We report on the use of a kinetic-inductance traveling-wave parametric amplifier (KITWPA) as the first amplifier in the readout chain of a microwave superconducting quantum interference device (SQUID) multiplexer (umux). This umux is designed to multiplex signals from arrays of low temperature detectors such as superconducting transition-edge sensor microcalorimeters. When modulated with a periodic flux-ramp to linearize the SQUID response, the flux noise improves, on average, from 1.6μΦ0/Hz with the KITWPA off, to 0.77μΦ0/Hz with the KITWPA on. When statically biasing the umux to the maximally flux-sensitive point, the flux noise drops from 0.45μΦ0/Hz to 0.2μΦ0/Hz. We validate this new readout scheme by coupling a transition-edge sensor microcalorimeter to the umux and detecting background radiation. The combination of umux and KITWPA provides a variety of new capabilities including improved detector sensitivity and more efficient bandwidth utilization.
@article{arxiv.2303.04181,
title = {Improved microwave SQUID multiplexer readout using a kinetic-inductance traveling-wave parametric amplifier},
author = {M. Malnou and J. A. B. Mates and M. R. Vissers and L. R. Vale and D. R. Schmidt and D. A. Bennett and J. Gao and J. N. Ullom},
journal= {arXiv preprint arXiv:2303.04181},
year = {2023}
}