声学气体温度计测量不确定度分析

Analysis of uncertainty in measurement of acoustic gas thermometers

声学气体温度计(AGT)是当前测量热力学温度最精确和应用最广泛的计量器具。该方法通过测量声学共鸣腔内的气相声速确定热力学温度,进而得到玻尔兹曼常数,从而实现国际温标开尔文的重新定义。声学气体温度计测量的关键技术包括气体纯度、腔体体积、声波及微波频率的测量。针对当前的研究成果,本文综述了其主要不确定度来源分析,并对未来低温区的精确测量做了展望。

Acoustic gas thermometer (AGT) is currently the most accurate and wide method in the measurement of κ. It can determine κ by measuring the speed of gas sound then determine the thermodynamic temperature in the acoustic resonance cavity. The uncertainty in the determination of the thermodynamic temperature by AGT is determined by the following major components: Purity of the test gases which cause uncertain average molar mass, the volume of the cavity resonators of different shape or dimensions and acoustic frequency that fitted for the function of the pressure on the isotherm. This paper reviewed main sources of uncertainty and the prospect of research, the accurate measurement of low temperature area in the future was prospected.