I. Giomataris
A5110797429- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Radiation Detection and Scintillator Technologies
- Atomic and Subatomic Physics Research
- Particle physics theoretical and experimental studies
- Astrophysics and Cosmic Phenomena
- Neutrino Physics Research
- CCD and CMOS Imaging Sensors
- Nuclear Physics and Applications
- Cosmology and Gravitation Theories
- Photocathodes and Microchannel Plates
- Plasma Diagnostics and Applications
- Astronomy and Astrophysical Research
- Particle Accelerators and Free-Electron Lasers
- Solar and Space Plasma Dynamics
- Muon and positron interactions and applications
- Scientific Research and Discoveries
- Silicon Carbide Semiconductor Technologies
- Radiation Therapy and Dosimetry
- Luminescence Properties of Advanced Materials
- Catalytic Processes in Materials Science
- Radiation Effects in Electronics
- Superconducting Materials and Applications
- Gas Dynamics and Kinetic Theory
- Age of Information Optimization
Institut de Recherche sur les Lois Fondamentales de l'Univers
2015-2024
CEA Paris-Saclay
2015-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015-2024
Université Paris-Saclay
2016-2023
DTU Space
2016
Technical University of Denmark
2016
Universidad Antonio Nariño
2015
European Organization for Nuclear Research
2010-2015
DSM (Netherlands)
2002-2015
Doğuş University
2015
Hypothetical low-mass particles, such as axions, provide a compelling explanation for the dark matter in universe. Such particles are expected to emerge abundantly from hot interior of stars. To test this prediction, CERN Axion Solar Telescope (CAST) uses 9 T refurbished Large Hadron Collider magnet directed towards Sun. In strong magnetic field, solar axions can be converted X-ray photons which recorded by detectors. 2013–2015 run, thanks low-background detectors and new telescope,...
We have searched for solar axions or similar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup with improved conditions in all detectors. From absence of excess X-rays when magnet was pointing Sun, we set an upper limit on axion-photon coupling 8.8 x 10^{-11} GeV^{-1} at 95% CL m_a <~ 0.02 eV. This result is best experimental over a broad range axion masses and eV also supersedes previous derived from energy-loss arguments globular-cluster stars.
The International Axion Observatory (IAXO) will be a forth generation axion helioscope. As its primary physics goal, IAXO look for axions or axion-like particles (ALPs) originating in the Sun via Primakoff conversion of solar plasma photons. In terms signal-to-noise ratio, about 4–5 orders magnitude more sensitive than CAST, currently most powerful helioscope, reaching sensitivity to axion-photon couplings down few × 10−12 GeV−1 and thus probing large fraction unexplored ALP parameter space....
Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by Primakoff process. In laboratory magnetic field ("axion helioscope"), they transformed into x-rays energies of few keV. Using decommissioned Large Hadron Collider test magnet, CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from analysis these data are presented here. No signal above background was observed, implying an upper limit to axion-photon coupling...
We have searched for solar axions or other pseudoscalar particles that couple to two photons by using the CERN Axion Solar Telescope (CAST) setup. Whereas we previously reported results from CAST with evacuated magnet bores (Phase I), setting limits on lower mass axions, here report where were filled 4He gas II) of variable pressure. The introduction generates a refractive photon mγ, thereby achieving maximum possible conversion rate those axion masses ma match mγ. With 160 different...
We present the case for a dark matter detector with directional sensitivity. This document was developed at 2009 CYGNUS workshop on detection, and contains contributions from theorists experimental groups in field. describe need sensitivity; each experiment presents their project's status; we close feasibility study scaling up to one ton detector, which would cost around $150M.
The CERN Axion Solar Telescope (CAST) has extended its search for solar axions by using 3He as a buffer gas. At T=1.8 K this allows larger pressure settings and hence sensitivity to higher axion masses than our previous measurements with 4He. With about 1 h of data taking at each 252 different we have scanned the mass range 0.39 eV < m_a 0.64 eV. From absence excess X-rays when magnet was pointing Sun set typical upper limit on axion-photon coupling g_ag 2.3 x 10^{-10} GeV^{-1} 95% CL, exact...
We study the feasibility of a new generation axion helioscope, most ambitious and promising detector solar axions to date. show that large improvements in magnetic field volume, x-ray focusing optics backgrounds are possible beyond those achieved CERN Axion Solar Telescope (CAST). For hadronic models, sensitivity axion-photon coupling gaγ ≳ few × 10−12 GeV−1 is conceivable, 1–1.5 orders magnitude CAST sensitivity. If also couple electrons, Sun produces larger flux for same value Peccei-Quinn...
A new Micromegas manufacturing technique, based on kapton etching technology, has been developed recently, resulting in further improvement of the characteristics detector, such as uniformity and stability. Excellent energy resolution obtained, reaching 11% FWHM for 5.9 keV photon peak the55Fe X-ray source 1.8% (with possible evidence less than 1%) 5.5 MeV alpha 241Am source. The Microbulk detector shows several advantages like flexible structure, low material high radio-purity, opening thus...
