低温气体声学温度计测量原理与实验系统研制

Research on experimental system of cryogenic gas acoustic thermometer

热力学温度是温度测量的基准,应用气体声学温度计测量热力学温度是目前应用最广泛和测量最精确的方法之一。本文基于国内对于低温标准的需求,针对低温温度的精密测量,分析了采用球形谐振腔的气体声学温度计测量原理,并对谐振腔进行了静力学特性仿真模拟。在综合考虑降低非理想因素扰动的基础上,研制了一套在液氦温区4.2~20 K、利用脉冲管制冷机冷却的气体声学温度计实验系统,该系统将用于高精度低温温度测量实验以及气体工质的热物性研究。

Thermodynamic temperature is the benchmark for measuring temperature. The application of gas acoustic thermometer to measure thermodynamic temperature is one of the most widely use and most accurate methods. Based on the demand of low temperature standards, this paper analysed the measurement principle of gas acoustic thermometer using spherical resonance cavity for the precise measurement of cryogenic temperature. The static characteristics of the cavity were simulated and analyzed. Based on the comprehensive consideration of reducing the disturbance of non-ideal factors, a set of liquid helium was developed. The low-temperature gas acoustic thermometer experimental system cooled by pulse tube refrigerator in the temperature range of 4.2~20 K will be used in the high-precision low-temperature measurement and the thermal property study of the working medium.