Long integration time is necessary to reach low uncertainty when measuring temperature through Johnson Noise Thermometry (JNT). The main goal of the NIST JNT experiment is to achieve a 6×10-6 relative uncertainty in the measurement of the water triple point, which could contribute to the re-determination of Boltzmann's constant. A four-channel JNT system, which will reduce the measurement time two-fold, is being developed with new components, including a switchboard, an analog to digital converter (ADC) and a programmable, recharging power supply system. While implementing the new ADC, a source of systematic error was revealed, as well as a means to increase the measurement bandwidth.
Citation: IEEE Transactions on Instrumentation and Measurement
Pub Type: Journals
Boltzmann s equation, correlation, digital analog conversion, Josephson arrays, measurement units, noise measurement, quantization, signal synthesis, standards, temperature.