Experimental measurements and noise analysis of a cryogenic radiometer

Published: July 10, 2014


Solomon I. Woods, Timothy M. Jung, Adriaan C. Carter, Raju V. Datla , Stephen M. Carr


A cryogenic radiometer device, intended for use as part of an electrical-substitution radiometer, was measured at low temperature. The device consists of a receiver cavity mechanically and thermally connected to a temperature-controlled stage through a thin-walled polyimide tube which serves as a weak thermal link. With the temperature diff erence between the receiver and the stage measured in milliKelvin and the electrical power measured in picoWatts, the measured responsivity was 4700 (K/mW) and the measured thermal time constant was 14 (s) at a stage temperature of 1.885(K). Noise analysis in terms of Noise Equivalent Power (NEP) was used to quantify the various fundamental and technical noise contributions, including phonon noise and Johnson-Nyquist noise. The noise analysis clarifi es the path toward a cryogenic radiometer with a noise floor limited by fundamental phonon noise, where the magnitude of the phonon NEP is 6.5 (fW/Hz^0.5) for the measured experimental parameters.
Citation: Review of Scientific Instruments
Pub Type: Journals

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bolometers, cryogenic detectors, radiometers, metrology, standards and calibration
Created July 10, 2014, Updated February 19, 2017