigerator which does not have 1K pot nor liq. ^4He bath. Further study of the combination of vibration isolation and good thermal contact is being carried out in order to obtain the condition to perform experiments below 10mK.

稀释制冷机是一种非常低温的制冷机，可连续运行至远低于1 K，在极端情况下可达到2毫开尔文[1]。机器和操作的复杂性通常限制了这种制冷机的多功能性，其覆盖了几百个因子左右的宽温度范围，这对于许多领域的基础研究是必不可少的[2]。制冷机的第一个简化是由于用于冷凝循环的3 He的泵送He浴的消失而实现的，相反，从蒸馏器泵出的3 He的焓在JT预冷却热交换器中使用[3]。我们已经使用了许多JT预冷稀释制冷机，其中一台由于其可靠性和简单性，多年来一直用于世界上最快转速下的实验，用于量子化涡旋物理的基础研究[4]。第二个重要的简化是通过消除制冷剂的使用而实现的。低温制冷机的发展使我们能够在没有制冷剂的情况下操作稀释制冷机[5]，然而振动限制了最终的低温以及实验类型。我们已经实现了连续操作稀释制冷机，其在不重新填充制冷剂的情况下运行许多周，同时保持温度低于40 mK。这是通过混合He制冷机，由第一级采用固体置换器的吉福德-麦克马洪循环和第二级采用双入口脉管制冷机的JT型预冷稀释制冷机组成。#24040;浴。为了获得在10 mK以下进行实验的条件，正在对隔振和良好的热接触的组合进行进一步的研究。