1,188 research outputs found

    Acute and chronic effects of foam rolling vs eccentric exercise on ROM and force output of the plantar flexors

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    Foam rolling and eccentric exercise interventions have been demonstrated to improve range of motion (ROM). However, these two modalities have not been directly compared. Twenty-three academy soccer players (age: 18 ± 1; height: 1.74 ± 0.08 m; body mass: 69.3 ± 7.5 kg) were randomly allocated to either a foam rolling (FR) or eccentric exercise intervention designed to improve dorsiflexion ROM. Participants performed the intervention daily for a duration of four weeks. Measurements of dorsiflexion ROM, isometric plantar flexion torque and drop jump reactive strength index were taken at baseline (pre-intervention) and at three subsequent time-points (30-min post, 24-hours post and 4-weeks post). A significant time x group interaction effect was observed for dorsiflexion (P = 0.036), but not for torque or reactive strength index. For dorsiflexion, there was a significant increase in both acute (30-min; P < 0.001) and chronic (4-week; P < 0.001) ROM for the eccentric group, whilst FR exhibited only an acute improvement (P < 0.001). Eccentric training would appear a more efficacious modality than foam rolling for improving dorsiflexion ROM in elite academy soccer players

    The T-REX projec t: Micromegas for rare event searches

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    Yıldız, Şükrü C. (Dogus Author) -- This paper was firstyly submitted to 2nd International Conference on Particle Physics in Memoriam Engin Arik and Her Colleagues.The T-REX project aims at developing novel readout techniques for Time Projection Chambers for experiments searching for Rare Events. The Micromegas detectors are a good option, because of their good performance regarding low background levels, energy and time resolution, gain and stability of operation. In the present we will shortly refer to two particular cases, on one hand their performance in the CAST experiment and on the other the studies carried out within NEXT, a neutrinoless double-beta decay experiment

    Performance of micromegas detectors in the CAST Experiment

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    Yıldız, Şükrü C. (Dogus Author) -- This paper was firstly submitted to 2nd International Conference on Particle Physics in Memoriam Engin Arik and Her Colleagues.CERN Axion Solar Telescope (CAST) experiment is searching for axions coming from the Sun. Inside transverse magnetic fields, axions can be converted into X-rays, which can be detected by X-ray detectors. The expected energy of the signal in CAST is in the 1-10 keV range. Low noise and low background detectors are necessary to increase the sensitivity of the experiment. Micro Mesh Gaseous Structure (micromegas) detectors have been used in CAST since the beginning, providing good energy and spatial resolution for CAST's needs. CAST has been intensely studying micromegas detectors to develop new technologies. Initially, CAST detectors consisted of a micromegas, a Time Projection Chamber (TPC) and a Charged Couple Device (CCD), however the improvements in micromegas technologies encouraged CAST to replace the TPC with 2 new micromegas detectors. In some periods during CAST run, ultra low background has been observed in one of the micromegas detectors and it is being investigated through simulations and laboratory tests carried out at Canfranc Underground Laboratory. If this low background is indeed not a systematic effect, it can open new possibilities on rare event searches

    The Micromegas detector of the CAST experiment

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    A low background Micromegas detector has been operating in the CAST experiment at CERN for the search of solar axions during the first phase of the experiment (2002-2004). The detector, made out of low radioactivity materials, operated efficiently and achieved a very low level of background rejection (5 x 10^-5 counts/keV/cm^2/s) without shielding.Comment: 13 pages, 12 figures and images, submitted to New Journal o

    Search for chameleons with CAST

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    In this work we present a search for (solar) chameleons with the CERN Axion Solar Telescope (CAST). This novel experimental technique, in the field of dark energy research, exploits both the chameleon coupling to matter (βm\beta_{\rm m}) and to photons (βγ\beta_{\gamma}) via the Primakoff effect. By reducing the X-ray detection energy threshold used for axions from 1\,keV to 400\,eV CAST became sensitive to the converted solar chameleon spectrum which peaks around 600\,eV. Even though we have not observed any excess above background, we can provide a 95% C.L. limit for the coupling strength of chameleons to photons of βγ ⁣ ⁣1011\beta_{\gamma}\!\lesssim\!10^{11} for 1<βm<1061<\beta_{\rm m}<10^6.Comment: 8 pages, 12 figure

