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Sample records for du collisionneur lhc

  1. L'aventure du grand collisionneur LHC du big bang au boson de Higgs

    CERN Document Server

    Denegri, Daniel; Hoecker, Andreas; Roos, Lydia; Rubbia, Carlo

    2014-01-01

    Qu'est-ce que la physique des particules élémentaires, le LHC, et le boson de Higgs ? Ce livre présente de manière simple le monde des quarks, des leptons et de leurs interactions, gouvernées par des symétries fondamentales de la nature, ainsi que le lien entre ce monde de l'infiniment petit et celui de l'infiniment grand. Cette conjonction entre la physique des particules élémentaires et l'évolution de la matière dans les premiers instants de l Univers qui ont suivi le Big-Bang est un des plus beaux acquis de la science de ces cinquante dernières années. Après une description du cadre théorique, le modèle standard, et de son élaboration durant la deuxième moitié du XXe siècle, l'accent est mis sur ses grands succès expérimentaux, mais aussi sur ses faiblesses ou insuffisances telles que nous les percevons aujourd'hui. La passionnante histoire du grand collisionneur de hadrons du CERN, le LHC, le plus grand projet purement scientifique jamais réalisé, est présentée à la fois sous ses...

  2. Electromagnetic calorimeter and accurate measurement with the ATLAS detector of the LHC collider; Calorimetrie electromagnetique et mesures de precision avec le detecteur ATLAS aupres du collisionneur LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pralavorio, P

    2007-06-15

    The main purpose of the ATLAS experiment is the understanding of the underlying mechanisms that drive the breaking of the electro-weak symmetry through the discovery of Higgs bosons. An important element to achieve this aim was the design of an electromagnetic calorimeter able to investigate the decay channels: H {yields} {gamma}{gamma} and H {yields} 4e. The high performance of the calorimeter will allow us to get a better accuracy on the measuring values of W and top masses which is essential to indirectly constrain the mass of the Higgs. In the same way, accurate measurements of top and W properties during the decays of top and tWb vertex will be necessary to question the standard model and to see beyond. The author has been working for 9 years in the ATLAS project, he has been involved in the design, construction, qualification and testing phases of the electromagnetic calorimeter of ATLAS. This document is a detailed presentation of the calorimeter, of its qualification and of its expectations when LHC is operating. This document is organized into 4 chapters: 1) assets and weaknesses of the standard model, 2) the ATLAS experiment, 3) the electromagnetic calorimeter, and 4) accurate measurements with ATLAS. This document presented before an academic board will allow its author to manage research works and particularly to tutor thesis students. (A.C.)

  3. Le collisionneur LHC dans la tourmente: retard important en perspective

    CERN Multimedia

    Sacco, Laurent

    2007-01-01

    Bad news for particle physicist community: LHC, the biggest protons collider in the world, will not probably work in 2007. Supports of the superconductive magnetic quadrupoles, intended to focus the beams of protons in the accelerator, have just broken during preliminary tests. (1,5page)

  4. Le Japon contribue au grand collisionneur de hadrons du CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1995-01-01

    Japan's Ministry of Education, Science and Culture (Monbusho), announced on May 10 that it would help to finance the construction of CERN*'s next particle accelerator, the Large Hadron Collider (LHC). This announcement follows the visit of a CERN delegation, led by Director-General Prof. Christopher Llewellyn Smith to Japan in March 1995.

  5. Preparation of the ATLAS experiment in the LHC proton collider, performances of the electromagnetic calorimeter and its potentialities for the top quark; Preparation de l'experience ATLAS aupres du futur grand collisionneur de protons LHC: performances du calorimetre electromagnetique et potentiels pour la physique du quark top

    Energy Technology Data Exchange (ETDEWEB)

    Hubaut, F

    2007-03-15

    ATLAS is the biggest and the more complex detector ever built, it will operate on the LHC and is the outcome of a huge international collaboration of 2000 physicists. This document reviews the theoretical and experimental achievements of one of them, his collaboration spread over 7 years and has followed 2 axis. First, the design, construction and test of the electromagnetic calorimeter of ATLAS and secondly, the development of analysis strategies in the physics of the top quark. The expected important production of top quarks in LHC will allow an accurate measurement of the properties of this particle and in the same way will provide new testing areas for the standard model. The top quark, being extremely massive, might play a significant role in the mechanism of electro-weak symmetry breaking. This document is organized into 5 chapters: 1) ATLAS detector, performance and progress, 2) the optimization of the energy measurement with the electromagnetic calorimeter, 3) the performance of the electromagnetic calorimeter, 4) the physics of the top quark, and 5) the potentialities of ATLAS in the top quark sector. This document presented before an academic board will allow its author to manage research works and particularly to tutor thesis students. (A.C.)

  6. La Physique du Futur Collisionneur Linéaire e+e- Partie I

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    Depuis la fin des années 80, une grande partie de notre communauté scientifique penche pour un collisionneur électron-positon avec une énergie dans le centre de masse pouvant aller jusqu'à 500 GeV et même 1 TeV. Les technologies possibles et le programme de Physique aux différentes énergies seront détaillés, avec un accent sur les points forts (mesures de précision, secteur de Higgs) et les faiblesses de cet outil.

  7. Mise en oeuvre du calorimètre électromagnétique d'ATLAS et de la reconstruction des électrons avec les premières données du collisionneur de protons LHC. Détermination du potentiel de découverte d'un boson de jauge lourd chargé W^(' )→ev

    CERN Document Server

    Kuna, Marine

    ATLAS is a general purpose particle detector based at the Large Hadron Collider which has been delivering collisions since the beginning of 2010, with an energy in the centre of mass of 7 TeV. The electron and the discovery potential it carries is the subject of my thesis. The electromagnetic calorimeter is a crucial sub-detector for the measurement of electrons kinematic properties. In order to verify its functioning, I contributed to the first in situ data analysis, cosmic muons in 2008 and LHC beam data in 2009. These analyses showed the electromagnetic calorimeter was operational and efficient over its whole coverage. The knowledge of the electrons energy losses before they reach the calorimeter is mandatory to achieve precise measurements. For that purpose, I contributed to a method evaluating the amount of material upstream using Monte Carlo simulations of high transverse momentum electrons. The information from the electron allows mapping of the material from the inner tracker to the calorimeter entran...

  8. Contribution supplémentaire de 5 milliards de yens du Japon au grand collisionneur de hadrons du CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1998-01-01

    Japan's Ministry of Education, Science, Sports and Culture (Monbusho), has announced, subject to approval by the Diet, a further contribution of 5 billion Yen (approximately 56 million Swiss francs) for the construction of the LHC. This generous gesture reinforces the excellent relations that have been established between CERN and Japan.

  9. Le futur du project LHC

    CERN Multimedia

    Heyoka

    2007-01-01

    Since 2004, and specitally during the long study in 2005, we used the results of the LHC Project to evaluate differents parameters of the machiene (LHC). The final choices for the design of the machine are based partly on these results. (1,5 page)

  10. LHC : sur la piste des mysteres de l`Univers par Michael Doser

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    Le CERN, le plus grand centre en physique des particules au monde, va mettre en service le Grand collisionneur de hadrons (Large Hadron Collider), le LHC. Cette machine, le plus grand rouage du complexe d’accélérateurs du CERN, doit répondre aux énigmes qui subsistent sur les briques élémentaires de la matière et l’histoire de l’Univers.

  11. Une force venant du futur chercherait à saboter l'expérience du LHC...

    CERN Multimedia

    Scappaticci, Bruno

    2009-01-01

    "A quelques jours de la reprise de l'expérience du LHC, on ne parle plus de la menace d'un trou noir, mais deux physicines souteinnent aujourd'hui une tout autres hypothèse: la nature, depuis le futur, va continuer de contrarier les travaux du Cern, afin d'éviter à l'Homme de mettre le doigt là où il ne faut pas..." (1.5 pages)

  12. Le grand collisionneur

    CERN Multimedia

    2007-01-01

    The great hadron collider (Large Hadron Collider - LHC) - the most powerful particle accelerator of the world - will start in may 2008. The advertisement was made by Robert Aymar, Director General of CERN, during a Council meeting on 22nd June. (2/3 page)

  13. Contribution de 531 MUSD des Etats-Unis d'Amérique au projet de grand collisionneur de hadrons du CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1997-01-01

    U.S. and European officials today signed an agreement for U.S. participation in the Large Hadron Collider (LHC), a particle accelerator under construction near Geneva, Switzerland. When completed in 2005, the 27 km circumference accelerator will be the most powerful in the world.

  14. LHC 2008 lectures "Une nouvelle vision du monde"

    CERN Multimedia

    2008-01-01

    The history of the science of the Universe and the science of matter have been marked by a small number of "revolutions" that have turned our understanding of the infinitesimally large and the infinitesimally small on its head. New ways of looking at the world have come about sometimes through conceptual advances and sometimes through innovations in scientific instrumentation. How do things stand at the beginning of the 21st century? Will today’s large-scale machine projects like the LHC and gravitational wave detectors pave the way for a new scientific revolution? Thursday, 15 May 2008 at 8.00 p.m. Une nouvelle vision du monde Jean-Pierre Luminet, Research Director at the CNRS The Globe, first floor No specialist knowledge required. Entrance free. To reserve call + 41 (0) 22 767 76 76 http://www.cern.ch/globe

  15. Construction of a hadronic calorimeter prototype for the future CERN LHC high energy accelerator; Construction d`un prototype de calorimetre hadronique pour le futur collisionneur a haute energie LHC du CERN

    Energy Technology Data Exchange (ETDEWEB)

    Rival, F

    1994-06-01

    The study of fragment-fragment correlations at small relative momentum can give informations on the space and time extend of the emitting source, and on the nuclear density, which is one of the variables used in the equation of state. This analysis shows the experimental results obtained with the FOPI detector at GSI Darmstadt, for Au + Au central collisions at 150 and 400 A.MeV. These results are the first studies at such high energies and for heavy systems. Two fragments correlation functions are compared with theoretical calculations of D.H. Boal, including the size of the source as a parameter. We must take into account effects of experimental biases (namely the relative momentum resolution) on the theoretical correlation function, in order to make a comparison with experimental results. The extracted experimental radii correspond to the final phase of the expansion, and the obtained densities are smaller than normal density of nuclear matter. In the final state of the interaction, intermediate mass fragments and their excited states are observed. We note a shift of these excited states at 400 A.MeV, which can be explained by the detector effects. We observe a weak sensibility of the source size versus the centrality of the collision. That can be explained either by a mixing of sources, or by the observation of a source at the end of expansion whose the radius is quite independent of the initial centrality. Energetic particles correspond to smaller size of the source, which can be explained as a higher compression, or as a different stage of the collision. We give some prospectives for the future experiments at GSI-Darmstadt. (author). 116 refs.

  16. Rapport final de la Collaboration CERN-CNRS pour la construction du LHC Accord Technique d'Exécution No 2 Cryostats et assemblage des sections droites courtes (SSS) du LHC

    CERN Document Server

    Bergot, JB; Poncet, A; Rohmig, P; Roy, E; Vincent, D

    2006-01-01

    Depuis 1995 et suite à la signature du protocole de Collaboration, le CERN, le CEA et le CNRS ont étroitement collaboré dans le cadre de la contribution exceptionnelle de la France à la construction du LHC. Pour le CNRS, l'Institut de Physique Nucléaire d'Orsay a pris en charge deux Accords Techniques d'Exécution. Le premier concerne la conception et l'assemblage des Sections Droites Courtes de la machine, et le deuxième, l'étalonnage des thermomètres cryogéniques du LHC. Dans le cadre de l'Accord Technique d'Exécution N°2, le Bureau d'Etudes de la Division Accélérateur de l'IPNO et le groupe AT-CRI du CERN ont travaillé de concert pour mener à bien la conception des SSS (Short Straight Section) et de tous les équipements nécessaires à l'assemblage. Ce rapport a donc pour objectif de dresser, en termes d'historique, d'organisation, de résultats quantitatifs et qualitatifs et de moyens mis en ?uvre, un tableau aussi complet que possible du déroulement de cette Collaboration entre le CERN e...

  17. Search for (exotic) strange matter in the Star and Alice experiments with the ultra-relativistic heavy ion colliders RHIC and LHC; Recherche de matiere etrange (exotique) dans les experiences STAR et ALICE aupres des collisionneurs d'ions lourds ultra-relativistes RHIC et LHC

    Energy Technology Data Exchange (ETDEWEB)

    Vernet, R

    2006-02-15

    Ultra-relativistic heavy ion collisions offer the possibility to create conditions of temperature and density that could lead nuclear matter to a state of deconfined partons, the quark-gluon plasma. Strange baryon production is one of the essential observables to understand the mechanisms involved in the medium. Furthermore, theories predict a possible production of strange dibaryons, still hypothetical particles, from which one could draw important inferences in nuclear physics and astrophysics. The experiments STAR at RHIC, and, soon, ALICE at LHC, allow one to search for strange baryons and dibaryons. The STAR sensitivity to the metastable dibaryon H{sup 0} in the {lambda}p{pi}{sup -} decay mode was calculated thanks to a dedicated simulation. The search for the H{sup 0}, and for the {xi}{sup -}p resonance as well, was performed in the STAR Au+Au data at {radical}(s{sub NN}) = 62.4 and 200 GeV energies. Within the framework of the preparation of ALICE to the first Pb+Pb data, the detector ability to identify strange baryons {lambda}, {xi} and {omega}, was estimated via several simulations. So as to favour the reconstruction efficiency in a large range of transverse momentum while keeping a reasonable S/B ratio, the influence of the geometrical selections and the size of the reconstruction zone was emphasized. The ALICE sensitivities to the metastable strange dibaryons H{sup 0} and ({xi}{sup 0}p){sub b} and to the {lambda}{lambda} resonance were calculated as well. (author)

  18. La cellule d'essais du LHC fonctionne avec succès pendant 24h

    CERN Multimedia

    CERN Press Office. Geneva

    1994-01-01

    On 6 and 7 December a string of powerful superconducting magnets for CERN's next particle accelerator the Large Hadron Collider (LHC) ran successfully at 8.36 Tesla for 24 hours. 8.36 Tesla is the magnetic field required to accelerate protons to the required energy for LHC and this result demonstrates that the key technical choices made for the construction of the LHC magnets were correct. The test magnets have shown that they can operate reliably under the same working conditions as the future accelerator.

  19. Top quark studies with Atlas at the LHC. Electromagnetic calorimeter commissioning; Etude du quark top avec Atlas au LHC. Mise en route du calorimetre electromagnetique

    Energy Technology Data Exchange (ETDEWEB)

    Resende Vaz de Melo Xavier, B

    2007-05-15

    The first proton-proton collisions in the Large Hadron Collider at CERN will take place on 2007. It aims at understanding the origins of mass. and it will also look for new physics. The ATLAS experiment will exploit all those physics potentialities. using a multilayer generalist detector. Quark top studies will be an important step in ATLAS physics program: its properties may reveal hints of new phenomena. One way to look for new physics is through quark top and W boson polarizations. which are studied here. This detailed simulation study has confirmed previous fast simulation results including extensive systematics estimation. ATLAS should thus yield a precision of a few percents with 10 fb{sup -1} of data. that is a year of LHC working. This precision is sufficient to select among several new physics models. Among ATLAS subsystems, the electromagnetic calorimeter plays a crucial role in the characterisation of electrons and photons. which are used in particular for the Higgs boson search. This document deals with the calorimeter commissioning as the time of the first collisions approaches. The detector itself and its electronics will be described, as well as its installation and calibration. Cosmic muons observation will then be presented. as the first overall test of the reading and reconstruction electronics chain in actual working conditions. (author)

  20. 23 octobre 2012 - Le Président du Conseil général de la Haute-Savoie C. Monteil signe le livre d'or en présence du Directeur général R. Heuer, la chef des Relations Internationales F. Pauss, le chef du département Physique P. Bloch et le chef du département Technologie F. Bordry; visite du hall de test des aimants supraconducteurs du LHC avec F. Bordry.

    CERN Multimedia

    Maximilien Brice

    2012-01-01

    23 octobre 2012 - Le Président du Conseil général de la Haute-Savoie C. Monteil signe le livre d'or en présence du Directeur général R. Heuer, la chef des Relations Internationales F. Pauss, le chef du département Physique P. Bloch et le chef du département Technologie F. Bordry; visite du hall de test des aimants supraconducteurs du LHC avec F. Bordry.

  1. Le LHC du CERN ne démarrera qu'en 2008

    CERN Multimedia

    2007-01-01

    During a speech at the 142nd Council Session, Robert Aymar, Director General of the Organisation, announced that the great hadron collider (LHC) will start in May 2008, for first study work in physics, in unexplored fields of high energies. (1,5 page)

  2. Pour une physique de puissance - Le grand collisionneur de hadron

    CERN Multimedia

    Baquiast, Jean-Paul

    2007-01-01

    On a technical level, the LHC is already the biggest and the most complex machine built by Man. On an human level, it gave work to hundreds of subonctractors, to thousands of ingeneers and technicians. (1,5 page)

  3. Coordination de la sécurité de l'installation du LHC et de ses expériences

    CERN Document Server

    Vadon, M

    2005-01-01

    La coordination de sécurité pour l'installation du LHC et de ses expériences a été mise en place lors du démantèlement du LEP. Depuis, les contractants et les surveillants de chantier ont fait beaucoup de progrès en matière de sécurité et les procédures en vigueur sont maintenant suivies. Néanmoins, des accidents et incidents se produisent encore et pourraient être facilement évités. Un incident important, des dommages sérieux aux équipements, ou pire un accident mortel affecteraient sérieusement le projet LHC. L'analyse des causes des accidents récents révèle toujours une marge d'amélioration, en particulier en ce qui concerne l'analyse à priori des procédures l'installation et des méthodes de travail. L'intégration des aspects de sécurité dès la phase de conception et l'application stricte des règles dans tout le projet sont les clefs pour une meilleure sécurité des chantiers. Ceci ne peut être réalisable que si la sécurité est abordée de la même manière que la qualit...

  4. Test of the little Higgs model in Atlas at LHC: simulation of the digitization of the electromagnetic calorimeter; Test du modele du petit Higgs dans ATLAS au LHC: simulation de la numerisation du calorimetre electromagnetique

    Energy Technology Data Exchange (ETDEWEB)

    Lechowski, M

    2005-04-15

    LHC is a proton-proton collider with an energy of 14 TeV in the center of mass, which will start operating in 2007 at CERN. Two of its experiments, ATLAS, and CMS, will search and study in particular the Higgs boson, Supersymmetry and other new physics. This thesis was about two aspects of the ATLAS experiment. On one hand the simulation of the liquid Argon electromagnetic calorimeter, with the emulation of the electronic chain in charge of the digitization of the signal and also the evaluation of the electronic noise and the pile-up noise (coming from minimum bias events of inelastic collisions at LHC). These two points have been validated by the analysis of the data taken during beam tests in 2002 and 2004. On the other hand, a physics study concerning the Little Higgs model. This recent model solves the hierarchy problem of the Standard Model, in introducing new heavy particles to cancel quadratic divergences arising in the calculation of the Higgs boson mass. These new particles, with a mass about the TeV/c{sup 2}, are a heavy quark top, heavy gauge bosons Z{sub H}, W{sub H} and A{sub H}, and a heavy Higgs boson triplet. The physics study dealt with the characteristic decays of the model, Z{sub H} in Z + H and W{sub H} in W + H, with a Higgs mass either at 120 GeV/c{sup 2} decaying in two photons or at 200 GeV/c{sup 2} decaying in ZZ or WW. Results show that in both cases, for 300 fb{sup -1} (3 years at high luminosity), an observation of the signal at 5 {sigma} for Z{sub H} et W{sub H} masses less than 2 TeV/c{sup 2} is possible, covering a large part of the parameter space. (author)

  5. M. G.-F. Leclerc, Préfet de la Haute-Savoie lors de sa visite dans le tunnel du LHC au Point 2 avec D. Delikaris, Département Technologie; dans la caverne de l'expérience ALICE avec B. Erazmus, Collaboration ALICE et lors de la signature du livre d'or avec F. Bordry, Chef du Département Technologie. P. Fassnacht, Conseiller au Bureau des Relations internationales présent.

    CERN Multimedia

    Jean-Claude Gadmer

    2013-01-01

    M. G.-F. Leclerc, Préfet de la Haute-Savoie lors de sa visite dans le tunnel du LHC au Point 2 avec D. Delikaris, Département Technologie; dans la caverne de l'expérience ALICE avec B. Erazmus, Collaboration ALICE et lors de la signature du livre d'or avec F. Bordry, Chef du Département Technologie. P. Fassnacht, Conseiller au Bureau des Relations internationales présent.

  6. Conception et réalisation de l'unité de décision du système de déclenchement de premier niveau du détecteur LHCb au LHC

    CERN Document Server

    Laubser, Julien

    2007-01-01

    Le detecteur LHCb est l'une des quatre experiences de physique des particules installees sur la nouvelle chaine d'acceleration LHC (Large Hadron Collider) du CERN a Geneve. Afin de reduire la quantite de donnees destinees au stockage pour les analyses hors ligne, un dispositif de selection en ligne des collisions interessantes selon la physique a etudier est mis en place en parallele de la chaine d'acquisition des donnees. Ce dispositif est compose d'un premier niveau(niveau 0) realise par un systeme electronique complexe et d'un second niveau de selection realise par informatique HLT (High Level Trigger). L'unite de decision de niveau 0 (L0DU) est le systeme central du niveau 0 de declenchement. L0DU prend la decision d'accepter ou de rejeter la collision pour ce premier niveau a partir d'une fraction d'informations issues des sous-detecteurs les plus rapides (432 bits a 80 MHz). L'unite de decision est un circuit imprime 16 couches integrant des composants de haute technologie de type FPGA (Field Programmab...

  7. Le CERN réagit à l'augmentation du coût du LHC à son achèvement

    CERN Multimedia

    CERN Press Office. Geneva

    2001-01-01

    Director-General, Luciano Maiani, stressed that CERN was now fully engaged in the LHC and outlined the first moves to react to the increased cost to completion of the LHC. The new accelerator is an extremely complex, high-tech project which CERN is building under very severe conditions. However, the technical challenges are solved and industrial production of accelerator elements, and installation are starting.

  8. Cryogénie hélium et efficacité énergétique: L'expérience du LHC au CERN

    CERN Document Server

    Claudet, S; Tavian, L

    2012-01-01

    Résumé La supraconductivité et la cryogénie hélium associée sont devenues des technologies clés des grands équipements de recherche en physique, et en particulier des accélérateurs de particules. Le coût thermodynamique du fonctionnement à basse température impose à leurs systèmes cryogéniques une haute efficacité énergétique dans la gestion des charges thermiques, la distribution des fluides et la production de froid, obtenue par une approche intégrée couvrant toutes les phases du projet, de la conception préliminaire jusqu'à l'exploitation. L'expérience du LHC au CERN vient illustrer le propos, tandis que quelques pistes de développements futurs sont évoquées. Abstract Superconductivity and associated helium cryogenics have become key technologies for large research infrastructures in physics, and particularly particle accelerators. The thermodynamic penalty for operating at low temperature requires their cryogenic systems to be highly energy efficient in managing heat loads, dis...

  9. Performance du spectrometre a muons d’ALICE. Production et mesure des bosons faibles dans des collisions d’ions lourds aupres du LHC

    CERN Document Server

    Conesa Del Valle, Zaida; Moreno, F Fernandez

    2007-01-01

    Nucleus-nucleus collisions are the unique tool available to investigate the QCD matter phase diagram in the laboratory. A lot of work has been devoted to explore it in different domains in the last 3 decades, and the forthcoming LHC collider will contribute to such research increasing the collision center-of-mass energy by a factor 30 and the energy densities by a factor 1-10 with respect to the RHIC collider [C+04, A+06].Only a comprehensive analysis of a wide spectrum of experimental observables can help to fully characterize the prospected matter. In particular, valuable information is expected from charm and beauty production, the situation from SPS and RHIC charmonia data being puzzling [GdC07, Lei07, A+00a, Sco07], and the c¯c (b¯b) yields per central nucleon-nucleon collision being increased from 10 (0.1) to 110 (5) from RHIC to LHC [C+04, MG07]. Whether quarkonia will thermalize, will develop collective motion, will be further suppressed or regenerated are still open questions that LHC data might re...

  10. Mise en service du calorimetre electromagnetique d'Atlas et determination du potentiel de decouverte d'un Z' --> e+e- dans les premieres donnees LHC

    CERN Document Server

    Mangeard, Pierre-Simon

    2009-01-01

    After about fifteen years of development, the ATLAS detector is ready to operate and recorded, in 2008, several millions of cosmic events as well as first LHC data. This achievement is based on the long experience of beam tests and on the large effort towards the detector in situ commissioning undertaken by the ATLAS collaboration. This promises fast ability to perform searches for evidence of Higgs boson and new physics. I heavily contributed to the in situ commissioning of the EM calorimeter. To verify its performance, I studied the first cosmic data taken in 2006 which allowed the first in situ analysis of dead channels, energy reconstruction and detector response uniformity. This participation to the commissioning has continued with the study of the single beam data recorded during the first week of LHC operation (Sept. 2008). Expanding on my expertise of the EM calorimeter, I focused my physics analysis, prepared with simulation, on the promising discovery potential of new physics at LHC via the di-elect...

  11. Chasseur de hadrons

    CERN Document Server

    Eytier, Jean-Louis

    2009-01-01

    Qu'aurait-il proposé comme solutions face aux déboires du LHC, le grand collisionneur du hadrons du CERN, arrêté peu après son démarrage à l'automne 2008? Lucien Edmond André Montanet était un des grands de la physique des particules. (2 pages)

  12. 20 fevrier 2012 - Le Vice-Président du Gouvernement Wallon et Ministre du Développement durable et de la Fonction Publique en charge de l’Energie du Logement et de la Recherche J.-M. Nollet, Royaume de Belgique, visite la salle de contrôle de CMS au Point 5, la caverne expérimentale CMS et le hall de tests des aimants supraconducteurs du LHC. Les chefs de département T. Lagrange et F. Hemmer accompagnent la délégation. L. Walckiers guide la visite SM18.

    CERN Multimedia

    Maximilien Brice

    2012-01-01

    20 fevrier 2012 - Le Vice-Président du Gouvernement Wallon et Ministre du Développement durable et de la Fonction Publique en charge de l’Energie du Logement et de la Recherche J.-M. Nollet, Royaume de Belgique, visite la salle de contrôle de CMS au Point 5, la caverne expérimentale CMS et le hall de tests des aimants supraconducteurs du LHC. Les chefs de département T. Lagrange et F. Hemmer accompagnent la délégation. L. Walckiers guide la visite SM18.

  13. De l'expérience ALEPH au LEP à la construction du détecteur ATLAS auprès du LHC

    CERN Document Server

    Martin, Franck

    This document summarizes ten years of activities in the field of experimental particle physics, which I have done just after my PhD defense in 1999. After a short introduction describing my PhD work and my activities during these ten years, the first chapter describes an analysis made in the ALEPH experiment about the measurement of the Bose-Einstein correlations in W pair decays, using an event mixing method. Nevertheless, the main part of the text is dedicated to the work I have done in the ATLAS experiment at the LHC, between the years 2000 and 2010. Four parts are distinguished. First, an analysis concerning some searches for possible supersymmetric top decays with R-parity violation is described. Then a second part is written about the test bench of the tile calorimeter front-end electronics, and its installation in the ATLAS experiment. Third, the work done in the transition radiation tracker concerning the validation and the installation of the endcap front-end electronics is fully explained. End, the ...

  14. Optimization of the ATLAS detector to search for the two-photon decaying Higgs boson at LHC; Optimisation du detecteur ATLAS pour la recherche du boson de Higgs se desintegrant en deux photons au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Tisserand, V [Paris-11 Univ., 91 - Orsay (France). Lab. de l' Accelerateur Lineaire; [Universite de Paris Sud, 91 - Orsay (France)

    1997-02-03

    The two photon decay channel is the most clear and promising way to detect a Higgs boson of an intermediate mass between 80 GeV/c{sup 2} and 150 GeV/c{sup 2} at the future large proton collider of CERN (LHC). As the Higgs mass is narrow in this range, the observation of this channel relies on the performance of the electromagnetic calorimeter. A full simulation study has been performed to evaluate the discovery potential of the ATLAS detector. The results of this simulation have been confirmed by beam tests with a prototype. This simulation includes different contributions such as energy resolution sampling term, electronic and pile-up noise, global constant term and angular measurement of the two photon opening angle. The levels of the irreducible background from prompt di-photon production and the reducible background from jets with isolated leading neutrals pions have been estimated, taking into account the rejection capability of the detector. After the computation of the two photon invariant mass resolution, and the evaluation of signal and background rates, the discovery potential of the Higgs boson with the ATLAS detector was calculated. The Higgs can be discovered at five sigma confidence level after less than a year of data taking at LHC with the nominal luminosity of 10{sup 34} cm{sup -2}.s{sup -1} if the Higgs mass is between 100 GeV/c{sup 2} and 150 GeV/c{sup 2}. The Higgs mass window between 80 GeV/c{sup 2} and 150 GeV/c{sup 2} will be covered with an integrated luminosity of 3.10{sup 5} pb{sup -1}. In the case of the Minimal Supersymmetric Model (MSSM) the plane (m{sub A{sup 0}}, tan({beta})) will be fully explored if m{sub A{sup 0}} > 175 GeV/c{sup 2}. (author)

  15. Trigger system study of the dimuon spectrometer in the ALICE experiment at CERN-LHC; Etude du systeme de declenchement du spectrometre dimuons de l'experience alice au Cern-LHC

    Energy Technology Data Exchange (ETDEWEB)

    Roig, O

    1999-12-01

    This work is a contribution to the study of nucleus-nucleus collisions at the LHC with ALICE. The aim of this experiment is to search for a new phase of matter, the quark-gluon plasma (QGP). The dimuon forward spectrometer should measure one of the most promising probes of the QGP, the production of heavy quark vector mesons (J/{psi}, {gamma}, {gamma}', {gamma}'') through their muonic decays. The dimuon trigger selects the interesting events performing a cut on the transverse momentum of the tracks. The trigger decision is taken by a dedicated electronics using RPC (''Resistive Plate Chambers'') detector information. We have made our own R and D program on the RPC detector with various beam tests. We show the performances obtained during these tests of a low resistivity RPC operating in streamer mode. The ALICE requirements concerning the rate capability, the cluster size and the time resolution are fulfilled. We have optimised the trigger with simulations which include a complete description of the read-out planes and the trigger logic (algorithm). In particular, a technique of clustering is proposed and validated. A method called ''Ds reduction'' is introduced in order to limit the effects of combinatorial background on the trigger rates. The efficiencies and the trigger rates are calculated for Pb-Pb, Ca-Ca, p-p collisions at the LHC. Other more sophisticated cuts, on the invariant mass for example, using again the RPC information have been simulated but have not shown significant improvements of the trigger rates. (author)

  16. Study of dimuon spectrometer tracking chambers of the ALICE experiment at LHC; Etude des chambres de trajectoire du spectrometre dimuons de l'experience ALICE aupres du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Kharmandarian, Liliane [Institut de Physique Nucleaire, CNRS - IN2P3, Universite Paris - Sud, 91406 Orsay Cedex (France)

    1999-12-16

    The ALICE (A Large Ion Collider Experiment) experiment will study ultrarelativistic heavy ion collisions at the Large Hadron Collider (LHC) in CERN as of 2005. An extensive R and D programme has been carried out on the dimuon spectrometer tracking chambers at the Nuclear Physics Institute in Orsay. Three multiwire proportional chamber prototypes with segmented cathodes, including a full-scale 1 m{sup 2} version, were constructed. In this thesis, the experimental tests are presented along with the simulations used to understand and optimize the detectors' performances. The prototypes were tested several times at the PS and SPS accelerators. The aims were to validate the choices made in terms of mechanical construction, geometrical parameters, gas mixture and read-out electronics. Analysis of the large amount of data collected has shown that the performances of this type of detector fulfill the required specifications. The results concerning the detectors' characteristics, spatial resolution efficiency, gain and homogeneity are given. Spatial resolutions of less than thirty microns were obtained. In parallel with the in-beam tests, several simulations have been developed in order to gain a better understanding of the detectors' response. They allowed, in particular, to define the segmentation of the cathode plane, to study the position reconstruction algorithm and to establish the future electronics specifications. (author)

  17. Mesure de la production de di-bosons WZ auprès du LHC avec l'experience ATLAS

    CERN Document Server

    Keoshkerian, Houry

    This thesis is performed in the frame of the ATLAS experiment at the LHC. A first part of the work presented in this document consists on the time calibration of the ATLAS Liquid Argon (LAr) calorimeter. The control of the time alignment of the calorimeter is important for the goodness of the quality of the energy reconstructed in the calorimeter. The results presented in this thesis have allowed an improvement of 30% of the global time resolution of the LAr calorimeter. The Standard model of particle physics predicts, during proton collisions, the production of the $W$ and $Z$ weak bosons as a pair due to the interaction of a quark with an anti-quark. The diboson production can be sensitive to the couplings between vector bosons. An anomalous deviation of these couplings from the prediction of the SM would point to the presence of new physics. The use of the full statistics of the 2012 ATLAS data allowed us to increase the precision of the measurement of these couplings compared to previous results based on...

  18. Au Cern, premières collisions de protons hier

    CERN Multimedia

    Galeazzi, Juliette

    2009-01-01

    "Hier, les scientifiques du monde entier ont salué le redémarrage du LHC, grand collisionneur de hadrons, au Cern à Genève. Après quatorze mois d'arrêt, à la suite d'une panne, les expériences ont pris et les premières collisions ont eu lieu" (2 pages)

  19. 9 décembre 2016 - Visite du hall d'assemblage des aimants supraconducteurs du LHC par le Prof. D. Le Bihan, Directeur, NeuroSpin; membre de l’Académie des Sciences, République française avec le Directeur des accélérateurs et de la technologie F. Bordry et le chef de groupe L. Bottura.

    CERN Multimedia

    Bennett, Sophia Elizabeth

    2016-01-01

    9 décembre 2016 - Visite du hall d'assemblage des aimants supraconducteurs du LHC par le Prof. D. Le Bihan, Directeur, NeuroSpin; membre de l’Académie des Sciences, République française avec le Directeur des accélérateurs et de la technologie F. Bordry et le chef de groupe L. Bottura.

  20. Test du modèle du "Petit Higgs" dans ATLAS au LHC, et simulation de la numérisation du calorimètre électromagnétique

    CERN Document Server

    Lechowski, Matthieu

    2005-01-01

    LHC is a proton-proton collider with an energy of 14 TeV in the center of mass, which will start in 2007 at CERN. Two of its experiments, ATLAS, and CMS, will search and study in particular the Higgs boson, Supersymmetry and other new Physics. This thesis was about two aspects of the ATLAS experiment : â on one hand the simulation of the liquid Argon electromagnetic calorimeter, with the emulation of the electronic chain in charge of the digitization of the signal and also the evaluation of the electronic noise and the pile-up noise (coming from minimum bias events at LHC). These two points have been validated by the analysis of the data taken during beam tests in 2002 and 2004. â on the other hand, a physics study concerning the Little Higgs model. This recent model solves the hierarchy problem of the Standard Model, in introducing new heavy particles to cancel quadratic divergences arising in the calculation of the Higgs boson mass. These new particles, with a mass about the TeV/c2, are one heavy quark to...

  1. Etude et modélisation du comportement du FPGA A54SX72A d’Actel en milieu radiatif et à températures contrôlées - Application a l’environnement du LHC

    CERN Document Server

    AUTHOR|(CDS)2080629; DEPASSE, Pierre; LAZIC, Dragoslav-Laza; CASAS-CUBILLOS, Juan; GALEZ, Christine; BOUTEMEUR, Madjid; PASSARD, Michelle

    The Large Hadrons Collider (LHC) at CERN (Geneva) will provide proton-proton collisions at center of mass energy of 14 TeV. The beam bending and trajectory in the 27 km ring is maintained by superconducting dipole magnets. The dipole coils are made of Nb-Ti filaments cooled at a temperature below 1.9 K and provide a nominal field of 8.65 T. The monitoring of the cryogenic system, such as the measurement of the temperature and the pressure, is provided by a set of resistive cryogenic sensors placed inside the magnets. However, some of these sensors should be fed with currents not exceeding 1A. Therefore the output voltages are very small and the readout electronics should be placed very close to the sensors. The readout electronic cards are placed under the dipole magnets. The main digital component, embedded in the cards, is an FPGA chip. It is an integrated circuit (IC) of type FPGA A54SX72A from Actel (CMOS technology) whose purpose is signal filtering and analysis. Depending of the location along the 27...

  2. LHC physics

    National Research Council Canada - National Science Library

    Binoth, T

    2012-01-01

    "Exploring the phenomenology of the Large Hadron Collider (LHC) at CERN, LHC Physics focuses on the first years of data collected at the LHC as well as the experimental and theoretical tools involved...

  3. Sprint final pour l'accélérateur Le LHC du CERN va entrer en service au mois de juin

    CERN Multimedia

    Du Brulle, Christian

    2008-01-01

    "Our new tool should be ready to function this summer", is delighted Jos Engelen, the scientific director of the international scientific organization. In more than hundred metres deep, under the French-Swiss border, the circular tunnel 27 kilometres in diameter of the LHC is almost equipped.

  4. Etude et optimisation des performances du calorimètre électromagnétique de l'expérience CMS pour la physique au LHC

    CERN Document Server

    Descamps, Julien; Jarry, Patrick

    2007-01-01

    The CMS experiment (Compact Muon Solenoid) is one of the two multi-purpose experiments of the proton-proton collider LHC (Large Hadron Collider) currently starting at CERN (Geneva). One of the main goals of CMS is the search for the Higgs boson. Because of the LHC challenging environment, the collaboration have chosen an electromagnetic calorimeter made of about 75000 scintillating lead tungstate crystals P bW O4 , at the same time fast, radiation hard, and extremely precise, especially in the energy range for the Higgs boson search, in the channel where it decays in two photons. The five first chapters of this thesis present the LHC, the CMS detector and notably the electro- magnetic calorimeter (ECAL). The sixth chapter presents a test beam analysis realized in 2004 at CERN with an electron beam of different energies (20-250 GeV) incident on a part (1/36) of the calorimeter barrel called “ supermodule ”. A study of the energy measurement variation within 9 (3×3) and 25 (5×5) crystals matrices as funct...

  5. Le LHC, un tunnel cosmique

    CERN Multimedia

    CERN. Geneva

    2009-01-01

    Et si la lumière au bout du tunnel du LHC était cosmique ? En d’autres termes, qu’est-ce que le LHC peut nous apporter dans la connaissance de l’Univers ? Car la montée en énergie des accélérateurs de particules nous permet de mieux appréhender l’univers primordial, chaud et dense. Mais dans quel sens dit-on que le LHC reproduit des conditions proches du Big bang ? Quelles informations nous apporte-t-il sur le contenu de l’Univers ? La matière noire est-elle détectable au LHC ? L’énergie noire ? Pourquoi l’antimatière accumulée au CERN est-elle si rare dans l’Univers ? Et si le CERN a bâti sa réputation sur l’exploration des forces faibles et fortes qui opèrent au sein des atomes et de leurs noyaux, est-ce que le LHC peut nous apporter des informations sur la force gravitationnelle qui gouverne l’évolution cosmique ? Depuis une trentaine d’années, notre compréhension de l’univers dans ses plus grandes dimensions et l’appréhension de son comportement aux plus peti...

  6. Study and optimization of the performances of the CMS electromagnetic calorimeter for the physics at LHC; Etude et optimisation des performances du calorimetre electromagnetique de l'experience CMS pour la physique au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Descamps, J

    2007-07-15

    The CMS experiment (Compact Muon Solenoid) is one of the two multi-purpose experiments of the proton-proton collider LHC (Large Hadron Collider). One of the main goals of CMS is the search for the Higgs boson. The collaboration has chosen an electromagnetic calorimeter made of about 75000 scintillating lead tungstate crystals PbWO{sub 4}, at the same time fast, radiation hard, and extremely precise, especially in the energy range for the Higgs boson search, in the channel where it decays in 2 photons. The five first chapters of this thesis present the LHC, the CMS detector and notably the electromagnetic calorimeter (ECAL). The sixth chapter presents a test beam analysis realized in 2004 at CERN with an electron beam of different energies (20-250 GeV) incident on a part (1/36) of the calorimeter barrel called super-module. A study of the energy measurement variation within 9 (3*3) and 25 (5*5) crystals matrices as function of the impact position of the initial electron was done to infer a correction method of the energy measured as function of different parameters. This method has improved very significantly the energy resolution of the calorimeter in the test beam configuration. The last chapter of this thesis presents an application of this correction method for the electrons and photons in the full simulation chain of CMS. The energy reconstruction of photons and electrons is more complicated compared to the test beam case, because of an important amount of matter in front of the calorimeter and of the strong magnetic field in the central part of the CMS detector. The photons have a non negligible probability to convert into an electron-positron pair before the calorimeter, while the electrons (and positrons), whose trajectory is bent in the transverse plan, lose energy in the matter and can emit a random number of Bremsstrahlung photons. A reconstruction algorithm of the electrons and photons energy has been developed to take into account this issue and to

  7. Optimisation of the muon spectrometer from the detector ALICE used for the study of the quark and gluon plasma at LHC; Optimisation du spectrometre a muons du detecteur ALICE pour l'etude du plasma de quarks et de gluons au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Guernane, R

    2001-01-01

    The ALICE experiment performed at the LHC will establish and study the phase transition from hadronic matter to a matter to a state of deconfined partons called Quark Gluon Plasma (QGP). The suppression of heavy flavour resonances (J{phi},{gamma}) is the most promising probe for diagnosing the formation and early stages of the QGP in ultrarelativistic heavy ion collisions. The complete spectrum of heavy quarkonia resonances, i.e. J/{phi}, {phi}', {gamma}, {gamma}' and {phi}' will be measured via their muonic decay in a forward spectrometer with a mass resolution sufficient to separate all states. It is composed of five tracking stations, each consisting of two Cathode Pad Chambers (CPC). In this work, we developed a prototype of CPC having the original feature of parallel charge read out from one segmented cathode. The geometry and operating parameters have been optimized for station 3. The expected multi-hit rate and multi-hit deconvolution have been evaluated with a complete detailed simulation and an efficient method to disentangle close hits has been proposed. The magnetic field effect on the intrinsic spatial resolution of the chambers has also been estimated. The simulated performance of the CPC's is confirmed by beam-test results obtained at CERN with prototypes. The measurement of dimuons is expected to be contaminated by beam-related background. The rate of beam-gas interactions is several orders of magnitude larger than the signal rate for p-p collisions which is the reference for further studies of p-A and A-A collisions. The ALICE Collaboration decided to equip the muon spectrometer with a level 0 trigger counter (V0) in order to validate the dimuon trigger signal in p-p mode. The various steps involved in designing the V0 scintillator hodoscope are presented in this thesis. (author)

  8. Asymétrie de charge et mesures angulaires des bosons W dans l’expérience ATLAS auprès du LHC

    CERN Document Server

    Blanchard, Jean-Baptiste

    2011-01-01

    The LHC is a proton collider, buried 100 meters below the franco-swiss border, built to work at sqrt(s) = 14 TeV. First collisions at sqrt(s) = 7 TeV occurred in the beginning of 2010, starting officially new particles hunting, like Higgs boson, super-symmetric partner... First data have also been used to do precision measurements in order to check detector performances and constrain many Standard Model parameters. The latter will be the main topic of this thesis. The work presented within this manuscript can be split in two different parts aiming to a common goal: reduce possible bias and systematic errors to provide a first precise W boson mass measurement at the LHC. On a technical aspect, an analysis has been done on the liquid argon in which lies calorimeters, in order to understand temperature fluctuation and quantify its effect on the electron energy scale. On the other hand, attention has been focused on polarization effects, by developing and proposing three new measurements : quantification of their...

  9. Contribution to the study of the readout of the electromagnetic calorimeter crystals in the CMS experiment at LHC; Contribution a l`etude de la lecture des cristaux du calorimetre electromagnetique de l`experience CMS au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Franck [Universite Claude Bernard Lyon-1, 69 - Lyon (France)

    1998-07-03

    The search for neutral Higgs boson through its decay into two photons provides a very promising signal for a mass between 90 and 150 GeV. It requires an electromagnetic calorimeter of very high resolution. The CMS (Compact Muon Solenoid) electromagnetic calorimeter must be made up of more than 80,000 lead tungstate crystals. In the central part (the barrel), the scintillation light readout is performed by means of avalanche photodiodes, a silicon photo-sensor with internal gain which is a relative novelty in high energy physics. Concerning the readout electronics, the energy available in the centre-of-mass (14 TeV) as well as the collision frequency (40 MHz) of LHC impose constraints with respect to the signal treatment up to the acquisition. The retained solution consists in pairing two avalanche photodiodes, the parameters of which (gain, temperature dependence, dark current, etc) must be controlled, and coupling them to a low noise preamplifier of high dynamical range (5 MeV - 2 TeV) followed by a four-slopes linear compressor and a analog-digital sampling converter of 12 bits, 40 MHz. The thesis presents the prototypes of different electromagnetic calorimeters tested in the high energy beam. An energy resolution of 0.6% at 100 GeV was obtained with a conventional readout circuitry, while the integrated associated circuits were radiation resistant 73 refs., 100 figs., 19 tabs.

  10. LHC report

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    This week's Report, by Gianluigi Arduini,  will be included in the LHC Physics Day, dedicated to the reviews of the LHC physics results presented at ICHEP 2010. Seehttp://indico.cern.ch/conferenceDisplay.py?confId=102669 

  11. Etiquetage des quarks $b$ par un détecteur de vertex à pixels dans l'expérience ATLAS auprès du LHC

    CERN Document Server

    Vacavant, L

    1997-01-01

    The capability of the \\atlas~detector to tag $b$-jets is studied, usin g the impact parameter of charged tracks. High $b$-tagging performance is needed at \\lhc, especially during the first years of running, in order to see evidence of the Higgs boson if its mass lies between 80 and 120 GeV$/c^{2}$. A pattern-recognition algorithm has been developed for this purpose, using a detailed simulation of the \\atlas~inner detector. Track-findin g starts from the pixel detector layers. A "hyper-plane" concept allows the use of a simple tracking algorithm though the complex geome try. High track-finding efficiency and reconstruction quality ensure the discrimination of $b$-jets from other kinds of jets. After full simulation and reconstruction of $H \\rightarrow b\\bar{b}$, $H \\rightarrow gg$, $H\\rightarrow u\\bar{u}$, $H \\rightarrow s\\bar{s}$ and $H\\rightarrow c\\bar{c}$ events ($m_{H}=100$ GeV$/c^{2}$), the mean rejections achieved against non-$b$-jets for a 50\\% $b$-jet tagging efficiency are as follows: \\vspace{-5mm} \\b...

