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Characterization of Aluminum Microwave SQUID Multiplexers for CE$ν$NS Detection
Authors:
James Amidei,
Antoine Armatol,
Corinne Augier,
Louis Bailly-Salins,
Guillaume Baulieu,
Laurent Bergé,
Julien Billard,
Juliette Blé,
Gaby Brenot,
Guillaume Bres,
Jean-Louis Bret,
Alexandre Broniatowski,
Martino Calvo,
Antonella Cavanna,
Antoine Cazes,
Emanuela Celi,
David Chaize,
Mohammed Chala,
Maurice Chapellier,
Luke Chaplinsky,
Ran Chen,
Ion Cojocari,
Jules Colas,
Laurent Couraud,
Elspeth Cudmore
, et al. (70 additional authors not shown)
Abstract:
We present the design, fabrication, and characterization of an aluminum-based six-channel microwave SQUID multiplexer ($μ$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$_x$/Al Josephson junctions. By measuring the resonator scattering parameters at a range of pro…
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We present the design, fabrication, and characterization of an aluminum-based six-channel microwave SQUID multiplexer ($μ$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$_x$/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 $μΦ_0/\sqrt{Hz}$. With flux-ramp modulation, low-frequency 1/f noise is suppressed, and the flux sensitivity is around 3-4 $μΦ_0/\sqrt{Hz}$, corresponding to a current sensitivity of 24-33 $pA/\sqrt{Hz}$ at the input coil. We further demonstrate a reduction in readout noise by incorporating a Josephson traveling-wave parametric amplifier (JTWPA) between the $μ$MUX and the HEMT. This achieves an open-loop flux sensitivity of 0.3-0.6 $μΦ_0/\sqrt{Hz}$ and an effective system noise temperature below 1 K. These results establish aluminum $μ$MUX devices as a viable and extensible readout technology for low-noise cryogenic detector arrays.
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Submitted 22 May, 2026;
originally announced May 2026.
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Spin waves excited by hard x-ray transient gratings
Authors:
Peter R. Miedaner,
Alexei A. Maznev,
Mykola Biednov,
Marwan Deb,
Carles Serrat,
Nadia Berndt,
Pietro Carrara,
Cristian Soncini,
Marta Brioschi,
Daniele Ronchetti,
Andrei Benediktovitch,
Danny Fainozzi,
Nupur Khatu,
Eugenio Ferrari,
Joan Vila-Comamala,
Peter Zalden,
Wojciech Gawelda,
Martin Knoll,
Paul Frankenberger,
Ludmila Leroy,
Talgat Mamyrbayev,
Grigory Smolentsev,
Simon Gerber,
Alessandro Gessini,
Filippo Bencivenga
, et al. (27 additional authors not shown)
Abstract:
Recent progress in ultrafast x-ray sources helped establish x-rays as an important tool for probing lattice and magnetic dynamics initiated by femtosecond optical pulses. Here, we explore the potential of ultrashort hard x-ray pulses for driving magnetic dynamics. We use a transient grating technique in which a spatially periodic x-ray excitation pattern gives rise to material excitations at a wel…
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Recent progress in ultrafast x-ray sources helped establish x-rays as an important tool for probing lattice and magnetic dynamics initiated by femtosecond optical pulses. Here, we explore the potential of ultrashort hard x-ray pulses for driving magnetic dynamics. We use a transient grating technique in which a spatially periodic x-ray excitation pattern gives rise to material excitations at a well-defined wave vector, whose dynamics are monitored via diffraction of an optical probe pulse. The excitation of a ferrimagnetic gadolinium bismuth iron garnet film placed in an external tilted magnetic field by x-rays at the Gd L3 edge results in both magnetic and non-magnetic transient gratings whose contributions to the diffracted signal are separated by polarization analysis. We observe the magnetization precession at both longitudinal acoustic and spin wave frequencies. An analysis with the Landau-Lifshitz-Gilbert equation indicates that the magnetization precession is driven by strain resulting from thermal expansion induced by absorbed x-rays. The results establish x-ray transient gratings as a tool for driving coherent phonons and magnons, with the potential of accessing wave vectors across the entire Brillouin zone.
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Submitted 9 January, 2026;
originally announced January 2026.
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Characterization of mini-CryoCube detectors from the Ricochet experiment commissioning at the Institut Laue-Langevin
Authors:
Antoine Armatol,
Corinne Augier,
Louis Bailly-Salins,
Guillaume Baulieu,
Laurent Bergé,
Julien Billard,
Juliette Blé,
Guillaume Bres,
Jean-Louis Bret,
Alexandre Broniatowski,
Martino Calvo,
Antonella Cavanna,
Antoine Cazes,
Emanuela Celi,
David Chaize,
Mohammed Chala,
Maurice Chappellier,
Luke Chaplinsky,
Guillaume Chemin,
Ran Chen,
Jules Colas,
Laurent Couraud,
Elspeth Cudmore,
Maryvonne De Jesus,
Nicole Dombrowski
, et al. (61 additional authors not shown)
Abstract:
The Ricochet experiment aims to measure the coherent elastic neutrino-nucleus scattering process from antineutrinos emitted by a research nuclear reactor operated by the Institut Laue-Langevin (Grenoble, France). This article presents a description of the Ricochet experimental installation and the detector performance achieved during its commissioning with a mini-CryoCube module consisting of thre…
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The Ricochet experiment aims to measure the coherent elastic neutrino-nucleus scattering process from antineutrinos emitted by a research nuclear reactor operated by the Institut Laue-Langevin (Grenoble, France). This article presents a description of the Ricochet experimental installation and the detector performance achieved during its commissioning with a mini-CryoCube module consisting of three 42-gram germanium cryogenic calorimeters. The baseline resolutions and background levels are reported both during reactor-on and reactor-off periods, and as noise mitigation techniques were improved. A baseline resolution of 40 eV electron equivalent was achieved for the ionization channel after setup improvements, and the phonon channel resolutions ranged from 50 to 80 eV of total phonon energy. In the energy region from 2 to 7 keV, a nuclear recoil rate of 15(2) events/(kg day keV) is measured during the reactor-off period selecting events in coincidence with muon veto signals. This rate is in agreement with the cosmogenic neutron rate calculated from GEANT4 simulations. After the rejection of events in coincidence with signals in the muon veto detectors, a combined 90% C.L. limit on the nuclear recoil background of < 9 events/(kg day keV) is obtained in that energy region during the reactor-on period, which is compatible with our GEANT4 model calculation corresponding to a total rate of 5 events/(kg day keV). The sensitivity of this analysis was however found to be limited by a surface event contamination which is currently being addressed by the Ricochet Collaboration with upgraded detectors.
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Submitted 30 July, 2025;
originally announced July 2025.