薄膜温度计安装接触热阻和激励功率的优化

Thermal contact resistances and optimal excitation power of thin-film thermometer

从温度计自热效应的角度出发,分析了温度计安装的接触热阻,计算求出了4.2—20 K温区的接触热阻值,并理论推导了接触热阻的不确定度计算公式;其次根据求出的接触热阻值分析得到了温度计在4.2—20 K温区的最优激励条件。实验结果表明:在不同的实验温区4.2—20 K范围内,温度计的最优激励电压均大于使用手册中的推荐值2 mV±25%;温度计自热效应引起的温度测量不确定度在20 K时达到最大值0.896 mK,在4.2 K时为最小值0.377 mK。

A mathematical model of the basic two-current method for measuring the thermal resistance on the mounted temperature sensor was presented based on the optimal selection of currents. Correcting e- quations were provided for calculating the optimal excitation power of cryogenic temperature sensor combined temperature measurement uncertainty due to instrumentation, self-heating and other potential sources of er- ror. The results show that the optimal sensor excitation voltages at different critical temperatures are all a- bove the 2 mV _＋ 25% range conservatively used in the calibration facility. The maximum temperature meas- urement uncertainty excited with the optimal operating power is 0. 896 mK at 20 K, and the minimum one is 0. 377 mK at 4.2 K respectively.