A. Tomas

Publications (11)0 Total impact

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  Available from: Thomas Papaevangelou

  Article: IAXO - The International Axion Observatory

  J. K. Vogel, F. T. Avignone, G. Cantatore, J. M. Carmona, S. Caspi, S. A. Cetin, F. E. Christensen, A. Dael, T. Dafni, M. Davenport, [......], H. H. J. ten Kate, A. Tomas, S. Troitsky, K. van Bibber, P. Vedrine, J. A. Villar, L. Walckiers, W. Wester, S. C. Yildiz, K. Zioutas
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  ABSTRACT: The International Axion Observatory (IAXO) is a next generation axion helioscope aiming at a sensitivity to the axion-photon coupling of a few 10^{-12} GeV^{-1}, i.e. 1-1.5 orders of magnitude beyond sensitivities achieved by the currently most sensitive axion helioscope, the CERN Axion Solar Telescope (CAST). Crucial factors in improving the sensitivity for IAXO are the increase of the magnetic field volume together with the extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested at CAST. Electron-coupled axions invoked to explain the white dwarf cooling, relic axions, and a large variety of more generic axion-like particles (ALPs) along with other novel excitations at the low-energy frontier of elementary particle physics could provide additional physics motivation for IAXO.
  02/2013;
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  Available from: Igor G. Irastorza

  Dataset: 1211.3961v1 (1)

  V. Alvarez, I. Bandac, A. Bettini, F. I. G. M. Borges, S. Carcel, J. Castel, J. M. Catala, S. Cebrian, A. Cervera, C. A. N. Conde, [......], J. Torrent, Z. Tsamalaidze, D. Vazquez, E. Velicheva, J. F. C. A. Veloso, J. A. Villar, R. C. Webb, T. Weber, J. White, N. Yahlali
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  Available from: Igor G. Irastorza

  Article: Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements

  V. Alvarez, I. Bandac, A. Bettini, F. I. G. M. Borges, S. Carcel, J. Castel, S. Cebrian, A. Cervera, C. A. N. Conde, T. Dafni, [......], J. F. Toledo, A. Tomas, J. Torrent, Z. Tsamalaidze, D. Vazquez, J. F. C. A. Veloso, J. A. Villar, R. C. Webb, J. T. White, N. Yahlali
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  ABSTRACT: The Neutrino Experiment with a Xenon TPC (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds. An extensive screening and material selection process is underway for NEXT since the control of the radiopurity levels of the materials to be used in the experimental set-up is a must for rare event searches. First measurements based on Glow Discharge Mass Spectrometry and gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr\'aneo de Canfranc (Spain) are described here. Activity results for natural radioactive chains and other common radionuclides are summarized, being the values obtained for some materials like copper and stainless steel very competitive. The implications of these results for the NEXT experiment are also discussed.
  11/2012;
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  Available from: Thomas Papaevangelou

  Article: The International Axion Observatory (IAXO)

  I. G. Irastorza, F. T. Avignone, G. Cantatore, S. Caspi, J. M. Carmona, T. Dafni, M. Davenport, A. Dudarev, G. Fanourakis, E. Ferrer-Ribas, [......], J. Ruz, I. Shilon, H. Ten Kate, A. Tomas, S. Troitsky, K. van Bibber, J. A. Villar, J. Vogel, L. Walckiers, K. Zioutas
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  ABSTRACT: The International Axion Observatory (IAXO) is a new generation axion helioscope aiming at a sensitivity to the axion-photon coupling of a few 10$^{12}$ GeV$^{-1}$, i.e. 1 - 1.5 orders of magnitude beyond the one currently achieved by CAST. The project relies on improvements in magnetic field volume together with extensive use of x-ray focusing optics and low background detectors, innovations already successfully tested in CAST. Additional physics cases of IAXO could include the detection of electron-coupled axions invoked to solve the white dwarfs anomaly, relic axions, and a large variety of more generic axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics. This contribution is a summary of our paper [1] to which we refer for further details.
  01/2012;
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  Available from: Thomas Papaevangelou

