Speaker
Description
We present the electrical modeling and preliminary noise characterization of a multi-mode Bulk Acoustic Wave (BAW) gravitational wave detector operating in the 100 kHz–10 MHz frequency range. The detector employs piezoelectric quartz resonators read out by two-stage DC SQUID amplifiers, whose ultra-low-noise performance is essential to approach strain sensitivities at the level of ~10⁻²¹ /√Hz.
We developed a lumped-element circuit model of the coupled BAW-SQUID system, incorporating the mechanical modes of the crystal, piezoelectric transduction, and noise contributions from both SQUID stages.
A Bayesian parameter estimation framework based on Markov Chain Monte Carlo (MCMC) techniques has been implemented to infer model parameters from the in-phase and quadrature components of measured resonances. We aim to infer the presence of noise contributions by looking at the correspondence between the extracted BAW modes temperatures and the cold plate temperatures.
Ongoing work includes direct measurements of key SQUID parameters (mutual inductance, dynamic resistance, and input coil inductance) and calibrated noise injection studies, aimed at improving the accuracy of the noise model and achieving consistent temperature estimates across multiple overtones. Results and experimental strategies will be presented.
| Parallel session | New Physics Searches: Dark Matter and High-Frequency Gravitational Waves |
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