    Results and perspectives of the solar axion search with the CAST experiment

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    The status of the solar axion search with the CERN Axion Solar Telescope (CAST) will be presented. Recent results obtained by the use of 3^3He as a buffer gas has allowed us to extend our sensitivity to higher axion masses than our previous measurements with 4^4He. With about 1 h of data taking at each of 252 different pressure settings we have scanned the axion mass range 0.39 eVma \le m_{a} \le 0.64 eV. From the absence of an excess of x rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of gaγ2.3×1010_{a\gamma} \le 2.3\times 10^{-10} GeV1^{-1} at 95% C.L., the exact value depending on the pressure setting. CAST published results represent the best experimental limit on the photon couplings to axions and other similar exotic particles dubbed WISPs (Weakly Interacting Slim Particles) in the considered mass range and for the first time the limit enters the region favored by QCD axion models. Preliminary sensitivities for axion masses up to 1.16 eV will also be shown reaching mean upper limits on the axion-photon coupling of gaγ3.5×1010_{a\gamma} \le 3.5\times 10^{-10} GeV1^{-1} at 95% C.L. Expected sensibilities for the extension of the CAST program up to 2014 will be presented. Moreover long term options for a new helioscope experiment will be evoked.Comment: 4 pages, 2 pages, to appear in the proceedings of the 24th Rencontres de Blois V2 A few affiliations were not corrected in previous version V3 Author adde

    Prospects for the CERN Axion Solar Telescope Sensitivity to 14.4 keV Axions

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    The CERN Axion Solar Telescope (CAST) is searching for solar axions using the 9.0 T strong and 9.26 m long transverse magnetic field of a twin aperture LHC test magnet, where axions could be converted into X-rays via reverse Primakoff process. Here we explore the potential of CAST to search for 14.4 keV axions that could be emitted from the Sun in M1 nuclear transition between the first, thermally excited state, and the ground state of 57Fe nuclide. Calculations of the expected signals, with respect to the axion-photon coupling, axion-nucleon coupling and axion mass, are presented in comparison with the experimental sensitivity.Comment: 4 pages, 1 figure. Submitted to Nucl. Instr. and Meth.

    The First Release COSMOS Optical and Near-IR Data and Catalog

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    We present imaging data and photometry for the COSMOS survey in 15 photometric bands between 0.3um and 2.4um. These include data taken on the Subaru 8.3m telescope, the KPNO and CTIO 4m telescopes, and the CFHT 3.6m telescope. Special techniques are used to ensure that the relative photometric calibration is better than 1% across the field of view. The absolute photometric accuracy from standard star measurements is found to be 6%. The absolute calibration is corrected using galaxy spectra, providing colors accurate to 2% or better. Stellar and galaxy colors and counts agree well with the expected values. Finally, as the first step in the scientific analysis of these data we construct panchromatic number counts which confirm that both the geometry of the universe and the galaxy population are evolving.Comment: 19 pages, 13 figures, 14 tables, Accepted to ApJS for COSMOS speciall issu

    First results from the CERN Axion Solar Telescope (CAST)

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    Hypothetical axion-like particles with a two-photon interaction would be produced in the Sun by the Primakoff process. In a laboratory magnetic field (``axion helioscope'') they would be transformed into X-rays with energies of a few keV. Using a decommissioned LHC test magnet, CAST has been running for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling < 1.16 10^{-10} GeV^-1 at 95% CL for m_a <~0.02 eV. This limit is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment in this axion mass range.Comment: 4 pages, accepted by PRL. Final version after the referees comment

    CAST solar axion search with 3^He buffer gas: Closing the hot dark matter gap

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    The CERN Axion Solar Telescope (CAST) has finished its search for solar axions with 3^He buffer gas, covering the search range 0.64 eV < m_a <1.17 eV. This closes the gap to the cosmological hot dark matter limit and actually overlaps with it. From the absence of excess X-rays when the magnet was pointing to the Sun we set a typical upper limit on the axion-photon coupling of g_ag < 3.3 x 10^{-10} GeV^{-1} at 95% CL, with the exact value depending on the pressure setting. Future direct solar axion searches will focus on increasing the sensitivity to smaller values of g_a, for example by the currently discussed next generation helioscope IAXO.Comment: 5 pages, 2 figures. Last version uploade
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