  Article: Low X-ray bakground measurements at the Underground Canfranc Laboratory

  J. Galan, S. Aune, T. Dafni, G. Fanourakis, E Ferrer-Ribas, J. A. Garcia, A. Gardikiotis, T Geralis, I. Giomataris, H. Gomez, [......], F. J. Iguaz, I. G. Irastorza, G. Luzon, T. Papaevangelou, A Rodriguez, J. Ruz, L. Segui, A. Tomas, T. Vafeiadis, S. C. Yildiz
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  ABSTRACT: Micromegas detectors, thanks to the good spatial and temporal discrimination capabilities, are good candidates for rare event search experiments. Recent X-ray background levels achieved by these detectors in the CAST experiment have motivated further studies in the nature of the background levels measured. In particular, different shielding configurations have been tested at the Canfranc Underground Laboratory, using a microbulk type detector which was previously running at the CAST experiment. The first results underground show that this technology, which is made of low radiative materials, is able to reach background levels up to $2 \times 10^{-7}$keV$^{-1}$s$^{-1}$cm$^{-2}$ with a proper shielding. Moreover, the experimental background measurements are complemented with Geant4 simulations which allow to understand the origin of the background, and to optimize future shielding set-ups.
  10/2011;
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  Available from: Thomas Papaevangelou

  Article: Towards a new generation axion helioscope

  I. G. Irastorza, F T Avignone, S. Caspi, J. M. Carmona, T. Dafni, M Davenport, A. Dudarev, G. Fanourakis, E Ferrer-Ribas, J. Galan, [......], J. Ruz, I. Shilon, H. Ten Kate, A. Tomas, S Troitsky, K van Bibber, J. A. Villar, J Vogel, L Walckiers, K. Zioutas
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  ABSTRACT: We study the feasibility of a new generation axion helioscope, the most ambitious and promising detector of solar axions to date. We show that large improvements in magnetic field volume, x-ray focusing optics and detector backgrounds are possible beyond those achieved in the CERN Axion Solar Telescope (CAST). For hadronic models, a sensitivity to the axion-photon coupling of $\gagamma\gtrsim {\rm few} \times 10^{-12}$ GeV$^{-1}$ is conceivable, 1--1.5 orders of magnitude beyond the CAST sensitivity. If axions also couple to electrons, the Sun produces a larger flux for the same value of the Peccei-Quinn scale, allowing one to probe a broader class of models. Except for the axion dark matter searches, this experiment will be the most sensitive axion search ever, reaching or surpassing the stringent bounds from SN1987A and possibly testing the axion interpretation of anomalous white-dwarf cooling that predicts $m_a$ of a few meV. Beyond axions, this new instrument will probe entirely unexplored ranges of parameters for a large variety of axion-like particles (ALPs) and other novel excitations at the low-energy frontier of elementary particle physics.
  03/2011;
• Conference Proceeding: Probing the eV-Mass range for solar axions with CAST

  S. Aune, K. Barth, A. Belov, S. Borghi, H. Brauninger, G. Cantatore, J.M. Carmona, S.A. Cetin, J.I. Collar, T. Dafni, [......], A. Tomas, M. Tsagri, K. van Bibber, T. Vafeiadis, J. Villar, J.K. Vogel, L. Walckiers, Y.Y.Y. Wong, S.C. Yildiz, K. Zioutas
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  ABSTRACT: The CERN Axion Solar Telescope (CAST) is searching for solar axions which could be produced in the core of the Sun via the so-called Primakoff effect. Not only would these hypothetical particles solve the strong CP problem, but they are also one of the favored candidates for dark matter. In order to look for axions originating from the Sun, CAST uses a decommissioned LHC prototype magnet. In its 10 m long magnetic field region of 9 Tesla, axions could be reconverted into X-ray photons. Different X-ray detectors are installed on both ends of the magnet, which is mounted on a structure built to follow the Sun during sunrise and sunset for a total of about 3 hours per day. The analysis of the data acquired during the first phase of the experiment with vacuum in the magnetic field region yielded the most restrictive experimental upper limit on the axion-to-photon coupling constant for axion masses up to about 0.02 eV. In order to extend the sensitivity of the experiment to a wider mass range, the CAST experiment continues its search for axions with helium in the magnet bores. In this way it is possible to restore coherence of conversion for larger masses. Changing the pressure of the helium gas enables the experiment to scan different axion masses in the range of up to about 1.2 eV. Especially at high pressures, a precise knowledge of the gas density distribution is crucial to obtain accurate results. In the first part of this second phase of CAST, ⁴He was used and the axion mass region was extended up to 0.39 eV, a part of phase space favored by axion models. In CAST's ongoing ³He phase the studied mass range is now being extended further. In this contribution the final results of CAST's ⁴He phase will be presented and the current status of the ³He run will be given. This includes latest results as well as prospects of future axion experiments.
  Nuclear Science Symposium Conference Record (NSS/MIC), 2010 IEEE; 12/2010
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  Available from: Andrew Inglis

