16 February 2012 - Chinese Taipei Ambassador to Switzerland F. Hsieh in the ATLAS visitor centre, ATLAS experimental area and LHC tunnel at Point 1 with Collaboration Deputy Sookesperson A. Lankford, throughout accompanied by International Relations Adviser R. Voss.

CERN Multimedia

Jean-Claude Gadmer

2012-01-01

16 February 2012 - Chinese Taipei Ambassador to Switzerland F. Hsieh in the ATLAS visitor centre, ATLAS experimental area and LHC tunnel at Point 1 with Collaboration Deputy Sookesperson A. Lankford, throughout accompanied by International Relations Adviser R. Voss.

28 June 2012 - Members of the European Brain Council led by President Mary Baker visiting the LHC tunnel at Point 5 with Technology Department Group Leader L. Bottura and CMS experimental area with Run Coordinator M. Chamizo-Llatas.

CERN Multimedia

Jean-Claude Gadmer

2012-01-01

28 June 2012 - Members of the European Brain Council led by President Mary Baker visiting the LHC tunnel at Point 5 with Technology Department Group Leader L. Bottura and CMS experimental area with Run Coordinator M. Chamizo-Llatas.

14 December 2011 - Czech Republic Delegation to CERN Council and Finance Committees visiting ATLAS experimental area, LHC tunnel and ATLAS visitor centre with Former Collaboration Spokesperson P. Jenni, accompanied by Physicist R. Leitner and Swiss student A. Lister.

CERN Multimedia

Estelle Spirig

2011-01-01

14 December 2011 - Czech Republic Delegation to CERN Council and Finance Committees visiting ATLAS experimental area, LHC tunnel and ATLAS visitor centre with Former Collaboration Spokesperson P. Jenni, accompanied by Physicist R. Leitner and Swiss student A. Lister.

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.

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...

ST/EL and ST/CV services for TI2 & TI8 LHC injection tunnels

CERN Document Server

Akhtar, S; CERN. Geneva. ST Division

2002-01-01

This paper describes the ST/EL and ST/CV services for TI2 & TI8 LHC injection tunnels. The cooling and ventilation part describes the requirements for design and installation of more than 10 km of pipeline that is going to be laid down in the tunnels. Main operating parameters as well as manufacture procedures are explained. Preliminary work schedule with the cost estimate is also presented. Electrical power will be distributed from the LHC side and the SPS side for the machine and the general services. All power converters will be installed on surface buildings. The link between the main bend converters and the main bend magnets will be realised with water-cooled cables. Rest of the magnets will be cabled by using conventional copper and aluminium cables. Due to long lengths of the injection tunnels a dry 18kV transformer will be installed in TJ8 to serve the general services for TI8. The same will apply to TI2 by installing a transformer at the bottom of the PMI2 shaft.

28th January 2011-Vice-President Max Planck Society-Prof. Martin Stratmann-Germany-visiting the ATLAS experimental area and the LHC Tunnel at CERN

CERN Multimedia

Jean-Claude Gadmer

2011-01-01

Photo 1:ATLAS visitor Center with P. Jenni, ATLAS Collaboration former spokesperson Photo 2-10:visiting the ATLAS cavern Photo 10:D. Hoppe,P. Jenni,M. Stratmann,S. Bethke,S. Braun,D. Klammer Photo 11-15:visiting the LHC tunnel Photo 16-18:Signature of the Guest Book with S. Lettow,Director for Administration and General Infrastructure

Breaking through the tranfer tunnel

CERN Document Server

Laurent Guiraud

2001-01-01

This image shows the tunnel boring machine breaking through the transfer tunnel into the LHC tunnel. Proton beams will be transferred from the SPS pre-accelerator to the LHC at 450 GeV through two specially constructed transfer tunnels. From left to right: LHC Project Director, Lyn Evans; CERN Director-General (at the time), Luciano Maiani, and Director for Accelerators, Kurt Hubner.

QPS/LHC Activities requiring important Tunnel Work During a future long Shutdown

CERN Document Server

Dahlerup-Petersen, K

2011-01-01

The MPE/circuit protection section is presently establishing a road map for its future LHC activities. The tasks comprise essential consolidation work, compulsory upgrades and extensions of existing machine facilities. The results of a first round of engineering exertion were presented and evaluated at a MPE activity review in December 2010. The technical and financial aspects of this program will be detailed in the ‘QPS Medium and Long-Term Improvement Plan’, to be published shortly. The QPS activities in the LHC tunnel during a future, long shutdown are closely related to this improvement chart. A project-package based program for the interventions has been established and will be presented in this report, together with estimates for the associated human and financial resources necessary for its implementation.

Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

Science.gov (United States)

Infantino, Angelo; Alía, Rubén García; Besana, Maria Ilaria; Brugger, Markus; Cerutti, Francesco

2017-09-01

As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh), running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee) as well as a lepton-hadron option (FCC-he). In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

Preliminary design of CERN Future Circular Collider tunnel: first evaluation of the radiation environment in critical areas for electronics

Directory of Open Access Journals (Sweden)

Infantino Angelo

2017-01-01

Full Text Available As part of its post-LHC high energy physics program, CERN is conducting a study for a new proton-proton collider, called Future Circular Collider (FCC-hh, running at center-of-mass energies of up to 100 TeV in a new 100 km tunnel. The study includes a 90-350 GeV lepton collider (FCC-ee as well as a lepton-hadron option (FCC-he. In this work, FLUKA Monte Carlo simulation was extensively used to perform a first evaluation of the radiation environment in critical areas for electronics in the FCC-hh tunnel. The model of the tunnel was created based on the original civil engineering studies already performed and further integrated in the existing FLUKA models of the beam line. The radiation levels in critical areas, such as the racks for electronics and cables, power converters, service areas, local tunnel extensions was evaluated.

Risk analysis of the LHC underground area fire risk due to faulty electrical equipment

CERN Document Server

Harrison, A

2007-01-01

The European Organisation for Nuclear Research (CERN) in Geneva, Switzerland, is currently building the latest generation of particle accelerators, the LHC (Large Hadron Collider). The machine is housed in a circular tunnel of 27 km of circumference and is situated approximately 100 metres beneath the surface astride the Franco-Swiss border. Electrically induced fires in the LHC are a major concern, since an incident could present a threat to CERN personnel as well as the public. Moreover, the loss of equipment would result in significant costs and downtime. However, the amount of electrical equipment in the underground area required for operation, supervision and control of the machine is essential. Thus the present thesis is assessing the risk of fire due to faulty electrical equipment in both a qualitative as well as quantitative way. The recommendations following the qualitative analysis suggest the introduction of fire protection zones for the areas with the highest risk of fire due to a combination of p...

Coldbox installation for HL-LHC crab cavity test in the SPS tunnel (BA6)

CERN Document Server

Ordan, Julien Marius

2018-01-01

The Cold-box, produced by Linde Kryotechnik for the SPS crab-cavity test stand for HL-LHC, on its arrival at CERN. It wll be transported into the tunnel in horizontal position and then will have to be tilted in its operational position, on its vertical axis, before connecting it to cryogenics lines.

No access to LHC from 7 to 13 January 2008

CERN Multimedia

ST Department

2007-01-01

From 7 to 13 January 2008, tests of the LHC access system will be carried out to validate its role in the operational safety of the LHC. During this period, no access will be permitted to the controlled zones of LHC: service zones, experimental areas and tunnels. Access to the machine shafts and the tunnels will only be possible for emergency interventions coordinated with the CCC operators or for fire brigade interventions. The biometric access card integrated with the dosimeter, as issued by Bldg. 55, must be used to access these areas during this period. Access to the experimental caverns will be managed by the respective technical coordinator. After the tests, the access system will be restored to installation mode, i.e. access will again be possible using the CERN access cards for authorised personnel. Please communicate this information to your contractors. Thank you in advance for your comprehension and collaboration. Pierre Ninin - "LHC Access" project leader

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...

Proposal for the award of a contract for the supply and installation of pipelines for the LHC accelerator tunnel

CERN Document Server

2001-01-01

This document concerns the award of a contract for the supply and installation of pipelines for the LHC accelerator tunnel. Following a market survey carried out among 92 firms in fifteen Member States, a call for tenders (IT-2682/ST/LHC) was sent on 7 September 2001 to seven firms, seven consortia consisting of two firms and three consortia consisting of four firms, in twelve Member States. By the closing date, CERN had received 11 tenders from five firms and six consortia in ten Member States. The Finance Committee is invited to agree to the negotiation of a contract with RENCO (IT), the lowest compliant bidder, for the supply and installation of pipelines for the LHC accelerator tunnel for a total amount of 21 995 304 Swiss francs, not subject to revision. The firm has indicated the following distribution by country of the contract value covered by this adjudication proposal: IT - 100%.

