Experimental measurements and noise analysis of a cryogenic radiometer
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.
bolometers, cryogenic detectors, radiometers, metrology, standards and calibration
, Jung, T.
, Carter, A.
, Datla, R.
and Carr, S.
Experimental measurements and noise analysis of a cryogenic radiometer, Review of Scientific Instruments, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=914915
(Accessed August 15, 2022)