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Dielectric resonator to measure surface resistance of accelerator components at room temperature and 77 K
/ Brunner, Kristóf (CERN) ; Krkotić, Patrick (CERN) ; Pinto, Pedro Costa (CERN) ; Diaz-Rato, Eduardo Gibbons (CERN) ; Pfeiffer, Stephan (CERN) ; Vollenberg, Wilhelmus (CERN) ; Calatroni, Sergio (CERN) ; Barna, Dániel (Wigner RCP, Budapest) ; Pont, Montse (CELLS - ALBA, LLS) ; O'Callaghan, Joan (Barcelona, Polytechnic U.)
We measured the surface resistance of titanium, amorphous carbon, and nonevaporable getter (NEG) coatings on copper samples, representative of surface treatments of beam-facing components in the High-Luminosity Large Hadron Collider at CERN. Measurements were done at room temperature as well as at liquid nitrogen temperature (77 K) by means of a novel large dielectric resonator operating at 3.4 GHz. [...]
2023 - 8 p.
- Published in : Phys. Rev. Accel. Beams 26 (2023) 083101
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Electron flux and pressure dynamic in the LHC vacuum pilot sector as a function of beam parameters and beam pipe properties
/ Buratin, Elena (CERN ; EPFL, Lausanne, FSL) ; Baglin, Vincent (CERN) ; Henrist, Bernard (CERN) ; Chiggiato, Paolo (CERN) ; Fasoli, Ambrogio (EPFL, Lausanne, FSL)
The Large Hadron Collider (LHC) is affected by the electron cloud (EC) phenomenon that can provoke beam instabilities, detrimental heat loads and pressure increases in the vacuum system. An innovative dedicated system called vacuum pilot sector (VPS) provides a continuous monitoring of the electron flux and of the pressure signals thanks to electron pickup and vacuum gauges. [...]
2020 - 10 p.
- Published in : Phys. Rev. Accel. Beams 23 (2020) 114802
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Characterisation of the Mechanical Behaviour of Superconducting Cables Used in High Field Magnets From Room Temperature Down to 77K
/ Sacristan De Frutos, Oscar (CERN) ; Daly, Michael (CERN) ; Ferracin, Paolo (CERN) ; Fichera, Claudio (CERN) ; Guinchard, Michael (CERN) ; Mikkola, Tommi (CERN) ; Savary, Frederic (CERN) ; Vallone, Giorgio (CERN)
A comprehensive knowledge of the mechanical properties of the superconducting cable used in high-field magnets is of paramount importance to study and model the behaviour of the magnet coil from assembly to the operational conditions at cryogenic temperature. The mechanical characterisation of such kind of materials presents practical challenges associated with the heterogeneity of the materials, the geometry, size and quality of the samples that can be produced out of actual cables. [...]
CERN-ACC-2017-242.-
2017 - 4 p.
- Published in : 10.18429/JACoW-IPAC2017-WEPVA112
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In : 8th International Particle Accelerator Conference, Copenhagen, Denmark, 14 - 19 May 2017, pp.WEPVA112
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Irradiation of Multimode Ge-doped and F-doped Optical Fibers at Cryogenic Temperatures Down to 10 K
/ Toccafondo, Iacopo (CERN) ; Alessi, Antonino (Fraunhofer Inst., Euskirchen) ; Blanc, Jeremy (CERN) ; Di Francesca, Diego (CERN) ; Kuhnhenn, Jochen (Fraunhofer Inst., Euskirchen) ; Ricci, Daniel (CERN) ; Weinand, Udo (Fraunhofer Inst., Euskirchen)
The combined effect of radiation and cryogenic temperatures on the response of two different multimode fibers (MMF), one conventional and one radiation resistant, has been investigated. This article presents the outcome of the measurements of the radiation induced attenuation (RIA) in those fibers at 830 nm and 1310 nm under gamma irradiation and at temperatures of 300 K, 218 K, 143 K and 10. [...]
2023 - 7 p.
- Published in : J. Lightwave Technol. 41 (2023) 286-292
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Evaluation of the nonlinear surface resistance of REBCO coated conductors for their use in the FCC-hh beam screen
/ Krkotić, P (CELLS - ALBA, LLS ; Barcelona, Polytechnic U.) ; Romanov, A (Barcelona, Autonoma U.) ; Tagdulang, N (CELLS - ALBA, LLS ; Barcelona, Polytechnic U.) ; Telles, G (Barcelona, Autonoma U.) ; Puig, T (Barcelona, Autonoma U.) ; Gutierrez, J (Barcelona, IFAE) ; Granados, X (Barcelona, Autonoma U.) ; Calatroni, S (CERN) ; Perez, F (CELLS - ALBA, LLS) ; Pont, M (CELLS - ALBA, LLS) et al.
To assess the feasibility of using high-temperature superconductors for the beam screens of future circular colliders, we have undertaken a study of the power dependence of the microwave surface resistance in state-of-the-art REBCO coated conductors at about 8 GHz and 50 K. We have employed a dielectric resonator to produce radio-frequency (RF) electromagnetic fields on the surface of the coated conductors having amplitudes similar to those generated by proton bunches circulating in the vacuum chamber of the proposed future circular collider Hadron-Hadron (FCC-hh) at CERN We show that surface resistances in REBCO coated conductors without artificial pinning centers are more affected by a RF magnetic field than those containing nano-inclusions. [...]
2022 - 11 p.
- Published in : Supercond. Sci. Technol. 35 (2022) 025015
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Mechanical analysis of the collaring process of the 11 T dipole magnet
/ Ferracin, Paolo (CERN) ; Bottura, Luca (CERN) ; Bourcey, Nicolas (CERN) ; Daly, Michael (CERN) ; Devred, Arnaud (CERN) ; Izquierdo Bermudez, Susana (CERN) ; Ferradas Troitino, Jose (CERN) ; Ferradas Troitino, Salvador (CERN) ; Grosclaude, Philippe (CERN) ; Guinchard, Michael (CERN) et al.
As part of the Large Hadron Collider (LHC) accelerator upgrades foreseen by the high luminosity-LHC project, the CERN 11 T program is aimed at replacing standard LHC Nb-Ti main dipole magnets, operating with a bore field of 8.3 T, with pairs of shorter Nb$_3$Sn dipole magnets with a bore field of 11 T and the same total integrated field, thus providing space for additional collimators in the dispersion suppressor region. At the time of the submission of this paper, six single-aperture and two double-aperture short models have been fabricated and tested. [...]
2019 - 5 p.
- Published in : IEEE Trans. Appl. Supercond. 29 (2019) 4002705
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Performance of high-temperature superconducting REBCO coated conductors under synchrotron irradiation for future circular colliders
/ Krkotić, Patrick (CELLS - ALBA, LLS ; Barcelona, Polytechnic U.) ; Traver, Oriol (CELLS - ALBA, LLS) ; Tagdulang, Nikki (CELLS - ALBA, LLS ; Barcelona, Polytechnic U.) ; Calatroni, Sergio (CERN) ; Manuel O’Callaghan, Juan (Barcelona, Polytechnic U.) ; Pont, Montse (CELLS - ALBA, LLS)
The influence of medium-to-high energy synchrotron radiation (SR) (≈10–100 keV) produced by the ALBA Synchrotron Light Source on state-of-the-art REBCO coated conductors (CCs) has been studied to assess the feasibility of using high-temperature superconductors for the beam screen of future circular colliders. Long-term irradiation studies were conducted with ex-situ surface resistance testing by using a dielectric resonator. [...]
2023 - 16 p.
- Published in : Supercond. Sci. Technol. 36 (2023) 105009
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