2004/02/24 by A. Kogut, Edward J. Wollack, E. Wollack +7
Engineering · Materials Science · Physics and Astronomy · #Calibration and Measurement Techniques #Optical Coatings and Gratings #Superconducting and THz Device Technology #astro-ph
paper · pdf · doi:10.1063/1.1821622
published as Rev.Sci.Instrum. 75 (2004) 5079-5083 · 5 pages including 5 figures. Submitted to Review of Scientific Instruments
arxiv created 2004/02/24 · openalex publication_date 2004/11/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We describe the design and calibration of an external cryogenic blackbody calibrator used for the first two flights of the Absolute Radiometer for Cosmology, Astrophysics, and Diffuse Emission (ARCADE) instrument. The calibrator consists of a microwave absorber weakly coupled to a superfluid liquid helium bath. Half-wave corrugations viewed 30° off axis reduce the return loss below −35 dB within a compact footprint. Ruthenium oxide resistive thermometers embedded within the absorber monitor the temperature across the face of the calibrator. The thermal calibration transfers the calibration of a reference thermometer to the flight thermometers using the flight thermometer readout system. The calibrator thermometry is stable in time over four years, with statistical uncertainty in the temperature calibration of order 2 mK near 2.7 K, limited primarily by thermal fluctuations in the liquid helium bath. Observations of the superfluid transition demonstrate that the absolute temperature scale is accurate within 0.3 mK.