量子电压标定的叠加型噪声温度计研究

Measuring the temperature with high accuracy and reliability has received lots of attention in precision measurement areas. The Johnson noise thermometer with switches is impossible to match the transmission line responses well. Moreover, it has a limit bandwidth and requires quite a long time to achieve a satisfactory uncertainty. The drawbacks limit its practical applications in industrial areas.. This project proposes a novel noise thermometer that measures the reference noise and the thermal noise simultaneously. The separation of the two noise is presented and we analyze the impacts of the internal resistor, sense resistor and lead resistor on the measurement results carefully. To simplify the system configuration and reduce the inductive voltage error, a novel pulse-driven scheme is used for waveform synthesis. Because the frequency response of the transmission line between the quantum voltage noise source and the sense resistor has a significant influence on the accuracy of the quantum voltage, polynomial fitting is applied to remove this error. We will measure the temperatures of triple point of water and melting point of Gallium to demonstrate the feasibility of the superposition noise thermometer.. The superposition noise thermometer is expected to provide a measurement uncertainty of 0.5% in a short measurement time. It is very suitable for temperature measurements in harsh environments. Moreover, the calibration process will be simplified with the thermometer.

准确可靠的温度测量是当前精密测量领域研究的热点和难点。传统开关切换型噪声温度计存在传输线难以匹配、带宽窄、测量时间长的问题，极大地限制了其在工业现场的实际应用。. 本项目提出一种全新的叠加型噪声温度计，从而实现量子电压参考噪声和热噪声的同时测量。项目理论研究参考噪声和热噪声的分离方法，分析内阻、测温电阻、引线电阻等因素的作用机制。采用新型编码方式合成参考电压噪声从而简化系统结构、减小感应电压误差。建立传输线模型并通过多项式拟合消除其频率响应特性的影响。在实验室环境测量水三相点、镓熔点的热力学温度，验证方案的可行性。. 本项目研制的叠加型噪声温度计经过短期测量预期可达到0.5%的不确定度，有望解决极端环境的热力学温度测量难题。同时，可以为温度计的原位校准打下基础，进而实现温度量值的扁平化传递。

小型化、实用化的原级测温方式是当前温度计量领域的研究热点。针对实用型噪声温度计参考信号标定的需求，本项目研制了包含脉冲源、微波放大器、隔离放大器、直流阻断、衰减器、多通道补偿信号源、数字化仪、约瑟夫森结阵、杜瓦、低温恒温平台的宽频交流量子电压系统。研究了补偿法、新型反脉冲法的工作原理。通过高速脉冲与多通道补偿的联合驱动，成功合成了国内首个1V宽频带交流量子电压。研制了一套直接溯源到宽频交流量子电压的单端叠加型噪声温度计。分析了单端叠加型噪声温度计的工作原理，探讨了系统测量过程中关键参数对结果的影响。研制了实现低噪声放大器中场效应管快速筛选的仪器，从而有效提高了筛选效率。研制了实现传感器电阻精密测量的仪器，从而降低系统成本。水三相点的测量结果为272.32K±1.01K。研制了一种全差分叠加型噪声温度计。我们详细比较了两种测量方案的频谱、传感器电阻对功率比值的影响。采用量子电压源合成的多频信号对便携式商用任意波形发生器产生的参考噪声源进行了标定。通过交叉验证，给出了拟合消除传输线效应时最佳的带宽和拟合阶数。利用搭建的系统对镓熔点进行了测量，得到的结果为302.86K±1.02K。本文工作对于解决特殊场景下的温度测量难题、实现铂电阻温度计的原位标校具有重要意义。