  12. Mesure de la section efficace de production de paires de quarks, top-antitop à l’aide des premières données du détecteur ATLAS auprès du LHC

    CERN Document Server

    Yu, Jie; Mansoulié, Bruno; Schwindling, Jérôme

    2011-01-01

    The essential purpose of the thesis is to measure the top pair cross section in lepton+jets channels in the ATLAS experiment at Large Hadron Collider (LHC). The analysis is using the proton-proton collision data at 7 TeV collected in 2010 with a luminosity of 33.7 pb-1. The event selection is based on the signature of top pair topology with 1 electron or muon, large missing transverse energy and at least 4 jets. The QCD multijet background is measured with the data driven “Matrix Method”. Three data driven methods are applied to measure the W+jets background, the charge asymmetry method, the Berends Scaling method and the method combining both. Other backgrounds are estimated from MC. The number of signal top pair events is obtained by fitting the distribution of the number of b-tagged jet, when the b-tagging efficiency is simultaneously fitted. The top pair cross section is measured to be 148.1±34.9 pb. It is consistent with the Standard Model prediction at NNLO calculated by Hathor tool. It also agree...

  13. Etude du système de déclenchement électronique pour le projet HL-LHC et recherche de nouvelle physique dans le spectre de masse invariante top anti-top au sein de l'expérience CMS du LHC

    CERN Document Server

    Beaupère, Nicolas; Perriès, S

    This manuscript describes my thesis work within the CMS experiment of the LHC collider. It presents both subjects on which I worked: a detector subject and a data analysis subject. The first subject, detector, is situated within the framework of the HL-LHC project which plans an increase by a factor five the instantaneous luminosity. Such an increase and the preservation of the high level trigger (HLT) system, generate new constraints on the CMS detector. This is particularly true for the electronic trigger (L1) system. The CMS collaboration intends to implant this within tracker detector. the associative memorie method is proposed. However, associative memorie method require a clever preselection of electric signals to be usable. The cluster width method is proposed to preselecte electric signals. The optimization of this method, in particular geometrical parameters of modules and thresholds applied for the electric signals preselection, is the result of my own work. It is detailed throughout the part III of...

  14. 1er mars 2017 - Signature du livre d'or, visite du tunnel du LHC au Point 5 et de la caverne expériementale de CMS par le Secrétaire d’Etat français aux Affaires européennes auprès du ministre des Affaires étrangères et du Développement international H. Désir.

    CERN Multimedia

    Bennett, Sophia Elizabeth

    2017-01-01

    Entourent le Secrétaire d'Etat pendant la signature du livre d'or: Le Préfet de l’Ain A. Cochet; le Directeur des accélérateurs et de la technologie F. Bordry; Ambassadeur, Représentant permanent de la France auprès de l’Office des Nations Unies à Genève et des Organisations internationales en Suisse E. Laurin; la Directrice générale du CERN F. Gianotti et la Directrice des relations internationales C. Warakaulle. Sont également présents: H. Bertrand, Maire de Saint-Genis-Pouilly; C. Bouvier, Maire de Cessy; G. Rousseau, Secrétaire Général de la sous-préfecture de Gex; Y. Mecibah, Directrice de Cabinet du Maire de Saint-Genis-Pouilly; F. Croquette, Ambassadeur pour les droits de l’homme, chargé de la dimension internationale de la Shoah, des spoliations et du devoir de mémoire; S. Bonbayl, Conseillère technique, Cabinet du Secrétaire d’Etat chargé des Affaires Européennes au MAEDI; F. Cormon-Veyssière, Sous-Directrice des droits de l’Homme et des Affaires humanitaires au MAEDI...

  15. The LHC

    CERN Multimedia

    2002-01-01

    The LHC will use the latest technologies on an enormous scale. 8000 superconducting magnets will keep the beams on track. The entire 27 km ring will be cooled by 700 000 litres of liquid helium to a temperature of -271 degrees Celsius , making the LHC the world's largest superconducting installation. Conventional superconducting wire will form the magnet coils, while high-temperature superconductors will carry a total of 2 300 000 amperes from the power supplies into the magnet cryostat

  16. LHC magnets

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Preparations for the LHC proton collider to be built in CERN's LEP tunnel continue to make good progress. In particular development work for the high field superconducting magnets to guide the almost 8 TeVproton beams through the 'tight' curve of the 27-kilometre ring are proceeding well, while the magnet designs and lattice configuration are evolving in the light of ongoing experience. At the Evian LHC Experiments meeting, this progress was covered by Giorgio Brianti

  17. LHC milestone

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    At the December meeting of CERN's Council, the Organization's Governing Body, the delegates from the 16 Member States unanimously agreed that the LHC proton-proton collider proposed for the 27-kilometre LEP tunnel is the 'right machine for the advance of the subject and of the future of CERN'

  18. LHC Create

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    LHC Create is an upcoming 2-day workshop held at IdeaSquare in November. Participants from CERN and IPAC school of design will compete to design an exhibit that explains why CERN does what it does. The winner will have their exhibit fully realised and made available to experiments, institutes, and tourism agencies around the world.

  19. LHC Supertable

    International Nuclear Information System (INIS)

    Pereira, M.; Lahey, T.E.; Lamont, M.; Mueller, G.J.; Teixeira, D.D.; McCrory, E.S.

    2012-01-01

    LHC operations generate enormous amounts of data. This data is being stored in many different databases. Hence, it is difficult for operators, physicists, engineers and management to have a clear view on the overall accelerator performance. Until recently the logging database, through its desktop interface TIMBER, was the only way of retrieving information on a fill-by-fill basis. The LHC Supertable has been developed to provide a summary of key LHC performance parameters in a clear, consistent and comprehensive format. The columns in this table represent main parameters that describe the collider operation such as luminosity, beam intensity, emittance, etc. The data is organized in a tabular fill-by-fill manner with different levels of detail. Particular emphasis was placed on data sharing by making data available in various open formats. Typically the contents are calculated for periods of time that map to the accelerator's states or beam modes such as Injection, Stable Beams, etc. Data retrieval and calculation is triggered automatically after the end of each fill. The LHC Supertable project currently publishes 80 columns of data on around 100 fills. (authors)

  20. Study of {upsilon} family resonances in ultrarelativistic heavy ions collisions within the frame of the Alice experiment at CERN-LHC; Etude des resonances de la famille du {upsilon} dans les collisions d'ions lourds ultra-relativistes a 2.75 TeV/ nucleon et par faisceau sur l'experience Alice du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Dumonteil, E

    2004-09-01

    Quantum Chromodynamics foresees, at high temperature and/or high energy density, a phase transition between hadronic matter and a phase where quarks and gluons are no more confined in the nucleons: the Quark Gluon Plasma (QGP). During the past fifteen years, a large experimental program has taken place at CERN and at BNL, to identify the QGP. ALICE is the LHC experiment dedicated to the study of the plasma via ultrarelativistic heavy ion collisions at 2.75 TeV/nucleon per beam. The measure of Upsilon's resonances suppression, a powerful signature of a deconfined medium, with the ALICE dimuon spectrometer, is the main topic of this thesis. The first part of the work aims at studying the multi-wires pad chambers of the dimuon arm, used to track the muons from resonances decays. The second part presents an in-beam alignment algorithm able to calculate the positions of the different chambers with a very good accuracy. Finally, the last part proposes a study to lead with the ALICE muon spectrometer, involving the measure of Upsilon and Upsilon's production ratio as a function of the transverse momentum. It has been showed that this study should allow to evidence the QGP and to extract some of its properties. (author)

  1. Contribution to the design and realisation of a specific circuit to code the information coming from the calorimeter of the LHC; Contribution a la conception et a la realisation d`un circuit specifique de codage des informations issues du calorimetre d`une experience aupres du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Chambert-Hermel, V

    1996-09-19

    LHC (Large Hadron Collider) signals required a sampling system with excess of 16 bit dynamic range and 8 hit precision. The sampling frequency is 40 MHz. The use of a floating point format which fits the precision of the calorimeter is proposed. The dynamic range is divided into 8 positive sub-ranges and 5 negative ones and so a conversion into 8 plus 1 (sign) bits mantissa and 4 bits exponent is proposed. The design is built around three main blocks: a range converter which computes the three exponent bits and the sign, a set of amplifiers controlled by the range converter and a classical 8 bit ADC for the mantissa. The main effort was concentrated on the range converter as this is the most sensitive part o the architecture which sees the whole dynamic range. To minimize the problems of perturbations on the signal and reference lines, we have chosen a fully differential sample and hold, differential latched comparators and the coding logic using the AMS BICMOS 1..2 micron technology. We present the floating point format we use, the converter architecture, the elementary circuits steps of conception, the simulation results, the layout and tests results on prototypes. (author) 17 refs.

  2. Design and implementation of the decision unit of the first level trigger system of the LHCb detector at the Large Hadron Collider (LHC); Conception et realisation de l'unite de decision du systeme de declenchement de premier niveau du detecteur LHCb au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Laubser, J

    2007-11-15

    The LHCb experiment is one of the four particle physic detector installed at the new Large Hadron Collider (LHC) at CERN in Geneva. In order to reduce the amount of data storage for offline analysis, an online trigger system of interesting event according to the studied physic is implemented in parallel of the Data Acquisition system. The trigger system is composed by a first level (Level-0) made by a complex electronic system and a second level made by a computing system called the High Level Trigger. The Level-0 Decision Unit is the central part of the first trigger level that takes the decision to accept or to reject the event by using a fraction of information coming from the fastest sub-triggers (432 bits at 80 MHz). It is a full custom 16 layers board using advanced FPGA (Field Programmable Gate Array) in BGA (Bill Grid Array) package. Each sub-trigger transmit their data via high speed optical links running at 1.6 Gbit/s. The processing is implemented using a 40 MHz synchronous pipelined architecture. It performs a simple physical algorithm to compute the Level-0 trigger decision in order to reduce the data flow from 40 MHz down to 1 MHz for the next trigger level. The internal design of the processing FPGA is mainly composed by a Partial Data Processing (PDP) and a Trigger Definition Unit (TDU). The aim of the PDP is to adjust the clock phase, perform the time alignment, prepare the data for the TDU and monitor the data processing. The TDU is flexible and allows to fully re-configure all the trigger conditions through the Experiment Control System without any FPGA re-programming. (author)

  3. Silicon tracker end cap of the CMS experiment at LHC and study of the discovery potential for resonances decaying in top quark pairs; Integration d'un bouchon du trajectographe au silicium de l'experience CMS au LHC et etude du potentiel de decouverte de resonances se desintegrant en paires de quarks top

    Energy Technology Data Exchange (ETDEWEB)

    Chabert, E

    2008-10-15

    The first part of this thesis is dedicated to the integration of one silicon tracker end cap of the CMS experiment. The procedures implemented and the tests that led to the qualification of the detection system are presented in this document. The first chapter is an introduction to the LHC and to the CMS experiment. The second chapter is dedicated to the CMS tracker, that is a detector made up of silicon micro-stripe whose purpose is to reconstruct the tracks of charged-particles, to measure their momentum, to reconstruct vertex and to contribute to the tagging of heavy flavour quarks. The third chapter presents the integration of one of the tracker end caps. The second part of this thesis is dedicated to the search for new physics in the top quark sector. One of the most promising channel is to look for a resonance in the invariant mass distribution of top quark pairs. The fourth chapter is a theoretical introduction to this work, the standard model is introduced and the top quarks physics as well as tt-bar resonances are highlighted. The fifth chapter describes the tools used to analyse data, all the data come from simulations. The search for tt-bar resonances is presented in the last chapter. This search involves a method to select right events, a strategy to reduce background noise and a method for the reconstruction of the events. A kinematical adjustment is made to identify the right combinations of jets and to improve the experimental resolution on the invariant mass. The full simulation analysis in the 'lepton + jets' channel shows that at the TeV scale, processes from a few hundred fb to one pb could be observed in the early years of data taking.

  4. Performance of the Alice muon spectrometer. Weak boson production and measurement in heavy-ion collisions at LHC; Performance du spectrometre a muons d'ALICE. Production et mesure des bosons faibles dans des collisions d'ions lourds aupres du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Conesa del valle, Z

    2007-07-15

    Lattice QCD predicts a transition from a hadronic phase to a Quark Gluon Plasma phase, QGP, for temperatures above 10{sup 13} K. Heavy-ion collisions are proposed to recreate it in laboratory. With such a purpose, the LHC (Large Hadron Collider) will provide Pb-Pb collisions at 5.5 TeV/u, and the ALICE experiment will permit to explore them. In particular, the ALICE muon spectrometer will permit to investigate the muon related probes (quarkonia, open beauty,...). The expected apparatus performances to measure muons and dimuons are discussed. A factorization technique is employed to unravel the different contributions to the global efficiency. Results indicate that the detector should be able to measure muons up to pT {approx} 100 GeV/c with a resolution of about 10 per cent. We show that weak bosons production could be measured for the first time in heavy-ion collisions. Single muon p{sub T} and dimuons invariant mass distributions will probe W and Z production. As mainly muons from b- and c-quarks decays will populate the intermediate-p{sub T} of 5 - 25 GeV/c, heavy quark in-medium energy loss calculations indicate that the single muon spectra would be suppressed by a factor 2-4 in the most central 0 - 10% Pb-Pb collisions at 5.5 TeV. However, for p{sub T} > 35 GeV/c the weak boson decays are predominant, and no suppression is expected. Estimations indicate that the b- and W-muons crossing point shifts down in transverse momenta by 5 to 7 GeV/c in the most central 0 - 10% Pb-Pb collisions at 5.5 TeV. (author)

  5. LHC: installation du plus grand trajectographe au silicium du monde

    CERN Multimedia

    2008-01-01

    The installation of the largest silicon trajectograph of the world was concluded at CERN. Thursday December 13 at dawn, the silicon trajectograph with ribbons of CMS (*) began its trip from the principal site of CERN to its installation of experimentation.

  6. LHC Supertable

    CERN Document Server

    Pereira, M; Lamont, M; Muller, GJ; Teixeira, D D; McCrory, ES

    2011-01-01

    LHC operations generate enormous amounts of data. This data is being stored in many different databases. Hence, it is difficult for operators, physicists, engineers and management to have a clear view on the overall accelerator performance. Until recently the logging database, through its desktop interface TIMBER, was the only way of retrieving information on a fill-by-fill basis. The LHC Supertable has been developed to provide a summary of key LHC performance parameters in a clear, consistent and comprehensive format. The columns in this table represent main parameters that describe the collider’s operation such as luminosity, beam intensity, emittance, etc. The data is organized in a tabular fill-by-fill manner with different levels of detail. Particular emphasis was placed on data sharing by making data available in various open formats. Typically the contents are calculated for periods of time that map to the accelerator’s states or beam modes such as Injection, Stable Beams, etc. Data retrieval and ...

  7. Performance du calorimètre à argon liquide et recherche du boson de Higgs dans son canal de désintégration $H\\to ZZ^{(*)} \\to 4\\ell$ avec l'expérience ATLAS auprès du LHC.

    CERN Document Server

    Tiouchichine, Elodie

    The work presented in this thesis within the ATLAS collaboration was performed in the context of the discovery of a new particle at the LHC in the search for the Standard Model Higgs boson. My contribution to the Higgs boson search is focused in the $H \\to ZZ^* \\to 4 \\ell$ channel at different level, from the data taking to the physics analysis. After a theoretical introduction, the LHC and the ATLAS detector are presented as well as their performance during the 2011 and 2012 runs. A particular consideration is given to the liquid argon calorimeters and to the data quality assessment of this system. The validation of the data recorded during non-nominal high voltage conditions is presented. This study allowed to recover 2\\% of the data collected available for physics analyses. This has a direct impact on the $H \\to ZZ^* \\to 4 \\ell$ channel were the number of signal events expected is very low. In order to optimize the acceptance of the four electrons decay channel, novel electron reconstruction algorithms wer...

  8. L'energie du moustique

    CERN Document Server

    Augereau, J F

    2002-01-01

    ENSEMBLE DE QUATRE ARTICLES - LARGE HADRON COLLIDER: Le dernier accelerateur de particules du CERN, le LEP, produisait des faisceaux d'electrons de 100 GeV chacun. Le LHC, qui accelere des faisceaux de protons, leur communiquera une energie de 7 TeV chacun. Une energie a la fois colossale et derisoire. Un TeV represente a peu pres l'energie cinetique d'un moustique (1/2 page).

  9. LHC Startup

    CERN Document Server

    AUTHOR|(CDS)2067853

    2008-01-01

    The Large Hadron Collider will commence operations in the latter half of 2008. The plans of the LHC experiments ALICE, ATLAS, CMS and LHCb are described. The scenario for progression of luminosity and the strategies of these 4 experiments to use the initial data are detailed. There are significant measurements possible with integrated luminosities of 1, 10 and 100 pb^-1. These measurements will provide essential calibration and tests of the detectors, understanding of the Standard Model backgrounds and a first oportunity to look for new physics.

  10. New aspects of the structure of the proton revealed by the collider Hera; Nouveaux aspects de la structure du proton avec le collisionneur HERA

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z

    2000-12-01

    Since its commissioning in 1991, the ep collider HERA has been running successfully for almost a decade without stopping improving its performance. In this report, the inclusive cross section and structure function measurements for the deep inelastic scattering of neutral and charged current processes in the full HERA kinematic domain are reviewed. The results are compared with the Standard Model expectations for the deep inelastic scattering processes. The new insights into the proton structure and on the underlying strong and electroweak interactions are discussed. (author)

  11. Chasseurs de Higgs au LHC - A la Recherche des l'Origines

    CERN Multimedia

    Yves Sirois

    To increase understanding of the LHC, why scientists collaborate on this experiment and what they hope to achieve with the LHC. A 51 slide presentation in French for a general audience. Delivered at the "Cité des Sciences" in Paris, "Rencontres du Ciel et de l'Espace," November, 2010 This presentation covers the following topics: - The LHC --what it is --what it looks like --where it is located --the international nature of CERN & experiment collaborations --the experiments - Accelerators --a brief history on accelerators --what accelerators can do - The scientific goals of the LHC - Particle Physics in General --history & the basics - Impact on Technology and Society - First LHC Results - Concluding remarks

  12. LHC Report

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    During last week the commissioning effort has been devoted to beam development work, required to accelerate beams with nominal bunch intensity to 3.5 TeV. Significant progress has been done with the commissioning of the systems required to control the beam size and bunch length during the ramp and accelerate the beam with reproducible characteristics. The setting-up of the collimation system for the operation with higher intensity is presently ongoing with the aim of delivering physics with nominal bunch intensity towards the end of next week. For more information about the LHC and a video of the presentation recently done by LHC operators, please visit: http://lpcc.web.cern.ch/LPCC/ http://indico.cern.ch/categoryDisplay.py?categId=2687

  13. Illuminating the LHC

    CERN Multimedia

    2004-01-01

    For the first time ever, on 29 September the LHC ring will be visible above ground. Spotlights aimed at the sky will light up the 27 km path of the ring to celebrate CERN's 50th anniversary. Also, everyone born in 1954 is invited to come to blow out birthday candles on a cake. To see the display, you can come to departure station for the gondola at Crozet*, France, starting at 18:30. There will be music, official speeches and food stands. At 20:00 the ring will light up, and to wrap it up at 21:15 there will be the cake and videoconferences with Robert Aymar, the Director-General of CERN, and the inventor of the Web, Tim Berners-Lee. The event is organized by the Department of Justice, Police and Security of the Canton of Geneva, Switzerland, in collaboration with communes of the Canton of Geneva, the Communauté des communes du Pays de Gex and the Préfecture de l'Ain. More information on the schedule for the night. * The event initially planned at Divonne has been moved to Crozet.

  14. Le Gouvernement français donne le feu vert définitif pour le démarrage des travaux de génie civil du LHC

    CERN Multimedia

    CERN Press Office. Geneva

    1998-01-01

    Civil engineering for CERN's next major particle accelerator, the Large Hadron Collider (LHC), got the green light from France last week when Prime Minister Lionel Jospin signed the decree allowing work to commence. This important landmark for the Laboratory, situated on the Franco-Swiss border, comes after a long and painstaking study of the environmental impact of the project and follows Swiss approval earlier this year.

  15. Radiography of the connection between a LHC magnet and its diode in sector 3-4

    CERN Multimedia

    Brice, Maximilien

    2015-01-01

    Fin mars 2015, les équipes du LHC ont réalisé différents tests pour identifier la cause d'un court-circuit vers la terre entre un aimant et sa diode de protection qui retardait le redémarrage du LHC. Le 25 mars, ils ont effectué des radiographies de la connexion. End of March 2015, LHC teams have performed different tests to identify the cause of a short-circuit to ground between a magnet and its protection diode. On 25 March they took an X-ray of the affected diode.

  16. Caractérisation d’un calorimètre hadronique semi-digital pour le futur collisionneur ILC

    CERN Document Server

    Kieffer, Robert; Grenier, Gérald

    The future electron-positon linear collider ILC is an international project aiming to follow and go forward the scientific program which is actually on-going at the Large Hadron Collider (LHC). Such a leptonic collider project implies also new concepts in particle detection to ensure a better event reconstruction : this can be achieved by using particle flow techniques. I worked for the last three years on one of those projects : the SDHCAL, a semi digital hadronic calorimeter based on glass resistive plate chambers (GRPC). This 48 layer sampling calorimeter is segmented in cells of one square centimeter for a total of 50 millions channels. To ensure such a high granularity without using any active cooling, a special care has to be taken concerning the power dissipation. To decrease the embedded front end boards consumption, a multi threshold readout (semi digital) is being used instead of an analog one. Thanks to the power pulsing mechanism using the spill structure of the collider, we have recently proven t...

  17. Experimental study of the test module of the electromagnetic end-cap calorimeter for the ATLAS experiment. Study of the spin correlation in the production of pairs tt-bar; Etude experimentale des performances du module 0 du calorimetre electromagnetique bouchon d'ATLAS. Etude de la correlation de spin dans la production des paires tt-bar au LHC

    Energy Technology Data Exchange (ETDEWEB)

    Hinz, L

    2001-06-01

    LHC, the future CERN proton collider, will start in 2006. It will be devoted to a better understanding of the Standard Model and new physics research. With a 10 {integral}b{sup -1} per year at low luminosity during the first three years, then 100 {integral}b{sup -1} per year, and energy of 14 TeV in the center of mass, the LHC is designed to discover the Standard or SUSY Higgs boson, or probe signature of new physics. ATLAS, one of the four experiments at the LHC, can study a large physics range, as Higgs boson, top and bottom, gauge bosons and new particles expected by SUSY model or other models beyond the Standard Model. The CPPM laboratory is responsible of a part of the electromagnetic end-cap calorimeter for the ATLAS experiment. In 1999, an ATLAS-like prototype of module was stacked in Marseille and intensively tested at CERN. Description of the calorimeter and a part of test-beam results are presented in this PhD manuscript. In parallel, a study about potentiality of the tt-bar spin correlation measurement was done. The high tt-bar statistic produced at the LHC allows to explore the quark top properties in details and being sensitive to new physics phenomena. Signatures of such physics can be extracted from tt-bar decay product angular distributions which are sensitive to tt-bar spin correlation. (authors)

  18. HL-LHC Accelerator

    CERN Document Server

    Zimmermann, F

    2013-01-01

    The tentative schedule, key ingredients, as well as progress of pertinent R&D and component prototypes for the LHC luminosity upgrade, "HL-LHC," are reviewed. Also alternative scenarios based on performance-improving consolidations (PICs) instead of a full upgrade are discussed. Tentative time schedules and expected luminosity evolutions for the different scenarios are sketched. The important role of HL-LHC development as a step towards a future HE-LHC or VHE-LHC is finally highlighted. Presented at "Higgs & Beyond" Conference Tohoku University, Sendai 7 June 2013.

  19. Safe LHC beam commissioning

    International Nuclear Information System (INIS)

    Uythoven, J.; Schmidt, R.

    2007-01-01

    Due to the large amount of energy stored in magnets and beams, safety operation of the LHC is essential. The commissioning of the LHC machine protection system will be an integral part of the general LHC commissioning program. A brief overview of the LHC Machine Protection System will be given, identifying the main components: the Beam Interlock System, the Beam Dumping System, the Collimation System, the Beam Loss Monitoring System and the Quench Protection System. An outline is given of the commissioning strategy of these systems during the different commissioning phases of the LHC: without beam, injection and the different phases with stored beam depending on beam intensity and energy. (author)

  20. Tagging calibration of the jets from beauty quarks and the search for Higgs boson in the tt-bar H {yields} l{nu}b, jjb, bb-bar channel in the ATLAS experiment at LHC; Calibration de l'etiquetage de jets issus de quarks beaux et recherche du boson de Higgs dans le canal tt-barH {yields} l{nu}b, jjb, bb-bar dans l'experience ATLAS aupres du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Correard, Sebastien [Faculte des Sciences de Luminy, Universite de la Mediterranee, Aix-Marseille II, 163 avenue de Luminy, 13288 Marseille cedex 09 (France)

    2006-02-15

    B-tagging calibration and search for the Higgs boson in the tt-bar H {yields} l{nu}b, jjb, bb-bar channel with ATLAS at LHC The ATLAS experiment, based at CERN, will use the LHC proton collisions to deepen the Standard Model measurements, and look for possible signs of new physics. One of its main tasks will be the search for the Higgs boson. This thesis first describes the latest b-tagging algorithms, shows the importance of its calibration, and proposes a b-tagging calibration method based on the first data recorded by ATLAS. Then, considering that the Higgs boson may be light (m{sub H} < 135 GeV/c{sup 2}), the ttH channel is studied, with H decaying in a b quark pair. Full simulation and the latest realistic b-tagging methods have been combined for the first time. For an integrated luminosity of 30 fb{sup -1} (3 years of data taking), the S/{radical}B ratio, determining the sensitivity of this analysis, is raised to 4.9. This should allow a non-ambiguous observation of the Higgs boson in this channel. (author)

  1. Intégration d'un bouchon du trajectographe au silicium de l'expérience CMS au LHC et étude du potentiel de découverte de résonances se désintégrant en paires de quarks top

    CERN Document Server

    Chabert, Eric

    2008-01-01

    La première partie de cette thèse porte sur l'intégration d'un bouchon du trajectographe au silicium de l'expérience CMS. Les procédures mises en œuvre et les tests qui ont permis d'aboutir à la qualification du système de détection sont présentés dans ce document. La deuxième partie est dédiée à la recherche de nouvelle physique dans le secteur du quark top. Une des voies les plus prometteuses consiste à rechercher une résonance dans la distribution en masse invariante des paires de quarks top. Une analyse réalisée en simulation complète dans le canal lepton+jets montre qu'à l'échelle du TeV, des processus de quelques centaines de fb à 1 pb pourraient être observés lors des premières années de prises de données.

  2. La Physique au LHC - Partie I

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    Le LHC devrait permettre l'observation du boson de Higgs et pouvoir lever le voile sur l'un des scénarios de nouvelle physique présentés dans la cours précédent. Ce cours détaillera les perspectives de physique au LHC (découvertes possibles et mesures de précision) ainsi que les méthodes et difficultés expérimentales. L'accent sera mis sur les problèmes liés à la brisure de la symétrie electrofaible. Les possibilités de développement futur à plus haute luminosité et/ou énergie seront également discutées.

  3. Study of the muon production from open heavy flavours predicted by the Color Glass Condensate model in proton-proton and proton-lead collision with the Alice muon spectrometer at LHC; Etude de la production de muons issus des saveurs lourdes predite par le modele de Color Glass Condensate dans les collisions proton-proton et proton-plomb dans l'acceptance du spectrometre a muons de l'experience Alice du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Charpy, A

    2007-10-15

    The whole particle physics community is waiting for the Large Hadron Collider (LHC) commissioning at CERN. Indeed, the potential of discovery is very large in lots of themes. In particular, it will be possible to test the developments of the Quantum Chromodynamics (QCD) achieved during last years. One of these, the Colour Glass Condensate, describes the parton distributions of the nucleus in the saturation region, i.e. at small x. This theoretical description of the initial conditions of the heavy ion collisions is necessary to predict the heavy quark cross section production which evolves in a possible deconfined matter: the Quark-Gluon Plasma (PQG). ALICE is the LHC experiment mainly dedicated to the study of the PQG produced in ultra-relativistic heavy ion collisions. The measurement of J /{psi} and {upsilon} resonance suppression is a signature of this deconfined medium which is studied with the ALICE muon spectrometer. Its acceptance at large rapidity is well adapted for studying the prediction of CGC at small-x. The first part of this report presents the results of beam test experiment at CERN. It was the first time that the muon spectrometer tracking chambers were tested equipped with the final version of the front end electronics and the data acquisition system CROCUS. The relevant calibration parameters of the front end electronics were introduced in the analysis in order to improve the quality of the track reconstruction. In the second part. these parameters were used in the simulations. The last part proposes a study of the CGC with the ALICE muon spectrometer. involving the measurements of open charm and open beauty. (author)

  4. LHC synchronization test successful

    CERN Multimedia

    The synchronization of the LHC's clockwise beam transfer system and the rest of CERN's accelerator chain was successfully achieved last weekend. Tests began on Friday 8 August when a single bunch of a few particles was taken down the transfer line from the SPS accelerator to the LHC. After a period of optimization, one bunch was kicked up from the transfer line into the LHC beam pipe and steered about 3 kilometres around the LHC itself on the first attempt. On Saturday, the test was repeated several times to optimize the transfer before the operations group handed the machine back for hardware commissioning to resume on Sunday. The anti-clockwise synchronization systems will be tested over the weekend of 22 August.Picture:http://lhc-injection-test.web.cern.ch/lhc-injection-test/

  5. Some LHC milestones...

    CERN Multimedia

    2008-01-01

    October 1995 The LHC technical design report is published. This document details the operation and the architecture of the future accelerator. November 2000 The first of the 1232 main dipole magnets for the LHC are delivered. May 2005 The first interconnection between two magnets of the accelerator is made. To carry out the 1700 interconnections of the LHC, 123 000 operations are necessary. February 2006 The new CERN Control Centre, which combines all the control rooms for the accelerators, the cryogenics and the technical infrastructure, starts operation. The LHC will be controlled from here. October 2006 Construction of the largest refrigerator in the world is complete. The 27 km cryogenic distribution line inside the LHC tunnel will circulate helium in liquid and gas phases to provide cryogenic conditions for the superconducting magnets of the accelerator. November 2006 Magnet production for the LHC is complete. The last of t...

  6. Towards LHC experiments

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    As plans for the LHC proton collider to be built in CERN's 27-kilometre LEP tunnel take shape, interest widens to bring in the experiments exploiting the big machine. The first public presentations of 'expressions of interest' for LHC experiments featured from 5-8 March at Evian-les-Bains on the shore of Lake Geneva, some 50 kilometres from CERN, at the special Towards the LHC Experimental Programme' meeting

  7. LHC superconducting strand

    CERN Multimedia

    Patrice Loiez

    1999-01-01

    This cross-section through a strand of superconducting matieral as used in the LHC shows the 8000 Niobium-Titanium filaments embedded like a honeycomb in copper. When cooled to 1.9 degrees above absolute zero in the LHC accelerator, these filaments will have zero resistance and so will carry a high electric current with no energy loss.

  8. The physics behind LHC

    CERN Multimedia

    CERN. Geneva

    2006-01-01

    What do physicists want to discover with experiments at the LHC? What is the Higgs boson? What are the new phenomena that could be observed at the LHC?I will try to answer these questions using language accessible also to non-experts. Organiser(s): L. Alvarez-Gaume / PH-THNote: * Tea & coffee will be served at 16:00.

  9. Le budget total du CERN restera plus ou moins constant

    CERN Document Server

    Van der Boon, J E

    2002-01-01

    The Director of Administration at CERN has written to the paper following an article titled "Licenciements chez les sous-traitants du CERN" : dismissals amongst CERN sub-contractors. As the CERN budget will remain constant and a greater part will be devoted to building the LHC, changes will be made to staffing balances (0.5 page)

  10. The LHC is safe

    CERN Document Server

    CERN. Geneva; Alvarez-Gaumé, Luís

    2008-01-01

    Concerns have been expressed from time to time about the safety of new high-energy colliders, and the LHC has been no exception. The LHC Safety Assessment Group (LSAG)(*) was asked last year by the CERN management to review previous LHC safety analyses in light of additional experimental results and theoretical understanding. LSAG confirms, updates and extends previous conclusions that there is no basis for any conceivable threat from the LHC. Indeed, recent theoretical and experimental developments reinforce this conclusion. In this Colloquium, the basic arguments presented by LSAG will be reviewed. Cosmic rays of much higher effective centre-of-mass energies have been bombarding the Earth and other astronomical objects for billions of years, and their continued existence shows that the Earth faces no dangers from exotic objects such as hypothetical microscopic black holes that might be produced by the LHC - as discussed in a detailed paper by Giddings and Mangano(**). Measurements of strange particle produc...

  11. An in-beam test study of the response of calorimeters in the ATLAS Experiment of LHC to charged pions of 3 to 350 GeV energy range; Etude en faisceau-test de la reponse des calorimetres de l'Experience ATLAS du LHC a des pions charges, d'energie comprise entre 3 et 350 Gev

    Energy Technology Data Exchange (ETDEWEB)

    Giangiobbe Vincent [Ecole Doctorale des Sciences Fondamentales, Universite Blaise Pascal, U.F.R de Recherches Scientifiques et Techniques, 34, avenue Carnot - BP 185, 63006 Clermont-Ferrand Cedex (France)

    2006-11-15

    ATLAS is one of the four main experiments under way of installing within the Large Hadron Project (LHC). LHC will provide two proton beams of high luminosity (1 x 10{sup 34} cm{sup -2} s{sup -1} at peak), colliding in the center of ATLAS detector at a 14 TeV rated COM energy. The aim of this study is an in-beam test characterization of the response of calorimeters in the central part of ATLAS. The study will be focused on the response to pions as main jet components. In the beginning a short presentation of the ATLAS program of physics is given enlightening the basic theoretical and experimental aspects of the experiment. A description of the ATLAS detector is also presented. The second chapter is devoted to detailed description of the central calorimetry of ATLAS. One starts from the mechanism of signal production in calorimeters, through the electronic processing up to the reconstruction of the released energy. The third chapter deals with the processing electronics of the TileCal hadron calorimeter the installation and certification at CERN of which was in charge of Clermont-Ferrand team. The chapter 4 gives a description of the SPS beam line and of the associated instrumentation tested in-beam in 2004. The chapters 6 and 7 are devoted to the study of the response of calorimeters to high energy pions (within 20 to 350 GeV range). The pion selection is described in the chapter 5. In the eighth chapter the calorimeter response to low energy pions (up to 9 GeV) is examined. In conclusion this study has shown that the data concerning pions obtained in-beam in 2004 are usable for energies within 3 to 350 GeV. The response and the energy resolution of LAr and TileCal were measured with a satisfactory accuracy,. A systematic comparison of these results with simulations (in the configuration of in-beam test) can now be done. Should the agreement be satisfying, the modelling could be used for the study of calibration of calorimeter response for the case of works with the

  12. An in-beam test study of the response of calorimeters in the ATLAS Experiment of LHC to charged pions of 3 to 350 GeV energy range; Etude en faisceau-test de la reponse des calorimetres de l'Experience ATLAS du LHC a des pions charges, d'energie comprise entre 3 et 350 Gev

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, Giangiobbe [Ecole Doctorale des Sciences Fondamentales, Universite Blaise Pascal, U.F.R de Recherches Scientifiques et Techniques, 34, avenue Carnot - BP 185, 63006 Clermont-Ferrand Cedex (France)

    2006-11-15

    ATLAS is one of the four main experiments under way of installing within the Large Hadron Project (LHC). LHC will provide two proton beams of high luminosity (1 x 10{sup 34} cm{sup -2} s{sup -1} at peak), colliding in the center of ATLAS detector at a 14 TeV rated COM energy. The aim of this study is an in-beam test characterization of the response of calorimeters in the central part of ATLAS. The study will be focused on the response to pions as main jet components. In the beginning a short presentation of the ATLAS program of physics is given enlightening the basic theoretical and experimental aspects of the experiment. A description of the ATLAS detector is also presented. The second chapter is devoted to detailed description of the central calorimetry of ATLAS. One starts from the mechanism of signal production in calorimeters, through the electronic processing up to the reconstruction of the released energy. The third chapter deals with the processing electronics of the TileCal hadron calorimeter the installation and certification at CERN of which was in charge of Clermont-Ferrand team. The chapter 4 gives a description of the SPS beam line and of the associated instrumentation tested in-beam in 2004. The chapters 6 and 7 are devoted to the study of the response of calorimeters to high energy pions (within 20 to 350 GeV range). The pion selection is described in the chapter 5. In the eighth chapter the calorimeter response to low energy pions (up to 9 GeV) is examined. In conclusion this study has shown that the data concerning pions obtained in-beam in 2004 are usable for energies within 3 to 350 GeV. The response and the energy resolution of LAr and TileCal were measured with a satisfactory accuracy,. A systematic comparison of these results with simulations (in the configuration of in-beam test) can now be done. Should the agreement be satisfying, the modelling could be used for the study of calibration of calorimeter response for the case of works with the

  13. LHC Report: LHC hit the target!

    CERN Multimedia

    Enrico Bravin for the LHC team

    2016-01-01

    Last week, the accumulated integrated luminosity reached the target value for 2016 of 25 fb-1 in both ATLAS and CMS.   The integrated luminosity delivered to ATLAS and CMS reached (and already passed!) 25 fb-1– the target for the whole year! Tuesday, 30 August was just a regular day for the 2016 LHC run. However,  on that day, the integrated luminosity delivered to ATLAS and CMS reached 25 fb-1 – the target for the whole year! How did we get here? A large group of committed scientists and technical experts work behind the scenes at the LHC, ready to adapt to the quirks of this truly impressive machine. After the push to produce as many proton-proton collisions as possible before the summer conferences, several new ideas and production techniques (such as Bunch Compression Multiple Splitting, BCMS) have been incorporated in the operation of LHC in order to boost its performance even further. Thanks to these improvements, the LHC was routinely operated with peak luminos...

  14. Study and analysis of failure modes of the electrolytic capacitors and thyristors, applied to the protection system of the LHC (Large Hadron Collider); Etude et analyse des modes de defaillances des condensateurs electrolytiques a l'aluminium et des thyristors: appliquees au systeme de protection du LHC (Large Hadron Collider)

    Energy Technology Data Exchange (ETDEWEB)

    Perisse, F

    2003-07-15

    The study presented in this thesis is a contribution about the analysis of failures modes of electrolytic capacitors and thyristors. The studied components are main elements of the protection system of the superconductive magnets of the LHC. The study of the ageing of the electrolytic capacitors has shown that their reliability is strongly related to their technological characteristic. Evolution of their principal indicator of ageing (ESR) can be modeled according to different laws chosen according to their running mode. It appears that the prediction of failure of these components other than that due to wear can be only statistical taking into account the many causes of failure involving various modes of failure. In order to be able to evaluate influence of the ageing of the electrolytic capacitors on a system, simple models taking into account this parameters as well as the effective temperature of the component are proposed. An acceptable precision taking into account the simplicity of the models is obtained. The study of the thyristors has shown that these components have little drift of parameters in static ageing, on the other hand of many failures by short-circuit were observed. These failures always have a local origin, and are due to defects of the components. The breakdown voltage strongly depends on the quality of the thyristor as well as the technology employed. (author)

  15. Study and analysis of failure modes of the electrolytic capacitors and thyristors, applied to the protection system of the LHC (Large Hadron Collider); Etude et analyse des modes de defaillances des condensateurs electrolytiques a l'aluminium et des thyristors: appliquees au systeme de protection du LHC (Large Hadron Collider)

    Energy Technology Data Exchange (ETDEWEB)

    Perisse, F

    2003-07-15

    The study presented in this thesis is a contribution about the analysis of failures modes of electrolytic capacitors and thyristors. The studied components are main elements of the protection system of the superconductive magnets of the LHC. The study of the ageing of the electrolytic capacitors has shown that their reliability is strongly related to their technological characteristic. Evolution of their principal indicator of ageing (ESR) can be modeled according to different laws chosen according to their running mode. It appears that the prediction of failure of these components other than that due to wear can be only statistical taking into account the many causes of failure involving various modes of failure. In order to be able to evaluate influence of the ageing of the electrolytic capacitors on a system, simple models taking into account this parameters as well as the effective temperature of the component are proposed. An acceptable precision taking into account the simplicity of the models is obtained. The study of the thyristors has shown that these components have little drift of parameters in static ageing, on the other hand of many failures by short-circuit were observed. These failures always have a local origin, and are due to defects of the components. The breakdown voltage strongly depends on the quality of the thyristor as well as the technology employed. (author)

  16. The LHC babies

    CERN Multimedia

    Laëtitia Pedroso

    2011-01-01

    With the machine restart and first collisions at 3.5 TeV, 2009 and 2010 were two action-packed years at the LHC. The events were a real media success, but one important result that remained well hidden was the ten births in the LHC team over the same period. The mothers – engineers, cryogenics experts and administrative assistants working for the LHC – confirm that it is possible to maintain a reasonable work-life balance. Two of them tell us more…   Verena Kain (left) and Reyes Alemany (right) in the CERN Control Centre. With the LHC running around the clock, LHC operations engineers have high-pressure jobs with unsociable working hours. These past two years, which will undoubtedly go down in the annals of CERN history, the LHC team had their work cut out, but despite their high-octane professional lives, several female members of the team took up no less of a challenge in their private lives, creating a mini-baby-boom by which the LHC start-up will also be remembe...

  17. LHC preparations change gear

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    After the formal approval by CERN Council in December (January, page 1) of the LHC protonproton collider for CERN's 27- kilometre LEP tunnel, preparations for the new machine change gear. Lyndon Evans becomes LHC Project Leader, and CERN's internal structure will soon be reorganized to take account of the project becoming a definite commitment. On the experimental side, the full Technical Proposals for the big general purpose ATLAS and CMS detectors were aired at a major meeting of the LHC Committee at CERN in January. These Technical Proposals are impressive documents each of some several hundred pages. (Summaries of the detector designs will appear in forthcoming issues of the CERN Courier.) The ALICE heavy ion experiment is not far behind, and plans for other LHC experiments are being developed. Playing an important role in this groundwork has been the Detector Research and Development Committee (DRDC), founded in 1990 to foster detector development for the LHC experimental programme and structured along the lines of a traditional CERN Experiments Committee. Established under the Director Generalship of Carlo Rubbia and initially steered by Research Director Walter Hoogland, the DRDC has done sterling work in blazing a trail for LHC experiments. Acknowledging that the challenge of LHC experimentation needs technological breakthroughs as well as specific detector subsystems, DRDC proposals have covered a wide front, covering readout electronics and computing as well as detector technology. Its first Chairman was Enzo larocci, succeeded in 1993 by Michal Turala. DRDC's role was to evaluate proposals, and make recommendations to CERN's Research Board for approval and resource allocation, not an easy task when the LHC project itself had yet to be formally approved. Over the years, a comprehensive portfolio of detector development has been built up, much of which has either led to specific LHC detector subsystems for traditional detector tasks

  18. Conference: STANDARD MODEL @ LHC

    CERN Multimedia

    2012-01-01

    HCØ institute Universitetsparken 5 DK-2100 Copenhagen Ø Denmark Room: Auditorium 2 STANDARD MODEL @ LHC Niels Bohr International Academy and Discovery Center 10-13 April 2012 This four day meeting will bring together both experimental and theoretical aspects of Standard Model phenomenology at the LHC. The very latest results from the LHC experiments will be under discussion. Topics covered will be split into the following categories:     * QCD (Hard,Soft & PDFs)     * Vector Boson production     * Higgs searches     * Top Quark Physics     * Flavour physics

  19. HL-LHC alternatives

    CERN Document Server

    Tomás, R; White, S

    2014-01-01

    The HL-LHC parameters assume unexplored regimes for hadron colliders in various aspects of accelerator beam dynamics and technology. This paper reviews three alternatives that could potentially improve the LHC performance: (i) the alternative filling scheme 8b+4e, (ii) the use of a 200 MHz RF system in the LHC and (iii) the use of proton cooling methods to reduce the beam emittance (at top energy and at injection). The alternatives are assessed in terms of feasibility, pros and cons, risks versus benefits and the impact on beam availability.

  20. The Lhc beam commissioning

    International Nuclear Information System (INIS)

    Redarelli, S.; Bailey, R.

    2008-01-01

    The plans for the Lhc proton beam commissioning are presented. A staged commissioning approach is proposed to satisfy the request of the Lhc experiments while minimizing the machine complexity in early commissioning phases. Machine protection and collimation aspects will be tackled progressively as the performance will be pushed to higher beam intensities. The key parameters are the number of bunches, k b , the proton intensity pe bunch, N, and the β in the various interaction points. All together these parameters determine the total beam power and the complexity of the machine. We will present the proposed trade off between the evolution of these parameters and the Lhc luminosity performance.

  1. The super-LHC

    CERN Document Server

    Mangano, Michelangelo L

    2010-01-01

    We review here the prospects of a long-term upgrade programme for the Large Hadron Collider (LHC), CERN laboratory's new proton-proton collider. The super-LHC, which is currently under evaluation and design, is expected to deliver of the order of ten times the statistics of the LHC. In addition to a non-technical summary of the principal physics arguments for the upgrade, I present a pedagogical introduction to the technological challenges on the accelerator and experimental fronts, and a review of the current status of the planning.

