Characterization of Aluminum Microwave SQUID Multiplexers for CE$\nu$NS Detection
Abstract
We present the design, fabrication, and characterization of an aluminum-based six-channel microwave SQUID multiplexer (MUX) prototype for transition-edge sensor (TES) readout in the RICOCHET experiment. The device consists of aluminum coplanar-waveguide resonators and RF SQUIDs with Dolan-style Al/AlO/Al Josephson junctions. By measuring the resonator scattering parameters at a range of probe tone frequencies, powers, and flux bias points, we demonstrate agreement between the device response and existing multiplexer models. We also characterize the noise performance in both open-loop and flux-ramping modes. With a high electron mobility transistor (HEMT) amplifier, open-loop measurements yield a flux sensitivity of 1-1.5 . With flux-ramp modulation, low-frequency 1/f noise is suppressed, and the flux sensitivity is around 3-4 , corresponding to a current sensitivity of 24-33 at the input coil. We further demonstrate a reduction in readout noise by incorporating a Josephson traveling-wave parametric amplifier (JTWPA) between the MUX and the HEMT. This achieves an open-loop flux sensitivity of 0.3-0.6 and an effective system noise temperature below 1 K. These results establish aluminum MUX devices as a viable and extensible readout technology for low-noise cryogenic detector arrays.
Keywords
Cite
@article{arxiv.2605.24272,
title = {Characterization of Aluminum Microwave SQUID Multiplexers for CE$\nu$NS Detection},
author = {James Amidei and Antoine Armatol and Corinne Augier and Louis Bailly-Salins and Guillaume Baulieu and Laurent Bergé and Julien Billard and Juliette Blé and Gaby Brenot and Guillaume Bres and Jean-Louis Bret and Alexandre Broniatowski and Martino Calvo and Antonella Cavanna and Antoine Cazes and Emanuela Celi and David Chaize and Mohammed Chala and Maurice Chapellier and Luke Chaplinsky and Ran Chen and Ion Cojocari and Jules Colas and Laurent Couraud and Elspeth Cudmore and Maryvonne De Jesus and Pierre de Marcillac and Nicole Dombrowski and Louis Dumoulin and Alan Durnez and Romain Faure and Sylvain Ferriol and Enectali Figueroa-Feliciano and Joseph A. Formaggio and Stephane Fuard and Jules Gascon and Cloé Girard-Carillo and Andrea Giuliani and Corinne Goy and Cyrille Guerin and Leïla Haegel and Patrick M. Harrington and Scott A. Hertel and Cyrus F. Hirjibehedin and Christophe Hoarau and Ziqing Hong and Daemon Howard and Jean-Christophe Ianigro and Yong Jin and Alexandre Juillard and Dimitar Karaivanov and Temirlan Khussainov and Andrew Kubik and Jacob Lamblin and Tatiana Le Bellec and Laetitia Leroy and Mingyu Li and Alexey Lubashevskiy and Stefanos Marnieros and Romain Martin and Nicolas Martini and Julien Minet and Alessandro Monfardini and Franck Mounier and Bethany M. Niedzielski and Valentina Novati and Wiliam D. Oliver and Emiliano Olivieri and H. Douglas Pinckney and Denys V. Poda and Dmitrii Ponomarev and Jean-Sébastien Real and Faith C. Reyes and Alejandro Rodriguez and Sergey Rozov and Irina Rozova and Brianna Ryan and Deeksha Sabhari and Silvia Scorza and Kyle Serniak and Renaud Serra and Yegor Shevchik and Torsten Soldner and Hannah Stickler and Caitlyn Stone-Whitehead and Christian Ulysse and Wouter Van De Pontseele and Sergey Vasilyev and Paul Vittaz and Steven Weber and Evan Wolfe and Wayne Woods and Evgeny Yakushev and Jiatong Yang and Daniya Zinatulina},
journal= {arXiv preprint arXiv:2605.24272},
year = {2026}
}