The CERN Axion Solar Telescope has finished its search for solar axions with (3)He buffer gas, covering the range 0.64 eV ≲ ma 1.17 eV. This closes gap to cosmological hot dark matter limit and actually overlaps it. From absence of excess x rays when magnet was pointing Sun we set a typical upper on axion-photon coupling gaγ 3.3 × 10(-10) GeV(-1) at 95% C.L., exact value depending pressure setting. Future direct axion searches will focus increasing sensitivity smaller values gaγ, example by...
We review the physics potential of a next generation search for solar axions: International Axion Observatory (IAXO) . Endowed with sensitivity to discover axion-like particles (ALPs) coupling photons as small gaγ∼ 10−12 GeV−1, or electrons gae∼10−13, IAXO has find QCD axion in 1 meV∼1 eV mass range where it solves strong CP problem, can account cold dark matter Universe and be responsible anomalous cooling observed number stellar systems. At same time, will have enough detect lower axions...
A new type of radiation detector based on a spherical geometry is presented. The consists large gas volume with central electrode forming radial electric field. Charges deposited in the conversion drift to sensor where they are amplified and collected. We introduce small located at center acting as proportional amplification structure. It allows high gains be reached operates wide range pressures. Signal development absolute amplitude response consistent predictions. Sub-keV energy threshold...
In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces strong flux by bremsstrahlung, Compton scattering, and axio-recombination, ``BCA processes.'' Based on new calculation of this flux, including for first time we derive limits Yukawa coupling gae axion-photon interaction strength gaγ using CAST phase-I data (vacuum phase). For ma≲10 meV/c2 find < 8.1 × 10−23 GeV−1 at 95% CL. We stress that next-generation helioscope such as proposed IAXO could...
The CERN Axion Solar Telescope (CAST) searches for $a\ensuremath{\rightarrow}\ensuremath{\gamma}$ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward Sun. Two parallel bores filled with helium adjustable pressure to match x-ray refractive mass ${m}_{\ensuremath{\gamma}}$ axion search ${m}_{a}$. After vacuum phase (2003--2004), which is optimal ${m}_{a}\ensuremath{\lesssim}0.02\text{ }\text{ }\mathrm{eV}$, we used $^{4}\mathrm{He}$ 2005--2007...
Abstract PICOSEC Micromegas (MM) is a precise timing gaseous detector based on Cherenkov radiator coupled with semi-transparent photocathode and an MM amplifying structure. The concept was successfully demonstrated through single-channel prototype, achieving sub-25 ps time resolution Minimum Ionizing Particles (MIPs). A series of studies followed, aimed at developing robust, large-area, scalable detectors high resolution, complemented by specialized fast-response readout electronics. This...
We have searched for 14.4 keV solar axions or more general axion-like particles (ALPs), that may be emitted in the M1 nuclear transition of 57Fe, by using axion-to-photon conversion CERN Axion Solar Telescope (CAST) with evacuated magnet bores (Phase I). From absence excess monoenergetic X-rays when was pointing to Sun, we set model-independent constraints on coupling constants pseudoscalar couple two photons and a nucleon gaγ|−1.19gaN0+gaN3| < 1.36 × 10−16 GeV−1 ma 0.03 eV at 95% confidence level.
In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in field of dark energy research, exploits both chameleon coupling to matter (βm) and photons (βγ) via Primakoff effect. By reducing X-ray detection threshold used axions from 1 keV 400 eV CAST became sensitive converted solar spectrum which peaks around 600 eV. Even though have not observed any excess above background, can provide 95% C.L. limit strength...
We report on the design, construction and operation of a low background x-ray detection line composed shielded Micromegas detector microbulk technology. The is made from radiopure materials placed at focal point ∼ 5 cm diameter, 1.5 m focal-length, cone-approximation Wolter I telescope (XRT) assembled thermally-formed (or "slumped") glass substrates deposited with multilayer coatings. system has been conceived as technological pathfinder for future International Axion Observatory (IAXO), it...
We report the performance of a 10 atm Xenon/trimethylamine time projection chamber (TPC) for detection X-rays (30 keV) and γ-rays (0.511–1.275 MeV) in conjunction with accurate tracking associated electrons. When operated at such high pressure ~1%-admixtures, trimethylamine (TMA) endows Xenon an extremely low electron diffusion (1.3±0.13mm-σ (longitudinal), 0.95±0.20mm-σ (transverse) along 1 m drift) besides forming convenient 'Penning-Fluorescent' mixture. The TPC, that houses 1.1 kg gas...
Abstract The New Experiments With Spheres-Gas (NEWS-G) collaboration intends to achieve sub-GeV/c 2 Weakly Interacting Massive Particles (WIMPs) detection using Spherical Proportional Counters (SPCs). SPCs are gaseous detectors relying on ionisation with a single ionization electron energy threshold. latest generation of SPC for direct dark matter searches has been installed at SNOLAB in Canada 2021. This article details the different processes involved fabrication NEWS-G experiment. Also...
We present a novel concept of proportional gas amplification for the read-out spherical counter. The standard single-ball presents limitations large diameter detectors and high-pressure operations. have developed multi-ball system which consists several balls placed at fixed distance from center vessel. Such module can tune volume electric field desired value also provide detector segmentation with individual ball read-out. In latter case, vessel becomes time projection chamber 3D capabilities.