  2. LHC brochure (Italian version)

    CERN Multimedia

    Lefevre, Christiane

    2011-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  3. LHC brochure (German version)

    CERN Multimedia

    Lefevre, Christiane

    2011-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  4. LHC brochure (French version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  5. LHC brochure (Danish version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  6. LHC brochure (English version)

    CERN Multimedia

    Lefevre, C

    2010-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  7. LHC brochure (French version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  8. LHC brochure (English version)

    CERN Multimedia

    AUTHOR|(CDS)2070305

    2014-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  9. CERN confirms LHC schedule

    CERN Document Server

    2003-01-01

    The CERN Council held its 125th session on 20 June. Highlights of the meeting included confirmation that the LHC is on schedule for a 2007 start-up, and the announcement of a new organizational structure in 2004.

  10. LHC Brochure (german version)

    CERN Multimedia

    Vanoli, C.

    2006-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  11. LHC brochure (German version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  12. CERN recognises LHC suppliers

    CERN Multimedia

    2002-01-01

    CERN has just presented the first awards recognising LHC suppliers. The Russian institute BINP, the Belgian firm Cockerill-Sambre and the US company Wah-Chang are the recipients of the first 'Golden Hadrons'.

  13. LHC Luminosity Performance

    CERN Document Server

    AUTHOR|(CDS)2091107; Fuchsberger, Kajetan; Papotti, Giulia

    This thesis adresses several approaches with the common goal of assessing, understanding and improving the luminosity of the Large Hadron Collider (LHC). To better exploit existing margins for maximum luminosity while fulfilling the requirements of the LHC experiments, new techniques for luminosity levelling are studied and developed to an operational state, such as changing the crossing angle or $\\beta^*$ (beam size) at the interaction points with the beams in collisions. In 2017 LHC operation, the crossing angle reduction in collisions improved the integrated luminosity by $\\mathrm{\\sim} 2\\,\\mathrm{fb^{-1}}$ ($\\mathrm{\\sim} 4\\,\\mathrm{\\%}$ of the yearly production). For additional diagnostics, a new method for measuring beam sizes and orbits for each circulating bunch using the luminosity measurement during beam separation scans is shown. The results of these Emittance Scans improved the understanding of the LHC luminosity reach and of the orbit offsets introduced by beam-beam long-range effects.

  14. LHC brochure (German version)

    CERN Multimedia

    Marcastel, Fabienne

    2014-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which started up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  15. LHC brochure (Spanish version)

    CERN Multimedia

    Lefevre, C

    2008-01-01

    A presentation of the largest and the most powerful particle accelerator in the world, the Large Hadron Collider (LHC), which will start-up in 2008. Its role, characteristics, technologies, etc. are explained for the general public.

  16. LHC: seven golden suppliers

    CERN Multimedia

    2005-01-01

    The fourth CERN Golden Hadron awards saw seven of the LHC's best suppliers receive recognition for the high quality of their work, compliance with delivery deadlines, flexibility and adaptability to the demanding working conditions of the project. The representatives of the seven companies which received awards during the Golden Hadron ceremony, standing with Lyn Evans, LHC Project Leader. 'The Golden Hadron awards are a symbol of our appreciation of not only the quality and timely delivery of components but also the collaborative and flexible way the firms have contributed to this very difficult project,' said Lyn Evans, head of the LHC project. The awards went to Kemppi-Kempower (Finland), Metso Powdermet (Finland), Transtechnik (Germany), Babcock Noell Nuclear (Germany), Iniziative Industriali (Italy), ZTS VVU Kosice (Slovakia), and Jehier (France). Babock Noell Nuclear (BNN) successfully produced one-third (416 cold dipole masses) of the LHC's superconducting dipole magnets, one of the most critical an...

  17. LHC First Beam 2008

    CERN Multimedia

    Tuura, L

    2008-01-01

    The CMS Centre played a major part in the LHC First Beam Event on September 10th 2008: it was a central point for CMS, hosting journalists from all over the world and providing live link-ups to collaborating institutes as well as, of course, monitoring events as they happened at Point 5. It was also a venue for celebration as the beam completed circuits of the LHC in both directions, passing successfully through the detector (Courtesy of Lassi Tuura)

  18. submitter LHC experiments

    CERN Document Server

    Tanaka, Shuji

    2001-01-01

    Large Hadron Collider (LHC) is under construction at the CERN Laboratory in Switzerland. Four experiments (ATLAS, CMS, LHCb, ALICE) will try to study the new physics by LHC from 2006. Its goal to explore the fundamental nature of matter and the basic forces. The PDF file of the transparency is located on http://www-atlas.kek.jp/sub/documents/lepsymp-stanaka.pdf.

  19. Future of LHC

    CERN Document Server

    Dova, Maria-Teresa; The ATLAS collaboration

    2018-01-01

    The High-Luminosity LHC aims to provide a total integrated luminosity of 3000 fb-1 from p-p collisions at  14 TeV over the course of 10 years. The upgraded ATLAS detector must be able to cope well with increased occupancies and data rates. The large data samples at the High-Luminosity LHC will enable precise measurements of the Higgs boson and other Standard Model particles, as well as searches for new phenomena BSM.

  20. LHC Report: astounding availability

    CERN Multimedia

    Andrea Apollonio for the LHC team

    2016-01-01

    The LHC is off to an excellent start in 2016, having already produced triple the luminosity of 2015. An important factor in the impressive performance so far this year is the unprecedented machine availability.   LHC integrated luminosity in 2011, 2012, 2015 and 2016 and the prediction of the 2016 performance foreseen at the start of the year. Following the 2015-2016 end of year shutdown, the LHC restarted beam operation in March 2016. Between the restart and the first technical stop (TS1) in June, the LHC's beam intensity was successively increased, achieving operation with 2040 bunches per beam. The technical stop on 7-8 June was shortened to maximise the time available for luminosity production for the LHC experiments before the summer conferences. Following the technical stop, operation resumed and quickly returned to the performance levels previously achieved. Since then, the LHC has been running steadily with up to 2076 bunches per beam. Since the technical stop, a...

  1. LHC INAUGURATION, LHC Fest highlights: exhibition time!

    CERN Multimedia

    2008-01-01

    David Gross, one of the twenty-one Nobel Laureates who have participated in the project.Tuesday 21 October 2008 Accelerating Nobels Colliding Charm, Atomic Cuisine, The Good Anomaly, A Quark Somewhere on the White Paper, Wire Proliferation, A Tale of Two Liquids … these are just some of the titles given to artworks by Physics Nobel Laureates who agreed to make drawings of their prize-winning discoveries (more or less reluctantly) during a special photo session. Science photographer Volker Steger made portraits of Physics Nobel Laureates and before the photo sessions he asked them to make a drawing of their most important discovery. The result is "Accelerating Nobels", an exhibition that combines unusual portraits of and original drawings by twenty-one Nobel laureates in physics whose work is closely related to CERN and the LHC. This exhibition will be one of the highlights of the LHC celebrations on 21 October in the SM18 hall b...

  2. LHC detectors trigger/DAQ at LHC

    CERN Document Server

    Sphicas, Paris

    1998-01-01

    At its design luminosity, the LHC will deliver hundreds of millions of proton-proton interactions per second. Storage and computing limitations limit the number of physics events that can be recorded to about 100 per second. The selection will be carried out by the Trigger and data acquisition systems of the experiments. This lecture will review the requirements, architectures and various designs currently considered.

  3. Étude de la production de saveurs lourdes et de la multiplicité de particules chargées dans le cadre du formalisme du Color Glass Condensate pour les collisions p+p et p+Pb dans l'expérience ALICE au LHC

    CERN Document Server

    Malek, M

    The classical nuclear matter is characterized by an energy density of the order of " = 0.17 GeV/fm3. For the critical values of the energy density (5 -10 ") or the temperature (150 - 200 MeV), the Lattice QuantumChromo Dynamics (LQCD) calculations predict a phase transition from the classical to a new form of nuclear matter called the Quark Gluon Plasma (QGP) in which quarks and gluons are deconfined. Heavy ion collisions allow to create the thermodynamical conditions needed for the QGP formation. The LHC will collide p+p and Pb+Pb nuclei at ultrarelativistic energies, reaching a few TeV per nucleon. At such ultra-relativistic energies, new theoretical approaches of QCD developed to understand high energy hadronic collisions can be tested experimentally. One of the most discussed topic is the Color Glass Condensate (CGC) approach allowing the description of the initial conditions of the heavy ion collision. The CGC approach predicts the saturation of the parton density of the nucleus for small values of the B...

  4. Mesure de la masse du quark top dans le canal électron-muon à l'aide de la méthode des éléments de matrice avec les données à 8 TeV de l'expérience ATLAS du LHC

    CERN Document Server

    Pires, Sylvestre

    2015-07-03

    The work presented in this thesis lies within the scope of the measurement of the top quark mass in the decay channel electron-muon. This experimental measurement is achieved by the use of the matrix element method with events produced at LHC at a centre of mass energy of 8 TeV and collected by the ATLAS detector in 2012. After introducing the theoretical context of the Standard Model and the physics of the top quark, a detailed description of the ATLAS detector design and of both the event simulation and reconstruction is given. The first analysis presented was done during the beginning of the thesis and focuses on the impact of the insertion of an innermost new pixel layer in the ATLAS detector on the b-tagging performance during the data taking starting in 2015 with an centre of mass energy of 13 TeV. The second part of the thesis is dedicated the top quark mass measurement. After reviewing the selection procedure to which the analysis is linked, the calibration of the matrix element method is presented. T...

  5. LHC Report: LHC smashes collision records

    CERN Multimedia

    Sarah Charley

    2016-01-01

    The Large Hadron Collider is now producing more than a billion proton-proton collisions per second.   The LHC is colliding protons at a faster rate than ever before: approximately 1 billion times per second. Since April 2016, the LHC has delivered more than 30 inverse femtobarns (fb-1) to both ATLAS and CMS. This means that around 2.4 quadrillion (2.4 million billion) collisions have been seen by each of the experiments this year. The inverse femtobarn is the unit of measurement for integrated luminosity, indicating the cumulative number of potential collisions. This compares with the total of 33.2 fb-1 produced between 2010 and 2015. The unprecedented performance this year is the result of both the incremental increases in collision rate and the sheer amount of time the LHC has been up and running. This comes after a slow start-up in 2015, when scientists and engineers still needed to learn how to operate the machine at a much higher energy. “With more energy, the machine is much more sen...

  6. Electronics for LHC experiments

    International Nuclear Information System (INIS)

    Bourgeois, Francois

    1995-01-01

    Full text: A major effort is being mounted to prepare the way handling the high interaction rates expected from CERN's new LHC proton-proton collider (see, for example, November, page 6). September saw the First Workshop on Electronics for LHC Experiments, organized by Lisbon's Particle Physics Instrumentation Laboratory (LIP) on behalf of CERN's LHC Electronics Review Board (LERB - March, page 2). Its purpose was not only for the LERB to have a thorough review of ongoing activities, but also to promote cross fertilization in the engineering community involved in electronics design for LHC experiments. The Workshop gathered 187 physicists and engineers from 20 countries including USA and Japan. The meeting comprised six sessions and 82 talks, with special focus on radiation-hard microelectronic processes, electronics for tracking, calorimetry and muon detectors, optoelectronics, trigger and data acquisition systems. Each topic was introduced by an invited speaker who reviewed the requirements set by the particular detector technology at LHC. At the end of each session, panel discussions were chaired by each invited speaker. Representatives from four major integrated circuit manufacturers covered advanced radiation hard processes. Two talks highlighted the importance of obsolescence and quality systems in the long-lived and demanding environment of LHC. The Workshop identified areas and encouraged efforts for rationalization and common developments within and between the different detector groups. As a result, it will also help ensure the reliability and the long term maintainability of installed equipment. The proceedings of the Workshop are available from LIP Lisbon*. The LERB Workshop on Electronics for LHC Experiments will become a regular event, with the second taking place in Hungary, by Lake Balaton, from 23-27 September 1996. The Hungarian institutes KFKIRMKI have taken up the challenge of being as successful as LIP Lisbon in the organization

  7. LHC physics results and prospects

    CERN Document Server

    Kono, Takanori; The ATLAS collaboration

    2018-01-01

    This talk presents the latest results from LHC Run-2 as of May 2018 which include Standard Model measurements, Higgs boson properties and beyond Standard Model search results. The prospects for future LHC runs are also shown.

  8. Commissioning of the LHC

    CERN Multimedia

    CERN. Geneva

    2007-01-01

    The LHC construction is now approaching the end and it is now time to prepare for commissioning with beam. The behavior of a proton storage ring is much different to that of LEP, which profited from strong radiation damping to keep the beam stable. Our last experience with a hadron collider at CERN goes back more than 15 years when the proton-antiproton collider last operated. Ppbar taught us a lot about the machine physics of bunched beam proton storage rings and was essential input for the design of the LHC. After a short presentation of where we stand today with machine installation and hardware commissioning, I will discuss the main machine physics issues that will have to be dealt with in the LHC.

  9. Electronics at LHC

    CERN Document Server

    Hall, Geoffrey

    1998-01-01

    An overview of the electronic readout systems planned for use in the CMS and ATLAS experiments at the LHC will be given, with an emphasis on the motivations for the designs adopted and major technologies to be employed, specially those which are specific to LHC. At its design luminosity, the LHC will deliver hundreds of millions of proton-proton interactions per second. Storage and computing limitations limit the number of physics events that can be recorded to about 100 per second. The selection will be carried out by the Trigger and data acquisition systems of the experiments. This lecture will review the requirements, architectures and various designs currently considered. Introduction. Structure of gauge theories. The QED and QCD examples. Chiral theories. The electroweak theory. Spontaneous symmetry breaking. The Higgs machanism.Gauge boson and fermion masses. Yukawa coupling. Charges current couplings. The Cabibbo-Kobayashi-Maskawa matrix and CP violation. neutral current couplings. the Clashow-Iliopoul...

  10. LHC bending magnet coil

    CERN Multimedia

    A short test version of coil of wire used for the LHC dipole magnets. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. Magnet coils are made of copper-clad niobium–titanium cables — each wire in the cable consists of 9’000 niobium–titanium filaments ten times finer than a hair.

  11. Lectures on LHC physics

    CERN Document Server

    Plehn, Tilman

    2015-01-01

    With the discovery of the Higgs boson, the LHC experiments have closed the most important gap in our understanding of fundamental interactions, confirming that such interactions between elementary particles can be described by quantum field theory, more specifically by a renormalizable gauge theory. This theory is a priori valid for arbitrarily high energy scales and does not require an ultraviolet completion. Yet, when trying to apply the concrete knowledge of quantum field theory to actual LHC physics - in particular to the Higgs sector and certain regimes of QCD - one inevitably encounters an intricate maze of phenomenological know-how, common lore and other, often historically developed intuitions about what works and what doesn’t. These lectures cover three aspects to help understand LHC results in the Higgs sector and in searches for physics beyond the Standard Model: they discuss the many facets of Higgs physics, which is at the core of this significantly expanded second edition; then QCD, to the deg...

  12. The LHC in numbers

    CERN Multimedia

    Alizée Dauvergne

    2010-01-01

    What makes the LHC the biggest particle accelerator in the world? Here are some of the numbers that characterise the LHC, and their equivalents in terms that are easier for us to imagine.   Feature Number Equivalent Circumference ~ 27 km   Distance covered by beam in 10 hours ~ 10 billion km a round trip to Neptune Number of times a single proton travels around the ring each second 11 245   Speed of protons first entering the LHC 299 732 500 m/s 99.9998 % of the speed of light Speed of protons when they collide 299 789 760 m/s 99.9999991 % of the speed of light Collision temperature ~ 1016 °C ove...

  13. UFOs in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Grob, Laura [CERN, Geneva (Switzerland); Technische Universitaet Darmstadt (Germany)

    2016-07-01

    In the Large Hadron Collider (LHC) localized and recurring beam losses have been observed, which usually persist for several hundred microseconds. With increasing beam energy these losses were found to pose a serious risk to the machine availability, as some of these events can cause quenches in the superconducting magnets. The current understanding is that these losses are caused by falling microparticles that interact with the proton beam. To describe these so-called UFOs (unidentified falling objects) and their dynamics, a model was developed starting from the approach that only gravitational and electrostatic forces act on a neutrally charged particle. However, the model's results cannot reproduce the actual data from the LHC's beam loss monitors (BLMs), which indicates a more complex UFO dynamic. Experimental studies and further analysis of the BLM data are planned to investigate the UFO dynamics in greater detail and to understand origins and release mechanisms for microparticles in the LHC beam pipe.

  14. Cryogenics will cool LHC

    International Nuclear Information System (INIS)

    Anon.

    2001-01-01

    Results of the investigation into the cryogenic regulating line (QRL) performed by the LHC laboratory are presented. It is projected that eight cryogenic units located in five places around the LHC ring will provide superconducting magnets by liquid helium through eight cryogenic regulating lines of 3.2 km each. All QRL zones remain to be independent. CERN uses three test units with the aim of the certification of chosen constructions and verification of their thermal and mechanical efficiency before starting full-scale production [ru

  15. LHC-ILC synergy

    CERN Document Server

    Godbole, Rohini M

    2006-01-01

    I will begin by making a few general comments on the synergy between the Large Hadron Collider (LHC) which will go in action in 2007 and the International Linear Collider (ILC) which is under planning. I will then focus on the synergy between the LHC and the PLC option at the ILC, which is expected to be realised in the later stages of the ILC program. In this I will cover the possible synergy in the Higgs sector (with and without CP violation), in the determination of the anomalous vector boson couplings and last but not the least, in the search for extra dimensions and radions.

  16. The LHC detector challenge

    CERN Document Server

    Virdee, Tejinder S

    2004-01-01

    The Large Hadron Collider (LHC) from CERN, scheduled to come online in 2007, is a multi-TeV proton-proton collider with vast detectors. Two of the more significant detectors for LHC are ATLAS and CMS. Currently, both detectors are more than 65% complete in terms of financial commitment, and the experiments are being assembled at an increasing pace. ATLAS is being built directly in its underground cavern, whereas CMS is being assembled above ground. When completed, both detectors will aid researchers in determining what lies at the high-energy frontier, in particular the mechanism by which particles attain mass. (Edited abstract).

  17. LHC beampipe interconnection

    CERN Document Server

    Particle beams circulate for around 10 hours in the Large Hadron Collider (LHC). During this time, the particles make four hundred million revolutions of the machine, travelling a distance equivalent to the diameter of the solar system. The beams must travel in a pipe which is emptied of air, to avoid collisions between the particles and air molecules (which are considerably bigger than protons). The beam pipes are pumped down to an air pressure similar to that on the surface of the moon. Much of the LHC runs at 1.9 degrees above absolute zero. When material is cooled, it contracts. The interconnections must absorb this contraction whilst maintaining electrical connectivity.

  18. LHC France 2013: French Meeting on High Energy Physics at the LHC

    CERN Document Server

    2013-01-01

    Cette 1ère édition des rencontres françaises sur la physique des hautes énergies au Large Hadron Collider réunira près de 300 physiciens membres des laboratoires IN2P3-CNRS et IRFU-CEA, participants aux collaborations Atlas, CMS, LHCb et Alice. La rencontre LHC France, aura lieu à une période particulièrement cruciale pour la discipline, les derniers résultats des expériences LHC, basés sur toutes les données collectées en 2011 et 2012 y seront présentés et discutés. Elle sera l'occasion de faire le point et le bilan des avancées des diverses thématiques de recherche: boson de Higgs, les interactions électrofaibles, le quark top, la Supersymétrie, les saveurs lourdes, la violation de CP et le Plasma de Quarks et de Gluons. Elle sera aussi l'occasion de discuter des plans d'amélioration des détecteurs en vue des futures phases de fonctionnement du LHC ainsi que les perspectives pour la physique. Cette rencontre se veut un moment d'échange privilégié pour la communauté française des ...

  19. LHC 2008 lectures
    The LHC: an accelerator of science

    CERN Multimedia

    2008-01-01

    In 2008, CERN will be switching on the greatest physics experiment ever undertaken. The Large Hadron Collider, or LHC, is a particle accelerator that will provide many answers to our questions about the Universe - What is the reason for mass? Where is the invisible matter in the Universe hiding? What is the relationship between matter and antimatter? Will we have to use a theory claiming more than four dimensions? … and what about "time" ? To understand better the raison d’être of the LHC, this gigantic, peerless scientific instrument and all the knowledge it can bring to us, members of the general public are invited to a series of lectures at the Globe of Science and Innovation. Thursday 8 May 2008 at 8.00 p.m. « Comment fonctionne l’Univers ? Ce que le LHC peut nous apprendre » Alvaro de Rujula, CERN physicist Thursday 15 May 2008 at 8.00 p.m. – « Une nouvelle vision du monde » Jean-Pierre Luminet, Director of...

  20. LHC Commissioning and First Operation

    OpenAIRE

    Myers, S

    2010-01-01

    A description is given of the repair of the LHC after the accident of September 2008. The LHC hardware and beam commissioning and initial operation are reviewed both in terms of beam and hardware performance. The implemented machine protection measures and their impact on LHC operation are presented.

  1. LHC challenges and upgrade options

    Energy Technology Data Exchange (ETDEWEB)

    Bruning, O [CERN AB/ABP, Y03600, 1211 Geneva 23 (Switzerland)], E-mail: Oliver.Bruning@cern.ch

    2008-05-15

    The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex.

  2. LHC challenges and upgrade options

    International Nuclear Information System (INIS)

    Bruning, O

    2008-01-01

    The presentation summarizes the key parameters of the LHC collider. Following a discussion of the main challenges for reaching the nominal machine performance the presentation identifies options for increasing the operation tolerances and the potential performance reach of the LHC by means of future hardware upgrades of the LHC and its injector complex

  3. Mesure de la Polarisation des Lambda Produits dans les Collisions Positron-Electron AU Lep a L'aide du Detecteur Opal

    Science.gov (United States)

    Vandenplas, Denis

    Le Modele Standard est le cadre theorique general qui, jusqu'a present, a permis l'interpretation de tous les resultats experimentaux en physique des hautes energies. Cette theorie decrit, entre autres, la production d'une paire de particules elementaires, formee d'un quark et d'un antiquark, a partir de la desintegration de l'un des bosons mediateurs de l'interaction faible, le Z^0. Cependant, dans ce cas precis, la transformation subsequente des quarks primaires en particules reelles, un processus appele hadronisation, n'est decrite qu'a l'aide de modeles phenomenologiques. Afin de sonder les mecanismes de l'hadronisation, cette these presente la mesure du transfert du spin d'un quark etrange primaire a une particule appelee Lambda lors des desintegrations hadroniques du Z^0. L'etude a ete realisee dans le cadre de la collaboration OPAL, une des quatre experiences menees au collisionneur LEP, la ou des electrons et des positrons sont acceleres jusqu'a une energie commune, sqrt{s} = {rm E_ {cm}}, voisine de l'energie de production du rm Z^0, M_{Z ^0} egale a 91.3 GeV. La theorie electrofaible precise la direction du spin, c'est-a-dire la polarisation, d'un quark etrange primaire provenant de la desintegration d'un Z ^0. Quant a lui, le modele des quarks etablit que l'orientation du spin d'un Lambda est directement reliee a la polarisation du quark etrange dont il provient. La question est de determiner dans quelle mesure la polarisation du quark primaire est transmise au Lambda a la suite du processus de l'hadronisation, decrit dans le cadre de la ChromoDynamique Quantique. Une estimation, qui tient compte de tous ces differents aspects theoriques, evalue a 30% la polarisation des Lambda dont l'impulsion est superieure a 15 GeV/c. La mesure experimentale de la polarisation repose sur l'identification des Lambda a partir de la reconstitution de la desintegration Lambdato ppi^-. Ce processus, qui se deroule par le biais de l'interaction faible, viole la parite car

  4. LHC Report: Summer temperatures in the LHC

    CERN Multimedia

    Jan Uythoven for the LHC Team

    2012-01-01

    The LHC experiments have finished their data-taking period before the summer conferences. The machine has already delivered substantially more collisions to the experiments this year than in the whole of 2011. The LHC has now started a six-day Machine Development period, which will be followed by the second Technical Stop of the year.   The number of collisions delivered to the experiments is expressed in integrated luminosity. In 2011, the integrated luminosity delivered to both ATLAS and CMS was around 5.6 fb-1. On Monday 18 June, experiments finished taking data before the summer conferences and the integrated luminosity for 2012 so far is about 6.6 fb-1, well above the unofficial target of 5 fb-1. The LHC’s performance over the last week of running was so efficient that the injection kicker magnets – which heat up due to the circulating beam – did not have time to cool down between the subsequent fills. As the time constants for warming up and cooli...

  5. CERN: LHC magnets

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    With test magnets for CERN's LHC proton-proton collider regularly attaining field strengths which show that 10 Tesla is not forbidden territory, attention turns to why and where quenches happen. If 'training' can be reduced, superconducting magnets become easier to commission

  6. LHC status report

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Following the great success of the first 3.5 TeV collisions in all four LHC experiments on 30 March, the focus of the LHC commissioning teams has turned to consolidating the beam injection and acceleration procedures.   During the last two weeks, the operators have adopted a cycle of beam commissioning studies by day and the preparation and delivery of collisions during the night shifts. The injection and acceleration processes for the beams are by now well established and almost all feedback systems, which are an essential ingredient for establishing reliable and safe machine operation, have been commissioned. Thanks to special current settings for the quadrupoles that are situated near the collision points, the LHC luminosity at high energy has been increased by a factor of 5 in three of the four experiments. Similar improvements are under way for the fourth experiment. The next steps include adjustments of the LHC machine protection and collimation devices, which will ensure 'stable beam' co...

  7. Fully transparent LHC

    CERN Multimedia

    2008-01-01

    Thanks to the first real signals received from the LHC while in operation before the incident, the experiments are now set to make the best use of the data they have collected. Report from the LHCC open session.The September open session of the LHCC (LHC Experiments Committee) came just a few days after the incident that occurred at the LHC. The packed auditorium was a testament to the huge interest raised by Lyn Evans’ talk about the status of the machine and the plans for the future. After being told that the actual consequences of the incident will be clear only once Sector 3-4 has been warmed up, the audience focussed on the reports from the experiments. For the first time, the reports showed performance results of the various detectors with particles coming from the machine and not just from cosmic rays or tests and simulations. "The first days of LHC beam exceeded all expectations and the experiments made extensive and rapid use of the data they collected", says ...

  8. Higgs physics at LHC

    OpenAIRE

    Unal, G

    2006-01-01

    This is a review of Higgs physics at LHC. The topics covered are the search of the Standard Model Higgs boson (with emphasis on the low mass region), the measurements of the Higgs boson properties (mass, width, spin, CP and couplings) and the Higgs sector of the MSSM.

  9. Mobilizing for the LHC

    CERN Multimedia

    2008-01-01

    A follow-up report on the incident that occurred in LHC Sector 3-4 was published on 5 December. It confirms that the accelerator will be restarted in the summer of 2009. From now until then, the teams will be pulling out all the stops to repair the sector and enhance the operational safety of the machine.

  10. LHC: forwards and onwards

    CERN Multimedia

    2008-01-01

    Following the recent incident in Sector 3-4, which has brought the start-up of the LHC to a halt, the various teams are working hard to establish the cause, evaluate the situation and plan the necessary repairs. The LHC will be started up again in spring 2009 following the winter shutdown for the maintenance of all the CERN installations. The LHC teams are at work on warming up Sector 3-4 and establishing the cause of the serious incident that occurred on Friday, 19 September. Preliminary investigations suggest that the likely cause of the problem was a faulty electrical connection between two magnets. The connections probably melted, leading to a mechanical failure and a large leak of helium into the tunnel. However, the teams will not be able to carry out a full evaluation and assess the repairs needed until the sector has been warmed up again and inspected. "We are not worried about repairing the magnets as spare parts are available", said Lyn Evans, the LHC Project Leade...

  11. LHC Report: Ion Age

    CERN Multimedia

    John Jowett for the LHC team

    2013-01-01

    The LHC starts the New Year facing a new challenge: proton-lead collisions in the last month before the shutdown in mid-February.    Commissioning this new and almost unprecedented mode of collider operation is a major challenge both for the LHC and its injector chain. Moreover, it has to be done very quickly to achieve a whole series of physics goals, requiring modifications of the LHC configuration, in a very short time. These include a switch of the beam directions halfway through the run, polarity reversals of the ALICE spectrometer magnet and Van der Meer scans.    The Linac3 team kept the lead source running throughout the end-of-year technical stop, and recovery of the accelerator complex was very quick. New proton and lead beams were soon ready, with a bunch filling pattern that ensures they will eventually match up in the LHC. The LEIR machine has even attained a new ion beam intensity record.  On Friday 11 January the first single bunches o...

  12. Higgs physics at LHC

    Indian Academy of Sciences (India)

    The large hadron collider (LHC) and its detectors, ATLAS and CMS, are being built to study TeV scale physics, and to fully understand the electroweak symmetry breaking mechanism. The Monte-Carlo simulation results for the standard model and minimal super symmetric standard model Higgs boson searches and ...

  13. Electronics for LHC Experiments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance.

  14. CERN: LHC magnets

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-08-15

    With test magnets for CERN's LHC proton-proton collider regularly attaining field strengths which show that 10 Tesla is not forbidden territory, attention turns to why and where quenches happen. If 'training' can be reduced, superconducting magnets become easier to commission.

  15. Electronics for LHC Experiments

    International Nuclear Information System (INIS)

    2004-01-01

    This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance

  16. ATLAS. LHC experiments

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    In Greek mythology, Atlas was a Titan who had to hold up the heavens with his hands as a punishment for having taken part in a revolt against the Olympians. For LHC, the ATLAS detector will also have an onerous physics burden to bear, but this is seen as a golden opportunity rather than a punishment. The major physics goal of CERN's LHC proton-proton collider is the quest for the long-awaited£higgs' mechanism which drives the spontaneous symmetry breaking of the electroweak Standard Model picture. The large ATLAS collaboration proposes a large general-purpose detector to exploit the full discovery potential of LHC's proton collisions. LHC will provide proton-proton collision luminosities at the aweinspiring level of 1034 cm2 s~1, with initial running in at 1033. The ATLAS philosophy is to handle as many signatures as possible at all luminosity levels, with the initial running providing more complex possibilities. The ATLAS concept was first presented as a Letter of Intent to the LHC Committee in November 1992. Following initial presentations at the Evian meeting (Towards the LHC Experimental Programme') in March of that year, two ideas for generalpurpose detectors, the ASCOT and EAGLE schemes, merged, with Friedrich Dydak (MPI Munich) and Peter Jenni (CERN) as ATLAS cospokesmen. Since the initial Letter of Intent presentation, the ATLAS design has been optimized and developed, guided by physics performance studies and the LHC-oriented detector R&D programme (April/May, page 3). The overall detector concept is characterized by an inner superconducting solenoid (for inner tracking) and large superconducting air-core toroids outside the calorimetry. This solution avoids constraining the calorimetry while providing a high resolution, large acceptance and robust detector. The outer magnet will extend over a length of 26 metres, with an outer diameter of almost 20 metres. The total weight of the detector is 7,000 tonnes. Fitted with its end

  17. Que nous réserve l’année 2008 ? Du futur LHC à l’examen des milliards de bactéries qui colonisent l’Homme, Science dresse la liste des progrès attendus.

    CERN Multimedia

    2008-01-01

    The biggest particle accelerator in the world should be operational this summer. This big hadron collider (LHC), digged under the Leman Plain, will accelerate protons and heavy ions to produce high-energy collisions.

  18. Proposal for building the LHC computing environment

    CERN Document Server

    2001-01-01

    Le présent document présente le "Projet de Grille de calcul LHC" et sa "Phase 1 de développement technologique et d'essais conduisant à un prototype de production", examinés à plusieurs reprises par le Comité des directives scientifiques et par le Comité du Conseil en mars 2001. Tous deux ont appuyé la présente proposition et demandé des informations complémentaires. La première phase a trait aux développements technologiques et aux essais conduisant à la réalisation d'un prototype de production. Les résultats de cette phase serviront de base à la définition et à réalisation du système initial de production à approuver en 2004 selon la description donnée dans le présent document.

  19. LHC Nobel Symposium Proceedings

    Science.gov (United States)

    Ekelöf, Tord

    2013-12-01

    In the summer of 2012, a great discovery emerged at the Large Hadron Collider (LHC) at CERN in Geneva. A plethora of new precision data had already by then been collected by the ATLAS and CMS experiments at LHC, providing further extensive support for the validity of the Standard Model of particle physics. But what now appeared was the first evidence for what was not only the last unverified prediction of the Standard Model, but also perhaps the most decisive one: the prediction made already in 1964 of a unique scalar boson required by the theory of François Englert and Peter Higgs on how fundamental particles acquire mass. At that moment in 2012, it seemed particularly appropriate to start planning a gathering of world experts in particle physics to take stock of the situation and try to answer the challenging question: what next? By May 2013, when the LHC Nobel Symposium was held at the Krusenberg Mansion outside Uppsala in Sweden, the first signs of a great discovery had already turned into fully convincing experimental evidence for the existence of a scalar boson of mass about 125 GeV, having properties compatible with the 50-year-old prediction. And in October 2013, the evidence was deemed so convincing that the Swedish Royal Academy of Sciences awarded the Nobel Prize in Physics to Englert and Higgs for their pioneering work. At the same time the search at the LHC for other particles, beyond those predicted by the Standard Model, with heavier masses up to—and in some cases beyond—1 TeV, had provided no positive result. The triumph of the Standard Model seems resounding, in particular because the mass of the discovered scalar boson is such that, when identified with the Higgs boson, the Standard Model is able to provide predictions at energies as high as the Planck mass, although at the price of accepting that the vacuum would be metastable. However, even if there were some feelings of triumph, the ambience at the LHC Nobel Symposium was more one of

  20. 2008 LHC Open Days LHC magnets on display

    CERN Multimedia

    2008-01-01

    Over the last few years you’ve probably seen many of the 15 m long blue LHC dipole magnets being ferried around the site. Most of them are underground now, but on the LHC Open Days on 5 and 6 April the magnets will also play a central role on the surface. Installation of one of the LHC dipole magnets on the Saint-Genis roundabout on 7 March. The LHC dipole testing facility with several magnets at various stages of testing. The 27 km ring of the LHC consists of 1232 double-aperture superconducting dipole magnets, 360 short straight sections (SSS) and 114 special SSS for the insertion regions. On the Open Day, you will be able to "Follow the LHC magnets" through different stages around the site, culminating in their descent into the tunnel. Discover all the many components that have to be precisely integrated in the magnet casings, and talk to the engine...

  1. LHC forward physics

    Energy Technology Data Exchange (ETDEWEB)

    Cartiglia, N. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Royon, C. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States). et al.

    2015-10-02

    The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.

  2. LHC Forward Physics

    CERN Document Server

    Akiba, K.

    2016-10-17

    The goal of this report is to give a comprehensive overview of the rich field of forward physics, with a special attention to the topics that can be studied at the LHC. The report starts presenting a selection of the Monte Carlo simulation tools currently available, chapter 2, then enters the rich phenomenology of QCD at low, chapter 3, and high, chapter 4, momentum transfer, while the unique scattering conditions of central exclusive production are analyzed in chapter 5. The last two experimental topics, Cosmic Ray and Heavy Ion physics are presented in the chapter 6 and 7 respectively. Chapter 8 is dedicated to the BFKL dynamics, multiparton interactions, and saturation. The report ends with an overview of the forward detectors at LHC. Each chapter is correlated with a comprehensive bibliography, attempting to provide to the interested reader with a wide opportunity for further studies.

  3. LHC Report: machine development

    CERN Multimedia

    Rogelio Tomás García for the LHC team

    2015-01-01

    Machine development weeks are carefully planned in the LHC operation schedule to optimise and further study the performance of the machine. The first machine development session of Run 2 ended on Saturday, 25 July. Despite various hiccoughs, it allowed the operators to make great strides towards improving the long-term performance of the LHC.   The main goals of this first machine development (MD) week were to determine the minimum beam-spot size at the interaction points given existing optics and collimation constraints; to test new beam instrumentation; to evaluate the effectiveness of performing part of the beam-squeezing process during the energy ramp; and to explore the limits on the number of protons per bunch arising from the electromagnetic interactions with the accelerator environment and the other beam. Unfortunately, a series of events reduced the machine availability for studies to about 50%. The most critical issue was the recurrent trip of a sextupolar corrector circuit –...

  4. The LHC superconducting cavities

    CERN Document Server

    Boussard, Daniel; Häbel, E; Kindermann, H P; Losito, R; Marque, S; Rödel, V; Stirbet, M

    1999-01-01

    The LHC RF system, which must handle high intensity (0.5 A d.c.) beams, makes use of superconducting single-cell cavities, best suited to minimizing the effects of periodic transient beam loading. There will be eight cavities per beam, each capable of delivering 2 MV (5 MV/m accelerating field) at 400 MHz. The cavities themselves are now being manufactured by industry, using niobium-on-copper technology which gives full satisfaction at LEP. A cavity unit includes a helium tank (4.5 K operating temperature) built around a cavity cell, RF and HOM couplers and a mechanical tuner, all housed in a modular cryostat. Four-unit modules are ultimately foreseen for the LHC (two per beam), while at present a prototype version with two complete units is being extensively tested. In addition to a detailed description of the cavity and its ancillary equipment, the first test results of the prototype will be reported.

  5. LHC, Astrophysics and Cosmology

    Directory of Open Access Journals (Sweden)

    Giulio Auriemma

    2014-12-01

    Full Text Available In this paper we discuss the impact on cosmology of recent results obtained by the LHC (Large Hadron Collider experiments in the 2011-2012 runs, respectively at √s = 7 and 8 TeV. The capital achievement of LHC in this period has been the discovery of a spin-0 particle with mass 126 GeV/c2, very similar to the Higgs boson of the Standard Model of Particle Physics. Less exciting, but not less important, negative results of searches for Supersymmetric particles or other exotica in direct production or rare decays are discussed in connection with particles and V.H.E. astronomy searches for Dark Matter.

  6. Cryogenics for LHC experiments

    CERN Multimedia

    2001-01-01

    Cryogenic systems will be used by LHC experiments to maximize their performance. Institutes around the world are collaborating with CERN in the construction of these very low temperature systems. The cryogenic test facility in hall 180 for ATLAS magnets. High Energy Physics experiments have frequently adopted cryogenic versions of their apparatus to achieve optimal performance, and those for the LHC will be no exception. The two largest experiments for CERN's new flagship accelerator, ATLAS and CMS, will both use large superconducting magnets operated at 4.5 Kelvin - almost 270 degrees below the freezing point of water. ATLAS also includes calorimeters filled with liquid argon at 87 Kelvin. For the magnets, the choice of a cryogenic version was dictated by a combination economy and transparency to emerging particles. For the calorimeters, liquid argon was selected as the fluid best suited to the experiment's physics requirements. High Energy Physics experiments are the result of worldwide collaborations and...

  7. MPI@LHC Talk.

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00392933; The ATLAS collaboration

    2016-01-01

    Draft version of talk for MPI@LHC, regarding the topic of "Monte Carlo Tuning @ ATLAS". The talk introduces the event generator chain, concepts of tuning, issues/problems with over tuning, and then proceeds to explain 3(4) tunes performed at ATLAS. A 4th tune known as A15-MG5aMC@NLO(-TTBAR) is also included, but is awaiting note approval.

  8. LHC Magnet test failure

    CERN Multimedia

    2007-01-01

    "On Tueday, March 22, a Fermilab-built quadrupole magnet, one of an "inner triplet" of three focusing magnets, failed a high-pressure test at Point 5 in the tunnel of the LHC accelerator at CERN. Since Tuesday, teams at CERN and Fermilab have worked closely together to address the problem and have identified the cause of the failure. Now they are at work on a solution.:" (1 page)

  9. The LHC on Google

    CERN Multimedia

    2009-01-01

    Where in the world could the LHC outdo Barack Obama in the popularity stakes? On Google, of course! The famous search engine has just published its Top Ten "most popular" and "fastest rising" searches for 2008 in each of 34 countries. Surprise, surprise, the term "Large Hadron Collider" was the 6th fastest rising topic in the United Kingdom and the 10th fastest in New Zealand. In the UK, "Large Hadron Collider" even beat "Obama" into 7th place!

  10. Lectures on LHC physics

    CERN Document Server

    Plehn, Tilman

    2012-01-01

    When we try to advance from a solid knowledge of field theory to LHC physics we usually encounter a frustrating problem: in particular Higgs physics and QCD techniques appear as a impenetrable granite block of phenomenological know-how, common lores, and historically grown intuition what works and what does not. I hope this lecture can drill a few holes into the rock and put you into a position to digest advanced writeups as well as some first research papers on the topic.

  11. The LHC project

    CERN Multimedia

    CERN. Geneva

    2002-01-01

    At the halfway point in the construction of the LHC, the project is now moving from the design and procurement phase to the installation phase, which officially started on 1st March. An overview of the progress of the project is given and the final schedule for installation and commissioning is discussed. The talk will be given in English but questions can be taken in French.

  12. LHC Report: Beam on

    CERN Multimedia

    Rossano Giachino for the LHC Team

    2012-01-01

    The powering tests described in the last edition of the Bulletin were successfully finished at the end of the first week of March opening the way for 4 TeV operations this year. The beam was back in the machine on Wednesday 14 March. The first collisions at 4 TeV are scheduled for the first week of April.   The first beam of 2012 is dumped after making a few rounds in the LHC. The magnet powering tests were followed by the machine checkout phase. Here the operations team in collaboration with the equipment groups performs a sequence of tests to ensure the readiness of the LHC for beam. The tests include driving all the LHC systems – beam dump, injection, collimation, RF, power converters, magnet circuits, vacuum, interlocks, controls, timing and synchronization – through the operational cycle. The “checkout phase” is really a massive de-bugging exercise, which is performed with the objective of ensuring the proper functioning of the whole machine and t...

  13. LHC Report: imaginative injectors

    CERN Multimedia

    Pierre Freyermuth for the LHC team

    2016-01-01

    A new bunch injection scheme from the PS to the SPS allowed the LHC to achieve a new peak luminosity record.   Figure 1: PSB multi-turn injection principle: to vary the parameters during injection with the aim of putting the newly injected beam in a different region of the transverse phase-space plan. The LHC relies on the injector complex to deliver beam with well-defined bunch populations and the necessary transverse and longitudinal characteristics – all of which fold directly into luminosity performance. There are several processes taking place in the PS Booster (PSB) and the Proton Synchrotron (PS) acting on the beam structure in order to obtain the LHC beam characteristics. Two processes are mainly responsible for the beam brightness: the PSB multi-turn injection and the PS radio-frequency (RF) gymnastics. The total number of protons in a bunch and the transverse emittances are mostly determined by the multi-turn Booster injection, while the number of bunches and their time spacin...

  14. LHC Report: Rocky XIV

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The LHC has been in luminosity production mode for the last couple of weeks. Peak luminosities have ranged between 6 and a record 7.74 x 1033 cm -2 s-1. Integrated luminosities per fill have been healthy, with 170 inverse picobarn per fill reached on five occasions in the last two weeks.  The total integrated luminosity for the year has passed 14 inverse femtobarns.   Injected bunch currents have peaked at an average of  1.69 x 1011 protons per bunch on average - a remarkable achievement for both the injectors and the LHC: the injectors to be able to produce good quality beam at these intensities; the LHC for being able to cope with these intensities without excessive losses. Peak performance from day to day depends strongly on the beam sizes and bunch intensities delivered by the injectors. It is a continual challenge to keep the Booster, PS and SPS optimally tuned while they deliver beams to their other wide range of users. Despite the excel...

  15. LHC Dipoles Accelerate

    CERN Multimedia

    2001-01-01

    Andrezej Siemko (left), Peter Sievers (centre), and Lucio Rossi (right), have the exciting challenge of preparing and testing 2000 magnets for the LHC. The LHC is going to require a lot of powerful magnets by the time it begins operation in 2006. More specifically, it is going to need 130 special magnets, 400 quadrupoles, and a whopping 1250 dipoles! Preparing and testing these magnets for the conditions they will encounter in the LHC is not an easy task. But evaluation of the most recently received magnet, from the German company Noell, is showing that while the monumental task of receiving and testing nearly 2000 magnets is going to be exhausting, the goals are definitely attainable. At the moment and over the next year, pre-series magnets (the magnets that CERN uses to fine tune performance) are arriving slowly (90 in total will arrive), but by 2003 the rate of series magnet arrival will accelerate to 9 per week, that's over 450 in a single year! And working with these magnets when they arrive is tough. ...