14 February 2012 - Ambassadors from Algeria, Brunei Darussalam, Canada, Chad, Tunisia, Permanent Representatives to the United Nations Office at Geneva in the LHC tunnel at Point 1, ATLAS visitor centre, and ATLAS underground experimental area, throughout accompanied by Advisers P. Fassnacht, E. Tsesmelis and R. Voss

CERN Multimedia

Jean-Claude Gadmer

2012-01-01

14 February 2012 - Ambassadors from Algeria, Brunei Darussalam, Canada, Chad, Tunisia, Permanent Representatives to the United Nations Office at Geneva in the LHC tunnel at Point 1, ATLAS visitor centre, and ATLAS underground experimental area, throughout accompanied by Advisers P. Fassnacht, E. Tsesmelis and R. Voss

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 February 2012 - Supreme Audit Institutions from Norway, Poland, Spain and Switzerland visiting the LHC tunnel at Point 5, CMS underground experimental area, CERN Control Centre and LHC superconducting magnet test hall. Delegations are throughout accompanied by Swiss P. Jenni, Polish T. Kurtyka, Spanish J. Salicio, Norwegian S. Stapnes and International Relations Adviser R. Voss. (Riksrevisjonen, Oslo; Tribunal de Cuentas , Madrid; the Court of Audit of Switzerland and Najwyzsza Izba Kontroli, Varsaw)

CERN Multimedia

Jean-Claude Gadmer

2012-01-01

6 February 2012 - Supreme Audit Institutions from Norway, Poland, Spain and Switzerland visiting the LHC tunnel at Point 5, CMS underground experimental area, CERN Control Centre and LHC superconducting magnet test hall. Delegations are throughout accompanied by Swiss P. Jenni, Polish T. Kurtyka, Spanish J. Salicio, Norwegian S. Stapnes and International Relations Adviser R. Voss. (Riksrevisjonen, Oslo; Tribunal de Cuentas , Madrid; the Court of Audit of Switzerland and Najwyzsza Izba Kontroli, Varsaw)

27 January 2012 - Mitglieder des Stiftungsrates Academia Engelberg und Gesellschaft zum Bettag Luzern Schweiz welcomed by Head of International Relations F. Pauss; visiting LHC tunnel at Point 5 and CMS experimental cavern; in the LHC superconducting magnet test hall SM18.

CERN Multimedia

Maximilien Brice

2012-01-01

27 January 2012 - Mitglieder des Stiftungsrates Academia Engelberg und Gesellschaft zum Bettag Luzern Schweiz welcomed by Head of International Relations F. Pauss; visiting LHC tunnel at Point 5 and CMS experimental cavern; in the LHC superconducting magnet test hall SM18.

10 February 2012 - Permanent Representative of the Republic of India to the Conference on Disarmament, United Nations Office at Geneva Ambassador Mehta signing the guest book with International Relations Adviser R. Voss;in the LHC tunnel at Point 2 and ALICE underground experimental area with Collaboration Deputy Spokesperson Y. Schutz.

CERN Document Server

Maximilien Brice

2012-01-01

10 February 2012 - Permanent Representative of the Republic of India to the Conference on Disarmament, United Nations Office at Geneva Ambassador Mehta signing the guest book with International Relations Adviser R. Voss;in the LHC tunnel at Point 2 and ALICE underground experimental area with Collaboration Deputy Spokesperson Y. Schutz.

Maintenance des équipements de transport pour l'installation des cryo-aimants dans le tunnel LHC

CERN Document Server

Chevalley, JM

2005-01-01

Le transport et l’installation de quelque 1800 cryo-aimants dans le tunnel LHC seront réalisés à l’aide d’équipements de transport et de manutention de haute technologie spécialement développés par le groupe TS-IC. La section HM devra assurer la maintenance de toute cette chaîne d’équipements : le pont roulant pour la descente des cryo-aimants dans le tunnel LHC, les véhicules de transport spéciaux alimentés dans le tunnel par la gaine monorail et enfin les tables de transfert utilisées pour la mise en place finale des cryo-aimants sur leurs vérins. Dans ce cadre, plusieurs aspects seront développés dans ce document : la mise en place et l’organisation de la maintenance, l’analyse des modes de défaillance et de leur criticité (AMDEC), les différentes méthodes possibles pour la recherche et résolution des pannes, ainsi que le suivi du projet, et ce dans le but de fiabiliser et d†™assurer le bon fonctionnement de t...

Excavating a transfer tunnel

CERN Multimedia

Laurent Guiraud

2000-01-01

The transfer tunnel being dug here will take the 450 GeV beam from the SPS and inject it into the LHC where the beam energies will be increased to 7 TeV. In order to transfer this beam from the SPS to the LHC, two transfer tunnels are used to circulate the beams in opposite directions. When excavated, the accelerator components, including magnets, beam pipes and cryogenics will be installed and connected to both the SPS and LHC ready for operation to begin in 2008.

