Superposition Johnson Noise Thermometry with a Quantum Voltage Noise Source for Calibration

Different from the noise thermometer in a substitution configuration, a superposition configuration allows a reference signal to be injected into the sense resistor so that the thermal voltage noise and the reference signal can be simultaneously transferred to the measurement electronics through the same transmission line. The construction of a quantum-voltage-calibrated superposition noise thermometer is presented in this paper and preliminary experiments are conducted to demonstrate its feasibility for temperature measurements. A polynomial fitting is used to fit the transfer function of the connection network between the QVNS and the sense resistor.