  16. LHC luminosity upgrade detector challenges

    CERN Multimedia

    CERN. Geneva; de Roeck, Albert; Bortoletto, Daniela; Wigmans, Richard; Riegler, Werner; Smith, Wesley H

    2006-01-01

    LHC luminosity upgrade: detector challenges The upgrade of the LHC machine towards higher luminosity (1035 cm -2s-1) has been studied over the last few years. These studies have investigated scenarios to achieve the increase in peak luminosity by an order of magnitude, as well as the physics potential of such an upgrade and the impact of a machine upgrade on the LHC DETECTORS. This series of lectures will cover the following topics: • Physics motivation and machine scenarios for an order of magnitude increase in the LHC peak luminosity (lecture 1) • Detector challenges including overview of ideas for R&D programs by the LHC experiments: tracking and calorimetry, other new detector developments (lectures 2-4) • Electronics, trigger and data acquisition challenges (lecture 5) Note: the much more ambitious LHC energy upgrade will not be covered

  17. Search for excited leptons in the data of the H1 experiment at the HERA collider; Recherche de leptons excites dans les donnees de l'experience H1 aupres du collisionneur HERA

    Energy Technology Data Exchange (ETDEWEB)

    Delerue, N

    2002-05-01

    Composite models are one of the possible extensions of the Standard Model. One of their implications, at the energy in the reach of present particles accelerators, would be the excitation of leptons. This PhD. thesis describes the search for excited leptons with the H1 detector installed on the electron-proton collider HERA in Hamburg (Germany). The data used were accumulated between 1994 and 2000 and amount to an integrated luminosity of 120 pb{sup -1}. The analysis of 6 different topologies were done and cover all the branching ratios of deexcitation of excited electron and neutrino. The numbers of candidates found during those analysis is in agreement with the Standard Model expectations. This means that no evidence of excited leptons production was found at HERA. This result was translated in the form of exclusion limits on the coupling of excited leptons (f/{lambda}) depending on the mass of the excited lepton. For the first time at HERA we addressed the case were the natural decay width of the excited neutrino is wider than the experimental resolution. For the first time also, a study of the variation of limit depending on the ratio f'/f was carried out. This study lead to the setting of limits independent of this ratio. The limits obtained extend results previously obtained at HEA and also the results of direct searches at LEP. (author)

  18. Search for excited leptons in the data of the H1 experiment at the HERA collider; Recherche de leptons excites dans les donnees de l'experience H1 aupres du collisionneur HERA

    Energy Technology Data Exchange (ETDEWEB)

    Delerue, N

    2002-05-01

    Composite models are one of the possible extensions of the Standard Model. One of their implications, at the energy in the reach of present particles accelerators, would be the excitation of leptons. This PhD. thesis describes the search for excited leptons with the H1 detector installed on the electron-proton collider HERA in Hamburg (Germany). The data used were accumulated between 1994 and 2000 and amount to an integrated luminosity of 120 pb{sup -1}. The analysis of 6 different topologies were done and cover all the branching ratios of deexcitation of excited electron and neutrino. The numbers of candidates found during those analysis is in agreement with the Standard Model expectations. This means that no evidence of excited leptons production was found at HERA. This result was translated in the form of exclusion limits on the coupling of excited leptons (f/{lambda}) depending on the mass of the excited lepton. For the first time at HERA we addressed the case were the natural decay width of the excited neutrino is wider than the experimental resolution. For the first time also, a study of the variation of limit depending on the ratio f'/f was carried out. This study lead to the setting of limits independent of this ratio. The limits obtained extend results previously obtained at HEA and also the results of direct searches at LEP. (author)

  19. Implementation and validation of the linear collider final focus prototype: ATF2 at KEK (Japan); Implementation et validation de la focalisation finale du collisionneur lineaire: ATF2 at KEK (Japan)

    Energy Technology Data Exchange (ETDEWEB)

    Renier, Y.

    2010-06-15

    The two linear collider projects (ILC and CLIC) require beam delivery systems with the same local chromaticity correction scheme in the final focus. ATF2 at KEK (Japan), an implementation of this scheme scaled down in energy, uses the beam extracted from ATF, which is one of the most successful damping rings in the world. The ATF2 goals are to prove the feasibility and the stability of the linear collider final focus system and to define and test the experimental correction procedures. The nominal beam sizes at the interaction point are 3 {mu}m horizontally and 37 nm vertically. The work in this thesis was started before the commissioning and covered its first year at KEK. At the beginning, we observed that the stripline BPMs were not working properly so we investigated their behavior in detail. The problem was characterized and later solved in 2010 by upgrading the electronics. We then developed an efficient procedure to check the modeling of the beam line, comparing measurements of transfer matrices to model predictions calculated on line. After obtaining a good agreement, we were able to successfully test the trajectory correction algorithm which had been developed, reducing the difference between BPM measurements and the target values down to 0.5 mm horizontally and 0.2 mm vertically. We also successfully developed an algorithm to reconstruct pulse to pulse beam trajectory fluctuations with sub-micron precision. This reconstruction also gave a precise determination of the energy fluctuation, allowing a global fit of the dispersion function along the beam line with a precision of a few mm. A simple and robust IP beam size tuning method using sextupoles displacements was also studied in simulation, whose performance indicates that, given some assumptions on the error level of the beam, convergence within 20% of the nominal beam size should be possible in 8 hours with a 80% probability. (author)

  20. LHC goes global

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1995-09-15

    As CERN's major project for the future, the LHC sets a new scale in world-wide scientific collaboration. As well as researchers and engineers from CERN's 19 European Member States, preparations for the LHC now include scientists from several continents. Some 50 per cent of the researchers involved in one way or another with preparations for the LHC experimental programme now come from countries which are not CERN Member States. Underlining this enlarged international involvement is the recent decision by the Japanese Ministry of Education, Science and Culture ('Monbusho') to accord CERN a generous contribution of five billion yen (about 65 million Swiss francs) to help finance the construction of the LHC. This money will be held in a special fund earmarked for construction of specific LHC components and related activities. To take account of the new situation, CERN is proposing to set up a totally new 'Associate State' status. This is foreseen as a flexible bilateral framework which will be set up on a case-by-case basis to adapt to different circumstances. This proposal was introduced to CERN Council in June, and will be further discussed later this year. These developments reflect CERN's new role as a focus of world science, constituting a first step towards a wider level of international collaboration. At the June Council session, as a first step, Japan was unanimously elected as a CERN Observer State, giving them the right to attend Council meetings. Introducing the topic at the Council session, Director General Chris Llewellyn Smith sketched the history of Japanese involvement in CERN research. This began in 1957 and has gone on to include an important experiment at the LEAR low energy antiproton ring using laser spectroscopy of antiprotonic helium atoms, the new Chorus neutrino experiment using an emulsion target, and a major contribution to the Opal experiment at the LEP electronpositron collider. In welcoming the development, many Council delegates looked

  1. LHC goes global

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    As CERN's major project for the future, the LHC sets a new scale in world-wide scientific collaboration. As well as researchers and engineers from CERN's 19 European Member States, preparations for the LHC now include scientists from several continents. Some 50 per cent of the researchers involved in one way or another with preparations for the LHC experimental programme now come from countries which are not CERN Member States. Underlining this enlarged international involvement is the recent decision by the Japanese Ministry of Education, Science and Culture ('Monbusho') to accord CERN a generous contribution of five billion yen (about 65 million Swiss francs) to help finance the construction of the LHC. This money will be held in a special fund earmarked for construction of specific LHC components and related activities. To take account of the new situation, CERN is proposing to set up a totally new 'Associate State' status. This is foreseen as a flexible bilateral framework which will be set up on a case-by-case basis to adapt to different circumstances. This proposal was introduced to CERN Council in June, and will be further discussed later this year. These developments reflect CERN's new role as a focus of world science, constituting a first step towards a wider level of international collaboration. At the June Council session, as a first step, Japan was unanimously elected as a CERN Observer State, giving them the right to attend Council meetings. Introducing the topic at the Council session, Director General Chris Llewellyn Smith sketched the history of Japanese involvement in CERN research. This began in 1957 and has gone on to include an important experiment at the LEAR low energy antiproton ring using laser spectroscopy of antiprotonic helium atoms, the new Chorus neutrino experiment using an emulsion target, and a major contribution to the Opal experiment at the LEP electronpositron collider. In welcoming the

  2. Fiche technique du spermogramme et du spermocytogramme ...

    African Journals Online (AJOL)

    En Afrique la stérilité du couple constitue un drame social. Selon l'OMS, environ 8 à 12 % des couples africains sont touchés par une infertilité. La responsabilité masculine dans la stérilité est comprise entre 30 à 40%. Les causes de l'infertilité masculine peuvent être l'impuissance et/ ou l'altération du sperme. L'étude de ...

  3. Les Cahiers du CREAD

    African Journals Online (AJOL)

    Admin

    politique de bas prix exercée par la Russie et le Qatar vient confirmer ce constat ; s'ajoute à cela l'entrée éventuelle du gaz non conven- tionnel, dont son prix actuel de 3/4 $US, offre aux USA l'opportunité d'être exportateur de ..... les compagnies à produire en matière du gaz naturel, tels le prix du gaz naturel, le prix des ...

  4. Bulletin du CRDI #124

    International Development Research Centre (IDRC) Digital Library (Canada)

    Les femmes jouent un rôle important dans les exploitations minières artisanales et à petite échelle en Afrique subsaharienne. De concert ... Couverture du livre: Une vie saine pour les femmes et les enfants vulnérables · Couverture du livre: Entre el activismo y la intervención · Couverture du livre: Revitalizing Health for All.

  5. Bulletin du CRDI #125

    International Development Research Centre (IDRC) Digital Library (Canada)

    L'IOSRS remporte le prix de la diplomatie scientifique · GrowInclusive : la plateforme tant attendue est en construction · Toutes les nouvelles. Activités à venir. Semaine du développement international 2018. Le CRDI célébrera la Semaine du développement international du 4 au 10 février 2018. Suivez-nous sur Twitter et ...

  6. PDF4LHC recommendations for LHC Run II

    NARCIS (Netherlands)

    Butterworth, Jon; Carrazza, Stefano; Cooper-Sarkar, Amanda; Roeck, Albert de; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert S.

    2015-01-01

    We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new

  7. RF upgrade program in LHC injectors and LHC machine

    International Nuclear Information System (INIS)

    Jensen, E.

    2012-01-01

    The main themes of the RF upgrade program are: the Linac4 project, the LLRF-upgrade and the study of a tuning-free wide-band system for PSB, the upgrade of the SPS 800 MHz amplifiers and beam controls and the upgrade of the transverse dampers of the LHC. Whilst LHC Splice Consolidation is certainly the top priority for LS1, some necessary RF consolidation and upgrade is necessary to assure the LHC performance for the next 3- year run period. This includes: 1) necessary maintenance and consolidation work that could not fit the shorter technical stops during the last years, 2) the upgrade of the SPS 200 MHz system from presently 4 to 6 cavities and possibly 3) the replacement of one LHC cavity module. On the longer term, the LHC luminosity upgrade requires crab cavities, for which some preparatory work in SPS Coldex must be scheduled during LS1. (author)

  8. LNV Higgses at LHC

    Science.gov (United States)

    Maiezza, Alessio; Nemevšek, Miha; Nesti, Fabrizio

    2016-06-01

    Lepton number is a fundamental symmetry that can be probed at the LHC. Here, we study the Higgs sector of theories responsible for neutrino mass generation. After a brief discussion of simple see-saw scenarios, we turn to theories where heavy Majorana neutrino mass is protected by a gauge symmetry and focus on the Left-Right symmetric theory. There, the SM-like Higgs boson can decay to a pair of heavy neutrinos and provide enough information to establish the origin of neutrino mass.

  9. Thermometry for the LHC

    International Nuclear Information System (INIS)

    Buhler, S.; Junquera, T.; Thermeau, J.P.

    1999-01-01

    The LHC project will use about 8000 thermometers to control the temperature of magnets. These thermometers will be operated at a temperature ranging from 1.6 K to 300 K and their calibration should be better than 0.25%. A small cryogenic thermometer calibration facility has been designed and tested. To select the cryogenic temperature sensors, an irradiation program is being performed to expose at high neutron fluences (>10 15 n/cm 2 ) the following thermometers: carbon resistors, Ge, thin film, RhFe and Pt. The resistance shifts under radiation of the different sensors at liquid helium are presented. (authors)

  10. QCD probes at LHC

    CERN Document Server

    Da Silveira, G. Gil

    2018-01-01

    The LHC experiments have reported new results with respect to the dynamics of the strong interactions in $pp$, $p$A, and AA collisions over the past years. In proton-proton collisions, the data analyses have focused in exploring the nature of underlying events and double parton scattering at high energies. For large systems, the heavy-ion collisions have provided new insights on physics aspects related to azimuthal correlations, jet quenching, and particle production, such as antiprotons. This Letter reports the recent results from the ATLAS, CMS, and LHCb Collaborations on these various topics and highlights its relevant findings for the high-energy community.

  11. First LHC beam in 2017

    CERN Multimedia

    ATLAS Collaboration

    2017-01-01

    Impressions from the ATLAS control room while waiting for the very first 2017 LHC beams, from the traditional croissants in the morning to the "beam splashes" in the evening. The shift crew, online experts, run coordinators and management are looking forward to the next steps of the LHC restart.

  12. Status of the LHC machine

    International Nuclear Information System (INIS)

    Faugeras, P.

    1997-01-01

    The report represents itself a set of diagrams, characterizing: the LHC main parameters for proton-proton collisions and lead ion collisions, parameters of SC dipole and quadrupole magnets and outlines of their designs, LHC cryogenic systems, injection complex and detectors [ru

  13. LHC Cryogenics on the mend

    CERN Multimedia

    2004-01-01

    On 29 September, repairs began on the LHC cryogenic distribution line, or QRL, to replace a faulty part that occurs in the hundreds of elements of the line that are already on-site. The Accelerator Technology Department is designing a work programme to finish the repairs as soon as possible and minimize delays to the rest of the LHC project.

  14. First LHC beam in 2017

    CERN Multimedia

    ATLAS Collaboration

    2017-01-01

    Impressions from the ATLAS control room while waiting for the very first 2017 LHC beams, from the traditional croissants in the morning to the "beam splashes" in the evening. The shift crew, online experts, run coordinators and management are looking forward the next steps of the LHC restart.

  15. Support for the LHC experiments

    CERN Document Server

    Butin, François; Gastal, M; Lacarrère, D; Macina, D; Perrot, A L; Tsesmelis, E; Wilhelmsson, M; CERN. Geneva. TS Department

    2008-01-01

    Experimental Area Teams have been put in place and charged with the general co-ordination and management of the LHC experimental areas and of the zones in the LHC tunnel hosting near-beam detectors of the experiments. This organization is responsible for the in situ co-ordination of work with the aim of providing a structure that enables the experiment collaborations and accelerator groups to carry out their work effectively and safely. This presentation will review some key elements in the support given to the LHC experimental areas and, given the track record and successful implementation during the LHC installation and commissioning phase, will argue that such an organization structure will be required also for the period of LHC exploitation for physics.

  16. Section of LHC beampipe

    CERN Multimedia

    2009-01-01

    A short section of the LHC beampipe including beam screen. Particle beams circulate for around 10 hours in the Large Hadron Collider (LHC). During this time, the particles make four hundred million revolutions of the machine, travelling a distance equivalent to the diameter of the solar system. The beams must travel in a pipe which is emptied of air, to avoid collisions between the particles and air molecules (which are considerably bigger than protons). The beam pipes are pumped down to an air pressure similar to that on the surface of the moon. Emptying the air from the two 27 km long Large Hadron Collider beam-pipes is equivalent in volume to emptying the nave of the Notre Dame cathedral in Paris. Initially, the air pressure is reduced by pumping. Then, cold sections of the beam-pipe are further emptied using the temperature gradient across special beam-screens inside the tube where particles travel. The warm sections are emptied using a coating called a getter that works like molecular fly-paper. This va...

  17. LHC beampipe section

    CERN Multimedia

    A short section of the LHC beam-pipe including beam screen. In the LHC, particles circulate under vacuum. The vacuum chamber can be at room temperature (for example, in the experimental areas), or at cryogenic temperature, in the superconductive magnets. This piece is located in the superconductive magnets. The outer pipe is the vacuum chamber, which is in contact with the magnets, at cryogenic temperature (1.9K). It is called the “cold bore”. The inner tube is the beam screen. Its main goal is to protect the magnets from the heat load coming from the synchrotron radiation. Indeed, when high energy protons’ trajectory is bent, photons are emitted by the beam. They are intercepted by the beam screen. The temperature of the beam screen is kept between 5 and 20K by a circulation of gaseous helium in the small pipes on both sides of the beam screen. As those surfaces are at cryogenic temperature. The residual gas present in the accelerator is sticking on the surfaces. This phenomenon called “adsorption”...

  18. CERN: LHC progress

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    The push for CERN's next major project, the LHC proton collider to be built in the 27-kilometre LEP tunnel, is advancing on a wide front. For the machine itself, there has been considerable progress in the detailed design. While the main thrust is for proton-proton collisions, heavy ions are also on the LHC collision menu. On the experimental side, proposals are coming into sharper focus. For the machine, the main aim is for the highest possible proton collision energies and collision rates in the confines of the existing LEP tunnel, and the original base design looked to achieve these goals in three collision regions. Early discussions on the experimental programme quickly established that the most probable configuration would have two collision regions rather than three. This, combined with hints that the electronics of several detectors would have to handle several bunch crossings at a time, raised the question whether the originally specified bunch spacing of 15 ns was still optimal

  19. LHC Power Distribution

    CERN Document Server

    Pedersen, J

    1999-01-01

    The power distribution for the LHC machine and its experiments will be realised making extensive use of the existing infrastructure for the LEP. The overall power requirement is approximately the same, about 125 MW. The load distribution will however change. The even points will loose in importance and the points 1 and 5 will, due to the installation of ATLAS and CMS, gain. A thorough reorganisation of the 18 kV distribution will thus be necessary. Due to the important cryogenic installations required for the LHC, the 3.3 kV distribution system, supplying mainly cryogenic compressors, will be extended with a number of new substations. The important number of new surface buildings, underground caverns and other underground structures all will receive general service installations: Lighting and power. The new injection tunnels will require complete installations: A.C. supplies for the power converters and for general service, and D.C. cabling for the magnets of the beam line. Special safe power installations ar...

  20. Vacuum system for LHC

    International Nuclear Information System (INIS)

    Groebner, O.

    1995-01-01

    The Large Hadron Collider (LHC) which is planned at CERN will be housed in the tunnel of the Large Electron Positron collider (LEP) and will store two counter-rotating proton beams with energies of up to 7 TeV in a 27 km accelerator/storage ring with superconducting magnets. The vacuum system for the LHC will be at cryogenic temperatures (between 1.9 and 20 K) and will be exposed to synchrotron radiation emitted by the protons. A stringent limitation on the vacuum is given by the energy deposition in the superconducting coils of the magnets due to nuclear scattering of the protons on residual gas molecules because this may provoke a quench. This effect imposes an upper limit to a local region of increased gas density (e.g. a leak), while considerations of beam lifetime (100 h) will determine more stringent requirements on the average gas density. The proton beam creates ions from the residual gas which may strike the vacuum chamber with sufficient energy to lead to a pressure 'run-away' when the net ion induced desorption yield exceeds a stable limit. These dynamic pressure effects will be limited to an acceptable level by installing a perforated 'beam screen' which shields the cryopumped gas molecules at 1.9 K from synchrotron radiation and which also absorbs the synchrotron radiation power at a higher and, therefore, thermodynamically more efficient temperature. (author)

  1. LHC progress report

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Last weekend saw a record physics fill with a tenfold increase in instantaneous luminosity (event rate from collisions), marking an important milestone for the LHC. This physics fill did not only establish luminosities above 1.1 x 1028 cm-2 s-1 in all four experiments but was also kept in "stable beam" mode for a new record length of 30 hours. The particle physics experiments were able to more than double the total number of events so far recorded at 3.5 TeV.   The LHC screen indicating that squeezed stable beams have been achieved for the first time. The very successful weekend had been preceded by hard work on the accelerator side. A factor 5 improvement in luminosity was achieved by "squeezing" (reducing) the beam sizes at all four interaction points. This process, one of the most complex stages in the operation of the accelerator, was finalised the week before. Once the machine is "squeezed", the experimental insertions become aperture bot...

  2. LHC Capabilities for Quarkonia

    CERN Document Server

    Petrushanko, Sergey

    2008-01-01

    The measurement of the charmonium and bottomonium resonances in nucleus-nucleus collisions provides crucial information on high-density QCD matter. First, the suppression of quarkonia production is generally agreed to be one of the most direct probes of quark-gluon plasma formation. The observation of anomalous J/$\\psi$ suppression at the CERN-SPS and at RHIC is well established but the clarification of some important remaining questions requires equivalent studies of the $\\Upsilon$ family, only possible at the LHC energies. Second, the production of heavy-quarks proceeds mainly via gluon-gluon fusion processes and, as such, is sensitive to saturation of the gluon density at low-x in the nucleus. Measured departures from the expected vacuum quarkonia cross-sections in Pb+Pb collisions at the LHC will thus provide valuable information not only on the thermodynamical state of the produced partonic medium, but also on the initial-state modifications of the nuclear parton distribution functions. The capabilities ...

  3. LHC Report: Rocky Recovery

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The last technical stop finished on Friday 8 July, but the machine returned to its pre-stop performance level over a week later.   Efficiency of LHC fills between 16 July and 20 July, 2011. The cryogenics team had the entire ring cold by Saturday morning and the usual post-technical stop tests with circulating beams started soon after. Unfortunately, they were interrupted by a major perturbation to CERN’s electrical network caused by an impressive thunderstorm that swept over the Pays de Gex. There were major knock-on effects, including the loss of cooling to the cryogenics and an inevitable recovery period once normal service had been re-established. The beams were circulating again by Tuesday afternoon and the post-technical stop checks continued, beefed up with further tests to address a number of issues related to the power cut.  Before the stop, the LHC had managed to get 1380 bunches per beam into collisions and the plan was to ramp back up relatively quickly to this leve...

  4. "Cirque du Freak."

    Science.gov (United States)

    Rivett, Miriam

    2002-01-01

    Considers the marketing strategies that underpin the success of the "Cirque du Freak" series. Describes how "Cirque du Freak" is an account of events in the life of schoolboy Darren Shan. Notes that it is another reworking of the vampire narrative, a sub-genre of horror writing that has proved highly popular with both adult and…

  5. LHC Injection Beam Quality During LHC Run I

    CERN Document Server

    AUTHOR|(CDS)2079186; Kain, Verena; Stapnes, Steinar

    The LHC at CERN was designed to accelerate proton beams from 450 GeV to 7 TeV and collide them in four large experiments. The 450 GeV beam is extracted from the last pre-accelerator, the SPS, and injected into the LHC via two 3 km long transfer lines, TI 2 and TI 8. The injection process is critical in terms of preservation of beam quality and machine protection. During LHC Run I (2009-2013) the LHC was filled with twelve high intensity injections per ring, in batches of up to 144 bunches of 1.7*10^11 protons per bunch. The stored beam energy of such a batch is already an order of magnitude above the damage level of accelerator equipment. Strict quality and machine protection requirements at injection have a significant impact on operational efficiency. During the first years of LHC operation, the injection phase was identified as one of the limiting factors for fast LHC turnaround time. The LHC Injection Quality Check (IQC) software framework was developed as a part of this thesis to monitor the beam quality...

  6. Tracking detectors for the sLHC, the LHC upgrade

    CERN Document Server

    Sadrozinski, Hartmut F W

    2005-01-01

    The plans for an upgrade of the Large Hadron Collider (LHC) to the Super-LHC (sLHC) are reviewed with special consideration of the environment for the inner tracking system. A straw-man detector upgrade for ATLAS is presented, which is motivated by the varying radiation levels as a function of radius, and choices for detector geometries and technologies are proposed, based on the environmental constraints. A few promising technologies for detectors are discussed, both for sensors and for the associated front-end electronics. On-going research in silicon detectors and in ASIC technologies will be crucial for the success of the upgrade.

  7. LHC-B: a dedicated LHC collider beauty experiment

    International Nuclear Information System (INIS)

    Erhan, S.

    1995-01-01

    LHC-B is a forward detector optimized for the study of CP-violation and other rare phenomena in the decays of beauty particles at the LHC. An open geometry forward detector design, with good mass, vertex resolution and particle identification, will facilitate the collection of a large numbers of event samples in diverse B decay channels and allow for a thorough understanding of the systematic uncertainties. With the expected large event statistics, LHC-B will be able to test the closure of the unitarity triangle and make sensitive tests of the Standard Model description of CP-violation. Here we describe the experiment and summarize its anticipated performance. (orig.)

  8. Keeping HL-LHC accountable

    CERN Multimedia

    2015-01-01

    This week saw the cost and schedule of the High Luminosity LHC (HL-LHC) and LHC Injectors Upgrade (LIU) projects come under close scrutiny from the external review committee set up for the purpose.    HL-LHC, whose implementation requires an upgrade to the CERN injector complex, responds directly to one of the key recommendations of the updated European Strategy for Particle Physics, which urges CERN to prepare for a ‘major luminosity upgrade’, a recommendation that is also perfectly in line with the P5 report on the US strategy for the field. Responding to this recommendation, CERN set up the HL-LHC project in 2013, partially supported by FP7 funding through the HiLumi LHC Design Study (2011-2015), and coordinated with the American LARP project, which oversees the US contribution to the upgrade. A key element of HL-LHC planning is a mechanism for receiving independent expert advice on all aspects of the project.  To this end, several technical reviews h...

  9. Physics Validation of the LHC Software

    CERN Multimedia

    CERN. Geneva

    2004-01-01

    The LHC Software will be confronted to unprecedented challenges as soon as the LHC will turn on. We summarize the main Software requirements coming from the LHC detectors, triggers and physics, and we discuss several examples of Software components developed by the experiments and the LCG project (simulation, reconstruction, etc.), their validation, and their adequacy for LHC physics.

  10. Dissecting an LHC dipole

    CERN Multimedia

    2004-01-01

    The cold mass of a 15-metre main dipole magnet has some fifteen different components. All the main components are manufactured under CERN's direct responsibility. Four of them transit through CERN before being shipped to the dipole assembly contractors, namely the cable, which constitutes the magnet's superconducting core (see Bulletin 14/2004), the beam screens, the heat exchanger tubes and the cold bore beam tubes. The two latter components transit via Building 927 where they undergo part of the production process. The 58-mm diameter heat exchanger tubes will remove heat from the magnets using superfluid helium. The 53-mm diameter cold bore tubes will be placed under vacuum to allow the twin beams to circulate around the LHC.

  11. Beam Scraping for LHC Injection

    CERN Document Server

    Burkhardt, H; Fischer, C; Gras, J-J; Koschik, A; Kramer, Daniel; Pedersen, S; Redaelli, S

    2007-01-01

    Operation of the LHC will require injection of very high intensity beams from the SPS to the LHC. Fast scrapers have been installed and will be used in the SPS to detect and remove any existing halo before beams are extracted, to minimize the probability for quenching of superconducting magnets at injection in the LHC. We briefly review the functionality of the scraper system and report about measurements that have recently been performed in the SPS on halo scraping and re-population of tails.

  12. CERN LHC dipole prototype success

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In a crash programme, the first prototype superconducting dipole magnet for CERN's LHC protonproton collider was successfully powered for the first time at CERN on 14 April, eventually sailing to 9T, above the 8.65T nominal LHC field, before quenching for the third time. The next stage is to install the delicate measuring system for making comprehensive magnetic field maps in the 10 m long, 50 mm diameter twin-apertures of the magnet. These measurements will check that the required LHC field quality has been achieved at both the nominal and injection fields

  13. PDF4LHC recommendations for LHC Run II

    CERN Document Server

    Butterworth, Jon; Cooper-Sarkar, Amanda; De Roeck, Albert; Feltesse, Joel; Forte, Stefano; Gao, Jun; Glazov, Sasha; Huston, Joey; Kassabov, Zahari; McNulty, Ronan; Morsch, Andreas; Nadolsky, Pavel; Radescu, Voica; Rojo, Juan; Thorne, Robert

    2016-01-01

    We provide an updated recommendation for the usage of sets of parton distribution functions (PDFs) and the assessment of PDF and PDF+$\\alpha_s$ uncertainties suitable for applications at the LHC Run II. We review developments since the previous PDF4LHC recommendation, and discuss and compare the new generation of PDFs, which include substantial information from experimental data from the Run I of the LHC. We then propose a new prescription for the combination of a suitable subset of the available PDF sets, which is presented in terms of a single combined PDF set. We finally discuss tools which allow for the delivery of this combined set in terms of optimized sets of Hessian eigenvectors or Monte Carlo replicas, and their usage, and provide some examples of their application to LHC phenomenology.

  14. Ecologie du phytoplancton du lac Kivu

    Directory of Open Access Journals (Sweden)

    Sarmento, H.

    2008-01-01

    Full Text Available Speciation within the African Coffee Pathogen. Cet article analyse s'il est avantageux d'utiliser le compost au lieu de l'engrais minéral pour produire la laitue dans la zone urbaine et péri-urbaine de Yaoundé. Les résultats de terrain montrent l'obtention de rendements et profits plus élevés lorsqu'on utilise le compost. Les résultats de la fonction de production Cobb-Douglas prouvent que l'utilisation du compost est statistiquement significative pour expliquer la variation de rendement de la laitue et que le compost est l'intrant le plus productif. D'autres résultats montrent que le compost fournit la matière organique utile au sol et que les besoins d'irrigation en eau de la culture sont réduits grâce à l'utilisation du compost. Par conséquent, malgré le fait que l'application du compost demande une main-d'oeuvre beaucoup plus élevée, son utilisation est généralement bénéfique pour les agriculteurs vivant aux alentours de Yaoundé. Les programmes de vulgarisation de cet intrant pour encourager son adoption devraient donc figurer parmi les points prioritaires dans la politique agricole du gouvernement camerounais.

  15. LHC Report: Tests of new LHC running modes

    CERN Document Server

    Verena Kain for the LHC team

    2012-01-01

    On 13 September, the LHC collided lead ions with protons for the first time. This outstanding achievement was key preparation for the planned 2013 operation in this mode. Outside of two special physics runs, the LHC has continued productive proton-proton luminosity operation.   Celebrating proton-ion collisions. The first week of September added another 1 fb-1 of integrated luminosity to ATLAS’s and CMS’s proton-proton data set. It was a week of good and steady production mixed with the usual collection of minor equipment faults. The peak performance was slightly degraded at the start of the week but thanks to the work of the teams in the LHC injectors the beam brightness – and thus the LHC peak performance – were restored to previous levels by the weekend. The LHC then switched to new running modes and spectacularly proved its potential as a multi-purpose machine. This is due in large part to the LHC equipment and controls, which have been designed wi...

  16. Élaboration et gestion des plans d'installation de la machine LHC

    CERN Document Server

    Corso, Jean Pierre

    2005-01-01

    Remplir 27 km de l’étroit tunnel du LEP avec plusieurs milliers d’équipements est le défi posé par le LHC et à relever par les techniciens et ingénieurs du CERN. Le LEP avait initié ce concept avec un outil nommé LEGO ; Le LHC a encore franchi une étape avec DMU (Digital Mock-Up), en tirant profit de l’évolution significative des outils informatiques (langages de programmation et logiciels). Utilisé comme interface entre une base de données Oracle® regroupant toutes les informations sur chaque équipement et les modèles 3D standard correspondants issus d’Euclid®, DMU a étendu, depuis, son champ d’application en permettant dorénavant de générer automatiquement tous les plans d’installation des 514 demi cellules de la Machine. Les évolutions futures de la configuration du LHC nous conduiront à modifier ou déplacer les équipements en place et à en insérer de nouveaux. Ceux-ci seront introduits dans la base de données avant de pouvoir être restitués via DMU sous forme de pl...

  17. To the LHC and beyond

    CERN Document Server

    Rodgers, Peter

    2004-01-01

    CERN was conceived in 1949 as a new European laboratory to halt the exodus of physics talent from Europe to North America. In 1954, the new lab formally came into existence upon ratification of the resolution by the first 12 European member states. To further strengthen its position as the top particle-physics laboratory in the world, the CERN council agreed a new seven-point strategy. Completing the Large Hadron Collider (LHC) on schedule in 2007 is the top priority, followed by consolidating the lab's infrastructure to guarantee reliable operation of the LHC; examining the lab's experimental program apart from the LHC; coordinating research in Europe; building a new injector for the LHC in 2006; increasing R&D on the Compact Linear Collider (CLIC); and working on a long-term strategy for the lab. CERN expects to complete half of these at the end of 2008. (Edited abstract).

  18. High Luminosity LHC Project Description

    CERN Document Server

    Apollinari, Giorgio; Rossi, Lucio

    2014-01-01

    The High Luminosity LHC (HL-LHC) is a novel configuration of the Large Hadron Collider, aiming at increasing the luminosity by a factor five or more above the nominal LHC design, to allow increasing the integrated luminosity, in the high luminosity experiments ATLAS and CMS, from the 300 fb-1 of the LHC original design up to 3000 fb-1 or more. This paper contains a short description of the main machine parameters and of the main equipment that need to be developed and installed. The preliminary cost evaluation and the time plan are presented, too. Finally, the international collaboration that is supporting the project, the governance and the project structure are discussed, too.

  19. Coming Soon: LHC's Big Chill

    CERN Multimedia

    2003-01-01

    Installation of the LHC cryogenic distribution line has begun. The line is crucial to the project, as it is to be used to distribute the liquid helium for cooling the superconducting magnets down to 1.8 K.

  20. The Workflow of LHC Papers

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Finally, the talk will focus on how the institutional repository (CDS) is being linked to the HEP disciplinary archive (INSPIRE) in order to provide users with a central access point to reach LHC results.

  1. NNLO corrections for LHC processes

    CERN Document Server

    Caola, Fabrizio

    2015-01-01

    To fully profit from the remarkable achievements of the experimental program at the LHC, very precise theoretical predictions for signal and background processes are required. In this contribution, I will review some of the recent progress in fully exclusive next-to-next-toleading-order (NNLO) QCD computations. As an example of the phenomenological relevance of these results, I will present LHC predictions for t-channel single-top production and Higgs boson production in association with one hard jet.

  2. The LHC personnel safety system

    International Nuclear Information System (INIS)

    Ninin, P.; Valentini, F.; Ladzinski, T.

    2011-01-01

    Large particle physics installations such as the CERN Large Hadron Collider require specific Personnel Safety Systems (PSS) to protect the personnel against the radiological and industrial hazards. In order to fulfill the French regulation in matter of nuclear installations, the principles of IEC 61508 and IEC 61513 standard are used as a methodology framework to evaluate the criticality of the installation, to design and to implement the PSS.The LHC PSS deals with the implementation of all physical barriers, access controls and interlock devices around the 27 km of underground tunnel, service zones and experimental caverns of the LHC. The system shall guarantee the absence of personnel in the LHC controlled areas during the machine operations and, on the other hand, ensure the automatic accelerator shutdown in case of any safety condition violation, such as an intrusion during beam circulation. The LHC PSS has been conceived as two separate and independent systems: the LHC Access Control System (LACS) and the LHC Access Safety System (LASS). The LACS, using off the shelf technologies, realizes all physical barriers and regulates all accesses to the underground areas by identifying users and checking their authorizations.The LASS has been designed according to the principles of the IEC 61508 and 61513 standards, starting from a risk analysis conducted on the LHC facility equipped with a standard access control system. It consists in a set of safety functions realized by a dedicated fail-safe and redundant hardware guaranteed to be of SIL3 class. The integration of various technologies combining electronics, sensors, video and operational procedures adopted to establish an efficient personnel safety system for the CERN LHC accelerator is presented in this paper. (authors)

  3. LHC magnet string in 1994

    CERN Multimedia

    1994-01-01

    On 6-7 December 1994, a string of powerful superconducting magnets for CERN's next particle accelerator, the Large Hadron Collider (LHC), ran successfully at 8.36 tesla for 24 hours. This magnetic field is 100 000 times that of the Earth and is required to keep beams of protons travelling on the correct circular path over 27 km at 7 TeV in the new LHC accelerator.

  4. LHC: from hot to cold

    CERN Multimedia

    2006-01-01

    The first cryogenic feedbox designed to supply electricity to the superconducting magnets of one arc has just been installed at Point 8 of the LHC. This latest milestone is the reward for the joint efforts of the AT and TS Departments at CERN, the IHEP Institute in Moscow and CERN’s industrial partners who collaborated in its manufacture, and is a precursor to the forthcoming cool down of the first 3.3 km sector of the LHC.

  5. LHC Results Highlights (CLASHEP 2013)

    CERN Document Server

    Gonzalez, O.

    2015-05-22

    The good performance of the LHC provided enough data at 7 TeV and 8 TeV to allow the experiments to perform very competitive measurements and to expand the knowledge about the fundamental interaction far beyond that from previous colliders. This report summarizes the highlights of the results obtained with these data samples by the four large experiments, covering all the topics of the physics program and focusing on those exploiting the possibilities of the LHC.

  6. Du Pont de Nemours

    NARCIS (Netherlands)

    Ros JPM; LAE

    1994-01-01

    Dit rapport over Du Pont de Nemours (produktie van o.a. chemische stoffen) is gepubliceerd binnen het Samenwerkingsproject Procesbeschrijvingen Industrie Nederland (SPIN). In het kader van dit project is informatie verzameld over industriele bedrijven of industriele processen ter ondersteuning

  7. LHC an unprecedented technological challenge

    International Nuclear Information System (INIS)

    Baruch, J.O.

    2002-01-01

    This article presents the future LHC (large hadron collider) in simple terms and gives some details concerning radiation detectors and supra-conducting magnets. LHC will take the place of the LEP inside the 27 km long underground tunnel near Geneva and is scheduled to operate in 2007. 8 years after its official launching the LHC project has piled up 2 year delay and has exceeded its initial budget (2 milliard euros) by 18%. Technological challenges and design difficulties are the main causes of these shifts. The first challenge has been carried out successfully, it was the complete clearing out of the LEP installation. In order to release 14 TeV in each proton-proton collision, powerful magnetic fields (8,33 Tesla) are necessary. 1248 supra-conducting 15 m-long bipolar magnets have to be built. 30% of the worldwide production of niobium-titanium wires will be used each year for 5 years in the design of these coils. The global cryogenic system will be gigantic and will use 94 tons of helium. 4 radiation detectors are being built: ATLAS (a toroidal LHC apparatus), CMS (compact muon solenoid), ALICE (a large ion collider experiment) and LHC-b (large hadron collider beauty). The 2 first will search after the Higgs boson, ALICE will be dedicated to the study of the quark-gluon plasma and LHC-b will gather data on the imbalance between matter and anti-matter. (A.C.)

  8. LHC Olympics flex physicists' brains

    CERN Multimedia

    2006-01-01

    Physicists from around the world met at CERN to strengthen their data-deciphering skills at the second LHC Olympics workshop. Physicists gather for the second LHC Olympics workshop. Coinciding with the kick-off of the winter Olympics in Turin, more than 70 physicists gathered at CERN from across the globe for the second LHC Olympics workshop on 9-10 February. Their challenge, however, involved brains rather than brawn. As the switch-on date for the LHC draws near, scientists excited by the project want to test and improve their ability to decipher the unprecedented amount of data that the world's biggest and most powerful particle accelerator is expected to generate. The LHC Olympics is a coordinated effort to do just that, minus the gold, silver and bronze of the athletics competition. 'In some ways, the LHC is not a precision instrument. It gives you the information that something is there but it's hard to untangle and interpret what it is,' said University of Michigan physicist Gordy Kane, who organiz...

  9. The LHC at level best

    CERN Multimedia

    Katarina Anthony

    2013-01-01

    On 10 March, a team of CERN surveyors descended into the LHC tunnel. Their aim: to take measurements of the height of the LHC magnets to see how geological shifts might be affecting the machine and to take reference positions of the machine before the interconnects are opened.    CERN surveyors take levelling measurements of the LHC magnets during LS1. The LHC tunnel is renowned for its geological stability: set between layers of sandstone and molasse, it has allowed the alignment of the world’s largest accelerators to be within sub-millimetre precision. But even the most stable of tunnels can be affected by geological events. To ensure the precise alignment of the LHC, the CERN survey team performs regular measurements of the vertical position of the magnets (a process known as “levelling”). Over the past month, the team has been taking measurements of the LHC before the temperature of the magnets reaches 100 K, beyond which there may be some mechanic...

  10. Last cast for the LHC

    CERN Multimedia

    2005-01-01

    The first major contract signed for the LHC is drawing to a close. Belgian firm Cockerill Sambre (a member of the Arcelor Group) has just completed production of 50,000 tonnes of steel sheets for the accelerator's superconducting magnet yokes, in what has proved to be an exemplary partnership with CERN. Philippe Lebrun, Head of the AT Department, Lyn Evans, LHC Project Leader, and Lucio Rossi, Head of the AT-MAS Group, in front of the last batch of steel for the LHC at Cockerill Sambre. It was a bright red-letter day at the end of May, when Belgian firm Cockerill Sambre of the Arcelor Group marked the completion of one of the largest contracts for the LHC machine by casting the last batch of steel sheets for the LHC superconducting magnet yokes in the presence of LHC Project Leader Lyn Evans, AT Department Head Philippe Lebrun, Magnets and Superconductors (AT-MAS) Group Leader Lucio Rossi and Head of the AT-MAS Group's components centre Francesco Bertinelli. The yokes constitute approximately 80% of the acc...

  11. The LHC on the table

    CERN Multimedia

    2002-01-01

    How many dipoles have been manufactured so far? How many have been delivered? To find out, you can now consult the LHC Progress Dashboard on the web. The dashboard tracks progress with regard to manufacture and delivery of thirty different types of LHC components. Do you want to know everything about progress on LHC construction? The LHC's engineers have recently acquired a very useful tracking tool precisely for that purpose. This is the LHC Progress Dashboard which makes it possible to track work progress in graph form. In the interests of transparency, the LHC Project Management has decided to make it accessible to the public on the web. You can now consult normalized graphs for each of the thirty different types of components that form part of machine construction, such as the cold masses of the dipole magnets, the vacuum chambers and the octupoles, etc. The graphs show: in blue: the contractual delivery curves, i.e. the delivery schedules to which the suppliers have committed themselves in their contra...

  12. The High Luminosity LHC Project

    Science.gov (United States)

    Rossi, Lucio

    The High Luminosity LHC is one of the major scientific project of the next decade. It aims at increasing the luminosity reach of LHC by a factor five for peak luminosity and a factor ten in integrated luminosity. The project, now fully approved and funded, will be finished in ten years and will prolong the life of LHC until 2035-2040. It implies deep modifications of the LHC for about 1.2 km around the high luminosity insertions of ATLAS and CMS and relies on new cutting edge technologies. We are developing new advanced superconducting magnets capable of reaching 12 T field; superconducting RF crab cavities capable to rotate the beams with great accuracy; 100 kA and hundred meter long superconducting links for removing the power converter out of the tunnel; new collimator concepts, etc... Beside the important physics goals, the High Luminosity LHC project is an ideal test bed for new technologies for the next hadron collider for the post-LHC era.

  13. Les Cahiers du CREAD

    African Journals Online (AJOL)

    Admin

    6 juil. 2007 ... La problématique du développement du secteur de l'artisanat en. Algérie a été très peu abordée par les chercheurs, qu'ils soient universitaires ou .... La loi a institué une taxe d'apprentissage dont le taux a été fixé à. 1% de la ...

  14. Les outils du CERN

    CERN Multimedia

    1999-01-01

    C'est le plus grand centre mondial de recherche en physique des particules. Les outils du Laboratoire, accélérateurs et détecteurs de particules, figurent parmi les instruments scientifiques les plus complexes au monde. Des prix Nobels ont d'ailleurs été attribués aux physiciens du CERN pour leurs développements.

  15. Bulletin du CRDI #127

    International Development Research Centre (IDRC) Digital Library (Canada)

    La mise à l'échelle de la recherche et de l'innovation en vue de créer un impact social constitue une priorité pour la communauté du développement. Toutefois ... Nous avons renouvelé notre soutien à la recherche auprès du gouvernement de l'Inde ... Des femmes étudient à l'École supérieure d'infotronique d'Haïti.

  16. Comment fonctionne l’Univers ? Ce que le LHC peut nous apprendre

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    L'Univers en son enfance était une "soupe" de particules, de plus en plus chaudes (de plus haute énergie) à mesure qu'on remonte vers sa naissance, le "big bang". C'est ainsi que les observations à des énergies de plus en plus élevées nous permettent, par exemple, de nous approcher de plus près de la prime jeunesse de l'Univers et, donc, de mieux le comprendre. L'étude du macro- et du micro-cosme sont une science unique dans laquelle, de façon surprenante, ce que nous comprenons le moins bien est le vide, qui ne semble pas l'être: il existe une différence fondamentale entre le vide et le néant. Le LHC pourrait nous permettre de voir les vibrations de la "substance" du vide, qu'on appelle les particules 'de Higgs'.

  17. LHC Report: Take Five

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The LHC is continuing to perform well and an integrated luminosity of over 5fb-1 has now been delivered to ATLAS and CMS. While keeping a close eye on beam induced heating and vacuum quality, the bunch current has been gently raised to over 1.4x1011 protons per bunch. This has given a peak luminosity of 3.6x1033 cm-2s-1. Some long fills have helped production and recent high points include 120pb-1 delivered in one fill and 580pb-1 delivered in one week.   Time has also been devoted to some special physics runs for TOTEM and ALFA. In these runs, the beam is de-squeezed to a ß* of 90 m in ATLAS and CMS. This is instead of the usual 1m ß*, and gives a larger beam size at interaction points. The increased beam size results in a reduced beam divergence at the interaction points. This permits TOTEM and ALFA to probe low-angle scattering and allows them to measure the total cross section of proton-proton interactions and the absolute luminosity cal...

  18. Tracking the LHC halo

    CERN Multimedia

    Antonella Del Rosso

    2015-01-01

    In the LHC, beams of 25-ns-spaced proton bunches travel at almost the speed of light and pass through many different devices installed along the ring that monitor their properties. During their whirling motion, beam particles might interact with the collimation instrumentation or with residual gas in the vacuum chambers and this creates the beam halo – an annoying source of background for the physics data. Newly installed CMS sub-detectors are now able to monitor it.   The Beam Halo Monitors (BHM) are installed around the CMS rotating shielding. The BHM are designed and built by University of Minnesota, CERN, Princeton University, INFN Bologna and the National Technical University of Athens. (Image: Andrea Manna). The Beam Halo Monitor (BHM) is a set of 20 Cherenkov radiators – 10-cm-long quartz crystals – installed at each end of the huge CMS detector. Their design goal is to measure the particles that can cause the so-called “machine-induced...

  19. LHC magnet support post

    CERN Multimedia

    1995-01-01

    A prototype magnet support for the Large Hadron Collider (LHC). The magnet supports have to bridge a difference in temperature of 300 degrees. Electrical connections, instrumentation and the posts on which the magnets stand are the only points where heat transfer can happen through conduction. They are all carefully designed to draw off heat progressively. The posts are made of 4 mm thick glass-fibre– epoxy composite material. Each post supports 10 000 kg of magnet and leaks just 0.1 W of heat. This piece required a long development period which started in the early ’90s and continued until the end of the decade. The wires next to the support post are wires from strain gauges, which are employed to measure the stress level in the material when the support is mechanically loaded. These supports are mechanically optimized to withstand a weight of up to 100Kn (10 tons) while being as thin as possible to minimize conduction heat to magnets. This is the reason why the stress measurement was extensively done...

