111 research outputs found
Search of dark-matter axions in the microwave frequency range with full-wave modal techniques
Axions, originally proposed to solve the strong Charge-Parity problem of
Quantum Chromo-Dynamics theory, emerge now as leading candidates of dark
matter. In fact, the search of dark-matter axions in the microwave frequency
range has been developed by different research groups during the last twenty
years. In this demanding scenario, several microwave passive components
(haloscopes) have been designed and fabricated for such axions detection based
on the use of cavities and multi-cavities. From an electromagnetic point of view,
comercial software (ANSFT HFSS, CST MICROWAVE STUDIO, etc ) has been
employed for the design of different kind of haloscopes. In this work we propose
to use the BI-RME 3D method (Boundary Integral â Resonant Mode Expansion)
as an alternative to analyze the axion-photon coupling existing within an
haloscope. This full-wave modal technique has provided interesting wide-band
results for the design of new haloscopes
A hydrogen beam to characterize the ASACUSA antihydrogen hyperfine spectrometer
The antihydrogen programme of the ASACUSA collaboration at the antiproton
decelerator of CERN focuses on Rabi-type measurements of the ground-state
hyperfine splitting of antihydrogen for a test of the combined
Charge-Parity-Time symmetry. The spectroscopy apparatus consists of a microwave
cavity to drive hyperfine transitions and a superconducting sextupole magnet
for quantum state analysis via Stern-Gerlach separation. However, the small
production rates of antihydrogen forestall comprehensive performance studies on
the spectroscopy apparatus. For this purpose a hydrogen source and detector
have been developed which in conjunction with ASACUSA's hyperfine spectroscopy
equipment form a complete Rabi experiment. We report on the formation of a
cooled, polarized, and time modulated beam of atomic hydrogen and its detection
using a quadrupole mass spectrometer and a lock-in amplification scheme. In
addition key features of ASACUSA's hyperfine spectroscopy apparatus are
discussed.
Hyperfine spectroscopy of hydrogen and antihydrogen in ASACUSA
The ASACUSA collaboration at the Antiproton Decelerator of CERN aims at a
precise measurement of the antihydrogen ground-state hyperfine structure as a
test of the fundamental CPT symmetry. A beam of antihydrogen atoms is formed in
a CUSP trap, undergoes Rabi-type spectroscopy and is detected downstream in a
dedicated antihydrogen detector. In parallel measurements using a polarized
hydrogen beam are being performed to commission the spectroscopy apparatus and
to perform measurements of parameters of the Standard Model Extension (SME).
The current status of antihydrogen spectroscopy is reviewed and progress of
ASACUSA is presented.Comment: Proceedings of the 7th International Syposium on Symmetries in
Subatomic Physics SSP2018, Aachen (Germany), 10 - 15 Jun 2018. Corrected
error in Fig. 1, updated caption, add titles to reference
First results on the search for chameleons with the KWISP detector at CAST
We report on a first measurement with a sensitive opto-mechanical force sensor designed for the direct detection of coupling of real chameleons to matter. These dark energy candidates could be produced in the Sun and stream unimpeded to Earth. The KWISP detector installed on the CAST axion search experiment at CERN looks for tiny displacements of a thin membrane caused by the mechanical effect of solar chameleons. The displacements are detected by a Michelson interferometer with a homodyne readout scheme. The sensor benefits from the focusing action of the ABRIXAS X-ray telescope installed at CAST, which increases the chameleon flux on the membrane. A mechanical chopper placed between the telescope output and the detector modulates the incoming chameleon stream. We present the results of the solar chameleon measurements taken at CAST in July 2017, setting an upper bound on the force acting on the membrane of 80pN at 95% confidence level. The detector is sensitive for direct
coupling to matter 104 = Ăm = 108, where the coupling to photons is locally bound to ĂÂż = 1011
Search for Dark Matter Axions with CAST-CAPP
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole
magnet, has searched for axions in the 19.74 eV to 22.47 eV mass
range. The detection concept follows the Sikivie haloscope principle, where
Dark Matter axions convert into photons within a resonator immersed in a
magnetic field. The CAST-CAPP resonator is an array of four individual
rectangular cavities inserted in a strong dipole magnet, phase-matched to
maximize the detection sensitivity. Here we report on the data acquired for
4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning
mechanism of 10 MHz/min between 4.774 GHz and 5.434 GHz. In the present work,
we exclude axion-photon couplings for virialized galactic axions down to
at the 90% confidence
level. The here implemented phase-matching technique also allows for future
large-scale upgrades.Comment: 24 pages, 5 figures, Published version available with Open Access at
https://www.nature.com/articles/s41467-022-33913-
Thin Film (High Temperature) Superconducting Radiofrequency Cavities for the Search of Axion Dark Matter
5 pages, 6 figures. v2: minor updates after referee comments, matches
published version in IEEEThe axion is a hypothetical particle which is a candidate for cold dark
matter. Haloscope experiments directly search for these particles in strong
magnetic fields with RF cavities as detectors. The Relic Axion Detector
Exploratory Setup (RADES) at CERN in particular is searching for axion dark
matter in a mass range above 30 eV. The figure of merit of our detector
depends linearly on the quality factor of the cavity and therefore we are
researching the possibility of coating our cavities with different
superconducting materials to increase the quality factor. Since the experiment
operates in strong magnetic fields of 11 T and more, superconductors with high
critical magnetic fields are necessary. Suitable materials for this application
are for example REBaCuO, NbSn or NbN. We designed a
microwave cavity which resonates at around 9~GHz, with a geometry optimized to
facilitate superconducting coating and designed to fit in the bore of available
high-field accelerator magnets at CERN. Several prototypes of this cavity were
coated with different superconducting materials, employing different coating
techniques. These prototypes were characterized in strong magnetic fields at
4.2 K.This project has received funding from the European Unionâs Horizon 2020
Research and Innovation programme under Grant Agreement No 730871
(ARIES-TNA). BD and JG acknowledge funding through the European
Research Council under grant ERC-2018-StG-802836 (AxScale). We also
acknowledge funding via the Spanish Agencia Estatal de Investigacion (AEI)
and Fondo Europeo de Desarrollo Regional (FEDER) under project PID2019-
108122GB-C33, and the grant FPI BES-2017-079787 (under project FPA2016-76978-C3-2-P). Furthermore we acknowledge support from SuMaTe
RTI2018-095853-B-C21 from MICINN co-financed by the European Regional
Development Fund, Center of Excellence award Severo Ochoa CEX2019-
000917-S and CERN under Grant FCCGOV-CC-0208 (KE4947/ATS).With funding from the Spanish government through the âSevero Ochoa Centre of Excellenceâ accreditation (CEX2019-000917-S).Peer reviewe
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