A microwave SQUID multiplexer optimized for bolometric applications

A microwave superconducting quantum interference device multiplexer has been optimized for reading out large arrays of transition-edge sensor (TES) bolometers. We present the scalable cryogenic chip design that may be used to construct an 1820-channel 4–8 GHz rf band. The key metrics yield, sensitivity, and crosstalk are determined through measurements 455 readout channels, which span 4–5 GHz. median white-noise level is 45 pA/Hz, evaluated at 2 Hz, with a 1/f knee ≤ 20 mHz after common-mode subtraction. decreases sensitivity TES bolometer detection cosmic background 150 by only 3%. measured between any channel pair 0.3%.