  20. LHC on the bus

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    On 15 December, an airport bus will be transformed in the image of CERN. The bus will be seen by the thousands of travellers arriving in Geneva, informing them of the possibility to visit CERN.   Sketch of the bus. The good relationship between Geneva International Airport and CERN started several years ago. In 2004 the airport put advertising space in the arrivals area at CERN's disposal free of charge. Now, starting on 15 December, a 40-foot long bus will display a giant sticker advertisement depicting CERN as it takes passengers over the airport tarmac to their planes. This is no ordinary sticker, and it was no mean task to attach it to the bus. The task of producing and attaching it was entrusted to Geneva-based specialists Mathys SA. With the ski season opening on 15 December, there will be many travellers arriving at the airport, and the bus will be ready to receive them. When one thinks of CERN, the subjects that naturally come to mind are the LHC, the mysteries of the Universe...

  1. Power to the LHC

    CERN Multimedia

    2016-01-01

    It’s March already, and time for the LHC to wake up from its short winter break. The first of 7000 powering tests began on 4 March: the first step on the way to the first beams of 2016. It’s a tight schedule, with the powering tests scheduled for just 12 days before moving on to machine checkout and then commissioning with beam around Easter.   Last year marked a great start to Run 2. The objective for the year was to establish proton-proton collisions at 13 TeV with 25 ns bunch spacing, and in that we were successful, delivering four inverse femtobarns (4 fb-1) of data to the experiments. This was a great result but, to put it into context, the goal for the whole of Run 2 is to deliver 100 fb-1 by the end of 2018, so we still have a long way to go. 2015 was a learning year, and by the time we switched off for the end-of-year break, we had learned a great deal about how to operate this superb machine at the new higher energy, with shorter bunch spacing allowing us to get many ...

  2. LHC Report: Ticking over

    CERN Multimedia

    Mike Lamont for the LHC Team

    2012-01-01

    The past two weeks have seen luminosity production rates vary somewhat but the overall upwards slope has remained steady. Over 17 fb-1 have been delivered to both ATLAS and CMS; LHCb is also doing well, with around 1.6 fb-1 delivered so far in 2012. The proton physics production also slotted in a five-day machine development period (Monday 8 to Saturday 13 October).   When producing the LHC beam in the PS, some parasitic low-intensity satellite bunches are formed 25 ns from the main bunches, which are spaced by 50 ns. ALICE, whose detector is designed to work with relatively low collision rates, has been taking data from satellite-main collisions. The population of these satellites has recently been increased thanks to gentle tweaks by the PS radio frequency experts. This has increased the peak luminosity in ALICE and will help them to reach their proton-proton integrated luminosity goal for the year. The October machine development programme was a mixed bag. While some studies were aimed at sho...

  3. LHC vacuum system

    CERN Document Server

    Gröbner, Oswald

    1999-01-01

    The Large Hadron Collider (LHC) project, now in the advanced construction phase at CERN, comprises two proton storage rings with colliding beams of 7-TeV energy. The machine is housed in the existing LEP tunnel with a circumference of 26.7 km and requires a bending magnetic field of 8.4 T with 14-m long superconducting magnets. The beam vacuum chambers comprise the inner 'cold bore' walls of the magnets. These magnets operate at 1.9 K, and thus serve as very good cryo-pumps. In order to reduce the cryogenic power consumption, both the heat load from synchrotron radiation emitted by the proton beams and the resistive power dissipation by the beam image currents have to be absorbed on a 'beam screen', which operates between 5 and 20 K and is inserted inside the vacuum chamber. The design of this beam screen represents a technological challenge in view of the numerous and often conflicting requirements and the very tight mechanical tolerances imposed. The synchrotron radiation produces strong outgassing from the...

  4. Crystals in the LHC

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    Bent crystals can be used to deflect charged particle beams. Their use in high-energy accelerators has been investigated for almost 40 years. Recently, a bent crystal was irradiated for the first time in the HiRadMat facility with an extreme particle flux, which crystals would have to withstand in the LHC. The results were very encouraging and confirmed that this technology could play a major role in increasing the beam collimation performance in future upgrades of the machine.   UA9 bent crystal tested with a laser. Charged particles interacting with a bent crystal can be trapped in channelling states and deflected by the atomic planes of the crystal lattice (see box). The use of bent crystals for beam manipulation in particle accelerators is a concept that has been well-assessed. Over the last three decades, a large number of experimental findings have contributed to furthering our knowledge and improving our ability to control crystal-particle interactions. In modern hadron colliders, su...

  5. The LHC collimators

    CERN Document Server

    Bertarelli, A

    2004-01-01

    In the framework of the LHC Collimator project, TS department has been assigned the task to design the series collimators and to manufacture prototypes to be tested in summer 2004. Their concept must comply with a very demanding specification, entailing a temperature on the collimating jaws not exceeding 50ºC in steady conditions and an unparalleled overall geometrical stability of 25 micro m on a 1200 mm span, meeting, at the same time, the challenging deadlines required by the project schedule. To respond to these tough and sometimes conflicting constraints, the chosen design appeals to a mixture of traditional and innovative technologies, largely drawing from LEP collimator experience. The specification imposes a low-Z material for the collimator jaws, directing the design towards graphite or such novel materials as 2-D and 3-D Carbon/Carbon composites. An accurate mechanical design has allowed to considerably reduce the mechanical play and to optimize the geometrical stability. The mechanical lay-out a...

  6. LHC Report: Level best

    CERN Multimedia

    Mike Lamont for the LHC team

    2012-01-01

    The LHCb experiment is special: there is a limit to the number of the events the detector can handle per bunch crossing. Consequently the maximum luminosity provided in 2012 has been around 4 x1032 cm-2s-1 (compared to the maximum of 7.7 x1033 cm-2s-1 seen by ATLAS and CMS). Nonetheless LHCb still wants to integrate as much luminosity as possible.    To meet LHCb's requirements a luminosity leveling technique is used. A machine setup is chosen that would give a peak luminosity well above the required maximum if the beams are collided head-on at LHCb's interaction point. This peak luminosity is then reduced to the required maximum by moving the two beams transversely apart at the interaction point. As the beam current goes down during a fill, the beams can be moved together in small increments to keep the collision rate constant throughout the fill. In practice, when the LHC goes into collisions in LHCb, the initial luminosity is safely below LHCb's demanded le...

  7. LHC Report: a record start for LHC ion operation

    CERN Multimedia

    Jan Uythoven for the LHC Team

    2011-01-01

    After the technical stop, the LHC switched over to ion operation, colliding lead-ions on lead-ions. The recovery from the technical stop was very smooth, and records for ion luminosity were set during the first days of ion operation.   The LHC technical stop ended on the evening of Friday, 11 November. The recovery from the technical stop was extremely smooth, and already that same evening ion beams were circulating in the LHC. ‘Stable beams’ were declared the same night, with 2 x 2 bunches of ions circulating in the LHC, allowing the experiments to have their first look at ion collisions this year. However, the next step-up in intensity – colliding 170 x 170 bunches – was postponed due to a vacuum problem in the PS accelerator, so the collisions on Sunday, 13 November were confined to 9 x 9 bunches. The vacuum problem was solved, and on the night of Monday, 14 November, trains of 24 lead bunches were injected into the LHC and 170 x 170 bunches were brough...

  8. LHC collimator controls for a safe LHC operation

    International Nuclear Information System (INIS)

    Redaelli, S.; Assmann, R.; Losito, R.; Donze, M.; Masi, A.

    2012-01-01

    The Large Hadron Collider (LHC) collimation system is designed to protect the machine against beam losses and consists of 108 collimators, 100 of which are movable, located along the 27 km long ring and in the transfer lines. The cleaning performance and machine protection role of the system depend critically on accurate jaw positioning. A fully redundant control system has been developed to ensure that the collimators dynamically follow optimum settings in all phases of the LHC operational cycle. Jaw positions and collimator gaps are interlocked against dump limits defined redundantly as functions of time, beam energy and the β functions, which describe the focusing property of the beams. In this paper, the architectural choices that guarantee a safe LHC operation are presented. Hardware and software implementations that ensure the required performance are described. (authors)

  9. Effet du Pediococcus acidilactici sur le bilan lipidique sanguin du ...

    African Journals Online (AJOL)

    Les résultats relatifs aux performances zootechniques ont montré que l'addition du probiotique a amélioré significativement le gain de poids pendant la phase de croissance se traduisant par un indice de consommation meilleur. Les dosages du cholestérol total, des triglycérides, du HDL et du LDL ont été déterminés à la ...

  10. Scenarios for the LHC Upgrade

    CERN Document Server

    Scandale, Walter

    2008-01-01

    The projected lifetime of the LHC low-beta quadrupoles, the evolution of the statistical error halving time, and the physics potential all call for an LHC luminosity upgrade by the middle of the coming decade. In the framework of the CARE-HHH network three principal scenarios have been developed for increasing the LHC peak luminosity by more than a factor of 10, to values above 1035 cm−2s−1. All scenarios imply a rebuilding of the high-luminosity interaction regions (IRs) in combination with a consistent change of beam parameters. However, their respective features, bunch structures, IR layouts, merits and challenges, and luminosity variation with β∗ differ substantially. In all scenarios luminosity leveling during a store would be advantageous for the physics experiments. An injector upgrade must complement the upgrade measures in the LHC proper in order to provide the beam intensity and brightness needed as well as to reduce the LHC turnaround time for higher integrated luminosity.

  11. Physics at LHC and beyond

    CERN Document Server

    2014-01-01

    The topics addressed during this Conference are as follows. ---An overview of the legacy results of the LHC experiments with 7 and 8 TeV data on Standard Model physics, Scalar sector and searches for New Physics. ---A discussion of the readiness of the CMS, ATLAS, and LHCb experiments for the forthcoming high-energy run and status of the detector upgrades ---A review of the most up-to-date theory outcome on cross-sections and uncertainties, phenomenology of the scalar sector, constraints and portals for new physics. ---The presentation of the improvements and of the expected sensibilities for the Run 2 of the LHC at 13 TeV and beyond. ---A comparison of the relative scientific merits of the future projects for hadron and e+e- colliders (HL-LHC, HE-LHC, ILC, CLIC, TLEP, VHE-LHC) towards precision measurements of the Scalar boson properties and of the Electroweak-Symmetry-Breaking parameters, and towards direct searches for New Physics.

  12. Heavy feet for the LHC

    CERN Document Server

    2003-01-01

    The first 800 jacks (adjustable supports) for one sector of the LHC have arrived from India in recent weeks. After the final acceptance of the preseries jacks at the end of October, they can now be used to support the LHC cryo-magnets. How do you move the weight of eight adult Indian elephants by the breadth of a human hair? If you are a surveyor at CERN who has to adjust the 32 ton LHC dipoles with a resolution of 1/20 of a millimetre, you use the 80 kg jacks which were designed and are being procured by the Centre for Advanced Technology (CAT) in India. The jacks are undergoing final pre-shipment inspection by CAT engineers in India. More than 800 jacks have arrived in recent weeks from India, enough to equip the first sector of the LHC (one octant of the ring). For all the cryo-magnets (dipoles and quadrupoles) of the LHC 7000 jacks are needed in total. They are now being continuously delivered to CERN up to mid-2005. The close collaboration between the Department of Atomic Energy (DAE) in India and CE...

  13. Hybrid beams in the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The first proton-ion beams were successfully circulated in the LHC a couple of weeks ago. Everything went so smoothly that the LHC teams had planned the first p-Pb collisions for Wednesday, 16 November. Unfortunately, a last-minute problem with a component of the PS required for proton acceleration prevented the LHC teams from making these new collisions. However, the way is open for a possible physics run with proton-lead collisions in 2012.   Members of the LHC team photographed when the first hybrid beams got to full energy. The proton and lead beams are visible on the leftmost screen up on the wall (click to enlarge the photo). The technical challenge of making different beams circulate in the LHC is by no means trivial. Even if the machine is the same, there are a number of differences when it is operated with beams of protons, beams of lead or beams of proton and lead. Provided that the beams are equal, irrespective of whether they consist of protons or lead nuclei, they revolve at the...

  14. The LHC and its successors

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    Not too long before the first long technical stop of the LHC, engineers and physicists are already working on the next generation of accelerators: HL-LHC and LHeC. The first would push proton-proton collisions to an unprecedented luminosity rate; the second would give a second wind to electron-proton collisions.   The ring-ring configuration of the LHeC would need this type of magnets, currently being studied for possible future use. In one year, the LHC will begin to change. During the first long shutdown, from December 2012 to late 2014, the machine will go through a first phase of major upgrades, with the objective of running at 7 TeV per beam at the beginning of 2015. With this long technical stop and the two others that will follow (in 2018 and 2022), a new project will see the light of day. Current plans include the study of something that looks more like a new machine rather than a simple upgrade: the High Luminosity LHC (HL-LHC). Much more powerful than the current machine, the HL-...

  15. Technological challenges for the LHC

    CERN Multimedia

    CERN. Geneva; Rossi, Lucio; Lebrun, Philippe; Bordry, Frederick; Mess, Karl Hubert; Schmidt, Rüdiger

    2003-01-01

    For the LHC to provide particle physics with proton-proton collisions at the centre of mass energy of 14 TeV with a luminosity of 1034 cm-2s-1, the machine will operate with high-field dipole magnets using NbTi superconductors cooled to below the lambda point of helium. In order to reach design performance, the LHC requires both, the use of existing technologies pushed to the limits as well as the application of novel technologies. The construction follows a decade of intensive R&D and technical validation of major collider sub-systems. The first lecture will focus on the required LHC performance, and on the implications on the technologies. In the following lectures several examples for LHC technologies will be discussed: the superconducting magnets to deflect and focus the beams, the cryogenics to cool the magnets to a temperature below the lambda point of helium along most of the LHC circumference, the powering system supplying about 7000 magnets connected in 1700 electrical circuits with a total curr...

  16. Le bureau d'études mécaniques du groupe TS-MME

    CERN Document Server

    Menot, C

    2004-01-01

    Le bureau d'études du groupe MME représente le principal support d'ingénierie mécanique pour le LHC et quelques projets autres. Il est constitué de trois sections au mandat distinct. Ses activités couvrent le design des divers équipements : des aimants supraconducteurs du LHC et leur alimentation électrique, le design pour le système vide et de l'instrumentation et calibration de faisceau. Le groupe a aussi en charge le design de tout système se rapportant aux complexes PS et SPS Les principaux sujets présentés dans ce rapport concernent la structure du bureau d'études et son effectif, les ressources à disposition, son domaine d'activité, son mode de fonctionnement, les outils et les méthodologies développés. La coordination entre sections du groupe, qui apportent chacune son expertise, sera mise en évidence. Une vision du futur avec les besoins en ressources liés aux activités vitales pour le CERN est abordée en conclusion.

  17. Computer graphic of LHC in the tunnel

    CERN Multimedia

    1996-01-01

    A computer-generated image of the LHC particle accelerator at CERN in the tunnel originally built for the LEP accelerator that was closed in 2000. The cross-section of an LHC superconducting dipole magnet is also seen.

  18. The HL-LHC accelerator physics challenges

    CERN Document Server

    Fartoukh, S

    2014-01-01

    We review the conceptual baseline of the HL-LHC project, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

  19. The HL-LHC Accelerator Physics Challenges

    Science.gov (United States)

    Fartoukh, S.; Zimmermann, F.

    The conceptual baseline of the HL-LHC project is reviewed, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

  20. The HL-LHC accelerator physics challenges

    CERN Document Server

    Fartoukh, S

    2015-01-01

    The conceptual baseline of the HL-LHC project is reviewed, putting into perspective the main beam physics challenges of this new collider in comparison with the existing LHC, and the series of solutions and possible mitigation measures presently envisaged.

  1. Dashboard for the LHC experiments

    International Nuclear Information System (INIS)

    Andreeva, J; Cirstoiu, C; Miguel, M D F D; Ivanchenko, A; Gaidioz, B; Herrala, J; Janulis, M; Maier, G; Maguire, E J; Rivera, R P; Rocha, R; Saiz, P; Sidorova, I; Belov, S; Berejnoj, A; Kodolova, O; Chen, Y; Chen, T; Chiu, S; Munro, C

    2008-01-01

    In this paper we present the Experiment Dashboard monitoring system, which is currently in use by four Large Hadron Collider (LHC) experiments. The goal of the Experiment Dashboard is to monitor the activities of the LHC experiments on the distributed infrastructure, providing monitoring data from the virtual organization (VO) and user perspectives. The LHC experiments are using various Grid infrastructures (LCG/EGEE, OSG, NDGF) with correspondingly various middleware flavors and job submission methods. Providing a uniform and complete view of various activities like job processing, data movement and publishing, access to distributed databases regardless of the underlying Grid flavor is the challenging task. In this paper we will describe the Experiment Dashboard concept, its framework and main monitoring applications

  2. The LHC road at CERN

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    To explore the 1 TeV energy scale where fundamental particle interactions should encounter new conditions, two major routes were proposed - a high magnetic field proton collider in the LEP tunnel, dubbed LHC for Large Hadron Collider, and the CERN Linear Collider (CLIC) to supply beams of electrons and positrons. Exploratory studies have shown that while CLIC remains a valid long-term goal, LHC appears as the most cost-effective way for CERN to enter the 1 TeV arena. High-field superconducting magnet prototype work demonstrates that a 'two-in-one' design supplying the 10 tesla fields needed to handle LHC's 8 TeV proton beams (collision energy 16 TeV) is a practical proposition. (orig./HSI).

  3. The first LHC insertion quadrupole

    CERN Multimedia

    2004-01-01

    An important milestone was reached in December 2003 at the CERN Magnet Assembly Facility. The team from the Accelerator Technology - Magnet and Electrical Systems group, AT-MEL, completed the first special superconducting quadrupole for the LHC insertions which house the experiments and major collider systems. The magnet is 8 metres long and contains two matching quadrupole magnets and an orbit corrector, a dipole magnet, used to correct errors in quadrupole alignment. All were tested in liquid helium and reached the ultimate performance criteria required for the LHC. After insertion in the cryostat, the superconducting magnet will be installed as the Q9 quadrupole in sector 7-8, the first sector of the LHC to be put in place in 2004. Members of the quadrupole team, from the AT-MEL group, gathered around the Q9 quadrupole at its inauguration on 12 December 2003 in building 181.

  4. The LHC inauguration in pictures

    CERN Multimedia

    2008-01-01

    The LHC inauguration ceremony was a memorable experience for everyone who attended. On Tuesday 21 October the ceremony hall, SMA18, was filled with over 1500 invited guests, VIPs included Swiss President Pascal Couchepin, French Prime Minister François Fillon and several ministers from CERN’s Member States and around the world. You can watch a video of the highlights of the ceremony at http://cds.cern.ch/record/1136012 The Heads of Delegations from all the Member and Observer States pose with the Director-General. "The LHC is a marvel of modern technology, which would not have been possible without the continuous support of our Member States," said the Director-General in his opening speech. "This is an opportunity for me to thank them on behalf of the world’s particle physics community." The LHC inauguration ceremony officially marked the end of 24 years of conception, development, constru...

  5. The LHC goes 3G

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    A new telecommunications network has been installed in the LHC tunnel to facilitate operations during the long shutdown. Anyone using a smartphone, tablet or laptop computer will now be able to access the Internet from the tunnel.   Results of a download (green) and upload (yellow) test carried out in the LHC tunnel using the new Universal Mobile Telecommunications System (UMTS). The first long shutdown has officially begun, and the teams are about to enter the various tunnels around the Laboratory. It’s a good opportunity to talk telecommunications. As you can well imagine, even the highest of high-tech smartphones remains stubbornly silent and unresponsive 100 metres below the ground. Except at CERN… The IT-CS Group has implemented an impressive state-of-the-art solution to tackle this problem - a new Universal Mobile Telecommunications System (UMTS), better known as “3G”, covering the entire 27-km circumference of the LHC tunnel. Established on th...

  6. Inclusive production at LHC energies

    International Nuclear Information System (INIS)

    Merino, C.; Pajares, C.; Shabelski, Yu.M.

    2011-01-01

    We consider the first LHC data for pp collisions in the framework of Regge theory. The integral cross sections and inclusive densities of secondaries are determined by the Pomeron exchange, and we present the corresponding predictions for them. The first measurements of inclusive densities in the midrapidity region are in agreement with these predictions. The contribution of the baryon-number transfer due to String Junction diffusion in the rapidity space is at the origin of the differences in the inclusive spectra of particle and antiparticle in the central region, and this effect could be significant at LHC energies. We discuss the first data of ALICE and LHCb collaborations on the baryon/antibaryon asymmetry at LHC. (orig.)

  7. Parton distributions with LHC data

    DEFF Research Database (Denmark)

    Ball, R.D.; Deans, C.S.; Del Debbio, L.

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinati......We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF...... fraction of the proton. We also present collider PDF sets, constructed using only data from HERA, the Tevatron and the LHC, but find that this data set is neither precise nor complete enough for a competitive PDF determination....

  8. Les mots du jazz

    OpenAIRE

    Roueff, Olivier

    2007-01-01

    L’ouvrage d’André Schaeffner constitue la première analyse savante du jazz (1926). Il a marqué une étape importante dans le processus de réinvention du jazz en France en contribuant notamment, par sa réception et les polémiques qu’il a suscitées, à transformer l’identification du jazz d’une musique « américaine » à une musique « noire-américaine » (c’est-à-dire aux « racines » africaines). Les analyses proposées dans cet ouvrage, alors qu’elles désignaient des musiques que la critique de jazz...

  9. Searches for SUSY at LHC

    International Nuclear Information System (INIS)

    Kharchilava, A.

    1997-01-01

    One of the main motivations of experiments at the LHC is to search for SUSY particles. The talk is based on recent analyses, performed by CMS Collaboration, within the framework of the Supergravity motivated minimal SUSY extension of the Standard Model. The emphasis is put on leptonic channels. The strategies for obtaining experimental signatures for strongly and weakly interacting sparticles productions, as well as examples of determination of SUSY masses and model parameters are discussed. The domain of parameter space where SUSY can be discovered is investigated. Results show, that if SUSY is of relevance at Electro-Weak scale it could hardly escape detection at LHC. (author)

  10. HL-LHC tracking challenge

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    We organize on the Kaggle platform a data science competition to stimulate both the ML and HEP communities to renew core tracking algorithms in preparation of the next generation of particle detectors at the LHC. In a nutshell : one event has 100.000 3D points ; how to associate the points onto 10.000 unknown approximately helicoidal trajectories ? avoiding combinatorial explosion ? you have a few seconds. But we do give you 100.000 events to train on. We ran ttbar+200 minimum bias event into ACTS a simplified (yet accurate) simulation of a generic LHC silicon detectors, and wrote out the reconstructed hits, with matching truth. ...

  11. Diffraction dissociation at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Jenkovszky, Laszlo [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680, Ukraine and Wigner Research Centre for Physics, Hungarian Academy of Sciences 1525 Budapest, POB 49 (Hungary); Orava, Risto [Institute of Physics, Division of Elementary Particle Physics, P.O. Box 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki, Finland and CERN, CH-1211 Geneva 23 (Switzerland); Salii, Andrii [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680 (Ukraine)

    2013-04-15

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  12. Diffraction dissociation at the LHC

    International Nuclear Information System (INIS)

    Jenkovszky, László; Orava, Risto; Salii, Andrii

    2013-01-01

    We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

  13. Searching dark matter at LHC

    International Nuclear Information System (INIS)

    Nojiri, Mihoko M.

    2007-01-01

    We now believe that the dark matter in our Universe must be an unknown elementary particle, which is charge neutral and weakly interacting. The standard model must be extended to include it. The dark matter was likely produced in the early universe from the high energy collisions of the particles. Now LHC experiment starting from 2008 will create such high energy collision to explore the nature of the dark matter. In this article we explain how dark matter and LHC physics will be connected in detail. (author)

  14. fibrosarcome du larynx

    African Journals Online (AJOL)

    pie du lit tumoral est employée comme complément thé- rapeutique [9] alors que la chimiothérapie est générale- ment indiquée dans les formes métastatiques. Le pronos- tic dépend essentiellement du degré de différentiation his- tologique. En fait, le fibrosarcome bien différencié est caractérisé par la fréquence de récidive ...

  15. du Chott Marouane

    African Journals Online (AJOL)

    plancton de 90 µm de vide de maille. Ils ont été conservés dans du formol à 5%. L'identification de l'espèce est basée sur des critères morphologiques [20]: la forme des furcas, les lobes frontaux des antennes des mâles, de l'organe copulateur (pénis) et du sac ovigère. Le comptage des soies furcales a été réalisé. L'étude ...

  16. LHC Report: The beam is back at the LHC

    CERN Multimedia

    Reyes Alemany

    2015-01-01

    A series of sector beam tests paved the way for the start-up of the LHC in 2008 and 2009. These tests and the follow-up of the issues that arose were part of the process that led to a smooth start-up with beam.   Given this experience, sector tests were scheduled to take place several weeks before the 2015 start-up. On the weekend of 6-9 March, beam from the SPS was injected into both LHC injection regions, followed by a first pass through the downstream LHC sectors. For the clockwise LHC beam (called “beam 1”) this meant passing through ALICE and into Sector 2-3, while the anticlockwise beam (called “beam 2”) was threaded through LHCb and all the way from Point 8 to Point 6, where it was extracted by the beam dump kickers onto the beam dump block. The dry runs in the previous weeks were mainly targeted at preparation for the sector tests. The systems tested included: injection, timing, synchronisation and beam instrumentation. The beam interlock ...

  17. High Luminosity LHC (HL-LHC) general infographics

    CERN Multimedia

    Landua, Fabienne

    2016-01-01

    The High-Luminosity LHC, which is expected to be operational after 2025, will increase the LHC’s luminosity by a factor of 10. To achieve this major upgrade, several technologies, some of which are completely innovative, are being developed.

  18. From the LHC to Future Colliders

    DEFF Research Database (Denmark)

    De Roeck, A.; Ellis, J.; Grojean, C.

    2010-01-01

    Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300/fb of integrated luminosity, of the proposed sLHC luminosity up...

  19. Budker INP in the LHC Machine (2)

    CERN Multimedia

    2001-01-01

    The main BINP contributions to the LHC machine are magnets for transfer lines (26 MCHF) and bus- bar sets (23 MCHF). Budker INP is also responsible for construction of some other LHC magnets and vacuum parts. In total, the contribution to the LHC machine will reach about 90 MCHF.

  20. Le LHC peut-il produire des trous noirs?

    CERN Document Server

    Chardin, Gabriel

    2009-01-01

    Dan Simmons, dans son ouvrage Ilium, imagine que les physiciens de l'Institut de Paris, à la suite d'une malencontreuse expérience, ont laissé s'échapper un trou noir microscopique qui, avant de se précipiter vers le centre de la Terre, a détruit une part non négligeable de Paris, appelé désormais « Paris Crater ». Les physiciens de tous pays rassemblés au CERN autour du LHC, le plus puissant accélérateur de particules au monde, sont-ils des apprentis sorciers et pourraient-ils déclencher la destruction de la Terre, voire de l’Univers entier ?

  1. LHC Report: Back in operation

    CERN Multimedia

    2016-01-01

    With the machine back in their hands since Friday, 4 March, the LHC operators are now performing the powering tests on the magnets. This is a crucial step before receiving the first beams and restarting Run 2 for physics.   A Distribution Feed-Box (DFB) brings power to the LHC magnets and maintains the stability of the current in the superconducting circuits. The LHC was the last machine to be handed back to operators after the completion of maintenance work carried out during the Year-End Technical Stop (YETS) that had started on 14 December 2015. During the eleven weeks of scheduled maintenance activities, several operations took place in all the accelerators and beam lines. They included the maintenance in several points of the cryogenic system, the replacement of 18 magnets in the Super Proton Synchrotron; an extensive campaign to identify and remove thousands of obsolete cables; the replacement of the LHC beam absorbers for injection (TDIs) that are used to absorb the SPS b...

  2. LHC machine: Status and plan

    International Nuclear Information System (INIS)

    Pojer, M.

    2013-01-01

    The LHC Run I was successfully concluded in March 2012. An incredible amount of data has been collected and the performance continuously improved during these three years. Important information on the limitations of the machine also emerged, which will be used to further increase the potential of the machine in the coming years. (authors)

  3. Perturbative QCD for the LHC

    International Nuclear Information System (INIS)

    Glover, N.

    2008-01-01

    The need for predictions of standard model processes at the LHC at leading order and beyond is motivated. Recent developments in computing scattering amplitudes are reviewed. I describe the limitations of tree-level predictions, and how they may be improved at next-to-leading order. The current status of the field is discussed. (author)

  4. LHC Report: focus on luminosity

    CERN Document Server

    Reyes Alemany Fernandez for the LHC team

    2016-01-01

    The intensity ramp-up of the LHC beams resumed last Friday after the main powering system of the PS accelerator was put back in service.    The image above shows the last twenty four hours of fill #4947 in the machine. The LHC operations team kept the beams of this fill in the machine for a record 35 and a half hours.  Beams are back in the LHC. On Friday, the accelerator resumed the intensity ramp-up, reaching 1752 bunches per beam last week-end. The intensity ramp-up was interrupted on 20 May because of a problem with the PS’s main power supply (see box). A steady increase in the total number of bunches per beam is required to check out all aspects of beam operation and make sure the LHC is fully safe before the nominal number of bunches per beam can be brought into collision. At present, four intensity steps have been completed: 313, 601, 889, and 1177 bunches per beam. The qualification of the next step with 1752 bunches is in progress. At every s...

  5. LHC and the neutrino paradigm

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of L-R symmetric theories, which predicted neutrino mass long before experiment and led to the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. I also discuss the collider signatures of the three types of seesaw mechanism, and show how in the case of Type II one can measure the PMNS mixing matrix at the LHC, complementing the low energy probes. Finally, I give an example of a simple realistic SU(5) grand unified theory that predicts the hybrid Type I + III seesaw with a weak fermion triplet at the LHC energies. The seminar will be fol...

  6. Post-LHC accelerator magnets

    International Nuclear Information System (INIS)

    Gourlay, Stephen A.

    2001-01-01

    The design and practicality of future accelerators, such as hadron colliders and neutrino factories being considered to supercede the LHC, will depend greatly on the choice of superconducting magnets. Various possibilities will be reviewed and discussed, taking into account recent progress and projected improvements in magnet design and conductor development along with the recommendations from the 2001 Snowmass workshop

  7. LHC physics: challenges for QCD

    OpenAIRE

    Frixione, S.

    2003-01-01

    I review the status of the comparisons between a few measurements at hadronic colliders and perturbative QCD predictions, which emphasize the need for improving the current computations. Such improvements will be mandatory for a satisfactory understanding of high-energy collisions at the LHC

  8. Higgs physics at the LHC

    CERN Document Server

    Mariotti, Chiara

    2017-01-01

    The first measurements of the mass, the width, and the couplings of the newly discovered Higgs boson at LHC at 7 and 8 TeV center of mass energy will be reviewed. Recent results at 13 TeV center of mass energy will be presented. Finally, searches for additional Higgs bosons in models beyond the standard model will be summarised.

  9. Parton distributions with LHC data

    NARCIS (Netherlands)

    Ball, Richard D.; Bertone, Valerio; Carrazza, Stefano; Deans, Christopher S.; Debbio, Luigi Del; Forte, Stefano; Guffanti, Alberto; Hartland, Nathan P.; Latorre, Jose I.; Rojo, Juan; Ubiali, Maria

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF

  10. The history of the LHC

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    Abstract: From the civil engineering, to the manufacturing of the various magnet types, each building block of this extraordinary machine required ambitious leaps in innovation. This lecture will review the history of the LHC project, focusing on the many challenges -- scientific, technological, managerial -- that had to be met during the various phases of R&D, industrialization, construction, installation and commissioning.

  11. LHC: Past, Present, and Future

    CERN Document Server

    Landsberg, Greg

    2013-01-01

    In this overview talk, I give highlights of the first three years of the LHC operations at high energy, spanning heavy-ion physics, standard model measurements, and searches for new particles, which culminated in the discovery of the Higgs boson by the ATLAS and CMS experiments in 2012. I'll discuss what we found about the properties of the new particle in 10 months since the discovery and then talk about the future LHC program and preparations to the 2015 run at the center-of-mass energy of ~13 TeV. These proceedings are meant to be a snapshot of the LHC results as of May 2013 - the time of the conference. Many of the results shown in these proceedings have been since updated (sometimes significantly) just 4 months thereafter, when these proceedings were due. Nevertheless, keeping this writeup in sync with the results shown in the actual talk has some historical value, as, for one, it tells the reader how short is the turnaround time to update the results at the LHC. To help an appreciation of this fact, I b...

  12. SPS in training for LHC

    CERN Document Server

    2003-01-01

    On 8 and 9 September the new beam extraction system of the SPS and the downstream transfer line were successfully commissioned and tested. Using this extraction, a beam will be sent towards LHC in 2004 and to the CNGS facility in 2006.

  13. Keeping the LHC in power

    CERN Multimedia

    CERN Bulletin

    2013-01-01

    The critical safety equipment around the LHC, including the machine protection systems, is connected to Uninterruptible Power Supplies (UPS).  In case of mains failure, the UPS systems continue to power, for a limited time, these critical systems and ensure a safe shutdown of the accelerator. This week, work began to upgrade and replace over 100 UPS systems in the LHC.   The new UPS installations. For the LHC, even a perturbation on the mains is more than just an inconvenience: it often results in beam dumps and, in some cases, requires an energy extraction from superconducting circuits. When this occurs, machine protection systems, and in particular the Quench Protection System, must remain active to correctly carry out the shutdown procedure. With the UPS systems, 10 minutes of crucial power can be provided to the protection systems during this critical phase. There are currently two UPS systems in place in each one of the 32 LHC UPS zones. Originally one was used as a backup if ...

  14. LHC magnets: the great descent

    CERN Multimedia

    2005-01-01

    A first dipole magnet was delivered to its final location in the LHC tunnel on Monday, 7 March. This achievement coincides with another important milestone in the installation of the future collider, the completion of the delivery of half the dipole magnets.

  15. Connecting LHC, ILC, and quintessence

    International Nuclear Information System (INIS)

    Chung, Daniel J.H.; Everett, Lisa L.; Kong, Kyoungchul; Matchev, Konstantin T.

    2007-01-01

    If the cold dark matter consists of weakly interacting massive particles (WIMPs), anticipated measurements of the WIMP properties at the Large Hadron Collider (LHC) and the International Linear Collider (ILC) will provide an unprecedented experimental probe of cosmology at temperatures of order 1 GeV. It is worth emphasizing that the expected outcome of these tests may or may not be consistent with the picture of standard cosmology. For example, in kination-dominated quintessence models of dark energy, the dark matter relic abundance can be significantly enhanced compared to that obtained from freeze out in a radiation-dominated universe. Collider measurements then will simultaneously probe both dark matter and dark energy. In this article, we investigate the precision to which the LHC and ILC can determine the dark matter and dark energy parameters under those circumstances. We use an illustrative set of four benchmark points in minimal supergravity in analogy with the four LCC benchmark points. The precision achievable together at the LHC and ILC is sufficient to discover kination-dominated quintessence, under the assumption that the WIMPs are the only dark matter component. The LHC and ILC can thus play important roles as alternative probes of both dark matter and dark energy

  16. Parton distributions with LHC data

    CERN Document Server

    Ball, Richard D.; Carrazza, Stefano; Deans, Christopher S.; Del Debbio, Luigi; Forte, Stefano; Guffanti, Alberto; Hartland, Nathan P.; Latorre, Jose I.; Rojo, Juan; Ubiali, Maria

    2013-01-01

    We present the first determination of parton distributions of the nucleon at NLO and NNLO based on a global data set which includes LHC data: NNPDF2.3. Our data set includes, besides the deep inelastic, Drell-Yan, gauge boson production and jet data already used in previous global PDF determinations, all the relevant LHC data for which experimental systematic uncertainties are currently available: ATLAS and LHCb W and Z lepton rapidity distributions from the 2010 run, CMS W electron asymmetry data from the 2011 run, and ATLAS inclusive jet cross-sections from the 2010 run. We introduce an improved implementation of the FastKernel method which allows us to fit to this extended data set, and also to adopt a more effective minimization methodology. We present the NNPDF2.3 PDF sets, and compare them to the NNPDF2.1 sets to assess the impact of the LHC data. We find that all the LHC data are broadly consistent with each other and with all the older data sets included in the fit. We present predictions for various ...

  17. A table-top LHC

    CERN Multimedia

    Barbara Warmbein

    2011-01-01

    Many years ago, when ATLAS was no more than a huge empty underground cavern and Russian artillery shell casings were being melted down to become part of the CMS calorimetry system, science photographer Peter Ginter started documenting the LHC’s progress. He was there when special convoys of equipment crossed the Jura at night, when cranes were lowering down detector slices and magnet coils were being wound in workshops. Some 18 years of LHC history have been documented by Ginter, and the result has just come out as a massive coffee table book full of double-page spreads of Ginter’s impressive images.   The new coffee table book, LHC: the Large Hadron Collider. Published by the Austrian publisher Edition Lammerhuber in cooperation with CERN and UNESCO Publishing, LHC: the Large Hadron Collider is an unusual piece in the company’s portfolio. As the publisher’s first science book, LHC: the Large Hadron Collider weighs close to five kilos and comes in a s...

  18. PHOBOS in the LHC era

    Energy Technology Data Exchange (ETDEWEB)

    Steinberg, Peter, E-mail: peter.steinberg@bnl.gov

    2015-01-15

    The PHOBOS experiment ran at the RHIC collider from 2000 to 2005, under the leadership of Wit Busza. These proceedings summarize selected PHOBOS results, highlighting their continuing relevance amidst the wealth of new results from the lead–lead program at the Large Hadron Collider (LHC)

  19. Dark Matter Searches at LHC

    CERN Document Server

    Terashi, Koji; The ATLAS collaboration

    2017-01-01

    This talk will present dark matter searches at the LHC in the PIC2017 conference. The main emphasis is placed on the direct dark matter searches while the interpretation of searches for SUSY and invisible Higgs signals for the dark matter is also presented.

  20. ELECTRONICS FOR CALORIMETERS AT LHC

    International Nuclear Information System (INIS)

    Radeka, V.

    2001-01-01

    Some principal design features of front-end electronics for calorimeters in experiments at the LHC will be highlighted. Some concerns arising in the transition from the research and development and design phase to the construction will be discussed. Future challenges will be indicated

  1. les cahiers du cread

    African Journals Online (AJOL)

    Our Journal “les cahiers du cread” is a quarterly economic review publishing original findings of empirical research and theoretical debates on fields pertaining to our mission coverage (Macro Economics, Industrial Economics and Firms, Human Development & Social Economics, Agriculture & Environment). Other websites ...

  2. LHC Accelerator Fault Tracker - First Experience

    CERN Document Server

    Apollonio, Andrea; Roderick, Chris; Schmidt, Ruediger; Todd, Benjamin; Wollmann, Daniel

    2016-01-01

    Availability is one of the key performance indicators of LHC operation, being directly correlated with integrated luminosity production. An effective tool for availability tracking is a necessity to ensure a coherent capture of fault information and relevant dependencies on operational modes and beam parameters. At the beginning of LHC Run 2 in 2015, the Accelerator Fault Tracking (AFT) tool was deployed at CERN to track faults or events affecting LHC operation. Information derived from the AFT is crucial for the identification of areas to improve LHC availability, and hence LHC physics production. For the 2015 run, the AFT has been used by members of the CERN Availability Working Group, LHC Machine coordinators and equipment owners to identify the main contributors to downtime and to understand the evolution of LHC availability throughout the year. In this paper the 2015 experience with the AFT for availability tracking is summarised and an overview of the first results as well as an outlook to future develo...

  3. Logistique de transport pour le projet LHC enseignements des premiers secteurs

    CERN Document Server

    Prodon, S

    2003-01-01

    Ce papier dresse un premier bilan de la logistique de transport mise en place pour l'installation du LHC. Les moyens de planification mis en oeuvre seront tout d'abord évoqués avec notamment les réunions avec les groupes utilisateurs, l'élaboration de procédures de transport, la génération de listings d'articles à transporter ou encore l'établissement d'un planning des ressources. Cependant, les premiers travaux d'installation du LHC ont fait apparaître des divergences importantes entre le planning logistique établi et la réalité du terrain. Ces écarts seront analysés, qu'il s'agisse de différences sur le volume de matériel à acheminer, d'opérations non planifiées, de changements de plannings entraînant de longues et délicates traversées de chantiers ou de manque de planification des besoins en personnel dans certaines zones. Tous ces enseignements acquis au cours des premiers travaux devraient permettre de dégager des voies d'amélioration à mettre en place pour les prochains secteur...

  4. Comparaison du filtre adaptatif RIF et du filtre a base de reseau de ...

    African Journals Online (AJOL)

    Comparaison du filtre adaptatif RIF et du filtre a base de reseau de neurones pour le filtrage du courant de reference pour la commande du filtre actif parallele. C Benachaiba, A Bassou, B Mazari ...

  5. Avancement des travaux électriques LHC point 1

    CERN Document Server

    Delidais, M

    2001-01-01

    Après la première phase d'analyse des principes de la distribution en électricité de la zone 1 du LHC et de l'expérience ATLAS, les études sont à présent orientées vers la définition des implantations des principaux équipements tels que transformateurs, tableaux basse tension, alimentations statiques de sécurité, ainsi que vers la détermination du cheminement des câbles dans les ouvrages de surface et à travers les ouvrages souterrains USA15, UX15 et les galeries de liaison. Les études des services généraux sont également menées pour les bâtiments de surface qui seront mis prochainement à disposition par le génie civil, en particulier la station de refroidissement SF1 ainsi que le bâtiment SUX1 pour lesquels les travaux d'installation devraient débuter sous peu pour être achevés dans le premier trimestre 2001.

  6. Cent troisième session du Conseil du CERN

    CERN Multimedia

    CERN Press Office. Geneva

    1995-01-01

    From the lowest energy levels at ISOLDE to the highest at LHC, the Director-General reported a successful year. The accelerators worked better than ever, and the LHC's baseline design was finalised. ISOLDE produces radioactive beams for applications in nuclear physics, particle and astrophysics, solid state physics, atomic physics, biology, and medicine.

  7. LHC? Of course we’ve heard of the LHC!

    CERN Multimedia

    2009-01-01

    Well, more or less. After its first outing in Meyrin (see last Bulletin issue), our street poll hits the streets of Divonne-les-Bains and the corridors of the University of Geneva. While many have heard of the LHC, the raison d’être of this "scientific whatsit" often remains a mystery.On first questioning, the "man-in-the-street" always pleads ignorance. "Lausanne Hockey Club?" The acronym LHC is not yet imprinted on people’s minds. "Erm, Left-Handed thingamajig?" But as soon as we mention the word "CERN", the accelerator pops straight into people’s minds. Variously referred to as "the circle" or "the ring", it makes you wonder whether people would have been so aware of the LHC if it had been shaped like a square. Size is another thing people remember: "It’s the world’s biggest. Up to now…" As for its purpose, well that’s another kettle of fish. &...

  8. LHC Report: Beams are back in the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The LHC has shaken itself awake after the winter break, and, as the snow melts on the lower slopes, the temperature in the magnets has dropped to a chilly 1.9 K once more.   Following the cool-down, the last few weeks have seen an intense few tests of the magnets, power supplies and associated protection systems. These tests, referred to as hardware commissioning, have been completed in record time. At the same time the other accelerator systems have been put through the preparatory machine checkout. In parallel, the injectors (LINAC2, Booster, PS and SPS) have also come out of the technical stop in order to prepare to deliver beam to the LHC very early in the season. Of particular note here was the remarkably seamless transition to POPS, the PS's new main power supply system. All this work culminated in the LHC taking beam again for the first time in 2011 on Saturday, 19 February. The careful preparation paid off, with circulating beams being rapidly re-established. There then followed a programme ...

  9. Le ministre du Commerce international du Canada rencontre des ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    17 juil. 2017 ... La promotion de l'entrepreneuriat, la façon dont le commerce peut profiter aux femmes et à leur famille, et la création d'emplois pour les plus vulnérables étaient au coeur de la discussion en table ronde du ministre du Commerce international du Canada, l'honorable François-Philippe Champagne, et des ...

  10. Portage vaginal du streptocoque du groupe B chez la femme ...

    African Journals Online (AJOL)

    Introduction: le streptocoque du groupe B est le principal agent impliqué dans les infections materno-fœtales, les septicémies et les méningites du nouveau-né à terme. L'objectif est de déterminer le taux de portage maternel du streptocoque du groupe B (SGB) à terme. Méthodes: un prélèvement vaginal a été réalisé de ...

  11. Aux origines du monde

    CERN Multimedia

    2004-01-01

    "C'est l'histoire d'une aventure humaine, scientifique, international qui a vu le jour il y a cinquante ans, aux confins de la Suisse et du département de l'Ain. Le plus grand laboratoire de physique des particules du monde, le Cern, a été fondé en 1954. Les festivités organisées à l occasion de cet anniversaire connaîtront leur point d'orgue le 16 octobre prochain, avec portes-ouvertes, accueil de personallités et inauguration d'un monumnet spécifique, le Globe de l'innovation" (2 pages)

  12. CHOEUR DU CERN

    CERN Multimedia

    CHOEUR DU CERN

    2010-01-01

    Les répétitions du chœur du CERN reprendront le mercredi 15 septembre à 20.00 heures à l’amphithéâtre principal – bâtiment 500. Au programme la préparation de notre concert de Noël avec la Missa Brevis, KV115, de Léopold Mozart et de la musique de Noël d’Europe. Les personnes qui aiment chanter, notamment des sopranes et des ténors, sont les bienvenues. Pour tout contact s’adresser à : Baudouin Bleus - (tél.CERN 767 82 44) -(baudouin.bleus@cern.ch) ou Martin Gatehouse ( martin.gatehouse@wanadoo.fr) ou Jean-Paul Diss (jean-pauldiss@wanadoo.fr).  

  13. LHC beam energy in 2012

    International Nuclear Information System (INIS)

    Siemko, A.; Charifouline, Z.; Dahlerup-Petersen, K.; Denz, R.; Ravaioli, E.; Schmidt, R.; Verweij, A.