The LHC Project Status and Prospects

CERN Document Server

Faugeras, Paul E

2001-01-01

The Large Hadron Collider (LHC), CERN's future major facility for high-energy physics, has entered into the construction and preparation for installation phases. After recalling briefly the main machine design choices and challenges, one will review the progress of civil works for the machine and experimental areas and the status of the main LHC components, which are presently series-built and for some of them procured in kind through world-wide collaborations. Report will also be given on the full-scale prototype of an elementary LHC lattice cell, called String 2, which is being commissioned and used for optimising the installation and testing procedures of the LHC. The size and duration of the LHC Project, its intrinsic complexity and the large number of world-wide collaborations involved require rather elaborate project management tools, which will be shortly described. Finally, following the extended running of the LEP and the delay for emptying of the machine tunnel, a new planning for project completion...

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

The Radiation Tolerant Electronics for the LHC Cryogenic Controls: Basic Design and First Operational Experience

CERN Document Server

Casas-Cubillos, J; Rodríguez-Ruiz, M A

2008-01-01

The LHC optics is based in the extensive use of superconducting magnets covering 23 km inside the tunnel. The associated cryogenic system for keeping the magnets in nominal conditions is hence distributed all around the 27 km LHC tunnel and the cryogenic instrumentation submitted to the LHC radiation environment is composed of about 18’000 sensors and actuators. Radiation Tolerant (RadTol) electronics was designed and procured in order to keep the signals integrity against electromagnetic interference and to reduce cabling costs required in case of sending the analog signals into the 30 radiation protected areas. This paper presents the basic design, the qualification of the main RadTol components and the first operational results.

Study for magnets and electronics protection in the LHC Betatron-cleaning insertion

International Nuclear Information System (INIS)

Magistris, Matteo; Ferrari, Alfredo; Santana, Mario; Tsoulou, Katerina; Vlachoudis, Vasilis

2006-01-01

The collimation system of the future LHC at CERN is a challenging project, since the transverse energy intensities of the LHC beams are three orders of magnitude greater than at other current facilities. The two cleaning insertions (IR3 and IR7) housing the collimators will be among the most radioactive areas of LHC. The 1.5 km long IR7 insertion was fully implemented with the Monte Carlo cascade code FLUKA. Extensive simulations were performed to estimate the radiation level along the tunnel, as well as the energy deposition in the most critical elements. In particular, this paper discusses the latest results of the FLUKA studies, including the design of passive absorbers (to protect warm magnets) and a comparison of W and Cu as material for the active absorber jaws (to protect cold magnets). Any electronic device operating in strong radiation fields such as those expected for the LHC tunnel will undergo degradation. A shielding study was done to reduce radiation damage to the electronics

16 March 2009 - HRH Princess Maha Chakri Sirindhorn, Kingdom of Thailand, visiting CMS experimental area and LHC tunnel with Coordinator for external relations F. Pauss and Collaboration Spokesperson T. Virdee.

CERN Multimedia

Maximilien Brice

2009-01-01

Photo 1: Relations with Non-Member State E. Tsesmelis, CMS Collaboration Spokesperson T. Virdee, HRH Princess Maha Chakri Sirindhorn and Coordinator for External relations F. Pauss, in CMS experimental area. Photo 2-12: Arrival of HRH at building 160: Posy presented to HRH by E. and F. Breedon; Welcome line: Director-General R. Heuer who introduces S. Bertolucci, F. Pauss, E. Tsesmelis, A. de Roeck, R. Breedon and Protocol Officer W. Korda. Photo 13-26:Presentation by Director-General R. Heuer and Head of Education R. Landua. Photo 27-30: Welcome at CMS by Spokesperson T. Virdee Photo 31-43: LHC tunnel visit Photo 44 - 60: CMS underground area visit Photo 61-63: HRH signs the guest book in the SCX5 conference room Photo 64-69: Signature of an expression of interest between SLRI and CMS Photo 75-88: Final discussion with Coordinator for External relation F. Pauss and Director-General R. Heuer.

CERN-HI-1202040 tirage 29 (front row) Russian Federation Secretary of the Security Council N. Patrushev with Adviser T. Kurtyka and Permanent Mission to the UN Adviser A. Petrov in the LHC tunnel at Point 1.

CERN Multimedia

Maximilien Brice

2012-01-01

On 14 February Nikolai Patrushev, secretary of the Security Council for the Russian Federation, was welcomed to CERN. He visited the ATLAS underground experimental area, the LHC tunnel and ATLAS Visitor Centre before viewing the Universe of Particles exhibition at the Globe of Science and Innovation.

