344 research outputs found

    Operational Experience with a LHC Collimator Prototype in the CERN SPS

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    A full-scale prototype of the Large Hadron Collider (LHC) collimator was installed in 2004 in the CERN Super Proton Synchrotron (SPS) and has been extensively used for beam tests, for control tests and also LHC simulation benchmarking during four years of operation. This operational experience has been extremely valuable in view of the final LHC implementation as well as for estimating the LHC operational scenarios, most notably to establish procedures for the beam-based alignment of the collimators with respect to the circulating beam. These studies were made possible by installing in the SPS a first prototype of the LHC beam loss monitoring system. The operational experience gained at the SPS and the lessons learnt for the LHC operation are presented

    A detector system for 'absolute' measurements of fission cross sections at n_TOF in the energy range below 200 MeV

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    A new measurement of the 235^{235}U(n,f) cross section was performed at the neutron time-of-flight facility n_TOF at CERN. The experiment focused on neutron energies from 20 MeV to several hundred MeV, and was normalized to neutron scattering on hydrogen. This is a measurement first of its kind at this facility, in an energy range that was until now not often explored, so the detector development phase was crucial for its success. Two detectors are presented, a parallel plate fission chamber (PPFC) and a recoil proton telescope (RPT), both dedicated to perform measurements in the incident neutron energy range from 30 MeV to 200 MeV. The experiment was designed to minimize statistical uncertainties in the allocated run time. Several efforts were made to ensure that the systematic effects were understood and under control. The results show that the detectors are suited for measurements at n_TOF above 30 MeV, and indicate the path for possible future lines of development.Comment: Added acknowledgement to Euratom fundin

    Design, construction, and beam tests of a rotatable collimator prototype for high-intensity and high-energy hadron accelerators

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    A rotatable-jaw collimator design was conceived as a solution to recover from catastrophic beam impacts which would damage a collimator at the Large Hadron Collider (LHC) or its High-Luminosity upgrade (HL-LHC). One such rotatable collimator prototype was designed and built at SLAC and delivered to CERN for tests with LHC-type circulating beams in the Super Proton Synchrotron (SPS). This was followed by destructive tests at the dedicated High Radiation to Materials (HiRadMat) facility to validate the design and rotation functionality. An overview of the collimator design, together with results from tests without and with beam are presented

    Radiative neutron capture cross-section measurement of ge isotopes at n_TOF CERN facility and its importance for stellar nucleosynthesis

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    This manuscript summarizes the results of radiative neutron capture cross-section measurements on two stable germanium isotopes, 70Ge and 73Ge. Experiments were performed at the n_TOF facility at CERN via the time-of-flight technique, over a wide neutron energy range, for all stable germanium isotopes (70,72,73,74, and 76). Results for 70Ge [Phys. Rev. C 100, 045804 (2019)] and 73Ge [Phys. Lett. B 790, 458 (2019)] are already published. In the field of nuclear structure, such measurements allow to study excited levels close to the neutron binding energy and to obtain information on nuclear properties. In stellar nucleosynthesis research, neutron induced reactions on germanium are of importance for nucleosynthesis in the weak component of the slow neutron capture processes.Peer ReviewedArticle signat per 134 autors/autores: A. Gawlik, C. Lederer-Woods, J. Andrzejewski, J. Perkowski, U. Battino, P. Ferreira, F. Gunsing, S. Heinitz, M. Krtička, C. Massimi, F. Mingrone, R. Reifarth, A. Tattersall, S. Valenta, C. Weiss, O. Aberle, L. Audouin, M. Bacak, J. Balibrea, M. Barbagallo, S. Barros, V. Bécares, F. Bečvář, C. Beinrucker, E. Berthoumieux, J. Billowes, D. Bosnar, M. Brugger, M. Caamaño, F. Calviño, M. Calviani, D. Cano-Ott, R. Cardella, A. Casanovas, D.M. Castelluccio, F. Cerutti, Y.H. Chen, E. Chiaveri, N. Colonna, G. Cortés, M.A. Cortés-Giraldo, L. Cosentino, L.A. Damone, M. Diakaki, M. Dietz, C. Domingo-Pardo, R. Dressler, E. Dupont, I. Durán, B. Fernández-Domínguez, A. Ferrari, P. Finocchiaro, V. Furman, K. Göbel, A.R. García, T. Glodariu, I.F. Gonçalves, E. González-Romero, A. Goverdovski, E. Griesmayer, C. Guerrero, H. Harada, T. Heftrich, J. Heyse, D.G. Jenkins, E. Jericha, F. Käppeler, Y. Kadi, T. Katabuchi, P. Kavrigin, V. Ketlerov, V. Khryachkov, A. Kimura, N. Kivel, I. Knapova, M. Kokkoris, E. Leal-Cidoncha, H. Leeb, J. Lerendegui-Marco, S. Lo Meo, S.J. Lonsdale, R. Losito, D. Macina, T. Martínez, P. Mastinu, M. Mastromarco, F. Matteucci, E.A. Maugeri, E. Mendoza, A. Mengoni, P.M. Milazzo, M. Mirea, S. Montesano, A. Musumarra, R. Nolte, A. Oprea, N. Patronis, A. Pavlik, J.I. Porras, J. Praena, J.M. Quesada, K. Rajeev, T. Rauscher, A. Riego-Perez, P.C. Rout, C. Rubbia, J.A. Ryan, M. Sabaté-Gilarte, A. Saxena, P. Schillebeeckx, S. Schmidt, D. Schumann, P. Sedyshev, A.G. Smith, A. Stamatopoulos, G. Tagliente, J.L. Tain, A. Tarifeño-Saldivia, L. Tassan-Got, A. Tsinganis, G. Vannini, V. Variale, P. Vaz, A. Ventura, V. Vlachoudis, R. Vlastou, A. Wallner, S. Warren, M. Weigand, C. Wolf, P.J. Woods, T. Wright, P. ŽugecObjectius de Desenvolupament Sostenible::7 - Energia Assequible i No ContaminantPostprint (author's final draft

    The measurement programme at the neutron time-of-flight facility n-TOF at CERN

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    Neutron-induced reaction cross sections are important for a wide variety of research fields ranging from the study of nuclear level densities, nucleosynthesis to applications of nuclear technology like design, and criticality and safety assessment of existing and future nuclear reactors, radiation dosimetry, medical applications, nuclear waste transmutation, accelerator-driven systems and fuel cycle investigations. Simulations and calculations of nuclear technology applications largely rely on evaluated nuclear data libraries. The evaluations in these libraries are based both on experimental data and theoretical models. CERN’s neutron time-of-flight facility n_TOF has produced a considerable amount of experimental data since it has become fully operational with the start of its scientific measurement programme in 2001. While for a long period a single measurement station (EAR1) located at 185 m from the neutron production target was available, the construction of a second beam line at 20 m (EAR2) in 2014 has substantially increased the measurement capabilities of the facility. An outline of the experimental nuclear data activities at n_TOF will be presented
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