    2012-01-01

    The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. The measurements performed in 2009 in the whole machine, in particular in sector 3-4 during the repair after the 2008 accident, demonstrated that there is a significant fraction of defective copper bus bar joints in the machine. In this paper, the limiting factors for operating the LHC at higher energies with defective 13 kA bus bar joints are briefly reviewed. The experience gained during the 2011 run, including the quench statistics and dedicated quench propagation tests impacting on maximum safe energy are presented. The impact of the by-pass diode contact resistance issue is also addressed. Finally, a proposal for running at the highest possible safe energy compatible with the pre-defined risk level is presented. (authors)

  14. Electroweak Physics at the LHC

    CERN Document Server

    Sommer, Philip; The ATLAS collaboration

    2018-01-01

    With the large integrated luminosities recorded at the LHC and the excellent understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. A review of the measurement of the $W$ boson mass by the ATLAS Collaboration as well as a new measurement of the electroweak mixing angle with the CMS detector are presented. Special emphasis is put on a discussion of the modelling uncertainties and the potential of the latest low-$\\mu$ runs, recorded at the end of 2017 by both collaboration. In addition, the latest measurements of multi-boson final states as well as the electroweak production of single gauge bosons at 13 TeV are summarised. The study of these processes can be used to constrain anomalous gauge couplings in an effective field theory approach, allowing to bridge tests of the electroweak sector of the Standard Models also to Higgs boson production.

  15. Electroweak Physics at the LHC

    CERN Document Server

    Sommer, Philip; The ATLAS collaboration

    2018-01-01

    With the high integrated luminosities recorded at the LHC and the very good understanding of the LHC detectors, it is possible to measure electroweak observables to the highest precision. In this talk, we review the measurement of the W boson mass by the ATLAS Collaboration as well as the new measurement of the electroweak mixing angle with the CMS detector. Special focus is drawn on a discussion of the modeling uncertainties and the physics potential of the latest low-mu runs, recorded at the end of 2017 by both collaboration. In addition, we will present the latest measurements of multi-boson final states as well as the electroweak production of single gauge bosons at 13 TeV. The study of these processes can be used to constrain anomalous gauge couplings in an effective field theory approach, allowing to bridge tests of the electroweak sector of the Standard Models also to the Higgs-boson production.

  16. Slice of LHC dipole wiring

    CERN Multimedia

    Dipole model slice made in 1994 by Ansaldo. The high magnetic fields needed for guiding particles around the Large Hadron Collider (LHC) ring are created by passing 12’500 amps of current through coils of superconducting wiring. At very low temperatures, superconductors have no electrical resistance and therefore no power loss. The LHC is the largest superconducting installation ever built. The magnetic field must also be extremely uniform. This means the current flowing in the coils has to be very precisely controlled. Indeed, nowhere before has such precision been achieved at such high currents. 50’000 tonnes of steel sheets are used to make the magnet yokes that keep the wiring firmly in place. The yokes constitute approximately 80% of the accelerator's weight and, placed side by side, stretch over 20 km!

  17. Operational beams for the LHC

    CERN Document Server

    Papaphilippou, Y.; Rumolo, G.; Manglunki, D.

    2014-01-01

    The variety of beams, needed to set-up in the injectors as requested in the LHC, are reviewed, in terms of priority but also performance expectations and reach during 2015. This includes the single bunch beams for machine commissioning and measurements (probe, Indiv) but also the standard physics beams with 50 ns and 25 ns bunch spacing and their high brightness variants using the Bunch Compression Merging and Splitting (BCMS) scheme. The required parameters and target performance of special beams like the doublet for electron cloud enhancement and the more exotic 8b$\\oplus$4e beam, compatible with some post-scrubbing scenarios are also described. The progress and plans for the LHC ion production beams during 2014-2015 are detailed. Highlights on the current progress of the setting up of the various beams are finally presented with special emphasis on potential performance issues across the proton and ion injector chain.

  18. Reliability issues at the LHC

    CERN Multimedia

    CERN. Geneva. Audiovisual Unit; Gillies, James D

    2002-01-01

    The Lectures on reliability issues at the LHC will be focused on five main Modules on five days. Module 1: Basic Elements in Reliability Engineering Some basic terms, definitions and methods, from components up to the system and the plant, common cause failures and human factor issues. Module 2: Interrelations of Reliability & Safety (R&S) Reliability and risk informed approach, living models, risk monitoring. Module 3: The ideal R&S Process for Large Scale Systems From R&S goals via the implementation into the system to the proof of the compliance. Module 4: Some Applications of R&S on LHC Master logic, anatomy of risk, cause - consequence diagram, decomposition and aggregation of the system. Module 5: Lessons learned from R&S Application in various Technologies Success stories, pitfalls, constrains in data and methods, limitations per se, experienced in aviation, space, process, nuclear, offshore and transport systems and plants. The Lectures will reflect in summary the compromise in...

  19. LHC Beam Energy in 2012

    CERN Document Server

    Siemko, A; Dahlerup-Petersen, K; Denz, R; Ravaioli, E; Schmidt, R; Verweij, A

    2012-01-01

    The interconnections between the LHC main magnets are made of soldered joints (splices) of two superconducting cables stabilized by a copper bus bar. The measurements performed in 2009 in the whole machine, in particular in sector 3-4 during the repair after the 2008 accident, demonstrated that there is a significant fraction of defective copper bus bar joints in the machine. In this paper, the limiting factors for operating the LHC at higher energies with defective 13 kA bus bar joints are briefly reviewed. The experience gained during the 2011 run, including the quench statistics and dedicated quench propagation tests impacting on maximum safe energy are presented. The impact of the by-pass diode contact resistance issue is also addressed. Finally, a proposal for running at the highest possible safe energy compatible with the pre-defined risk level is presented.

  20. The LHC at the AAAS

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The American Association for the Advancement of Science held its annual meeting in the Walter E. Washington Convention Center in Washington D.C. last week.   Veteran science writer Tim Radford introduces LHC scientists during a media briefing at the AAAS annual meeting. Left to right: Felicitas Pauss, Tom LeCompte, Yves Schutz and Nick Hadley. As the world’s largest popular science meeting, the AAAS meeting is a major event in the calendar of science journalists.  At this year’s LHC session, CERN’s coordinator for international relations, Felicitas Pauss, opened the discussion, paving the way for Tom LeCompte of ATLAS, Joe Incandela of CMS, Yves Schutz of ALICE and Monica Pepe-Altarelli of LHCb to report on the status of the first year’s analysis from their experiments.    

  1. Photodetection in the LHC experiments

    International Nuclear Information System (INIS)

    Joram, C.

    2012-01-01

    The challenging requirements on photodetection in the LHC experiments have motivated large-scale R and D efforts on various detector technologies, which started already in the 1990s. The state-of-the-art of the LEP era would not have allowed satisfying the demanding needs, particularly from calorimetry and particle identification. After almost two decades of intense development, construction and integration efforts, the LHC and its four major experiments are performing in a just exemplary manner, in many respects exceeding the expectations. Hundreds of thousands of photodetectors with millions of readout channels contribute to this success story. This article aims at reviewing the main activities in photodetection, the initial achieved performance as well as some consolidation and first upgrade efforts.

  2. LHC technical data goes mobile

    CERN Multimedia

    Jordan Juras

    2010-01-01

    The Computerized Maintenance Management System (CMMS), which has been in use at CERN for many years, has recently been enhanced with an innovative new feature for managing and exploiting existing information regarding the LHC: a system to read the barcodes on the LHC components and easily obtain data and information on the many thousands of items of equipment that make up the accelerator. The feature will eventually be made available for any other scientific instrumentation located at CERN.   Example of a magnet's barcode Systems like CERN's CMMS, which is based on an Enterprise Asset Management (EAM) system from Infor, are today standard practice in organizations managing large volumes of information about their facilities. However, the way in which CERN has adapted its system is rather unique: the CMMS not only manages the manufacturing, installation, maintenance and disposal of the components of CERN’s infrastructure but now has the potential to provide equipment information interact...

  3. Beam Loss Monitors at LHC

    CERN Document Server

    Dehning, B.

    2016-01-01

    One of the main functions of the LHC beam loss measurement system is the protection of equipment against damage caused by impacting particles creating secondary showers and their energy dissipation in the matter. Reliability requirements are scaled according to the acceptable consequences and the frequency of particle impact events on equipment. Increasing reliability often leads to more complex systems. The downside of complexity is a reduction of availability; therefore, an optimum has to be found for these conflicting requirements. A detailed review of selected concepts and solutions for the LHC system will be given to show approaches used in various parts of the system from the sensors, signal processing, and software implementations to the requirements for operation and documentation.

  4. Hepatiques du Surinam

    NARCIS (Netherlands)

    Jovet-Ast, S.

    1957-01-01

    Il n’existe pas, actuellement, de catalogue des Hépatiques du Surinam. Les Hépatiques de ce pays restent très peu connues. Cependant, certaines ont attiré l’attention des Bryologues et ont été citées dans quelques ouvrages anciens ou récents. Je ne ferai pas ici une révision complète de ces

  5. (l.) Medik du Maroc

    African Journals Online (AJOL)

    PR BOKO

    Résumé. Dipcadi serotinum (L.) Medik, est une plante de la famille des Hyacinthaceae, elle est largement utilisée comme réchauffant et aussi pour combattre la jaunisse. Cette plante trouve une large utilisation par la population de la région côtière du Maroc. À notre connaissance l'huile essentielle de cette espèce n'a ...

  6. Études sur la reconstruction des électrons et mesure de la section efficace de production de paires de quarks top dans les canaux dileptoniques dans l’expérience ATLAS auprès du LHC

    CERN Document Server

    Theveneaux-Pelzer, Timothée

    The LHC produced proton-proton collision data with 7 TeV of center of mass energy corresponding to an integrated luminosity of 40 pb-1 in 2010 and of 5 fb-1 in 2011. The data collected by ATLAS have led to the validation the understanding of the detector, to the evaluation of its performance and to many measurements of physical quantities. In this context the top quark is a privileged field of study for TeV scale physics as well as for performance studies. After a reminder of the phenomenology of the standard model the first part of this thesis is devoted to the description of the detector and in particular of the liquid argon calorimeters for which the influence of the variations of the high voltage values is detailed. The second part is focused on studies about the reconstruction and the identification of electrons conducted on simulated data, but also on 2010 collision data thanks to J/psi->e+e- events with the tag-and-probe method. The last part is devoted to top quark studies. A description of the...

  7. The TOTEM project at LHC

    International Nuclear Information System (INIS)

    Buenerd, M.

    1996-01-01

    The TOTEM (TOTal cross section and Elastic scattering Measurement) collaboration at the LHC aims at measuring the total, elastic scattering over a large range of 4-momentum transfer, and single diffractive scattering and double Pomeron exchange cross sections in proton-proton collisions at 10 to 14 TeV center of mass energies. The physics motivations are outlined, the beam optics requirements are presented together with a first solution for a dedicated insertion. The instrumental aspects are only quoted qualitatively. (author)

  8. LHC magnet quench protection system

    Science.gov (United States)

    Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

    1994-07-01

    The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called 'cold diode' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements - so called 'cold diodes'. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a 'natural' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages.

  9. LHC magnet quench protection system

    International Nuclear Information System (INIS)

    Coull, L.; Hagedorn, D.; Remondino, V.; Rodriguez-Mateos, F.

    1994-01-01

    The quench protection system for the superconducting magnets of the CERN Large Hadron Collider (LHC) is described. The system is based on the so called ''cold diode'' concept. In a group of series connected magnets if one magnet quenches then the magnetic energy of all the magnets will be dissipated in the quenched magnet so destroying it. This is avoided by by-passing the quenched magnet and then rapidly de-exciting the unquenched magnets. For the LHC machine it is foreseen to use silicon diodes situated inside the cryostat as by-pass elements--so called ''cold diodes''. The diodes are exposed to some 50 kGray of radiation during a 10 year operation life-time. The high energy density of the LHC magnets (500 kJ/m) coupled with the relatively slow propagation speed of a ''natural'' quench (10 to 20 m/s) can lead to excessive heating of the zone where the quench started and to high internal voltages. It is therefore necessary to detect quickly the incipient quench and fire strip heaters which spread the quench out more quickly over a large volume of the magnet. After a quench the magnet chain must be de-excited rapidly to avoid spreading the quench to other magnets and over-heating the by-pass diode. This is done by switching high-power energy-dump resistors in series with the magnets. The LHC main ring magnet will be divided into 16 electrically separated units which has important advantages

  10. Discovery Physics at the LHC

    CERN Document Server

    Höcker, A

    2006-01-01

    Introductory lecture to the phenomenology of, and the LHC search for physics beyond the Standard Model (BSM). The first lecture discusses the empirical and theoretical reasons that require BSM physics, and how Supersymmetry, extra dimension and little Higgs models can cope with these. The second lecture introduces the experimental approaches adopted by ATLAS and CMS to search for BSM physics signals, and to measure some of their properties.

  11. LHC Detectors and Early Physics

    CERN Document Server

    Dissertori, Guenther

    2010-01-01

    In this review I sketch the basic criteria and boundary conditions which have guided the design of the LHC detectors. The discussion will concentrate on the so-called general-purpose experiments, ATLAS and CMS. After an overview of the detector's characteristics and performance, I will elaborate on the expected measurements of hard processes, with emphasis on jet and vector boson production, i.e., tests of Quantum Chromodynamics (QCD) and Electroweak Physics.

  12. In Particular: Podcasting the LHC

    CERN Document Server

    Holmes, Tova Ray; The ATLAS collaboration

    2016-01-01

    "In Particular" is a podcast about physics and the process of discovering physics at the high energy frontier. Produced by members of the ATLAS Collaboration, the show tells the stories of particle physics from the ground level. Aimed at science enthusiasts interested in understanding what drives LHC physicists and what their work entails, "In Particular" gives a voice directly to the researchers. Details about the philosophy, production, and goals of the show will be presented.

  13. La mesure du danger

    CERN Document Server

    Manceron, Vanessa; Revet, Sandrine

    2014-01-01

    La mesure du danger permet d’explorer des dangers de nature aussi diverse que la délinquance, la pollution, l’écueil maritime, la maladie ou l’attaque sorcellaire, l’extinction d’espèces animales ou végétales, voire de la Planète tout entière. Au croisement de la sociologie, de l’anthropologie et de l’histoire, les différents articles analysent les pratiques concrètes de mesure pour tenter de comprendre ce qui se produit au cours de l’opération d’évaluation du danger sans préjuger de la nature de celui-ci. L’anthropologie a contribué à la réflexion sur l’infortune en s’intéressant aux temporalités de l’après : maladies, catastrophes, pandémies, etc. et en cherchant à rendre compte de l’expérience des victimes, de leur vie ordinaire bouleversée, de la recomposition du quotidien. Elle s’intéresse aussi aux autres types de mesures, les savoirs incorporés, qui reposent sur l’odorat, la vue ou le toucher et ceux qui ressortent d’une épistémologie « non ...

  14. The LHC magnets' trip underground

    CERN Multimedia

    2002-01-01

    Buildings SMI 2 and SDI 2 are currently a big blue construction at the end of the Meyrin site. When they are finished, in 2003, they will be the departure point from where the magnets for the LHC will be lowered down into the tunnel. View of the new building at the end of the Meyrin site. If you live in neighbouring France, you have probably noticed a new blue steel construction that has changed the view from Saint Genis Pouilly since last March. It's the first of two contiguous buildings, SMI 2 and SDI 2, which will make it possible to prepare and lower the 1232 dipole magnets, the 400 short straight sections and some 60 insertion magnets down into the TI2 tunnel, and from there, to their final location in the LHC tunnel. According to Paul Faugeras, Technical Co-ordinator for the LHC machine, 'the installation of the magnets will start in early 2004, and hopefully everything will be done by October 2006'. The first part of the magnets' journey will take place on surface. The 15 metre-long dipole magnets a...

  15. Half way round the LHC

    CERN Multimedia

    CERN Bulletin

    The LHC operations teams are preparing the machine for circulating beams and things are going very smoothly. ALICE and LHCb are getting used to observing particle tracks coming from the LHC beams. During the weekend of 7-8 November, CMS also  saw its first signals from beams dumped just upstream of  the experiment cavern.   Operators in the CMS control room observe the good performance of their detector. Particles are smoothly making their way around the 27 km circumference of the LHC. Last weekend (7-8 November), the first bunches of injection energy protons completed their journey (anti-clockwise) through three octants of the LHC’s circumference and were dumped in a collimator just before entering the CMS cavern. The particles produced by the impact of the protons on the tertiary collimators (used to stop the beam) left their tracks in the calorimeters and the muon chambers of the experiment. The more delicate inner detectors were switched off for protection reasons....

  16. The LHC quench protection system

    CERN Multimedia

    2009-01-01

    The new quench protection system (QPS) has the crucial roles of providing an early warning for any part of the superconducting coils and busbars that develop high resistance, as well as triggering the switch-off of the machine. Over 2000 new detectors will be installed around the LHC to make sure every busbar segment between magnets is monitored and protected. One of the major consolidation activities for the LHC is the addition of two new detectors to the quench protection system. A magnet quench occurs when part of the superconducting cable becomes normally-conducting. When the protection system detects an increased resistance the huge amount of energy stored in the magnet chains is safely extracted and ‘dumped’ into specially designed resistors. In the case of the main dipole chain, the stored energy in a single LHC sector is roughly the same as the kinetic energy of a passenger jet at cruising speed. The first new detector is designed to monitor the superconducting...

  17. Heatwave warning for the LHC

    CERN Multimedia

    Anaïs Schaeffer

    2013-01-01

    Engineers have been able to start warming up the first sectors of the LHC where the tests on the superconductor circuits have been completed. Raising the temperature from 1.9 K to 300 K is a remarkable but delicate process.   Filling the first liquid-helium truck for external storage. The first update on LS1, published in the previous edition of the Bulletin, announced the start of the Electrical Quality Assurance (ElQA) tests on the LHC magnets. These tests began on 22 February and have already been completed in two Sectors: “The integrity of the magnets’ electrical insulation has been fully verified in sectors 4-5 and 5-6,” reports Mirko Pojer, Engineer in Charge of the LHC. “This is vital in order for the magnets to function properly at the nominal current, which we should reach in 2015. The ElQA team has also run other tests, in particular to verify the electrical insulation between the coils. Fortunately, we have not detected any major problems so...

  18. Latest news from the LHC

    CERN Document Server

    CERN Bulletin

    2010-01-01

    Last week the LHC passed the threshold of 3 pb-1 total integrated luminosity delivered to the experiments, of which about half was delivered in just one week. These excellent results were achieved by operating the machine with up to 50 nominal bunches per beam.   After a very successful week that saw intense beams circulating for long periods (a total of 76.5 hours of stable beams, corresponding to about 40% of the time), there has been a technical stop this week. Over the coming days, experts will work on bunch trains with 150 ns spacing between bunches (the current minimum spacing is 1000 ns). This will involve making the necessary changes throughout the injector chain, as well as in the LHC itself. In the LHC, bunch trains imply working with a crossing angle throughout the machine cycle, in order to avoid unwanted parasitic collisions, which means that the whole process of injection, ramp and squeeze will have to be re-commissioned. The task also includes re-commissioning all the protection syste...

  19. LHC gets the ball rolling

    CERN Multimedia

    2007-01-01

    A technique involving a small ball with a transmitter embedded inside it has been successfully tested in Sector 7-8. The ball is sent through the LHC beam pipes to check the LHC interconnections. The multidisciplinary team responsible for the RF ball project to check the interconnections. From left to right: Rhodri Jones (AB/BI), Eva Calvo (AB/BI), Francesco Bertinelli (AT/MCS), Sonia Bartolome Jimenez (TS/IC), Sylvain Weisz (TS/IC), Paul Cruikshank (AT/VAC), Willemjan Maan (AT/VAC), Alain Poncet (AT/MCS), Marek Gasior (AB/BI). During the tests the ball is inserted very carefully into the vacuum chamber.A game of ping-pong at the LHC? On 13 September a rather unusual test was carried out in Sector 7-8 of the accelerator. A ball just a bit smaller than a ping-pong ball was carefully introduced into one of the accelerator’s two vacuum pipes, where it travelled 800 metres in the space of a few mi...

  20. Cryogenics for HL-LHC

    Science.gov (United States)

    Tavian, L.; Brodzinski, K.; Claudet, S.; Ferlin, G.; Wagner, U.; van Weelderen, R.

    The discovery of a Higgs boson at CERN in 2012 is the start of a major program of work to measure this particle's properties with the highest possible precision for testing the validity of the Standard Model and to search for further new physics at the energy frontier. The LHC is in a unique position to pursue this program. Europe's top priority is the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with an objective to collect ten times more data than in the initial design, by around 2030. To reach this objective, the LHC cryogenic system must be upgraded to withstand higher beam current and higher luminosity at top energy while keeping the same operation availability by improving the collimation system and the protection of electronics sensitive to radiation. This chapter will present the conceptual design of the cryogenic system upgrade with recent updates in performance requirements, the corresponding layout and architecture of the system as well as the main technical challenges which have to be met in the coming years.

  1. LHC Report: a brief deceleration

    CERN Multimedia

    Rossano Giachino & Markus Albert

    2015-01-01

    The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, an earth fault developed in the main dipole circuit. Full evaluation of the situation is ongoing.   The various systems are put through their operational paces from the CCC. This includes important tests of the beam dump system and full-scale tests of the beam interlock system (BIS) and its many inputs from other systems around the ring. All magnetic circuits are driven through the ramp, squeeze, ramp-down, and pre-cycle along with the collimators and RF. Instrumentation, feedbacks, and the control system are also stress tested. Inevitably there is some final frantic debugging but, up to now, things seem to be in reasonable shape. The machine checkout is an important coming together of all LHC systems. During this final phase before beam, the operations team tests all of the LHC subsystem...

  2. LHC Report: Timeout is over!

    CERN Multimedia

    Jan Uythoven for the LHC Team

    2012-01-01

    Over the last two weeks the LHC has been collecting luminosity at a steady pace, but not delivering the canonical 1 fb-1 per week. This is because machine timeouts were necessary to solve some beam-stability problems. Also, the beam development programme was moved forward, taking advantage of a timeout caused by an emergency ramp-down of the CMS solenoid magnet. With all these problems solved and with good injector performance, the past week has seen the LHC back to new record luminosities.   Previous LHC reports have mentioned that the peak luminosity at the beginning of the “stable beams” period had gone down by about 10% with respect to previous records. This is explained by the reduction of bunch intensities, as higher bunch intensities were leading to beam instabilities and important beam losses. When beams become unstable, octupole magnets can be used to correct them. These magnets can be powered at two different polarities and several days were needed to find new optimu...

  3. Switch on to the LHC!

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The LHC is preparing to collide beams at 3.5 TeV for the first time ever! Be part of the event and follow live what goes on at the world’s most powerful particle accelerator by connecting to LHC1. Hereafter we give you a key to understand the display as well as a typical event display from the ATLAS and CMS experiments. Click on the image to enlarge it 1. This is the energy of beams. 1 TeV=1000 GeV. The LHC set the energy world’s record of 3.48 TeV per beam, today, 19 March 2010. 2. Intensity of, respectively, B1 (blue) and B2 (red). 3. The information in these boxes can vary. Operators display the graphs that are relevant to the specific operation. 4. Most of the flags are set automatically. They provide a quick summary of the machine status. In order to have collisions the ‘Stable Beams’ flag must be set to green. 5. Here operators write down their messages to the experiments. Often, they write the ongoing activity, followed by the plan for the coming hou...

  4. The LHC on an envelope

    CERN Multimedia

    2007-01-01

    The series of envelopes featuring CERN issued this summer was a huge success. The French postal services of the Pays de Gex will shortly be launching the second set of pre-paid envelopes issued in collaboration with the Laboratory this year, this time highlighting the LHC. Five thousand envelopes describing the accelerator’s capabilities will go on sale on 12 November, and some of the packs will even contain a small sample of the cables from the heart of the LHC magnets. The sets of ten pre-paid envelopes will tell you everything about CERN’s flagship accelerator, from its astounding technical capabilities to its spin-offs in the fields of technology and human resources. Each envelope will feature a different attribute or spin-off of the LHC. People will be invited to consult CERN’s public website for more detailed explanations if they want to know more. The new envelopes will be available from five post offices in the Pays ...

  5. The LHC in an envelope

    CERN Multimedia

    2007-01-01

    The series of envelopes featuring CERN issued this summer was a huge success. The French postal services of the Pays de Gex will shortly be launching the second set of pre-paid envelopes issued in collaboration with the Laboratory this year, this time highlighting the LHC. Five thousand envelopes describing the accelerator’s capabilities will go on sale on 12 November, and some of the packs will even contain a small sample of the cables from the heart of the LHC magnets. The sets of ten pre-paid envelopes will tell you everything about CERN’s flagship accelerator, from its astounding technical capabilities to its spin-offs in the fields of technology and human resources. Each envelope will feature a different attribute or spin-off of the LHC. People will be invited to consult CERN’s public website for more detailed explanations if they want to know more. The new envelopes will be available from five post offices in the Pays de Gex (Ferney-Voltaire, Prévessin...

  6. Warmer amps for the LHC

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    CERN is working together with an Italian company to develop superconducting cables that can function at temperatures of up to 25 K (-248°C). This will make it possible to move LHC magnet power supplies out of the tunnel, protecting them from exposure to the showers of very high-energy particles produced by the accelerator.   Figure 1: devices of this type, which measure approximately 10 metres in length, are inserted between the accelerating magnets at different points along the LHC. When it comes to consuming electricity, the magnets that steer particles through large accelerators can be characterised with just one word: greedy. For the LHC, the total current can reach 1.5 million amps. At the present time, this current is brought in via copper cables of up to 10 cm in diameter. In the tunnel, these cables connect the current leads - which provide the transition between the ambient-temperature cables and the magnets in their bath of superfluid helium - to the power supply. In the a...

  7. Detector technologies for LHC experiments

    CERN Document Server

    Hansl-Kozanecka, Traudl

    1999-01-01

    Abstract The Large Hadron Collider (LHC) at CERN will provide proton-proton collisions ata centre-of-mass energy of 14 TeV with a design luminosity of 10^34cm^-2s^-1. The exploitation of the rich physics potential is illustrated using the expected performance of the two general-purpose detectors ATLAS and CMS.The lecture introduces the physics motivation for experiments at the LHC energy.The design parameters and expected performance of the LHC machine are then discussed, followed by the design objectives for the detectors. The technical solutions are presented for each detector system (calorimetry, muon system, inner tracker, trigger). For each system the requirements, the technology choices and the achieved and expected performance are discussed. Lectures given at Herbstschule fu:r Hochenergiephysik, Maria Laach, 1999Copies of the transparencies are available in reduced format (black-and-white) from the secretariats of ATLAS and CMS (1999-093 Talk). A full-size colour version is available for consultation.e...

  8. QCD@LHC International Conference

    CERN Document Server

    2016-01-01

    The particle physics groups of UZH and ETH will host the QCD@LHC2016 conference (22.8.-26.8., UZH downtown campus), which is part of an annual conference series bringing together theorists and experimentalists working on hard scattering processes at the CERN LHC, ranging from precision studies of Standard Model processes to searches for new particles and phenomena. The format of the conference is a combination of plenary review talks and parallel sessions, with the latter providing a particularly good opportunity for junior researchers to present their results. The conference will take place shortly after the release of the new data taken by the LHC in sping 2016 at a collision energy of 13TeV, expected to more than double the currently available data set. It will be one of the first opportunities to discuss these data in a broader context, and we expect the conference to become a very lively forum at the interface of phenomenology and experiment.

  9. The latest from the LHC

    CERN Multimedia

    2009-01-01

    Work on closing up sectors in the LHC tunnel. The foreseen shutdown work on the LHC is proceeding well, including the powering tests with the new quench protection system. However, during the past week vacuum leaks have been found in two "cold" sectors of the LHC. The leaks were found in Sectors 8-1 and 2-3 while they were being prepared for the electrical tests on the copper stabilizers at around 80 K. In both cases the leak is at one end of the sector, where the electrical feedbox, DFBA, joins Q7, the final magnet in the sector. Unfortunately, the repair necessitates a partial warm-up of both sectors. This involves the end sub-sector being warmed to room temperature, while the adjacent sub-sector "floats" in temperature and the remainder of the sector is kept at 80 K. As the leak is from the helium circuit to the insulating vacuum, the repair work will have no impact on the vacuum in the beam pipe. However the intervention wil...

  10. Important step towards the LHC

    CERN Document Server

    2001-01-01

    The TI2 tunnel, one of the two tunnels that will transfer protons from the SPS to the LHC, broke through into the LEP/LHC ring on 15 May. TI2 will carry clockwise-moving protons from under the Laboratory's West Area to Point 2, future home of the ALICE experiment. It is coming up to 16:00 on 15 May and a group of some 50 people, fully kitted out in boots, helmets, and masks is intently watching a point on the wall in front of them. They are down in the LEP/LHC tunnel waiting for civil engineers to excavate the last few centimetres separating them from the TI2 transfer tunnel. The noise of machines begins, and just five minutes later the wall comes tumbling down. The excavator breaks through right on target, bringing a two-year project to a happy conclusion. Later, the survey team published the outstanding result that the tunnel junction was made within 6 millimetres of target. TI2 measures 2648 metres in length and three metres in diameter. Around 32,000 cubic metres of rock have been excavated to make it, so...

  11. LHC Inner Triplet Powering Strategy

    CERN Document Server

    Bordry, Frederick

    2001-01-01

    In order to achieve a luminosity in excess of 10**34 cm**-2s**-1 at the Large Hadron Collider (LHC), special high gradient quadrupoles are required for the final focusing triplets. These low-b triplets, located in the four experimental insertions (ATLAS, CMS, ALICE, LHC-B), consist of four wide-aperture superconducting magnets: two outer quadrupoles, Q1 and Q3, with a maximum current of 7 kA and a central one divided into two identical magnets, Q2a and Q2b, with a maximum current of 11.5 kA. To optimise the powering of these mixed quadrupoles, it was decided to use two nested high-current power converters : [8kA, 8V] and [6kA, 8V]. This paper presents the consequence of the interaction between the two galvanically coupled circuits. A control strategy, using two independent, standard, LHC digital controllers, to decouple the two systems is proposed and described. The converter protection during the discharge of the magnet energy due to quenches or interlocks of the magnets are discussed. Simulation and experim...

  12. CERN Technical Training Programme: Learning for the LHC ! Cotations selon les normes GPS de l'ISO - French version only

    CERN Document Server

    Davide Vitè

    2002-01-01

    Suite à la proposition du Groupe de travail « Mechanical Design » du Technical Training, et dans le cadre des activités de construction du LHC, nous allons offrir prochainement une séance en français du cours Cotations selon les normes GPS de l'ISO les 29 et 30 avril prochains. Le coût du cours est pour l'instant fixé à 400.- CHF, mais il pourrait être réduit suivant le nombre de participants. Les objectifs de cette formation sont la maîtrise du tolérancement géométrique ISO décrit dans les normes GPS (Spécifications Géométriques des Produits), et une correcte démarche, par la suite, pour la cotation des produits. Le cours est ciblé pour une audience de projeteurs et dessinateurs devant concevoir, dimensionner et tolérancer des pièces mécaniques, et pour ...

  13. Robust Tracking at the High Luminosity LHC

    CERN Document Server

    Woods, Natasha Lee; The ATLAS collaboration

    2018-01-01

    The High Luminosity LHC (HL-LHC) aims to increase the LHC data-set by an order of magnitude in order to increase its potential for discoveries. Starting from the middle of 2026, the HL-LHC is expected to reach the peak instantaneous luminosity of 7.5×10^34cm^-2s^-1 which corresponds to about 200 inelastic proton-proton collisions per beam crossing. To cope with the large radiation doses and high pileup, the current ATLAS Inner Detector will be replaced with a new all-silicon Inner Tracker. In this talk the expected performance of tracking and vertexing with the HL-LHC tracker is presented. Comparison is made to the performance with the Run2 detector. Ongoing developments of the track reconstruction for the HL-LHC are also discussed.

  14. Review of LHC dark matter searches

    International Nuclear Information System (INIS)

    Kahlhoefer, Felix

    2017-02-01

    This review discusses both experimental and theoretical aspects of searches for dark matter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting dark matter signals. A special emphasis is placed on the interplay between LHC dark matter searches and other kinds of dark matter experiments, as well as among different types of LHC searches.

  15. Gravitino LSP scneario at the LHC

    International Nuclear Information System (INIS)

    Heisig, Jan

    2010-05-01

    In this thesis we discuss the phenomenology of the gravitino LSP scenario at the large hadron collider (LHC) experiment. We concentrate on a long-lived stau NLSP which gives rise to a prominent signature in the LHC detector as a 'slow muon'. We discuss the production channels and compute the cross sections for direct production via the Drell-Yan process. On this basis we claim a conservative estimation of the discovery potential for this scenario at the LHC. (orig.)

  16. Review of LHC dark matter searches

    Energy Technology Data Exchange (ETDEWEB)

    Kahlhoefer, Felix

    2017-02-15

    This review discusses both experimental and theoretical aspects of searches for dark matter at the LHC. An overview of the various experimental search channels is given, followed by a summary of the different theoretical approaches for predicting dark matter signals. A special emphasis is placed on the interplay between LHC dark matter searches and other kinds of dark matter experiments, as well as among different types of LHC searches.

  17. QCD and hard diffraction at the LHC

    International Nuclear Information System (INIS)

    Albrow, Michael G.; Fermilab

    2005-01-01

    As an introduction to QCD at the LHC I given an overview of QCD at the Tevatron, emphasizing the high Q 2 frontier which will be taken over by the LHC. After describing briefly the LHC detectors I discuss high mass diffraction, in particular central exclusive production of Higgs and vector boson pairs. I introduce the FP420 project to measure the scattered protons 420 m downstream of ATLAS and CMS

  18. Highlights from LHC experiments and future perspectives

    International Nuclear Information System (INIS)

    Campana, P.

    2016-01-01

    The experiments at LHC are collecting a large amount of data in a kinematic of the (x, Q 2 ) variables never accessed before. Boosted by LHC analyses, Quantum Chromodynamics (QCD) is experiencing an impressive progress in the last few years, and even brighter perspectives can be foreseen for the future data taking. A subset of the most recent results from the LHC experiments in the area of QCD (both perturbative and soft) are reviewed

  19. LHC computing (WLCG) past, present, and future

    CERN Document Server

    Bird, I G

    2016-01-01

    The LCG project, and the WLCG Collaboration, represent a more than 10-year investment in building and operating the LHC computing environment. This article gives some of the history of how the WLCG was constructed and the preparations for the accelerator start-up. It will discuss the experiences and lessons learned during the first 3 year run of the LHC, and will conclude with a look forwards to the planned upgrades of the LHC and the experiments, discussing the implications for computing.

  20. Physics programmes of the restarted LHC

    International Nuclear Information System (INIS)

    Tokushuku, Katsuo

    2011-01-01

    Experimental programs at the Large Hadron Collider (LHC) have started. On March 30th in 2010, proton beams collided at 7 TeV in the LHC, at the highest center-of-mass energy the humankind has ever produced. The machine will be operated almost continuously until the end of 2011, providing many collision data to explore new physics in the TeV region. The LHC has recovered from the unfortunate helium-leak incident in September 2009. In this article, after describing the history of the consolidation works in the LHC, physics prospects from the 2 year run are discussed. (author)

  1. The LHC access system LACS and LASS

    CERN Document Server

    Ninin, P

    2005-01-01

    The LHC complex is divided into a number of zones with different levels of access controls.Inside the interlocked areas, the personnel protection is ensured by the LHC Access System.The system is made of two parts:the LHC Access Safety System and the LHC Access Control System. During machine operation,the LHC Access Safety System ensures the collective protection of the personnel against the radiation hazards arising from the operation of the accelerator by interlocking the LHC key safety elements. When the beams are off, the LHC Access Control System regulates the access to the accelerator and its many subsystems.It allows a remote, local or automatic operation of the access control equipment which verifies and identifies all users entering the controlled areas.The global architecture of the LHC Access System is now designed and is being validated to ensure that it meets the safety requirements for operation of the LHC.A pilot installation will be tested in the summer 2005 to validate the concept with the us...

  2. Abort Gap Cleaning for LHC Run 2

    Energy Technology Data Exchange (ETDEWEB)

    Uythoven, Jan [CERN; Boccardi, Andrea [CERN; Bravin, Enrico [CERN; Goddard, Brennan [CERN; Hemelsoet, Georges-Henry [CERN; Höfle, Wolfgang [CERN; Jacquet, Delphine [CERN; Kain, Verena [CERN; Mazzoni, Stefano [CERN; Meddahi, Malika [CERN; Valuch, Daniel [CERN; Gianfelice-Wendt, Eliana [Fermilab

    2014-07-01

    To minimize the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.

  3. LHC related projects and studies - Part (II)

    International Nuclear Information System (INIS)

    Rossi, L.; De Maria, R.

    2012-01-01

    The session was devoted to address some aspects of the HL-LHC (High Luminosity LHC) project and explore ideas on new machines for the long term future. The session had two parts. The former focused on some of the key issues of the HL-LHC projects: beam current limits, evolution of the collimation system, research plans for the interaction region magnets and crab cavities. The latter explored the ideas for the long term future projects (LHeC and HE-LHC) and how the current research-development program for magnets and RF structures could fit in the envisaged scenarios

  4. Physics possibilities at LHC/SSC

    International Nuclear Information System (INIS)

    Hinchliffe, I.

    1991-01-01

    This document reviews some recent work on physics simulations for SSC/LHC. Included are reviews of some of the recent developments in physics simulations for the SSC/LHC and comments upon the requirements that are placed upon detectors by the need to extract specific physics signatures. The material in the various EOI/LOI documents submitted to the SCC Laboratory and the work done at the Aachen LHC workshop are discussed. In the following discussion 1 SSC (LHC) year corresponds to an integrated luminosity of 10 (100) fb -1 . 41 refs., 14 figs

  5. LHC crab-cavity aspects and strategy

    International Nuclear Information System (INIS)

    Calaga, R.; Tomas, R.; Zimmermann, F.

    2010-01-01

    The 3rd LHC Crab Cavity workshop (LHC-CC09) took place at CERN in October 2009. It reviewed the current status and identified a clear strategy towards a future crab-cavity implementation. Following the success of crab cavities in KEK-B and the strong potential for luminosity gain and leveling, CERN will pursue crab crossing for the LHC upgrade. We present a summary and outcome of the variousworkshop sessions which have led to the LHC crab-cavity strategy, covering topics like layout, cavity design, integration, machine protection, and a potential validation test in the SPS.

  6. Abort Gap Cleaning for LHC Run 2

    CERN Document Server

    Uythoven, J; Bravin, E; Goddard, B; Hemelsoet, GH; Höfle, W; Jacquet, D; Kain, V; Mazzoni, S; Meddahi, M; Valuch, D

    2015-01-01

    To minimise the beam losses at the moment of an LHC beam dump the 3 μs long abort gap should contain as few particles as possible. Its population can be minimised by abort gap cleaning using the LHC transverse damper system. The LHC Run 1 experience is briefly recalled; changes foreseen for the LHC Run 2 are presented. They include improvements in the observation of the abort gap population and the mechanism to decide if cleaning is required, changes to the hardware of the transverse dampers to reduce the detrimental effect on the luminosity lifetime and proposed changes to the applied cleaning algorithms.

  7. SUSY confronts LHC results - LHC results confront SUSY?

    International Nuclear Information System (INIS)

    Feigl, B.; Zeppenfeld, D.; Rzenak, H.

    2014-01-01

    Two of the key points of the LHC research program are searches for supersymmetry on the one hand and Higgs boson searches on the other hand. Though usually treated separately, if supersymmetry is realized in nature, the searches might be entangled. We first give a brief status of the validity of supersymmetric models. Then we discuss how Higgs boson searches might be affected by the existence of supersymmetric particles not yet directly detected. We focus on the search channels with the Higgs boson decay mode H → WW where data driven background estimation methods are applied. (authors)

  8. Mise en oeuvre des protections électriques dans les réseaux de distribution du CERN

    CERN Document Server

    Delidais, M

    2002-01-01

    Depuis 1957, date de la création de la première sous-station électrique du CERN, le réseau électrique a connu une constante évolution en relation avec l'extension du laboratoire et à la réalisation des nouvelles machines ainsi qu'à une évolution rapide du matériel de distribution électrique ; ce vaste réseau construit sur une période de plus de 40 ans subit encore de profondes transformations et extensions liées au projet LHC et à son adaptation à l'ouverture du marché européen de l'énergie à la concurrence. Les dispositifs de protection des réseaux CERN ont du s'adapter à ces évolutions et aux progrès réalisés dans le domaine des relais de protection, en particulier avec l'introduction des relais électroniques dans les années 1975 puis en 1994 avec la venue des systèmes utilisant les microprocesseurs et des outils de programmation. La transformation des équipements de protection d'origine vers les systèmes actuels sont mis en évidence tant du point de vue du matériel lui-mê...

  9. Archives: les cahiers du cread

    African Journals Online (AJOL)

    Items 1 - 24 of 24 ... Archives: les cahiers du cread. Journal Home > Archives: les cahiers du cread. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives. 1 - 24 of 24 Items. 2016 ...

  10. Le commerce du Nord

    OpenAIRE

    Pourchasse, Pierrick; Bouëdec, Gérard Le

    2015-01-01

    Au XVIIIe siècle, la France s'approvisionne abondamment dans les pays du Nord : bois, chanvre et goudron de la Baltique, tonnellerie de Poméranie, pêche de rogue de Norvège, graines de lin de Courlande, barres de fer suédois… Sa balance commerciale est pourtant positive grâce aux sels, aux vins et surtout des nouvelles marchandises coloniales. Or, la plupart des transactions passent par l’incontournable intermédiaire hollandais. Les explications sur l’absence des Français dans le Nord sont re...

  11. La voie du Centre

    OpenAIRE

    2017-01-01

    Après avoir quelque peu louvoyé dans un discours apparemment anarchique où les souvenirs semblent se bousculer sans autre fil conducteur que la référence obsédante au mal satanique, brusquement le narrateur annonce un événement primordial : Foi um fato que se deu, um dia, se abriu. O primeiro. Depois o senhor verá por quê, me devolvendo minha razão (79). Cette introduction situe la rencontre du Menino comme fondatrice d’un destin dont il reviendrait au narrataire de dégager les enchaînements....

  12. Bulletin du CRDI #126

    International Development Research Centre (IDRC) Digital Library (Canada)

    26 févr. 2018 ... Dans ce numéro, découvrez comment la recherche financée par le CRDI permet d'améliorer la santé des mères et des enfants dans les pays du Sud et comment les innovations techniques et sociales de l'initiative SEARCH permettent de surmonter les défis liés à la cybersanté. N'oubliez pas non plus de ...

  13. The LHC's peta-bytes

    International Nuclear Information System (INIS)

    Malek, Fairouz

    2013-01-01

    As the LHC generates each second billions of billions of collisions between protons, each of these collisions generates about a megabyte of data. The author first recalls the different detectors which record traces of collisions, outlines that the Higgs boson is rarely produced by these collisions, and moreover, disintegrates into two Z bosons. This means that the detection rate is very low. She outlines the huge number of data generated by each experiment, and evokes how they are processed, and outlines the associated required computing capacities

  14. Hard QCD Measurements at LHC

    CERN Document Server

    Pasztor, Gabriella

    2018-01-01

    The rich proton-proton collision data of the LHC allow to study QCD processes in a previously unexplored region with ever improving precision. This paper summarises recent results of the ATLAS, CMS and LHCb Collaborations using primarily multi-jet and vector boson plus jet data collected at $\\sqrt s$ = 8 and 13 TeV. Comparisons to higher-order theoretical calculations and sophisticated Monte Carlo predictions are presented, as well as the impact of the data on the determination of the parton distribution functions and the measurement of the strong coupling constant, $\\alpha_s$.

  15. Record current in the LHC

    CERN Multimedia

    On 19 December, just before CERN's end-of-year break, Sector 4-5, which had been cooled to 1.9 K, beat the LHC current record for 2007. The current was raised to 8500 amperes in the main magnets. The current of the dipole circuit was repeatedly ramped up and quenches were provoked. The magnets were maintained at 4.5 K over the holiday period so that they could be quickly brought back down to the nominal temperature after the shutdown. The testing of the sector has now resumed.

  16. LHC Status and Upgrade Challenges

    Science.gov (United States)

    Smith, Jeffrey

    2009-11-01

    The Large Hadron Collider has had a trying start-up and a challenging operational future lays ahead. Critical to the machine's performance is controlling a beam of particles whose stored energy is equivalent to 80 kg of TNT. Unavoidable beam losses result in energy deposition throughout the machine and without adequate protection this power would result in quenching of the superconducting magnets. A brief overview of the machine layout and principles of operation will be reviewed including a summary of the September 2008 accident. The current status of the LHC, startup schedule and upgrade options to achieve the target luminosity will be presented.

  17. The TOTEM Detector at LHC

    OpenAIRE

    Ruggiero, G; Antchev, G; Aspell, P; Atanassov, I; Avati, V; Berardi, V; Berretti, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Ciocci, M A; Csanád, M

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-section with the luminosity-independent method and to the study of elastic and diffractive scattering. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot (RP) stations...

  18. Radiation Levels around the LHC

    CERN Document Server

    Mala, P; Calviani, M; Nordt, A

    2013-01-01

    This work discuss on the radiation levels measured around the LHC machine during the 2012 operational year. The doses and particle fluences are measured primarily by RadMon detectors – about 300 RadMons are installed around the accelerator – and by thermoluminescent detectors. In addition, BLMs, IG5/PMI ionisation chambers as well as FGCs can be used for corresponding cumulated dose evaluations. The probability of SEE depends directly on the high-energy hadron (HEH) fluence, so this is the main parameter that is calculated based on RadMons counts.

  19. The LHC's equipment all in step

    CERN Multimedia

    2005-01-01

    Over 80% of the control equipment for the LHC will be connected by a special communication network known as WorldFIP, which has been chosen for its very precise timing, excellent operating performance and robustness in difficult environments. Over 350 kilometres of this network are currently being installed in the LHC tunnel and checked for compliance with the required standards.

  20. Physics with heavy ions at LHC

    International Nuclear Information System (INIS)

    Safarik, K.

