Patras 2022 - 37 - Caterina Braggio - Status of the QUAX experiment

Dr. Caterina Braggio from the University of Padova and INFN, Italy, talks about the "Status of the QUAX experiment" at the 17th Patras Workshop on Axions, WIMPs and WISPs.
The Patras Workshop took place at the Johannes Gutenberg University of Mainz as the second week of events within the Wavy Dark Matter Summer event series in August 2022. www.wavydarkmatter.org
Abstract:
The QUest for Axion (QUAX) is a direct-detection CDM axion
search which reaches the sensitivity necessary for the detection of
galactic QCD-axion in the range of frequency 8.5-11 GHz. The
QUAX collaboration is operating two haloscopes, located at LNLand
LNF-INFN laboratories in Italy, that work in synergy and operate
in different mass ranges. In this talk we will report about the
LNL haloscope, currently talking data at 10.3 GHz with a dielectric
resonator cooled at less than 100 mK inside a dilution refrigerator
equipped with a 8 T magnet. In addition, the system noise is
minimised in the wide frequency range where the cavity can be
tuned by means of a new generation traveling wave parametric amplifier
(TWPA) developed by the group of N. Roch (Grenoble), with
measured noise temperature of 2 K or better. We will describe the
results of preliminary runs, where a narrow range tuning system (1
MHz) was employed. Data sets were acquired with significantly
different antenna couplings, to investigate the experimental requirements
that are needed for running the experiment with a cavity
exceeding the axion quality factor. We will also report about R&D
activity aimed at increasing the scanning speed with application of
single microwave photon detectors (SMPDs) for cavity readout, in
collaboration with E. Flurin (Quantronics, Saclay). The prototype
haloscope is based on a cylindrical copper cavity sputtered with
NbTi, with a quality factor of 5 105 at 5 K and the experiments will
be conducted at 7 GHz frequency in a dilution refrigerator where a
moderate magnetic field (3 T) can be applied. Systematic studies of
the SMPD dark count and efficiency will be described.