单圆柱微波谐振法测量热力学温度的研究

利用氩气的量子力学“从头算”理论和相关实验测量结果,基于圆柱微波谐振法建立了气体折射率热力学温度计实验系统,测量了253~303 K范围内的热力学温度。通过测量圆柱微波谐振腔内4个横磁模式的微波谐振频率,获得了氩气在700 kPa附近的气体折射率,不同微波模式得到的氩气折射率一致性优于1×10^-8,进一步结合氩气的维里状态方程得到热力学温度。热力学温度T和ITS-90国际温标T90差异不确定度为11.6 mK,与国际温度咨询委员会的评估值具有良好的一致性。未来随着氩气理论计算和实验系统压力测量不确定度的深入研究,该方法测定热力学温度的不确定度会进一步改善。

Thermodynamic Temperature Measurement Using Single Cylindrical Microwave Resonator

Using the microwave resonant method, the thermodynamic temperature is measured in the temperature range from 253 K to 303 K based on the gas refractive index primary thermometry by using the properties for argon from“ab initio”quantum mechanics calculation theory and experimental results and the microwave resonant method. Four transverse magnetic microwave resonance frequencies were measured to obtain the refractive index in argon at 700 kPa, the consistence of the refractive index from different microwave modes was better than 1×10-8. The thermodynamic temperature then was determined by combining the refractive index measurement results and the viral equation of state for argon. The uncertainty of the difference of the thermodynamic temperature T and the ITS-90 international temperature T90 was evaluated to be 11.6 mK, and the results agreed with the Consultative Committee for Thermometry (CCT) recommendation values well. The uncertainty from this method will be decreased with the development of the theoretical calculation for argon and the improvement of the pressure measurement in the next future.