    2004-01-01

    We discuss the motivation to study heavy ion collisions at LHC, and the experimental conditions under which detectors will have to operate. A short description of the detectors under construction is given. Physics performance is illustrated in two examples, which will become accessible at LHC energies, jet quenching and heavy-flavor production. (author)

  1. LHC Experiments: refinements for the restart

    CERN Multimedia

    2009-01-01

    As the LHC restart draws closer, the Bulletin will be taking a look at how the six LHC experiments are preparing and what they have been up to since last September. In this issue we start with a roundup of the past 10 months of activity at CMS and ATLAS, both technical work and outreach activities.

  2. Wie passt der LHC in den Physikunterricht?

    CERN Document Server

    AUTHOR|(CDS)2084439; Woithe, Julia; Brown, Alex; Jende, Konrad

    2017-01-01

    Der LHC bietet sich als aktuelles und prominentes Beispiel der Grundlagenforschung an, im Unterricht behandelt zu werden. Der Artikel gibt einen kurzen Überblick über Komponenten und Funktionsweise des LHC. Zudem wird auf hilfreiche Ressourcen und Anknüpfungspunkte zum Curriculum verwiesen.

  3. Standard Model at the LHC 2017

    CERN Document Server

    2017-01-01

    The SM@LHC 2017 conference will be held May 2-5, 2017 at Nikhef, Amsterdam. The meeting aims to bring together experimentalists and theorists to discuss the phenomenology, observational results and theoretical tools for Standard Model physics at the LHC.

  4. Parton Distribution Benchmarking with LHC Data

    NARCIS (Netherlands)

    Ball, Richard D.; Carrazza, Stefano; Debbio, Luigi Del; Forte, Stefano; Gao, Jun; Hartland, Nathan; Huston, Joey; Nadolsky, Pavel; Rojo, Juan; Stump, Daniel; Thorne, Robert S.; Yuan, C. -P.

    2012-01-01

    We present a detailed comparison of the most recent sets of NNLO PDFs from the ABM, CT, HERAPDF, MSTW and NNPDF collaborations. We compare parton distributions at low and high scales and parton luminosities relevant for LHC phenomenology. We study the PDF dependence of LHC benchmark inclusive cross

  5. Partons and jets at the LHC

    Indian Academy of Sciences (India)

    Partons and jets at the LHC. DAVISON E SOPER. Institute of Theoretical Science, University of Oregon, Eugene, OR 97403-5203, USA. Abstract. I review some issues related to short distance QCD and its relation to the experimental program of the large hadron collider (LHC) now under construction in Geneva. Keywords.

  6. Protons on the doorstep of the LHC

    CERN Multimedia

    Mertens, Volker

    2005-01-01

    The first of the two new beam transfer lines to the LHC was successfully commissioned in autumn 2004. At the first attempt a low-intensity proton beam passed down the line to a few meters before the LHC tunnel (3 pages)

  7. The last LHC dipole magnet is lowered

    CERN Multimedia

    Claudia Marcelloni

    2007-01-01

    A ceremony is held as the last of 1746 superconducting magnets is lowered into the 27-km circumference tunnel that houses the LHC. The LHC project leader, Lyn Evans, changes a banner reading ‘first magnet for the LHC’ to ‘last magnet for the LHC’ in his native Welsh.

  8. PS, SL and LHC Auditoria change names

    CERN Multimedia

    2003-01-01

    Following the replacement of the PS, SL and LHC Divisions by the AB and AT Divisions, the Auditoria are also changing their names. PS Auditorium is renamed AB Meyrin SL Auditorium is renamed AB Prévessin LHC Auditorium is renamed AT

  9. Prospects on electroweak physics from the LHC

    International Nuclear Information System (INIS)

    Vikas, Pratibha

    2001-01-01

    The abundant production of gauge bosons, gauge boson pairs and top quarks at the LHC will offer the opportunity for comprehensive and challenging tests of theoretical predictions in the electroweak sector. Some issues which influence these measurements followed by prospects on some possible measurements by the ATLAS and CMS experiments at the Large Hadron Collider (LHC), at CERN are discussed. (author)

  10. Choeur du CERN : Concert

    CERN Multimedia

    CERN Choir

    2017-01-01

    Une œuvre à découvrir! La grande Missa pro defunctis de François-Joseph Gossec (1734-1829) est le chef-d’œuvre tôt venu (à vingt-cinq ans) d’un compositeur qui vivra encore 70 ans après sa création. Elle a connu la gloire, puis s’est fait un peu oublier. Pas du tout le monde cependant : des musicologues ont montré ce que le Requiem de Mozart lui devait ; et il suffit de l’avoir entendue pour comprendre pourquoi Berlioz (qui avait vingt-six ans à la mort de Gossec) en a été impressionné : les nombreux cuivres et bois répartis dans des endroits plus ou moins cachés de la salle de concert pour exprimer les frayeurs du Jugement dernier annoncent son Requiem – et celui de Verdi. Mais « plus encore que par...

  11. Les risques du travail

    CERN Document Server

    Thébaud-Mony, Annie

    2015-01-01

    Depuis les années 1990, les conditions de travail se sont peu à peu imposées dans le débat social. Néanmoins, la situation reste critique. Les risques traditionnels n'ont pas disparu : les manutentions lourdes, l'exposition professionnelle aux cancérogènes, au bruit ou aux vibrations demeurent répandues... De plus, certaines " améliorations " n'ont fait que déplacer et dissimuler les problèmes, telle l'externalisation des risques grâce à la sous-traitance. Dans le même temps, les transformations du travail et des modalités de gestion de la main-d'œuvre ont fragilisé les collectifs et accru l'isolement des salariés, conduisant à une montée visible de la souffrance psychique. Face à ces évolutions, il est plus que jamais nécessaire que tous les acteurs concernés, en particulier les salariés eux-mêmes et leurs représentants, s'approprient les connaissances indispensables pour améliorer la protection de la santé sur les lieux du travail. Tel est le but de ce livre, qui renouvelle int�...

  12. HL-LHC parameter space and scenarios

    International Nuclear Information System (INIS)

    Bruning, O.S.

    2012-01-01

    The HL-LHC project aims at a total integrated luminosity of approximately 3000 fb -1 over the lifetime of the HL-LHC. Assuming an exploitation period of ca. 10 years this goal implies an annual integrated luminosity of approximately 200 fb -1 to 300 fb -1 per year. This paper looks at potential beam parameters that are compatible with the HL-LHC performance goals and discusses briefly potential variation in the parameter space. It is shown that the design goal of the HL-LHC project can only be achieved with a full upgrade of the injector complex and the operation with β* values close to 0.15 m. Significant margins for leveling can be achieved for β* values close to 0.15 m. However, these margins can only be harvested during the HL-LHC operation if the required leveling techniques have been demonstrated in operation

  13. Helium Inventory Management For LHC Cryogenics

    CERN Document Server

    Pyarali, Maisam

    2017-01-01

    The LHC is a 26.7 km circumference ring lined with superconducting magnets that operate at 1.9 K. These magnets are used to control the trajectory of beams of protons traveling in opposite directions and collide them at various experimental sites across the LHC where their debris is analyzed. The focus of this paper is the cryogenic system that allows the magnets to operate in their superconducting states. It aims to highlight the operating principles of helium refrigeration and liquefaction, with and without nitrogen pre-cooling; discuss the various refrigerators and liquefiers used at CERN for both LHC and Non-LHC applications, with their liquefaction capacities and purposes; and finally to deliberate the management of the LHC inventory and how it contributes to the strategic decision CERN makes regarding the inventory management during the Year-End Technical Stop (YETS), Extended Year-End Technical Stop (EYETS) and long shutdowns.

  14. Looking back over the LHC Project

    CERN Multimedia

    2007-01-01

    Have you always wanted to delve into the history of the phenomenal LHC Project? Well, now you can. A chronological history of the LHC Project is now available on the web. It traces the Project's key milestones, from its first approval in 1994 to the most recent spectacular transport operations for detector components. The photographs used to illustrate these events are linked to the CDS database, allowing visitors who wish to do so the opportunity to download them or to search for photographs associated with subjects that are of interest to them. To explore the history of the LHC Project, go to the CERN Public Welcome page and click on 'LHC Milestones' or simply go directly to the following link: http://cern.ch/LHC-Milestones/

  15. The latest from the LHC

    CERN Multimedia

    2009-01-01

    View of the LHC tunnel after the repairs.Three weeks ago vacuum leaks occurred in both Sector 8-1 and 2-3 (See previous update). While the cause and exact locations of the leaks are still unknown, it is suspected that they occurred in both cases from a flexible hose in the liquid helium transport circuits, which vented helium into the vacuum insulation. In Sector 8-1 the leaks occurred while it was being maintained at 80 K in order to perform the resistance measurements on the copper part of the superconducting busbars. Less than 24 hours later a similar leak occurred in Sector 2-3 while it was being warmed from superconducting temperatures to 80 K to perform the busbar resistance measurement. Both leaks happened where the final magnet of the sector (known as Q7) joins the electrical feedbox (called the DFBA). The end vacuum subsectors – a 200-metre stretch of the LHC sealed off by vacuum barriers – will be warmed to room temp...

  16. The Latest from the LHC

    CERN Multimedia

    In SM18 six magnets have been cold tested with good results. It has also been a good week for cyostating with five more magnets completed. In sector 3-4 interconnection work and welding has started in the area damaged on 19 September last year. Interconnection work is also ongoing on the replacement magnet for the faulty dipole removed from sector 1-2. Three separate teams are now working in the three sectors to install the new DN200 pressure release nozzles. In total 27 magnets have been completed so far, with 34 nozzles welded. A new study is also underway to include a similar pressure release system for both the stand-alone magnets (SAMs) and the triplet magnets. All about Chamonix At the public session of the LHCC (the LHC experiments committee) held Wednesday, 18 February Steve Myers, Director for Accelerators and Technology, reviewed the discussions on the LHC at the Chamonix workshop. He explained the scenarios being studied to implement the machine consolidation measures and resume operation. The ...

  17. Elastic scattering at the LHC

    CERN Document Server

    Kaspar, Jan; Deile, M

    The seemingly simple elastic scattering of protons still presents a challenge for the theory. In this thesis we discuss the elastic scattering from theoretical as well as experimental point of view. In the theory part, we present several models and their predictions for the LHC. We also discuss the Coulomb-hadronic interference, where we present a new eikonal calculation to all orders of alpha, the fine-structure constant. In the experimental part we introduce the TOTEM experiment which is dedicated, among other subjects, to the measurement of the elastic scattering at the LHC. This measurement is performed primarily with the Roman Pot (RP) detectors - movable beam-pipe insertions hundreds of meters from the interaction point, that can detect protons scattered to very small angles. We discuss some aspects of the RP simulation and reconstruction software. A central point is devoted to the techniques of RP alignment - determining the RP sensor positions relative to each other and to the beam. At the end we pres...

  18. Forward Physics at the LHC

    CERN Document Server

    Martin, A D; Khoze, V A

    2009-01-01

    We review two inter-related topics. First, we consider the behaviour of "soft" scattering observables, such as sigma_{tot}, dsigma_{el}/dt, dsigma_{SD}/dtdM^2, particle multiplicities etc., at high-energy proton-(anti)proton colliders. We emphasize the sizeable effects of absorption on high-energy `soft' processes, and, hence, the necessity to include multi-Pomeron-Pomeron interactions in the usual multi-channel eikonal description. We describe a multi-component model which has been tuned to the available data for soft processes in the CERN-ISR to Tevatron energy range, and which therefore allows predictions to be made for `soft' observables at the LHC. The second topic concerns the calculation of the rate of exclusive processes of the form pp --> p+A+p at high energy colliders, where A is a heavy system. In particular, we discuss the survival probability of the rapidity gaps (denoted by the + signs) to both eikonal and enhanced soft rescattering effects. At the LHC energy, the most topical case is when A is ...

  19. LHC Report: A tough restart

    CERN Multimedia

    Jan Uythoven for the LHC team

    2012-01-01

    The third LHC Technical Stop of five days took place in the week of September 17. Getting back to normal operation after a technical stop  can sometimes be difficult, with debugging, testing and requalification required on the systems that have seen interventions. Folding in a selection of other problems can make for a frustrating time.   The new injector magnet is transported to the LHC. Photo: TE/ABT group. The restart experienced over the last days was one of the tougher ones. Many problems occurred, both small and large, one after the other; in the end it took until Sunday afternoon, 9 days after the end of the technical stop, to have a physics fill in the machine that delivered an initial luminosity similar to those before the technical stop. Most problems encountered were, in fact, not related to the technical stop. The technical stop consisted of the usual maintenance and consolidation of the various systems, but two items stand out: the replacement of the mirrors an...

  20. TOTEM, a different LHC experiment

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    TOTEM will pursue a physics program (complementary to that of the other LHC detectors) spanning a wide range from total cross-section and elastic scattering measurements to the study of diffractive and forward phenomena. The TOTEM program will lead to a better understanding of the fundamental aspects of strong interactions. For the first time at hadron colliders, the very forward rapidity range, containing 90% of the energy flow and explored in high-energy cosmic ray experiments, is covered, allowing the search for unusual phenomena hinted at by cosmic ray experiments. The technical implementation of all TOTEM detectors is described. Silicon sensors housed in so-called Roman pots allow measurements of elastic and diffractive protons at distances as small as 1 mm from the beam centre. A scheme to tag events from Double-Pomeron-Exchange by diffractive protons on both sides transforms the LHC into an almost clean “gluon” collider, where the centre-of-mass energy is determined by the momentum losses of the ...

  1. The LHC Lead Injector Chain

    CERN Document Server

    Beuret, A; Blas, A; Burkhardt, H; Carli, Christian; Chanel, M; Fowler, A; Gourber-Pace, M; Hancock, S; Hourican, M; Hill, C E; Jowett, John M; Kahle, K; Küchler, D; Lombardi, A M; Mahner, E; Manglunki, Django; Martini, M; Maury, S; Pedersen, F; Raich, U; Rossi, C; Royer, J P; Schindl, Karlheinz; Scrivens, R; Sermeus, L; Shaposhnikova, Elena; Tranquille, G; Vretenar, Maurizio; Zickler, T

    2004-01-01

    A sizeable part of the LHC physics programme foresees lead-lead collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines [1,2]. Each LHC ring will be filled in 10 min by almost 600 bunches, each of 7×107 lead ions. Central to the scheme is the Low Energy Ion Ring (LEIR) [3,4], which transforms long pulses from Linac3 into high-brilliance bunches by means of multi-turn injection, electron cooling and accumulation. Major limitations along the chain, including space charge, intrabeam scattering, vacuum issues and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR involves new magnets and power converters, high-current electron cooling, broadband RF cavities, and a UHV vacuum system with getter (NEG) coatings to achieve a few 10-12 mbar. Major hardware changes in Linac3 and the PS are also covered. An early ion scheme with fewer bunches (but each at nominal...

  2. LHC Report: Positive ion run!

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The current LHC ion run has been progressing very well. The first fill with 358 bunches per beam - the maximum number for the year - was on Tuesday, 15 November and was followed by an extended period of steady running. The quality of the beam delivered by the heavy-ion injector chain has been excellent, and this is reflected in both the peak and the integrated luminosity.   The peak luminosity in ATLAS reached 5x1026 cm-2s-1, which is a factor of ~16 more than last year's peak of 3x1025 cm-2s-1. The integrated luminosity in each of ALICE, ATLAS and CMS is now around 100 inverse microbarn, already comfortably over the nominal target for the run. The polarity of the ALICE spectrometer and solenoid magnets was reversed on Monday, 28 November with the aim of delivering another sizeable amount of luminosity in this configuration. On the whole, the LHC has been behaving very well recently, ensuring good machine availability. On Monday evening, however, a faulty level sensor in the cooling towe...

  3. LHC Report: plumbing new heights

    CERN Multimedia

    John Jowett for the LHC team

    2015-01-01

    Following the end of the arduous 2015 proton run on 4 November, the many teams working on the LHC and its injector complex are naturally entitled to a calmer period before the well-earned end-of-year break. But that is not the way things work.       The CCC team after stable heavy-ion beams are declared in the LHC. Instead, the subdued frenzy of setting up the accelerators for a physics run has started again, this time for heavy-ion beams, with a few additional twists of the time-pressure knob. In this year’s one-month run, the first week was devoted to colliding protons at 2.51 TeV per beam to provide reference data for the subsequent collisions of lead nuclei (the atomic number of lead is Z=82, compared to Z=1 for protons) at the unprecedented energy of 5.02 TeV in the centre of mass per nucleon pair. The chain of specialised heavy-ion injectors, comprising the ECR ion source, Linac3 and the LEIR ring, with its elaborate bunch-forming and c...

  4. The TOTEM Detector at LHC

    CERN Document Server

    Ruggiero, G; Aspell, P; Atanassov, I; Avati, V; Berardi, V; Berretti, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Ciocci, M A; Csanád, M; Csörgö, T; Deile, M; Dénes, E; Dimovasili, E; Doubek, M; Eggert, K; Ferro, F; Garcia, F; Giani, S; Greco, V; Grzanka, L; Heino, J; Hilden, T; Janda, M; Kaspar, J; Kopal, J; Kundrát, V; Kurvinen, K; Lami, S; Latino, G; Lauhakangas, R; Lippmaa, E; Lokajícek, M; Lo Vetere, M; Lucas Rodriguez, F; Macrí, M; Magazzù, G; Minutoli, S; Niewiadomski, H; Notarnicola, G; Novak, T; Oliveri, E; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Palazzi, P; Pedreschi, E; Petäjäjärvi, J; Quinto, M; Radermacher, E; Radicioni, E; Ravotti, F; Robutti, E; Ropelewski, L; Rummel, A; Saarikko, H; Sanguinetti, G; Santroni, A; Scribano, A; Sette, G; Snoeys, W; Spearman, W; Spinella, F; Ster, A; Taylor, C; Trummal, A; Turini, N; Vacek, V; Vitek, M; Whitmore, J; Wu, J

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton–proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an...

  5. The LHC Computing Grid Project

    CERN Multimedia

    Åkesson, T

    In the last ATLAS eNews I reported on the preparations for the LHC Computing Grid Project (LCGP). Significant LCGP resources were mobilized during the summer, and there have been numerous iterations on the formal paper to put forward to the CERN Council to establish the LCGP. ATLAS, and also the other LHC-experiments, has been very active in this process to maximally influence the outcome. Our main priorities were to ensure that the global aspects are properly taken into account, that the CERN non-member states are also included in the structure, that the experiments are properly involved in the LCGP execution and that the LCGP takes operative responsibility during the data challenges. A Project Launch Board (PLB) was active from the end of July until the 10th of September. It was chaired by Hans Hoffmann and had the IT division leader as secretary. Each experiment had a representative (me for ATLAS), and the large CERN member states were each represented while the smaller were represented as clusters ac...

  6. The LHC taken with philosophy

    CERN Multimedia

    2009-01-01

    "Whether or not scientists at the LHC will find the Higgs boson, they will learn something about the secrets of Nature that will greatly advance human understanding". These are the words of Anthony Grayling, Professor of Philosophy at Birkbeck College, University of London, and presenter of the forthcoming BBC series "Exchanges at the Frontier". He visited CERN to prepare for his next interview with Jim Virdee, CMS Spokesperson.Grayling’s interview with Virdee is part of a series of events at Welcome Trust Collection in London: five of the biggest names in the world of science will discuss the social impact of their discoveries. These events will be broadcast to over 40 million people worldwide in December 2009 by the BBC World Service in the framework of the Exchanges at the Frontier series. Grayling has been following the LHC via the media but his tour of the CMS experiment increased his philosophical awareness of the international cooperation that has enabled it be bu...

  7. The LHC Superconducting RF System

    CERN Document Server

    Boussard, Daniel

    1999-01-01

    The European Laboratory for Particle Physics (CERN), the largest high energy physics laboratory worldwide, is constructing the Large Hadron Collider (LHC) in the existing 27 km circumference LEP (Large Electron Positron) collider tunnel. For the LHC, superconducting cavities, operating at 4.5 K, will provide the required acceleration field for ramping the beam energy up to 7 TeV and for keeping the colliding proton beams tightly bunched. Superconducting cavities were chosen, not only because of their high acceleration field leading to a small contribution to the machine impedance, but also because of their high stored energy which minimises the effects of periodic transient beam loading associated with the high beam intensity (0.5 A). There will be eight single-cell cavities per beam, each delivering 2 MV (5.3 MV/m) at 400 MHz. The cavities themselves are now being manufactured by industrial firms, using niobium on copper technology which gives full satisfaction at LEP. A complete cavity prototype assembly in...

  8. Leading lead through the LHC

    CERN Multimedia

    2011-01-01

    Three of the LHC experiments - ALICE, ATLAS and CMS - will be studying the upcoming heavy-ion collisions. Given the excellent results from the short heavy-ion run last year, expectations have grown even higher in experiment control centres. Here they discuss their plans:   ALICE For the upcoming heavy-ion run, the ALICE physics programme will take advantage of a substantial increase of the LHC luminosity with respect to last year’s heavy-ion run.  The emphasis will be on the acquisition of rarely produced signals by implementing selective triggers. This is a different operation mode to that used during the first low luminosity heavy-ion run in 2010, when only minimum-bias triggered events were collected. In addition, ALICE will benefit from increased acceptance coverage by the electromagnetic calorimeter and the transition radiation detector. In order to double the amount of recorded events, ALICE will exploit the maximum available bandwidth for mass storage at 4 GB/s and t...

  9. The LHC Low Level RF

    CERN Document Server

    Baudrenghien, Philippe; Molendijk, John Cornelis; Olsen, Ragnar; Rohlev, Anton; Rossi, Vittorio; Stellfeld, Donat; Valuch, Daniel; Wehrle, Urs

    2006-01-01

    The LHC RF consists of eight 400 MHz superconducting cavities per ring, with each cavity independently powered by a 300 kW klystron, via a circulator. The challenge for the Low Level is to cope with very high beam current (more than 1 A RF component) and achieve excellent beam lifetime (emittance growth time in excess of 25 hours). Each cavity has an associated Cavity Controller rack consisting of two VME crates which implement high gain RF Feedback, a Tuner Loop with a new algorithm, a Klystron Ripple Loop and a Conditioning system. In addition each ring has a Beam Control system (four VME crates) which includes a Frequency Program, Phase Loop, Radial Loop and Synchronization Loop. A Longitudinal Damper (dipole and quadrupole mode) acting via the 400 MHz cavities is included to reduce emittance blow-up due to filamentation from phase and energy errors at injection. Finally an RF Synchronization system implements the bunch into bucket transfer from the SPS into each LHC ring. When fully installed in 2007, the...

  10. La particule de Dieu à la découverte du boson de Higgs

    CERN Document Server

    Baggott, Jim

    2013-01-01

    De quoi le monde est-il constitué? Des questions aussi simples que celle-ci ont taraudé l'esprit de l'Homme depuis les origines. Même si les raisonnements sont devenus de plus en plus complexes au fil du temps, au fond, cette question centrale reste très basique. Ce livre raconte la quête des scientifiques pour élaborer un modèle permettant d'expliquer la structure de la matière à son niveau le plus élémentaire, jusqu'à l'annonce de la découverte du fameux boson de Higgs, au LHC, le 4 juillet 2012. Qu'est-ce que le boson de Higgs et en quoi sa découverte est-elle si importante? La réponse à cette question réside dans l'histoire du modèle standard de la physique des particules. Ce modèle, élaboré découverte après découverte, depuis le début du XXe siècle, recense toutes les particules constitutives de l'univers. Il prédisait jusqu'ici l'existence d'un champs dit de Higgs indispensable pour donner leur masse aux autres particules du modèle. Sans le boson de Higgs, l'univers ne pouv...

  11. Jouer du piano

    Directory of Open Access Journals (Sweden)

    Fériel Kaddour

    2011-04-01

    Full Text Available La réflexion s’appuie dans un premier temps sur une opposition entre deux attitudes de pianistes  à l’égard du travail à l’instrument : Gould, qui revendique une séparation d’avec le clavier pour ne privilégier que la lecture; Arrau, dont la technique au contraire vise à « faire corps » avec son piano. L’étude de ces deux démarches d’interprètes conduit à une conclusion croisée : l’abstraction gouldienne n’est rien d’autre qu’un déplacement du jeu vers d’autres instruments (ceux qui servent à la prise de son et au montage de ses enregistrements ; le « faire-corps » hérité de la culture pianistique romantique est plus dialectique que fusionnel, et en cela implique une capacité de mise à distance. A partir de cette double conclusion, on tâche enfin de repenser la place du jeu à l’instrument dans la mise en œuvre d’une interprétation, en interrogeant le dialogue qui s’instaure entre la partition telle qu’elle s’écrit et le geste tel qu’il se joue.Our study leans on an opposition between two pianists' attitudes about their work with the instrument. Gould claims a necessary separation from the keyboard in order to prioritize reading. Arrau, on the contrary, relies on a technique which consists in “being one” with his piano. The analysis of these two interprets’ behaviours leads to a crossed conclusion: the gouldian abstraction is nothing else than a displacement of the playing towards another kind of instruments, the ones he uses in sound recording and cut up; Arrau’s “being one” is more dialectic than at first sight, and it therefore implies a real distancing from the piano. This constatation leads to rethink the place of the piano playing in the setting of an interpretation, and to highlight the real dialogue which develops itself between the score as it has been written and the gesture as it is played.

  12. La grammaticalisation du monde.

    Directory of Open Access Journals (Sweden)

    Etienne Pingaud

    2010-01-01

    Full Text Available Ouvrage atypique par le fond comme par la forme, Le devoir et la grâce rend compte du minutieux travail d’élaboration théorique auquel s’attelle Cyril Lemieux depuis plusieurs années. Et le résultat final se veut pour le moins ambitieux : l’auteur propose un système total supposé dépasser d’un même élan le relativisme, le mentalisme, l’universalisme ethnocentrique, l’historicisme, le naturalisme et l’herméneutisme, tout en réconciliant les sciences sociales avec le ...

  13. Le sacre du printemps

    Directory of Open Access Journals (Sweden)

    Denise Pumain

    2002-03-01

    Full Text Available Cybergeo aura six ans en avril : dans la réalité du virtuel, dans l'univers récent et fluctuant de la publication en ligne, cela fait de nous, tout à la fois, des pionniers et des vétérans. De façon plus surprenante, il se trouve que nous sommes aussi uniques : parmi toutes les revues électroniques de sciences sociales, aucune ne combine comme Cybergeo ancienneté, publication exclusivement électronique, liberté d'accès au texte intégral, édition et gestion par des chercheurs, et comité de lec...

  14. Le Brahmane du Komintern

    Directory of Open Access Journals (Sweden)

    Elizabeth Burgos

    2008-01-01

    Full Text Available Le Brahmane du Komintern, largometraje documental del realizador francés Vladimir León, constituye un ejercicio ejemplar de investigación histórica y  de lograda factura de realización. Y, pese a no haber contado con la ayuda de ninguno organismo público, se trata de un ambicioso proyecto que cubre una amplia extensión geográfica que abarca: Estados Unidos, México, Moscú, Berlín, y la India. Gira en torno a una figura que tuvo en su tiempo su hora de gloria. Un bengalí, hijo de braman, la c...

  15. (Sorghum bicolor (L.) Moench) du Nord du Burkina Faso

    African Journals Online (AJOL)

    SARAH

    29 déc. 2014 ... sorghos à grains sucrés ont un cycle court et arrivent donc à maturité avant les autres sorghos et le mil d'où leur exploitation comme aliment de soudure par les paysans. L'organisation de la diversité morphologique des accessions de sorghos à grains sucrés du Nord du. Burkina autour principalement des ...

  16. OPERATION DU FOISONNEMENT

    Directory of Open Access Journals (Sweden)

    Gholamreza Djelveh

    2010-04-01

    Full Text Available Mousses alimentaires sont un sous-ensemble des aliments connus sous le nom de produits fouettés ou des produits aérés. Ils sont des produits formulés avec des qualités telles que la légèreté et la souplesse et sont principalement consommés à l'apéritif ou au dessert. Les produits en mousse obtenue par dispersion d'un gaz dans une matrice alimentaire (la phase continue ont connu un développement croissant au cours des années 80 et 90. Le processus d'aération liés à leurs activités de production est appelée l'expansion ou à fouetter. Le document présente les principaux-paramètres du procédé du point permanent de la formulation, la mise en œuvre processus dans les installations pilotes et à l'échelle industrielle, la caractérisation des produits finis, la base énergétique de l'échelle de processus en place, et le lien entre la formulation, émulsion préparation de l'expansion. Cette vue d'ensemble de l'opération d'expansion continue, nous a permis de mettre en évidence le fait qu'il ya des opérations de l'unité encore mal décrite par le génie des procédés et pour lesquels les méthodes et outils pour l'extrapolation et la prédiction sont encore à leurs balbutiements.

  17. Alimentation du nouveau-ne et du nourrisson dans la region ...

    African Journals Online (AJOL)

    Alimentation du nouveau-ne et du nourrisson dans la region centrale du togo : pratiques familiales et communautaires avant la mise en oeuvre de la strategie « prise en charge integree des maladies de l'enfant »

  18. HL-LHC updates in Japan

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    At a recent meeting in Japan, updates on the High Luminosity LHC (HL-LHC) project were presented, including the progress made so far and the deadlines still to be met for the upgraded machine to be operational from 2020.   New magnets made with advanced superconductor Nb3Sn in the framework of the HL-LHC project. These magnets are currently under construction at CERN by the TE-MSC group. The LHC is the world’s most powerful particle accelerator, and in 2015 it will reach yet another new record for the energy of its colliding beams. One key factor of its discovery potential is its ability to produce collisions described in mathematical terms by the parameter known as “luminosity”. In 2025, the HL-LHC project will allow the total number of collisions in the LHC to increase by a factor of 10. The first step in this rich upgrade programme is the delivery of the Preliminary Design Report (PDR), which is also a key milestone of the HiLumi LHC Design Study partly fund...

  19. The whole world behind the LHC

    CERN Multimedia

    2001-01-01

    The LHC Board, which includes representatives of the non-Member State organisations directly involved in the construction of the LHC accelerator and representatives of CERN, held its fourth meeting on Monday 21 May 2001. From left to right: 1st row, A. Yamamoto (KEK, Japan), P. Pfund (FNAL, United States), L. Maiani (CERN Director-General), L. Evans (LHC Project Leader), F. Dupont (IN2P3, France), D.D. Bhawalkar (CAT, India) ; 2nd row, P. Brossier (CEA, France), N. Tyurin (IHEP, Russia), A. Skrinsky (BINP, Russia), A. Astbury (TRIUMF, Canada), P. Lebrun (LHC Division Leader, CERN); 3rd row, T. Taylor (Deputy Division Leader LHC Division, CERN), A. Shotter (TRIUMF, Canada), P. Bryant (LHC, CERN), K. Hübner (Director for Accelerators, CERN), J. van der Boon (Director of Administration, CERN). Although Canada, the United States, India, Japan and the Russian Federation are not members of CERN, they are all playing an active part in the construction of the LHC through important technical and financial co...

  20. Warm liquid calorimetry for LHC

    CERN Document Server

    Geulig,E; Wallraff,W; Bézaguet, Alain-Arthur; Cavanna, F; Cinnini, P; Cittolin, Sergio; Dreesen, P; Demoulin, M; Dunps, L; Fucci, A; Gallay, G; Givernaud, Alain; Gonidec, A; Jank, Werner; Maurin, Guy; Placci, Alfredo; Porte, J P; Radermacher, E; Samyn, D; Schinzel, D; Schmidt, W F; CERN. Geneva. Detector Research and Development Committee

    1990-01-01

    Results from the beam tests of the U/TMP "warm liquid" calorimeter show that such a technique is very promising for the LHC. Our aim is to extend this programme and design a calorimeter that can satisfy the requirements of high rates, high radiation levels, compensation, uniformity and granularity, as well as fully contain hadronic showers. We propose to construct liquid ionization chambers operated at very high fields, capable of collecting the total charge produced by ionizing particles within times comparable to the bunch crossing time of the future Collider. For this reason we plan to extend the current programme on tetramethylpentane (TMP) to tetramethylsilane (TMSi). An electromagnetic calorimeter consisting of very high field ionization chambers filled with TMSi as sensitive medium with Uranium and/or other high density material as absorber will first be built (to be followed by a full-scale calorimeter module), on which newly designed fast amplifiers and readout electronics will be tested. In addition...

  1. Small systems at the LHC

    Science.gov (United States)

    Preghenella, Roberto

    2018-02-01

    In these proceedings, I report on a selection of recent LHC results in small systems from ALICE [1], ATLAS [2] and CMS [3] experiments. Due to the fact that the investigation of QCD in small systems at high multiplicity is becoming an increasingly large subject, interesting the heavy-ion community and more in general the high-energy physics community, not all the related topics can be discussed in this paper. The focus will be given to some of the measurements addressing the physics of collective phenomena in small systems and to the recent results on strangeness enhancement in proton-proton collisions. The reader must be informed that a large number of interesting results did not find space in the discussion reported here.

  2. Diffractive processes at the LHC

    CERN Document Server

    Martin, A D; Ryskin, M G

    2009-01-01

    We present a model of high energy soft $pp$ interactions that has multi s- and t-channel components, which has been tuned to describe all the available data. The t-channel components allow matching of the soft to the hard (QCD) Pomeron. Absorptive effects are found to be large, and, for example, suppress the prediction of the total $pp$ cross section to about 90 mb at the LHC. We use the model to calculate the survival probability, S^2, of the rapidity gaps in the exclusive process pp \\to p+H+p, a process with great advantages for searching for the H \\to \\bb signal. We consider both eikonal and enhanced rescattering.

  3. Baryonic Higgs at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Duerr, Michael [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fileviez Perez, Pavel [Case Western Reserve Univ., Cleveland, OH (United States). CERCA, Physics Dept.; Smirnov, Juri [INFN, Sezione di Firenze (Italy); Florence Univ., Sesto Fiorentino (Italy). Dept. of Physics and Astronomy

    2017-04-15

    We investigate the possible collider signatures of a new Higgs in simple extensions of the Standard Model where baryon number is a local symmetry spontaneously broken at the low scale. We refer to this new Higgs as ''Baryonic Higgs''. This Higgs has peculiar properties since it can decay into all Standard Model particles, the leptophobic gauge boson, and the vector-like quarks present in these theories to ensure anomaly cancellation. We investigate in detail the constraints from the γγ, Zγ, ZZ, and WW searches at the Large Hadron Collider, needed to find a lower bound on the scale at which baryon number is spontaneously broken. The di-photon channel turns out to be a very sensitive probe in the case of small scalar mixing and can severely constrain the baryonic scale. We also study the properties of the leptophobic gauge boson in order to understand the testability of these theories at the LHC.

  4. The TOTEM detector at LHC

    Science.gov (United States)

    Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Berardi, V.; Berretti, M.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.; Calicchio, M.; Catanesi, M. G.; Ciocci, M. A.; Csanád, M.; Csörgő, T.; Deile, M.; Dénes, E.; Dimovasili, E.; Doubek, M.; Eggert, K.; Ferro, F.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Janda, M.; Kaˇspar, J.; Kopal, J.; Kundrat, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Lippmaa, E.; Lokajicek, M.; Lo Vetere, M.; Lucas Rodriguez, F.; Macri`, M.; Magazzu`, G.; Minutoli, S.; Niewiadomski, H.; Notarnicola, G.; Novak, T.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Osterberg, K.; Palazzi, P.; Pedreschi, E.; Petajajarvi, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Rummel, A.; Saarikko, H.; Sanguinetti, G.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spearman, W.; Spinella, F.; Ster, A.; Taylor, C.; Trummal, A.; Turini, N.; Vacek, V.; Vitek, M.; Whitmore, J.; Wu, J.

    2010-05-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

  5. The TOTEM detector at LHC

    International Nuclear Information System (INIS)

    Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Berardi, V.; Berretti, M.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.; Calicchio, M.; Catanesi, M.G.; Ciocci, M.A.; Csanad, M.; Csoergo, T.; Deile, M.; Denes, E.; Dimovasili, E.; Doubek, M.; Eggert, K.

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

  6. The TOTEM detector at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Antchev, G.; Aspell, P.; Atanassov, I. [CERN, CH-1211 Geneva 23 (Switzerland); Avati, V. [CERN, CH-1211 Geneva 23 (Switzerland); Penn State University, Dept. of Physics, University Park, PA (United States); Berardi, V. [INFN Sezione di Bari and Politecnico di Bari, Bari (Italy); Berretti, M. [INFN Sezione di Pisa and Universita di Siena (Italy); Bozzo, M. [Universita di Genova and Sezione INFN, Genova (Italy); Brucken, E. [Helsinki Institute of Physics and Department of Physics, University of Helsinki (Finland); Buzzo, A. [Universita di Genova and Sezione INFN, Genova (Italy); Cafagna, F.; Calicchio, M.; Catanesi, M.G. [INFN Sezione di Bari and Politecnico di Bari, Bari (Italy); Ciocci, M.A. [INFN Sezione di Pisa and Universita di Siena (Italy); Csanad, M.; Csoergo, T. [MTA KFKI RMKI, Budapest (Hungary); Deile, M. [CERN, CH-1211 Geneva 23 (Switzerland); Denes, E. [MTA KFKI RMKI, Budapest (Hungary); Dimovasili, E. [CERN, CH-1211 Geneva 23 (Switzerland); Penn State University, Dept. of Physics, University Park, PA (United States); Doubek, M.; Eggert, K. [Penn State University, Dept. of Physics, University Park, PA (United States)

    2010-05-21

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-sections with a luminosity-independent method and to the study of elastic and diffractive scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the IP5 interaction point, two tracking telescopes, T1 and T2, will be installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot stations will be placed at distances of 147 and 220 m from IP5. The telescope closest to the interaction point (T1, centred at z=9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centred at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the Roman Pots are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature. It maximizes the experimental acceptance for protons scattered elastically or interactively at polar angles down to a few micro-radians at IP5. To measure protons at the lowest possible emission angles, special beam optics have been conceived to optimize proton detection in terms of acceptance and resolution. The read-out of all TOTEM subsystems is based on the custom-developed digital VFAT chip with trigger capability.

  7. Scintillating Fibre Calorimetry at the LHC

    CERN Multimedia

    2002-01-01

    Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. The lead/scintillating fibre calorimeter technique provides a fast signal response well matched to the LHC rate requirements. It can be made to give equal response for electrons and hadrons (compensation) with good electromagnetic and hadronic energy resolutions.\\\\ \\\\ The aim of this R&D proposal is to study in detail the aspects that are relevant for application of this type of calorimeter in an LHC environment, including its integration in a larger system of detectors, e.g.~projective geometry, radiation hardness, light detection, calibration and stability monitoring, electron/hadron separation.....

  8. Requirements for the LHC collimation system

    CERN Document Server

    Assmann, R W; Brugger, M; Bruno, L; Burkhardt, H; Burtin, G; Dehning, Bernd; Fischer, C; Goddard, B; Gschwendtner, E; Hayes, M; Jeanneret, J B; Jung, R; Kain, V; Kaltchev, D I; Lamont, M; Schmidt, R; Vossenberg, Eugène B; Weisse, E; Wenninger, J

    2002-01-01

    The LHC requires efficient collimation during all phases of the beam cycle. Collimation plays important roles in prevention of magnet quenches from regular beam diffusion, detection of abnormal beam loss and subsequent beam abort, radiation protection, and passive protection of the superconducting magnets in case of failures. The different roles of collimation and the high beam power in the LHC impose many challenges for the design of the collimation system. In particular, the collimators must be able to withstand the expected particle losses. The requirements for the LHC collimation system are presented.

  9. Gravitino LSP scneario at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Heisig, Jan

    2010-06-15

    In this thesis we discuss the phenomenology of the gravitino LSP scenario at the large hadron collider (LHC) experiment. We concentrate on a long-lived stau NLSP which gives rise to a prominent signature in the LHC detector as a 'slow muon'. We discuss the production channels and compute the cross sections for direct production via the Drell-Yan process. On this basis we claim a conservative estimation of the discovery potential for this scenario at the LHC. (orig.)

  10. Plan of SPS to LHC transfer tunnels

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    This diagram shows the LHC and the SPS pre-accelerator (in blue) and the transfer lines that will connect them (in red). Spanning the France-Swiss border (shown by green crosses), the 27-km LHC tunnel will receive a beam that has been pre-accelerated to 450 GeV in the smaller SPS storage ring. The transfer lines will remove each beam from the SPS and inject them into the LHC where they will be accelerated to the full energy of 7 TeV.

  11. Slice through an LHC bending magnet

    CERN Multimedia

    Slice through an LHC superconducting dipole (bending) magnet. The slice includes a cut through the magnet wiring (niobium titanium), the beampipe and the steel magnet yokes. Particle beams in the Large Hadron Collider (LHC) have the same energy as a high-speed train, squeezed ready for collision into a space narrower than a human hair. Huge forces are needed to control them. Dipole magnets (2 poles) are used to bend the paths of the protons around the 27 km ring. Quadrupole magnets (4 poles) focus the proton beams and squeeze them so that more particles collide when the beams’ paths cross. There are 1232 15m long dipole magnets in the LHC.

  12. Links between astroparticle physics and the LHC

    International Nuclear Information System (INIS)

    Pinfold, James L

    2005-01-01

    Research into the fundamental nature of matter at the high energy frontier takes place in three main areas: accelerator-based particle physics, high energy astrophysics, and the cosmology of the early universe. As a consequence the study of astroparticle physics can have significant implications for collider physics at the LHC. Likewise, the LHC project provides the laboratory to perform measurements of great importance for cosmic ray astrophysics and cosmology. This paper reviews some of the important synergistic links between astroparticle and LHC physics. (topical review)

  13. Particle Physics at the LHC Start

    CERN Document Server

    Altarelli, Guido

    2011-01-01

    I present a concise review of the major issues and challenges in particle physics at the start of the LHC era. After a brief overview of the Standard Model and of QCD, I will focus on the electroweak symmetry breaking problem which plays a central role in particle physics today. The Higgs sector of the minimal Standard Model is so far just a mere conjecture that needs to be verified or discarded by the LHC. Probably the reality is more complicated. I will summarize the motivation for new physics that should accompany or even replace the Higgs discovery and a number of its possible forms that could be revealed by the LHC.

  14. HL-LHC and HE-LHC Upgrade Plans and Opportunities for US Participation

    Science.gov (United States)

    Apollinari, Giorgio

    2017-01-01

    The US HEP community has identified the exploitation of physics opportunities at the High Luminosity-LHC (HL-LHC) as the highest near-term priority. Thanks to multi-year R&D programs, US National Laboratories and Universities have taken the leadership in the development of technical solutions to increase the LHC luminosity, enabling the HL-LHC Project and uniquely positioning this country to make critical contributions to the LHC luminosity upgrade. This talk will describe the shaping of the US Program to contribute in the next decade to HL-LHC through newly developed technologies such as Nb3Sn focusing magnets or superconducting crab cavities. The experience gained through the execution of the HL-LHC Project in the US will constitute a pool of knowledge and capabilities allowing further developments in the future. Opportunities for US participations in proposed hadron colliders, such as a possible High Energy-LHC (HE-LHC), will be described as well.

  15. Le plurilinguisme du perroquet

    Directory of Open Access Journals (Sweden)

    Manuel Mühlbacher

    2012-05-01

    Full Text Available La figure du perroquet occupe une position ambiguë face à la question de la traduction. Il est capable d’imiter des paroles en toutes les langues, mais il n’est capable d’en comprendre aucune — il ne peut que répéter des sons, c’est-à-dire des signifiants. Le traducteur semble faire le contraire quand il passe d’une langue à une autre en tâchant de transmettre une signification semblable par d’autres signes. L’article vise à discuter le rôle du traducteur et sa relation, éventuellement équivoque, au perroquet, en analysant la traduction allemande de Trois Contes par André Stoll et Cora van Kleffens. Un décalage au niveau sémantique peut éclairer l’interprétation du texte, par exemple en explicitant des allusions sous-jacentes, tandis que le transfert de la syntaxe française en allemand pose souvent des problèmes considérables. Comment le traducteur peut-il reproduire des structures syntaxiques qui n’existent pas en allemand, mais qui ne cessent de revenir dans le texte français ? Que faire si le texte se met à jouer au perroquet et finit par se singer lui-même ? André Stoll et Cora van Kleffens ont su trouver des stratégies pour affronter ces difficultés.The figure of the parrot holds an ambiguous position towards the question of translation. It is able to imitate all languages, but it will never understand any of them – its only skill is to mimic sounds, i.e. mere signifiers. On the contrary, the translator seems to be the antithesis of the parrot when he moves from one language to another. He endeavours to convey a similar meaning, but by different signs. The article aims at discussing the role of the translator and his or her eventually equivocal relation to the parrot by means of analysing the German translation of Trois Contes by André Stoll and Cora van Kleffens. Whereas a semantic divergence can result in a different tendency on the level of interpretation, as in the case of an underlying

  16. Reduction des effectifs ou licenciements

    CERN Multimedia

    Maiani, Luciano

    2002-01-01

    "Vous faites un amalgame entre la reduction en cours des effectifs du CERN (organisation europeenne pour la recherche nucleaire) et les economies que le laboratoire doit realiser dans les cinq ans a venir pour financer le projet de grand collisionneur de hadrons (Le Monde du 4 septembre)" (1/2 page).

  17. LHC@home gets new home

    CERN Multimedia

    Oates, John

    2007-01-01

    "The distributed computing project LHC@home is moving to London from Cern in Switzerland. Researchers at Qeen Mary University have been trialling the system since June, but are now ready for the offical launch" (1 page)

  18. Beam-gas Background Observations at LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00214737; The ATLAS collaboration; Alici, Andrea; Lazic, Dragoslav-Laza; Alemany Fernandez, Reyes; Alessio, Federico; Bregliozzi, Giuseppe; Burkhardt, Helmut; Corti, Gloria; Guthoff, Moritz; Manousos, Athanasios; Sjoebaek, Kyrre; D'Auria, Saverio

    2017-01-01

    Observations of beam-induced background at LHC during 2015 and 2016 are presented in this paper. The four LHC experiments use the non-colliding bunches present in the physics-filling pattern of the accelerator to trigger on beam-gas interactions. During luminosity production the LHC experiments record the beam-gas interactions using dedicated background monitors. These data are sent to the LHC control system and are used to monitor the background levels at the experiments during accelerator operation. This is a very important measurement, since poor beam-induced background conditions can seriously affect the performance of the detectors. A summary of the evolution of the background levels during 2015 and 2016 is given in these proceedings.

