Speaker
Description
We present the latest results from the QUAX haloscope experiment at LNL, which searches for post‑inflationary QCD axions around 10.2 GHz. Compared to earlier QUAX runs, a quasi‑automatic tuning protocol now allows adjustment of the cavity frequency without significantly degrading the detector’s performance.
The haloscope uses a TM$_{030}$ Bragg resonator made of a copper cylindrical cavity housing a sapphire tube, providing a five-fold increase in effective volume relative to an empty‑cavity TM$_{010}$ mode at the same frequency. A clamshell mechanism enables tuning from 10.212 GHz to 10.126 GHz with minimal impact on the TM$_{030}$ mode quality factor.
Axion‑to‑photon conversion is driven by an 8 T NbTi magnet. The first amplification stage employs a near–quantum‑limited TWPA, achieving sensitivity to post‑inflationary QCD axions at the $10^{-14}\,\mathrm{GeV}^{-1}$ level with one hour of data.
We demonstrate that, after manual calibration, the TWPA can track cavity tuning over several MHz automatically. Combined with an improved mechanical tuning system, this enables automated data taking for one to several days, advancing the development of a cosmological QCD axion haloscope observatory in the 9–11 GHz range.
Finally, we outline the improvements scheduled for the apparatus for the next years, including implementation of a Single Microwave Photon Detector.
| Parallel session | New Physics Searches: Dark Matter and High-Frequency Gravitational Waves |
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