2009/01/30 by Luca Callegaro, Vincenzo D'Elia, Callegaro, Luca +6
Computer Science · Decision Sciences · Physics and Astronomy · #Experimental and Theoretical Physics Studies #FOS: Physical sciences #General Physics (physics.gen-ph) #Instrumentation and Detectors (physics.ins-det) #Scientific Measurement and Uncertainty Evaluation #Sensor Technology and Measurement Systems #physics.gen-ph #physics.ins-det
paper · pdf · doi:10.48550/arxiv.0901.4859
12 pages, 5 figures, 1 table
arxiv created 2009/01/30 · openalex publication_date 2009/01/30 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We developed an absolute Johnson noise thermometer (JNT), an instrument to measure the thermodynamic temperature of a sensing resistor, with traceability to voltage, resistance and frequency quantities. The temperature is measured in energy units, and can be converted to SI units (kelvin) with the accepted value of the Boltzmann constant kb; or, conversely, it can be employed to perform measurements at the triple point of water, and obtain a determination of kb. The thermometer is composed of a correlation spectrum analyzer an a calibrated noise source, both constructed around commercial mixed-signal boards. The calibrator generates a pseudorandom noise, by digital synthesis and amplitude scaling with inductive voltage dividers; the signal spectrum is a frequency comb covering the measurement bandwidth. JNT measurements at room temperature are compatible with those of a standard platinum resistance thermometer within the combined uncertainty of 60 ppm. A path towards future improvements of JNT accuracy is also sketched.