ANALYSIS OF THE FACTORS AFFECTING THE REALIZATION OF LAMBDA TRANSITION TEMPERATURE OF (HE)-H-4

作者：Yin, L.; Lin, P.; Zhao, J. J.; Qi, X.^*

来源：Metrology and Measurement Systems, 2011, 18(1): 13-23.

DOI：10.2478/v10178-011-0002-7

• He-4
• lambda transition temperature
• sealed-cell
• realization

Owing to the dramatic change in the thermal conductivity of He-4 when its temperature crosses the transition of superfluid (HeI) and normalfluid (HeII), a sealed-cell with a capillary is used to realize the lambda transition temperature, T-lambda. A small heat flow is controlled through the capillary of the sealed-cell so as to realize the coexistence of Hel and Hell and maintain the stay of HeI/HeII interface in the capillary. A stable and flat lambda transition temperature "plateau" is obtained. Because there is a depression effect of T-lambda caused by the heat flow through the capillary, a series of heat flows and several temperature plateaus are made and an extrapolation is applied to determine T-lambda with zero heat flow. A rhodium-iron resistance thermometer with series number A34 (RIRT A34) has been used in 24 T-lambda -realization experiments to derive T-lambda with a standard deviation of 0.022mK, which proves the stability and reproducibility of T-lambda.

• 出版日期2011
• 单位北京化工大学; 中国计量科学研究院