Conceptual design of 4He film suppressor in Still of Dilution Refrigerator

26th International Cryogenic Engineering Conference & International Cryogenic Materials Conference 2016

材料科学;物理学

Chandra, Mandal Bidhan^1 ; Kr Das, Nisith^1

Variable Energy Cyclotron Centre, Kolkata

700 064, India^1

关键词: Base temperature;    Cooling power;    Dilution refrigerator;    Gas circulation;    Geometrical configurations;    Isotopic mixtures;    Novel design;    Thermodynamic conditions;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/171/1/012143/pdf
DOI  :  10.1088/1757-899X/171/1/012143

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

The capacity of a dilution refrigerator in terms of its cooling power and base temperature is primarily governed by the flow rate of the isotopic mixture of helium. In the process of circulation of gas mixture, geometrical configuration of3He distillation chamber (Still) maintained at a temperature of around 0.7 K plays a significant role in controlling the flow rate. We have already employed a still in our existing dilution refrigerator, however, a new conceptual design is presented here and it is envisaged that this novel design will improve the gas circulation efficiency. Even though, thermodynamic conditions are major issues in eliminating unwanted4He film as compared to3He molecules, this design based on a new geometry is likely to enhance the pressure and the temperature at the still that helps in burning out the super-fluid4He film. The conceptual design of film suppressor and its relevance in the recently commissioned indigenous dilution refrigerator at Variable Energy Cyclotron Centre is presented in this paper.