A cross correlation noise thermometer for thermodynamic temperature measurement at low temperatures

摘要

A cross-correlation noise thermometer is designed and developed for practical and thermodynamic temperature measurements at low temperatures using the digital techniques. The basic characteristics of the noise thermometer are investigated at both room and liquid nitrogen temperatures. The thermal noise spectrum across a resistance sensor is analyzed by the FFT method. As preliminary results, the mean square of the noise voltage, which is proportional to thermodynamic temperature, is compared with the international temperature scale of 1990 at about 84 K.