  Article: The case for a directional dark matter detector and the status of current experimental efforts

  S. Ahlen, N. Afshordi, J. B. R. Battat, J. Billard, N. Bozorgnia, S. Burgos, T. Caldwell, J. M. Carmona, S. Cebrian, P Colas, [......], E. Tziaferi, K Ueno, S. Vahsen, R. Vanderspek, J. Vergados, J. A. Villar, H. Wellenstein, I. Wolfe, R K Yamamoto, H. Yegoryan
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  ABSTRACT: We present the case for a dark matter detector with directional sensitivity. This document was developed at the 2009 CYGNUS workshop on directional dark matter detection, and contains contributions from theorists and experimental groups in the field. We describe the need for a dark matter detector with directional sensitivity; each directional dark matter experiment presents their project's status; and we close with a feasibility study for scaling up to a one ton directional detector, which would cost around $150M. Comment: 48 pages, 37 figures, whitepaper on direct dark matter detection with directional sensitivity
  11/2009;
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  Available from: Luis Serra

  Article: NEXT, a HPGXe TPC for neutrinoless double beta decay searches

  The NEXT Collaboration, F. Granena, T Lux, F. Nova, J. Rico, F. Sanchez, D. R. Nygren, J.A.S. Barata, F.I.G.M. Borges, C.A.N. Conde, [......], J. Galan, H. Gomez, F. J. Iguaz, I. G. Irastorza, G. Luzon, J Morales, A Rodriguez, J. Ruz, A. Tomas, J. A. Villar
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  ABSTRACT: We propose a novel detection concept for neutrinoless double-beta decay searches. This concept is based on a Time Projection Chamber (TPC) filled with high-pressure gaseous xenon, and with separated-function capabilities for calorimetry and tracking. Thanks to its excellent energy resolution, together with its powerful background rejection provided by the distinct double-beta decay topological signature, the design discussed in this Letter Of Intent promises to be competitive and possibly out-perform existing proposals for next-generation neutrinoless double-beta decay experiments. We discuss the detection principles, design specifications, physics potential and R&D plans to construct a detector with 100 kg fiducial mass in the double-beta decay emitting isotope Xe(136), to be installed in the Canfranc Underground Laboratory. Comment: Letter of Intent to the LSC Scientific Committee 115 pages
  07/2009;
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  Available from: Igor G. Irastorza

  Article: Energy resolution of alpha particles in a microbulk Micromegas detector at high pressure Argon and Xenon mixtures

  T. Dafni, E Ferrer-Ribas, I. Giomataris, Ph. Gorodetzky, F. Iguaz, I. G. Irastorza, P. Salin, A. Tomas
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  ABSTRACT: The latest Micromesh Gas Amplification Structures (Micromegas) are achieving outstanding energy resolution for low energy photons, with values as low as 11% FWHM for the 5.9 keV line of $^{55}$Fe in argon/isobutane mixtures at atmospheric pressure. At higher energies (MeV scale), these measurements are more complicated due to the difficulty in confining the events in the chamber, although there is no fundamental reason why resolutions of 1% FWHM or below could not be reached. There is much motivation to demonstrate experimentally this fact in Xe mixtures due to the possible application of Micromegas readouts to the Double Beta Decay search of $^{136}$Xe, or in other experiments needing calorimetry and topology in the same detector. In this paper, we report on systematic measurements of energy resolution with state-of-the-art Micromegas using a 5.5 MeV alpha source in high pressure Ar/isobutane mixtures. Values as low as 1.8% FWHM have been obtained, with possible evidence that better resolutions are achievable. Similar measurements in Xe, of which a preliminary result is also shown here, are under progress. Comment: 16 pages, 19 figures, version after referees comments. Accepted for publication in Nuclear Instruments and Methods A
  06/2009;
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  Available from: N. Yahlali

  Article: NEXT: A Neutrinoless Double Beta Decay Experiment with a Gaseous Xenon TPC

  Thorsten Lux, F Granena, F Nova, J Rico, D R Nygren, J A S Barata, F I G M Borges, C A N Conde, T H V T Dias, L M P Fernandes, [......], J Galan, H Gomez, F J Iguaz, I G Irastorza, G Luzon, J Morales, A Rodriguez, J Ruz, A Tomas, J A Villar