A Microwave SQUID Multiplexer Optimized for Bolometric Applications

Authors :: Dober, B.
Ahmed, Z.
Arnold, K.
Becker, D. T.
Bennett, D. A.
Connors, J. A.
Cukierman, A.
D'Ewart, J. M.
Duff, S. M.
Dusatko, J. E.
Frisch, J. C.
Gard, J. D.
Henderson, S. W.
Herbst, R.
Hilton, G. C.
Hubmayr, J.
Li, Y.
Mates, J. A. B.
McCarrick, H.
Reintsema, C. D
Silva-Feaver, M.
Ruckman, L.
Ullom, J. N.
Vale, L. R.
Van Winkle, D. D.
Vasquez, J.
Wang, Y.
Young, E.
Yu, C.
Zheng, K.
Publication Year :: 2020
Abstract: A microwave SQUID multiplexer ($\mu$MUX) has been optimized for coupling to large arrays of superconducting transition-edge sensor (TES) bolometers. We present the scalable cryogenic multiplexer chip design in a 1820-channel multiplexer configuration for the 4-8 GHz rf band. The key metrics of yield, sensitivity, and crosstalk are determined through measurements of 455 readout channels, which span 4-5 GHz. The median white-noise level is 45 pA/$\sqrt{\textrm{Hz}}$, evaluated at 2 Hz, with a 1/f knee $\leq$ 20 mHz after common-mode subtraction. The white-noise level decreases the sensitivity of a TES bolometer optimized for detection of the cosmic microwave background at 150 GHz by only 3%. The measured crosstalk between any channel pair is $\leq$ 0.3%.<br />Comment: 6 pages, 5 figures