  19. Japanese contributions to CERN-LHC

    International Nuclear Information System (INIS)

    Kondo, Takahiko; Shintomi, Takakazu; Kimura, Yoshitaka

    2001-01-01

    The Large Hadron Collider (LHC) is now under construction at CERN, Geveva, to study frontier researches of particle physics. The LHC is the biggest superconducting accelerator using the most advanced cryogenics and applied superconductivities. The accelerator and large scale detectors for particle physics experiments are being constructed by collaboration with European countries and also by participation with non-CERN countries worldwide. In 1995, the Japanese government decided to take on a share in the LHC project with funding and technological contributions. KEK contributes to the development of low beta insertion superconducting quadrupole magnets and of components of the ATLAS detector by collaboration with university groups. Some Japanese companies have received contracts for technically key elements such as superconducting cable, cold compressor, nonmagnetic steel, polyimide film, and so on. An outline of the LHC project and Japanese contributions are described. (author)

  20. Superconducting magnet development for the LHC upgrades

    International Nuclear Information System (INIS)

    Rossi, Lucio

    2012-01-01

    LHC is now delivering proton and heavy ion collisions at the highest energy. Upgrading the LHC beyond its design performance is a long term program that started during the LHC construction, with some fundamental R and D programs. The upgrade program is based on a vigorous superconductor and magnet R and D, aimed at increasing the field in accelerator magnets from 8 T to 12 T for the luminosity upgrade, with the scope of increasing the collider luminosity by a factor 5 to 10 from 2022. The upgrade program might continue with the LHC energy upgrade, which would require magnets producing field in the range of 16-20 T. The results obtained so far and the future challenges are discussed together with the possible plan to reach the goals. (author)

  1. Optical fibres bringing the LHC into focus

    CERN Multimedia

    2003-01-01

    New components are being added to CERN's optical fibre network, which will transport the torrents of data produced by the LHC. 1500 kilometres of cables will be installed in the tunnels and at ground level.

  2. LHC: Collisions on course for 2007

    CERN Document Server

    2006-01-01

    In the LHC tunnel and caverns, a particle accelerator and detectors are rapidly taking shape. At last week's Council meeting, delegates took stock of the year's progress towards first collisions in 2007.

  3. Impedance and collective effects in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gareyte, J [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-08-01

    After a review of the main LHC parameters, and a brief description of the RF and vacuum systems, the coupling impedances of the main machine elements are given, as well as the resulting thresholds for instabilities. (author)

  4. Collaborators await European approval of LHC

    CERN Multimedia

    Sweet, William N

    1994-01-01

    Physicists are awaiting the authorization of the proposed $2.5 billion European LHC. Germany, France, the UK and Switzerland are still arguing on how much extra contributions host countries should provide for the proton-proton collider's construction.

  5. LHC Interaction Region Upgrade Phase I

    CERN Document Server

    Ostojic, R

    2009-01-01

    The LHC is starting operation with beam in 2008. The primary goal of CERN and the LHC community is to ensure that the collider is operated efficiently, maximizing its physics reach, and to achieve the nominal performance in the shortest term. Since several years the community has been discussing the directions for upgrading the experiments, in particular ATLAS and CMS, the LHC machine and the CERN proton injector complex. A well substantiated and coherent scenario for the first phase of the upgrade, which is foreseen in 2013, is now approved by CERN Council. In this paper, we present the goals and the proposed conceptual solution for the Phase-I upgrade of the LHC interaction regions. This phase relies on the mature Nb-Ti superconducting magnet technology, with the target of increasing the luminosity by a factor of 2-3 with respect to the nominal luminosity of 1034 cm-2s-1, while maximising the use of the existing infrastructure.

  6. Physics motivations for SSC/LHC detectors

    International Nuclear Information System (INIS)

    Hinchliffe, I.

    1993-06-01

    In this talk, I review the some of the physics goals and simulation work done in the SSC and LHC experimental proposal. I select the processes that illustrate the strengths and weaknesses the proposed detectors

  7. Supersymmetry Breaking, Gauge Mediation, and the LHC

    International Nuclear Information System (INIS)

    Shih, David

    2015-01-01

    Gauge mediated SUSY breaking (GMSB) is a promising class of supersymmetric models that automatically satisfies the precision constraints. Prior work of Meade, Seiberg and Shih in 2008 established the full, model-independent parameter space of GMSB, which they called 'General Gauge Mediation' (GGM). During the first half of 2010-2015, Shih and his collaborators thoroughly explored the parameter space of GGM and established many well-motivated benchmark models for use by the experimentalists at the LHC. Through their work, the current constraints on GGM from LEP, the Tevatron and the LHC were fully elucidated, together with the possible collider signatures of GMSB at the LHC. This ensured that the full discovery potential for GGM could be completely realized at the LHC.

  8. Working on an LHC superconducting cavity

    CERN Multimedia

    Laurent Guiraud

    2000-01-01

    The delicate superconducting equipment for CERN’s LHC collider has to be assembled in ultra-clean conditions to safeguard performance. Here we see the power supply being installed on one of the superconducting cavities.

  9. UFOs in the LHC after LS1

    International Nuclear Information System (INIS)

    Baer, T.; Barnes, M.J.; Carlier, E.; Cerutti, F.; Dehning, B.; Ducimetiere, L.; Ferrari, A.; Garrel, N.; Gerardin, A.; Goddard, B.; Holzer, E.B.; Jackson, S.; Jimenez, J.M.; Kain, V.; Lechner, A.; Mertens, V.; Misiowiec, M.; Moron Ballester, R.; Nebot del Busto, E.; Norderhaug Drosdal, L.; Nordt, A.; Uythoven, J.; Velghe, B.; Vlachoudis, V.; Wenninger, J.; Zamantzas, C.; Zimmermann, F.; Fuster Martinez, N.

    2012-01-01

    UFOs (Unidentified Falling Objects) are potentially a major luminosity limitation for nominal LHC operation. With large-scale increases of the BLM thresholds, their impact on LHC availability was mitigated in the second half of 2011. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. Therefore, in 2011, the diagnostics for UFO events were significantly improved, dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. In this paper, the state of knowledge is summarized and extrapolations for LHC operation after LS1 are presented. Mitigation strategies are proposed and related tests and measures for 2012 are specified. (authors)

  10. UFOs in the LHC after LS1

    CERN Document Server

    Baer, T; Carlier, E; Cerutti, F; Dehning, B; Ducimetière, L; Ferrari, A; Garrel, N; Gérardin, A; Goddard, B; Holzer, E B; Jackson, S; Jimenez, J M; Kain, V; Lechner, A; Mertens, V; Misiowiec, M; Morón Ballester, R; Nebot del Busto, E; Norderhaug Drosdal, L; Nordt, A; Uythoven, J; Velghe, B; Vlachoudis, V; Wenninger, J; Zamantzas, C; Zimmermann, F; Fuster Martinez, N

    2012-01-01

    UFOs (Unidentified Falling Objects) are potentially a major luminosity limitation for nominal LHC operation. With large-scale increases of the BLM thresholds, their impact on LHC availability was mitigated in the second half of 2011. For higher beam energy and lower magnet quench limits, the problem is expected to be considerably worse, though. Therefore, in 2011, the diagnostics for UFO events were significantly improved, dedicated experiments and measurements in the LHC and in the laboratory were made and complemented by FLUKA simulations and theoretical studies. In this paper, the state of knowledge is summarized and extrapolations for LHC operation after LS1 are presented. Mitigation strategies are proposed and related tests and measures for 2012 are specified.

  11. Magnet production for the LHC is complete!

    CERN Multimedia

    2006-01-01

    On 27 November, the LHC teams celebrated the end of production of the machine's main magnets. Some 1232 main dipole and 392 main quadrupole magnets have been manufactured in an unprecedented collaboration effort between CERN and European industry.

  12. LHC injection optics measurements at commissioning (2015)

    CERN Document Server

    Garcia-Tabares Valdivieso, Ana; Coello De Portugal - Martinez Vazquez, Jaime Maria; Garcia-Bonilla, Alba-Carolina; Langner, Andy Sven; Maclean, Ewen Hamish; Malina, Lukas; Mcateer, Meghan Jill; Persson, Tobias Hakan Bjorn; Skowronski, Piotr Krzysztof; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    This report describes the measurement and correction process followed during the 2015 LHC injection optics commissioning which extended into Machine Developments (MDs). Results have been analyzed and compared to the 2012 measurements.

  13. The LHC test string first operational experience

    CERN Document Server

    Bézaguet, Alain-Arthur; Casas-Cubillos, J; Coull, L; Cruikshank, P; Dahlerup-Petersen, K; Faugeras, Paul E; Flemsæter, B; Guinaudeau, H; Hagedorn, Dietrich; Hilbert, B; Krainz, G; Kos, N; Lavielle, D; Lebrun, P; Leo, G; Mathewson, A G; Missiaen, D; Momal, F; Parma, Vittorio; Quesnel, Jean Pierre; Richter, D; Riddone, G; Rijllart, A; Rodríguez-Mateos, F; Rohmig, P; Saban, R I; Schmidt, R; Serio, L; Skiadelli, M; Suraci, A; Tavian, L; Walckiers, L; Wallén, E; Van Weelderen, R; Williams, L; McInturff, A

    1996-01-01

    CERN operates the first version of the LHC Test String which consists of one quadrupole and three 10-m twin aperture dipole magnets. An experimental programme aiming at the validation of the LHC systems started in February 1995. During this programme the string has been powered 100 times 35 of which at 12.4 kA or above. The experiments have yielded a number of results some of which, like quench recovery for cryogenics, have modified the design of subsystems of LHC. Others, like controlled helium leaks in the cold bore and quench propagation bewteen magnets, have given a better understanding on the evolution of the phenomena inside a string of superconducting magnets cooled at superfluid helium temperatures. Following the experimental programme, the string will be powered up and powered down in one hour cycles as a fatigue test of the structure thus simulating 20 years of operation of LHC.

  14. Literature in Focus Perspectives on LHC Physics

    CERN Multimedia

    2008-01-01

    The CERN Library invites you to a book presentation, a Literature in Focus event. The Large Hadron Collider (LHC) will be the world’s largest, highest energy and highest intensity particle accelerator. This is a timely book with several perspectives on the hoped-for discoveries from the LHC. This book provides an overview of the techniques that will be crucial for finding new physics at the LHC, as well as perspectives on the importance and implications of the discoveries. Among the accomplished contributors to this book are leaders and visionaries in the field of particle physics beyond the Standard Model, including two Nobel Laureates (Steven Weinberg and Frank Wilczek). With its blend of popular and technical contents, the book will have wide appeal, not only to physical scientists but also to those in related fields. Perspectives on LHC Physics (World Scientific Publishing) Gordon Kane and Aaron Pierce (eds.) Tuesday 12 August, 4.30pm Council Chamber Refresh...

  15. First beam splashes at the LHC

    CERN Multimedia

    CERN Bulletin

    2015-01-01

    After a two-year shutdown, the first beams of Run 2 circulated in the LHC last Sunday. On Tuesday, the LHC operators performed dedicated runs to allow some of the experiments to record their first signals coming from particles splashed out when the circulating beams hit the collimators. Powerful reconstruction software then transforms the electronic signals into colourful images.     “Splash” events are used by the experiments to test their numerous subdetectors and to synchronise them with the LHC clock. These events are recorded when the path of particles travelling in the LHC vacuum pipe is intentionally obstructed using collimators – one-metre-long graphite or tungsten jaws that are also used to catch particles that wander too far from the beam centre and to protect the accelerator against unavoidable regular and irregular beam losses. The particles sprayed out of the collision between the beam and the collimators are mostly muons. ATLAS and CMS&...

  16. LHC and CLIC LLRF final reports

    CERN Document Server

    Dexter, A; Woolley, B; Ambattu, P; Tahir, I; Syratchev, Igor; Wuensch, Walter

    2013-01-01

    Crab cavities rotate bunches from opposing beams to achieve effective head-on collision in CLIC or collisions at an adjustable angle in LHC. Without crab cavities 90% of achievable luminosity at CLIC would be lost. In the LHC, the crab cavities allow the same or larger integrated luminosity while reducing significantly the requested dynamic range of physics detectors. The focus for CLIC is accurate phase synchronisation of the cavities, adequate damping of wakefields and modest amplitude stability. For the LHC, the main LLRF issues are related to imperfections: beam offsets in cavities, RF noise, measurement noise in feedback loops, failure modes and mitigations. This report develops issues associated with synchronising the CLIC cavities. It defines an RF system and experiments to validate the approach. It reports on the development of hardware for measuring the phase performance of the RF distributions system and cavities. For the LHC, the hardware being very close to the existing LLRF, the report focuses on...

  17. VIP visit of LHC Computing Grid Project

    CERN Multimedia

    Krajewski, Yann Tadeusz

    2015-01-01

    VIP visit of LHC Computing Grid Project with Dr -.Ing. Tarek Kamel [Senior Advisor to the President for Government Engagement, ICANN Geneva Office] and Dr Nigel Hickson [VP, IGO Engagement, ICANN Geneva Office

  18. Etat Du Magnesium Dans Quelques Sols Sales Du Sud Et Du ...

    African Journals Online (AJOL)

    étude a été réalisée sur 86 échantillons de sols provenant du Centre et du Sud de l´Irak. L\\'expérimentation a consisté, d´une part, à calculer les différents sels dominants dans les sols salés par la méthode de combinaison hypothétique et, ...

  19. Caractérisation des sables et morphologie du fond du lac du ...

    African Journals Online (AJOL)

    Une analyse sédimentologique et minéralogique réalisée sur un cycle hydrologique entre octobre 2004 et août 2005 a permis d\\'évaluer les charges solides en suspension et de caractériser les sédiments du lac du barrage de Taabo. La concentration moyenne en matières en suspension (12 mg.L-1) et la turbidité ...

  20. Caractérisation des sables et morphologie du fond du lac du ...

    African Journals Online (AJOL)

    Administrateur

    Une analyse sédimentologique et minéralogique réalisée sur un cycle hydrologique entre octobre 2004 et août 2005 a permis d'évaluer les charges solides en suspension et de caractériser les sédiments du lac du barrage de Taabo. La concentration moyenne en matières en suspension (12 mg.L-1) et la turbidité ...

  1. CERN - the W and the LHC

    CERN Document Server

    Rodgers, P

    2003-01-01

    Construction of the Large Hadron Collider (LHC) and its detectors at the CERN laboratory in Geneva is a challenge of Himalayan proportions. The LHC will collide protons at energies of 14 TeV (14 million million electrons volts) and two detectors - ATLAS and CMS - will survey the debris of these collisions for signs of the Higgs boson, supersymmetric particles, large extra dimensions and other evidence of new physics beyond the Standard Model. (U.K.)

  2. A worker inside the LHC tunnel

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Technicians and engineers worked days and nights, carefully installing 20 magnets a week between 7 March 2005 and 26 April 2006. Each dipole weighs 34 tonnes and is 15 m long. Once they have been lowered down the specially constructed shaft, they begin a slow progression to their final destinations in the LHC tunnel, taking about 10 hours to arrive at the furthest point on the LHC ring.

  3. Status and prospects from the LHC

    International Nuclear Information System (INIS)

    Hawkings, Richard

    2010-01-01

    This article reviews the status of the CERN Large Hadron Collider and associated experiments as of July 2010. After a brief discussion of the progress in accelerator and experiment commissioning, the LHC physics landscape is presented, together with a selection of the experimental results achieved so far. Finally the prospects for the 2010-11 LHC physics run are reviewed, with an emphasis on possible discoveries in the Higgs and supersymmetry sectors.

  4. The LHC AC Dipole system: an introduction

    CERN Document Server

    Serrano, J; CERN. Geneva. BE Department

    2010-01-01

    The LHC AC Dipole is an instrument to study properties of the LHC lattice by inducing large transverse displacements in the beam. These displacements are generated by exciting the beam with an oscillating magnetic field at a frequency close to the tune. This paper presents the system requirements and the technical solution chosen to meet them, based of high-power audio amplifiers and a resonant parallel RLC circuit.

  5. Loss Control and Collimation for the LHC

    Science.gov (United States)

    Burkhardt, H.

    2005-06-01

    The total energy stored in the LHC is expected to reach 360 Mega Joule, which is about two orders of magnitude higher than in HERA or the Tevatron. Damage and quench protection in the LHC require a highly efficient and at the same time very robust collimation system. The currently planned system, the status of the project and the expected performance of the collimation system from injection up to operation with colliding beams will be presented.

  6. Loss Control and Collimation for the LHC

    International Nuclear Information System (INIS)

    Burkhardt, H.

    2005-01-01

    The total energy stored in the LHC is expected to reach 360 Mega Joule, which is about two orders of magnitude higher than in HERA or the Tevatron. Damage and quench protection in the LHC require a highly efficient and at the same time very robust collimation system. The currently planned system, the status of the project and the expected performance of the collimation system from injection up to operation with colliding beams will be presented

  7. Design of superconducting corrector magnets for LHC

    International Nuclear Information System (INIS)

    Baynham, D.E.; Coombs, R.C.; Ijspeert, A.; Perin, R.

    1994-01-01

    The Large Hadron Collider (LHC) will require a range of superconducting corrector magnets. This paper presents the design of sextupole and decapole corrector coils which will be included as spool pieces adjacent to reach main ring dipole. The paper gives detailed 3D field computations of the coil configurations to meet LHC beam dynamics requirements. Coil protection within a long string environment is addressed and mechanical design outlines are presented

  8. Design of superconducting corrector magnets for LHC

    Science.gov (United States)

    Baynham, D. E.; Coombs, R. C.; Ijspeert, A.; Perin, R.

    1994-07-01

    The Large Hadron Collider (LHC) will require a range of superconducting corrector magnets. This paper presents the design of sextupole and decapole corrector coils which will be included as spool pieces adjacent to each main ring dipole. The paper gives detailed 3D field computations of the coil configurations to meet LHC beam dynamics requirements. Coil protection within a long string environment is addressed and mechanical design outlines are presented.

  9. MICROCOSM - INSTALLATION OF THE LHC MODEL

    CERN Multimedia

    2002-01-01

    This week, installation of a 6m long section of the LHC starts in Microcosm. This full-scale model is the first part of a new exhibition highlighting the technological challenges and the exciting physics of the LHC era. Many people at CERN have helped with the preparations for the model and the Microcosm team would like to thank all those involved. An inauguration for the press will take place at the start of the next school term.

  10. ATLAS and the LHC in the limelight

    CERN Document Server

    Pauline Gagnon

    As we approach the starting time for the LHC, increasing visibility is given in the international press to the LHC in general and ATLAS in particular. We have noted a few of these comprehensive articles last month. Please let us know if you read about ATLAS in your favorite newspaper or magazine. The New York Times article published in the science section on May 15, 2007: Le Temps from Geneva: article published on May 9, 2007

  11. LHC suppliers win Golden Hadron awards

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    In a ceremony on 30 July, three of the 200 suppliers for the Large Hadron Collider (LHC) were presented with Golden Hadron awards. It is the third year that the awards have been presented to suppliers, not only for their technical and financial achievements but also for their compliance with contractual deadlines. This year the three companies are all involved in the supplies for the LHC's main magnet system.

  12. The LHC Transverse Damper (ADT) Performance Specification

    CERN Document Server

    Boussard, Daniel; Linnecar, Trevor Paul R; CERN. Geneva. SPS and LEP Division

    1997-01-01

    The appended document specifies the performance of the transverse damper (ADT) for the LHC. As Annex 1 of the Addendum No.1 to the Protocol of April 18, 1997; it forms part of the 1992 co-operation agreement between CERN and JINR (Dubna, Russia) concerning its participation in the LHC project. The current text is a reprint of the original version. Changes that have been agreed upon are inserted as footnotes.

  13. Delivering LHC software to HPC compute elements

    CERN Document Server

    Blomer, Jakob; Hardi, Nikola; Popescu, Radu

    2017-01-01

    In recent years, there was a growing interest in improving the utilization of supercomputers by running applications of experiments at the Large Hadron Collider (LHC) at CERN when idle cores cannot be assigned to traditional HPC jobs. At the same time, the upcoming LHC machine and detector upgrades will produce some 60 times higher data rates and challenge LHC experiments to use so far untapped compute resources. LHC experiment applications are tailored to run on high-throughput computing resources and they have a different anatomy than HPC applications. LHC applications comprise a core framework that allows hundreds of researchers to plug in their specific algorithms. The software stacks easily accumulate to many gigabytes for a single release. New releases are often produced on a daily basis. To facilitate the distribution of these software stacks to world-wide distributed computing resources, LHC experiments use a purpose-built, global, POSIX file system, the CernVM File System. CernVM-FS pre-processes dat...

  14. Introduction to the HL-LHC Project

    Science.gov (United States)

    Rossi, L.; Brüning, O.

    The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11-12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federates efforts and R&D of a large community in Europe, in the US and in Japan, which will facilitate the implementation of the construction phase as a global project.

  15. Considerations on Energy Frontier Colliders after LHC

    Energy Technology Data Exchange (ETDEWEB)

    Shiltsev, Vladimir [Fermilab

    2016-11-15

    Since 1960’s, particle colliders have been in the forefront of particle physics, 29 total have been built and operated, 7 are in operation now. At present the near term US, European and international strategies of the particle physics community are centered on full exploitation of the physics potential of the Large Hadron Collider (LHC) through its high-luminosity upgrade (HL-LHC). The future of the world-wide HEP community critically depends on the feasibility of possible post-LHC colliders. The concept of the feasibility is complex and includes at least three factors: feasibility of energy, feasibility of luminosity and feasibility of cost. Here we overview all current options for post-LHC colliders from such perspective (ILC, CLIC, Muon Collider, plasma colliders, CEPC, FCC, HE-LHC) and discuss major challenges and accelerator R&D required to demonstrate feasibility of an energy frontier accelerator facility following the LHC. We conclude by taking a look into ultimate energy reach accelerators based on plasmas and crystals, and discussion on the perspectives for the far future of the accelerator-based particle physics. This paper largely follows previous study [1] and the presenta ion given at the ICHEP’2016 conference in Chicago [2].

  16. Introduction to the HL-LHC Project

    CERN Document Server

    Rossi , L

    2015-01-01

    The Large Hadron Collider (LHC) is one of largest scientific instruments ever built. It has been exploring the new energy frontier since 2010, gathering a global user community of 7,000 scientists. To extend its discovery potential, the LHC will need a major upgrade in the 2020s to increase its luminosity (rate of collisions) by a factor of five beyond its design value and the integrated luminosity by a factor of ten. As a highly complex and optimized machine, such an upgrade of the LHC must be carefully studied and requires about ten years to implement. The novel machine configuration, called High Luminosity LHC (HL-LHC), will rely on a number of key innovative technologies, representing exceptional technological challenges, such as cutting-edge 11–12 tesla superconducting magnets, very compact superconducting cavities for beam rotation with ultra-precise phase control, new technology for beam collimation and 300-meter-long high-power superconducting links with negligible energy dissipation. HL-LHC federa...

  17. 1754 Days to the LHC and counting!

    CERN Multimedia

    2001-01-01

    At the 118th session of CERN Council, held on Friday 15 June under the chairmanship of Professor Maurice Bourquin of Switzerland, Director-General, Luciano Maiani, presented the commissioning schedule for the Large Hadron Collider (LHC) for the first time. The LHC will collide its first beams in a pilot run starting on 1 April 2006. 'We are 1754 days from the LHC', said Professor Maiani. A full seven-month physics run will begin in August 2006, and the LHC's heavy-ion programme will start in February 2007. Left to right: Lyn Evans, Luciano Maiani, Alexander Skrinsky, and Kurt Hubner with the magnets from Novosibirsk. Professor Maiani underlined to Council that the LHC is now CERN's most important single activity, accounting for over 70% of the Laboratory's resources. Moreover, with some 70% of the total LHC cost adjudicated and 30% paid, the project is very far advanced. With the adjudication this Autumn of the contracts for the 1236 fifteen metre superconducting dipole magnets, the placing of major contrac...

  18. From the LHC to Future Colliders

    Energy Technology Data Exchange (ETDEWEB)

    De Roeck, A.; Ellis, J.; /CERN; Grojean, C.; Heinemeyer, S.; /Cantabria Inst. of Phys.; Jakobs, K.; /Freiburg U.; Weiglein, G.; /Durham U., IPPP; Azuelos, G.; /TRIUMF; Dawson, S.; /Brookhaven; Gripaios, B.; /CERN; Han, T.; /Wisconsin U., Madison; Hewett, J.; /SLAC; Lancaster, M.; /University Coll. London; Mariotti, C.; /INFN, Turin; Moortgat, F.; /Zurich, ETH; Moortgat-Pick, G.; /Durham U., IPPP; Polesello, G.; /INFN, Pavia; Riemann, S.; /DESY; Assamagan, K.; /Brookhaven; Bechtle, P.; /DESY; Carena, M.; /Fermilab; Chachamis, G.; /PSI, Villigen /Taiwan, Natl. Taiwan U. /INFN, Florence /Bonn U. /CERN /Bonn U. /Freiburg U. /Oxford U. /Louvain U., CP3 /Bangalore, Indian Inst. Sci. /INFN, Milan Bicocca /Munich, Max Planck Inst. /Taiwan, Natl. Taiwan U. /Frascati /Fermilab /Warsaw U. /Florida U. /Orsay, LAL /LPSC, Grenoble /Warsaw U. /Yale U. /Stockholm U., Math. Dept. /Durham U., IPPP /DESY /Rome U. /University Coll. London /UC, San Diego /Heidelberg U. /Florida State U. /SLAC /Durham U., IPPP /Southern Denmark U., CP3-Origins /McGill U. /Durham U., IPPP; /more authors..

    2010-06-11

    Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300 fb{sup -1} of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb{sup -1} of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, theWorking Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.

  19. Le bal du loup

    CERN Multimedia

    Happy Children's Home

    2013-01-01

    The Bord'eau amateur theatre group will graciously perform a play of their creation Le bal du loup Saturday 19 October 2013 at 20:00 Sunday 20 October at 17:00 in the Théâtre des Grottes Rue Louis Favre 43, 1201 Genève Children from age 12 upwards. Summary: The new-elected mayoress of a small village would like to clean up the town by prohibiting alcohol and getting rid of its prostitutes. Then along comes « Massimo Lupo » the pimp... The performances will be given to support the Happy Children's Home charity, which runs a foster-home in Pokhara for Nepali children:  http://www.happychildrenshome.org/ Admission : minimum charge of 10 CHF per person requested, to cover the cost of technical assistance and theatre rental. Any profit will be used solely for the foster-home. At the end of each performance members of the HCH charity will be happy to answer any questions you may have. The theatre has 86 seats, thank you for reserv...

  20. LHC Report: playing with angles

    CERN Multimedia

    Mike Lamont for the LHC team

    2016-01-01

    Ready (after a machine development period), steady (running), go (for a special run)!   The crossing angles are an essential feature of the machine set-up. They have to be big enough to reduce the long-range beam-beam effect. The LHC has recently enjoyed a period of steady running and managed to set a new record for “Maximum Stable Luminosity Delivered in 7 days” of 3.29 fb-1 between 29 August and 4 September. The number of bunches per beam remains pegged at 2220 because of the limitations imposed by the SPS beam dump. The bunch population is also somewhat reduced due to outgassing near one of the injection kickers at point 8. Both limitations will be addressed during the year-end technical stop, opening the way for increased performance in 2017. On 10 and 11 September, a two day machine development (MD) period took place. The MD programme included a look at the possibility of reducing the crossing angle at the high-luminosity interaction points. The crossing angles are an ess...

  1. RF Power Generation in LHC

    CERN Document Server

    Brunner, O C; Valuch, D

    2003-01-01

    The counter-rotating proton beams in the Large Hadron Collider (LHC) will be captured and then accelerated to their final energies of 2 x 7 TeV by two identical 400 MHz RF systems. The RF power source required for each beam comprises eight 300 kW klystrons. The output power of each klystron is fed via a circulator and a waveguide line to the input coupler of a single-cell super-conducting (SC) cavity. Four klystrons are powered by a 100 kV, 40A AC/DC power converter, previously used for the operation of the LEP klystrons. A five-gap thyratron crowbar protects the four klystrons in each of these units. The technical specification and measured performance of the various high-power elements are discussed. These include the 400MHz/300kW klystrons with emphasis on their group delay and the three-port circulators, which have to cope with peak reflected power levels up to twice the simultaneously applied incident power of 300 kW. In addition, a novel ferrite loaded waveguide absorber, used as termination for port No...

  2. The LHC injection kicker magnet

    CERN Document Server

    Ducimetière, Laurent; Barnes, M J; Wait, G D

    2003-01-01

    Proton beams will be injected into LHC at 450 GeV by two kicker magnet systems, producing magnetic field pulses of approximately 900 ns rise time and up to 7.86 s flat top duration. One of the stringent design requirements of these systems is a flat top ripple of less than ± 0.5%. Both injection systems are composed of 4 travelling wave kicker magnets of 2.7 m length each, powered by pulse forming networks (PFN's). To achieve the required kick strength of 1.2 Tm, a low characteristic impedance has been chosen and ceramic plate capacitors are used to obtain 5 Omega. Conductive stripes in the aperture of the magnets limit the beam impedance and screen the ferrite. The electrical circuit has been designed with the help of PSpice computer modelling. A full size magnet prototype has been built and tested up to 60 kV with the magnet under ultra high vacuum (UHV). The pulse shape has been precision measured at a voltage of 15 kV. After reviewing the performance requirements the paper presents the magnet...

  3. The LHC, de-squeezed

    CERN Multimedia

    CERN Bulletin

    2012-01-01

    Rare processes like the Higgs production require maximizing the number of proton collisions. This is done by squeezing the beams to very small sizes. However, interesting physics processes also happen when beams are not squeezed at interaction points. Last week, a dedicated run showed that the LHC is a record-breaking machine also with de-squeezed beams.   This figure shows an online hit map of one of the ATLAS/ALFA detectors. The narrow elliptical shape is the typical signal produced by elastically scattered protons. The removal of the background (central bulge) is a challenge for both experiments. The beam squeezing parameter is known by experts as beta-star (ß*): the smaller the ß*, the stronger the squeezing. To obtain as many collisions as possible in the heart of the experiments, the ß* at full energy is 0.60 m – that is, beams are squeezed to very small beam sizes. This maximizes the rate of proton collisions as required for rare process...

  4. LHC Report: reaching high intensity

    CERN Multimedia

    Jan Uythoven

    2015-01-01

    After both beams having been ramped to their full energy of 6.5 TeV, the last two weeks saw the beam commissioning process advancing on many fronts. An important milestone was achieved when operators succeeded in circulating a nominal-intensity bunch. During the operation, some sudden beam losses resulted in beam dumps at top energy, a problem that needed to be understood and resolved.   In 2015 the LHC will be circulating around 2800 bunches in each beam and each bunch will contain just over 1 x 1011 protons. Until a few days ago commissioning was taking place with single bunches of 5 x 109 protons. The first nominal bunch with an intensity of 1 x 1011 protons was injected on Tuesday, 21 April. In order to circulate such a high-intensity bunch safely, the whole protection system must be working correctly: collimators, which protect the aperture, are set at preliminary values known as coarse settings; all kicker magnets for injecting and extracting the beams are commissioned with beam an...

  5. The latest from the LHC

    CERN Multimedia

    2009-01-01

    The consolidation campaign, managed by the Quench Protection team, is advancing well. Phase 1 of the campaign is focused on the new protection system designed to monitor the superconducting busbars. This system will be able to detect tiny electrical resistances on these busbars, similar to the one that caused the incident in Sector 3-4. Following completion of the design of the two principal electronics boards, the first order for 2500 and 500 such boards will be placed this week. The manufacture of the cable segments for the first three LHC sectors is going ahead, and the installation programme has already begun in Sector 4-5. In total, more than 230 km of various types of cables will have to be laid. The complete system will consist of a network of 2132 detectors housed in 436 crates around the machine. These will monitor the interconnections of the main dipoles and quadrupoles in the three major circuits. The detectors will precisely measure the electrical resistance of each busbar segment, including the ...

  6. LHC rap: a global phenomenon

    CERN Multimedia

    2008-01-01

    Do you think the LHC is super duper fly? Does it make you want to compose some slick rhymes and bust out some killer beats? It did for one CERN rapper, and the results have become a YouTube smash hit! Katie McAlpine will sing for the CMS party on 24 September, and for the ATLAS Fest on 4 October.The Large Hadron Rap, to give it its full name, is the brainchild of AlpineKat, AKA Katie McAlpine, who is currently working for ATLAS e-News and outreach. To date, the YouTube video rap has been viewed more than 2.5 million times, to say nothing of the media coverage. Featured in newspapers around the world, including the New York Times in the US, The Telegraph in the UK and Geneva’s very own Matin Bleu, the rap is officially a sensation! Katie wrote the inspired (and pretty accurate) physics lyrics during her commute on the number 56 bus between Geneva and CERN. After obtaining permission to film in the experiment caverns and tunnel,...

  7. Powering CERN and the LHC

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    CERN's electricity network is denser than that of the Canton of Geneva, is powered by two different national grids and has to provide users with an availability rate as close to 100% as possible. To ensure the smooth running of the machines throughout the period of LHC physics operation, the teams from the EN Department are implementing a continuous programme of consolidation and modernisation on all the Laboratory's sites, but the biggest projects will have to wait until the long technical shutdown scheduled for 2013.   An electrical installation at CERN. CERN's annual electricity consumption is around one terawatt hour (TWh), which roughly corresponds to a fifth of the consumption of the Canton of Geneva. However, during periods when all the machines are operating at the same time, our demand can reach the equivalent of a third of Geneva's total consumption. While the grid of the Geneva public utility company SIG (Services Industriels de Genève) covers distances of around 50 km, the ...

  8. LHC Report: First collisions soon

    CERN Multimedia

    Jan Uythoven for the LHC team

    2012-01-01

    On the evening of Friday 16 March beams were accelerated in the LHC at 4 TeV for the first time: a new world record! According to the schedule for the machine restart it will take another three weeks before the stable beams mode – the requirement for the detectors to start taking data – is achieved.   During the beam commissioning period the equipment teams make sure that their systems – beam instrumentation, radio frequency, beam interlock, feedback on orbit and tune, etc. – are working flawlessly with beam. Confidence in the correct functioning of all the magnets, their settings and their alignment is obtained by detailed measurements of the optics and the physical aperture. The optics measurements include the beta* of the squeezed beam at the centre of the experiments where the collisions will soon take place. This year the aim is to have a smaller beta* of 60 cm for the ATLAS and CMS experiments. As a reminder, smaller values of beta* mean thinner and m...

  9. The latest from the LHC

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    The setting-up to prepare the LHC for running with nominal ramp rates and with bunch trains instead of single-bunch injection have continued over the last two weeks. The goal is to reduce the machine filling time and increase its luminosity. Running with bunch trains requires the careful setting-up of crossing angles in order to avoid unwanted collisions on either side of the experiments.   The technical target for 2010 in terms of bunch spacing in the trains is 150 ns, which corresponds to a physical distance of about 45 m. This target will be progressively reduced next year to eventually attain the nominal value of 25 ns, equivalent to a distance of about 7.5 m between two bunches in the trains. Following initial setting-up last week, this week tests were made to check the size of the crossing angle needed to avoid parasitic collisions when 150 ns trains are injected into the machine, and to measure the aperture with the nominal crossing angle –at injection – of 170 micro radi...

  10. LHC Report: Restart preparations continue

    CERN Multimedia

    Katy Foraz for the LHC team and Julia Trummer for the RP Group

    2012-01-01

    Maintenance and consolidation work has been progressing well in both the machine and the experiments in preparation for the March restart.   A sample material is attached to the LHC (the white bag taped to the green line), to measure the radiation doses. Additional work was required around Point 5 due to the discovery and repair of a problem with the RF fingers at the connection of two beam vacuum chambers in CMS. The repair has been completed successfully and the sector is now under vacuum. In order to avoid rushing the delicate final operations required for closing the detector, the restart of the machine has been postponed by one week, from 7 March to 14 March. In the machine, the first cool-down to 1.9 K has started in several sectors ,and the cool-down of the whole machine is still planned to be finished by 21 February. The time window between 22 February and 14 March will be dedicated to powering and cryogenic tests. Since 12 December, the Radiation Protection (RP) group has been deep...

  11. Composite Leptoquarks at the LHC

    CERN Document Server

    Gripaios, Ben

    2010-01-01

    If electroweak symmetry breaking arises via strongly-coupled physics, the observed suppression of flavour-changing processes suggests that fermion masses should arise via mixing of elementary fermions with composite fermions of the strong sector. The strong sector then carries colour charge, and may contain composite leptoquark states, arising either as TeV scale resonances, or even as light, pseudo-Nambu-Goldstone bosons. The latter, since they are coupled to colour, get a mass of the order of several hundred GeV, beyond the reach of current searches at the Tevatron. The same generic mechanism that suppresses flavour-changing processes suppresses leptoquark-mediated rare processes, making it conceivable that the many stringent constraints may be evaded. The leptoquarks couple predominantly to third-generation quarks and leptons, and the prospects for discovery at LHC appear to be good. As an illustration, a model based on the Pati-Salam symmetry is described, and its embedding in models with a larger symmetr...

  12. Latest news from the LHC

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Over the past two weeks the LHC operations team has focused on pushing the LHC’s performance into new territory in terms of stored beam power. Moving to 25 bunches per beam with almost nominal bunch intensities at the end of July implied operation with a stored energy in each beam of more than 1 MJ. This corresponds to the current record for stored beam energy in existing hadron accelerators (e.g. CERN’s SPS and Fermilab’s Tevatron) and it marks an energy regime where a sudden loss of beam or operational errors can result in serious damage to equipment: an energy of 1 MJ is sufficient to melt 2 kg of copper. Extreme care and a thorough optimization of all operational procedures are therefore required in making this important transition in the machine’s performance.   The focus of the past two weeks has been on optimizing the operational procedures and the machine protection systems, with the aim of gaining experience with the reliability and reproducibility of...

  13. LHC Report: Freshly squeezed beams!

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    After careful validation of  new machine settings, the LHC was ready for higher luminosity operation. New luminosity records have been set, but the operations team continues to wrestle with machine availability issues.   The commissioning of the squeeze to a ß* of 1 m in ATLAS and CMS described in the last Bulletin took until Wednesday, 7 September to complete. In order to validate the new set-up, beam losses were provoked in a controlled way with low intensity beams. The distribution of beam loss around the machine in these tests is known as a loss map. The loss maps showed that the collimation system is catching the large majority of beam losses as it should, and that the machine was ready for us to ramp the number of bunches back up and go to physics production. The ramp-up of the number of bunches went smoothly with fills at 264, 480, and 912 bunches on the way back to the machine’s previous record of 1380 bunches (first fill on Friday, 9 Se...

  14. LHC Report: 2 inverse femtobarns!

    CERN Multimedia

    Mike Lamont for the LHC Team

    2011-01-01

    The LHC is enjoying a confluence of twos. This morning (Friday 5 August) we passed 2 inverse femtobarns delivered in 2011; the peak luminosity is now just over 2 x1033 cm-2s-1; and recently fill 2000 was in for nearly 22 hours and delivered around 90 inverse picobarns, almost twice 2010's total.   In order to increase the luminosity we can increase of number of bunches, increase the number of particles per bunch, or decrease the transverse beam size at the interaction point. The beam size can be tackled in two ways: either reduce the size of the injected bunches or squeeze harder with the quadrupole magnets situated on either side of the experiments. Having increased the number of bunches to 1380, the maximum possible with a 50 ns bunch spacing, a one day meeting in Crozet decided to explore the other possibilities. The size of the beams coming from the injectors has been reduced to the minimum possible. This has brought an increase in the peak luminosity of about 50% and the 2 x 1033 cm...

  15. LHC Report: Ions cross protons

    CERN Multimedia

    Reyes Alemany Fernandez for the LHC team

    2013-01-01

    The LHC starts the New Year facing a new challenge: proton-lead collisions in the last month before the shutdown in mid-February.    The first stable beams were achieved on 20 January with 13 individual bunches per beam. In the next fill, the first bunch-trains were injected and stable beams were achieved with 96 proton on 120 ion bunches.  This fill was very important because we were able to study the so-called moving long-range beam-beam encounters. Long-range encounters, which are also seen in proton-proton runs, occur when the bunches in the two beams “see” each other as they travel in the same vacuum chamber at either side of the experiments.  The situation becomes more complicated with proton-lead ions because the two species have different revolution times (until the frequencies are locked at top energy- see “Cogging exercises”) and thus these encounters move. We found that this effect does not cause significant beam losses...

  16. The latest from the LHC

    CERN Multimedia

    Mathew Stracy

    As promised by the Director-General, we will start a series of regular updates detailing the status of the LHC repairs, consolidation and commissioning.As of last week all magnets in the damaged area of sector 3-4 have been removed and raised to the surface. In total 39 dipoles and 14 short straight sections are now on the surface. Four replacement magnets have been lowered and installed, and by the end of this week this figure should total seven. Cold testing replacement magnets in SM18 has resumed after the Christmas shutdown. The civil engineering work to repair the slight damage to the concrete has been completed. Outside the damaged area the Vacuum Group are cleaning some of the beam screens in situ.Both sector 1-2 and sector 5-6 are also now at room temperature and accessible. As well as routine maintenance in these sectors, one magnet from sector 1-2 which was found to have high resistance (approximately 100 nano-ohms, two orders of magnitude higher than the specified resistance) has been removed and ...

  17. The latest from the LHC

    CERN Document Server

    2009-01-01

    On 26 August, the first two fully tested crates for the new quench protection system (QPS) were installed in Sector 1-2. These are the first of 436 crates that will be installed around the ring. The two crates include detectors for both the enhanced busbar protection and the symmetric quench protection (more details). To test the crates before installation, a dedicated test bed has been created, capable of simulating all the conditions in the LHC, from a symmetric quench to an increase in busbar resistance. The teams are working two shifts a day, including weekends, to test the new crates. Two more test benches are also being built to increase the production rate. The whole task is on target for completion in mid October. Another important new task for the QPS team is to try and speed up the energy extraction from the magnets. The quicker the energy can be extracted the lower the risk of dangerously high temperatures should a quench occur. The time constant for the dipoles...

  18. The TOTEM Detector at LHC

    CERN Document Server

    Ruggiero, G; Aspell, P; Atanassov, I; Avati, V; Berardi, V; Berretti, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Ciocci, M A; Csanád, M; Csörgö, T; Deile, M; Dénes, E; Dimovasili, E; Doubek, M; Eggert, K; Ferro, F; Garcia, F; Giani, S; Greco, V; Grzanka, L; Heino, J; Hilden, T; Janda, M; Kaspar, J; Kopal, J; Kundrát, V; Kurvinen, K; Lami, S; Latino, G; Lauhakangas, R; Lippmaa, E; Lokajícek, M; Lo Vetere, M; Lucas Rodriguez, F; Macrí, M; Magazzù, G; Minutoli, S; Niewiadomski, H; Notarnicola, G; Novak, T; Oliveri, E; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Pedreschi, E; Petäjäjärvi, J; Quinto, M; Radermacher, E; Radicioni, E; Ravotti, F; Robutti, E; Ropelewski, L; Rummel, A; Saarikko, H; Sanguinetti, G; Santroni, A; Scribano, A; Sette, G; Snoeys, W; Spearman, W; Spinella, F; Ster, A; Taylor, C; Trummal, A; Turini, N; Vacek, V; Vitek, M; Whitmore, J; Wu, J

    2010-01-01

    The TOTEM experiment, small in size compared to the others at the LHC, is dedicated to the measurement of the total proton-proton cross-section with the luminosity-independent method and to the study of elastic and diffractive scattering. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side in the pseudo-rapidity region between 3.1 and 6.5, and Roman Pot (RP) stations are placed at distances of 147m and 220m from IP5. The telescope closest to the interaction point (T1, centered at z = 9 m) consists of Cathode Strip Chambers (CSC), while the second one (T2, centered at 13.5 m), makes use of Gas Electron Multipliers (GEM). The proton detectors in the RPs are silicon devices designed by TOTEM with the specific objective of reducing down to a few tens of microns the insensitive area at the edge. High efficiency as close as possible to the physical detector boundary is an essential feature...

  19. The latest from the LHC

    CERN Multimedia

    2009-01-01

    The LHC will run with an energy of 3.5 TeV per beam when it starts up in November this year. The 80 K resistance measurements on the copper stabilizer of the superconducting busbars were completed in the remaining sectors, Sectors 8-1 and 2-3. No abnormally high resistance measurements were found, indicating that no further repairs are necessary for safe running. Detailed analysis of the resistance data from the entire ring determined a safe initial energy of 3.5 TeV per beam. Once a significant data sample has been collected and the operations team has gained experience in running the machine, the energy will be taken towards 5 TeV per beam. More information is available in the recent press release http://press.web.cern.ch/press/PressReleases/Releases2009/PR13.09E.html. Following the helium leaks into the insulation vacuum in Sectors 2-3 and 8-1 (see previous update) the cause of the leak in Sector 2-3 has been confirmed as the flexible hose. This has now been replaced...

  20. MSSM Forecast for the LHC

    CERN Document Server

    Cabrera, Maria Eugenia; de Austri, Roberto Ruiz

    2009-01-01

    We perform a forecast of the MSSM with universal soft terms (CMSSM) for the LHC, based on an improved Bayesian analysis. We do not incorporate ad hoc measures of the fine-tuning to penalize unnatural possibilities: such penalization arises from the Bayesian analysis itself when the experimental value of $M_Z$ is considered. This allows to scan the whole parameter space, allowing arbitrarily large soft terms. Still the low-energy region is statistically favoured (even before including dark matter or g-2 constraints). Contrary to other studies, the results are almost unaffected by changing the upper limits taken for the soft terms. The results are also remarkable stable when using flat or logarithmic priors, a fact that arises from the larger statistical weight of the low-energy region in both cases. Then we incorporate all the important experimental constrains to the analysis, obtaining a map of the probability density of the MSSM parameter space, i.e. the forecast of the MSSM. Since not all the experimental i...