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...

A Virtual CAD Model of the LHC

CERN Document Server

Chemli, S; Messerli, R; Muttoni, Y; Prin, H; Van Uytvinck, E

2000-01-01

Integrating the large and complex LHC machine into the existing LEP tunnel is a major challenge. Space was not really a problem to fit the LEP machine into its tunnel, but LHC cryostats are much larger than the LEP quadrupoles and the external cryogenic line fills even more the tunnel. Space problems lead to small clearances. Possible conflicts, or at least the most penalising ones, between installed equipment or with transport, must be solved beforehand in order to avoid unacceptable delays and extra costs during the installation. Experience gained with LEP has already shown the help that Computer-Aided Engineering tools could provide for the integration. A virtual model of the LHC is presently prepared. The actual LEP tunnel, known with a quite good accuracy (centimetre level), has been modelled and all the elements of the machine constructed as 3D objects with the CAD system are positioned accurately on the basis of data generated from the theoretical definition. These layouts are used to generate the refe...

Remote Inspection, Measurement and Handling for LHC

CERN Document Server

Kershaw, K; Coin, A; Delsaux, F; Feniet, T; Grenard, J L; Valbuena, R

2007-01-01

Personnel access to the LHC tunnel will be restricted to varying extents during the life of the machine due to radiation, cryogenic and pressure hazards. The ability to carry out visual inspection, measurement and handling activities remotely during periods when the LHC tunnel is potentially hazardous offers advantages in terms of safety, accelerator down time, and costs. The first applications identified were remote measurement of radiation levels at the start of shut-down, remote geometrical survey measurements in the collimation regions, and remote visual inspection during pressure testing and initial machine cool-down. In addition, for remote handling operations, it will be necessary to be able to transmit several real-time video images from the tunnel to the control room. The paper describes the design, development and use of a remotely controlled vehicle to demonstrate the feasibility of meeting the above requirements in the LHC tunnel. Design choices are explained along with operating experience to-dat...

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)

LHC Report: The machine under maintenance

CERN Multimedia

Katy Foraz for the LHC Team

2012-01-01

The LHC Christmas break started on 12 December. Since then, teams have been working hard to complete all the maintenance work planned to ensure the reliable operation of the LHC in 2012.   Installation of shielding at Point 1. The maintenance work is being carried out on key infrastructure such as the cooling, ventilation, electricity and safety systems. Maintenance work is being carried out not just in the LHC but also across the whole accelerator complex, which makes planning the work even more complicated. At the time of going to print, 50% of the cryogenics system maintenance has been finished, which, according to the schedule, will allow the LHC teams to start cooling down the first sectors next week to have the entire machine cold by the end of February. A lot of activity is going on in order to mitigate the effects of radiation on equipment installed in the LHC tunnel and underground areas during 2012 operation. To this end, teams have installed additional shielding at Point 1 (see ph...

18 January 2011 - The British Royal Academy of Engineering in the LHC tunnel with CMS Collaboration Spokesperson G. Tonelli and Beams Department Head P. Collier; in the CERN Control Centre with P. Collier and LHC superconducting magnet test hall with Technology Department Head F. Bordry.

CERN Multimedia

Jean-Claude Gadmer

2011-01-01

18 January 2011 - The British Royal Academy of Engineering in the LHC tunnel with CMS Collaboration Spokesperson G. Tonelli and Beams Department Head P. Collier; in the CERN Control Centre with P. Collier and LHC superconducting magnet test hall with Technology Department Head F. Bordry.

6 March 2013 - Committee for Employment and Learning, Northern Ireland Legislative Assembly, United Kingdom of Great Britain and Northern Ireland in the LHC tunnel and visiting the LHCb experiment at LHC Point 8. Director for Accelerators and Technology S. Myers with Vice-Chair T. Buchanan.

CERN Multimedia

Anna Pantelia

2013-01-01

6 March 2013 - Committee for Employment and Learning, Northern Ireland Legislative Assembly, United Kingdom of Great Britain and Northern Ireland in the LHC tunnel and visiting the LHCb experiment at LHC Point 8. Director for Accelerators and Technology S. Myers with Vice-Chair T. Buchanan.

9th January 2012 - Indonesian Extraordinary and Plenipotentiary Ambassador Triansyah Djani to to the United Nations, WTO and other International Organisations in Geneva signing the guest book with Head of International Relations F. Pauss and Adviser E. Tsesmelis, visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela.

CERN Document Server

Estelle Spirig

2012-01-01

9th January 2012 - Indonesian Extraordinary and Plenipotentiary Ambassador Triansyah Djani to to the United Nations, WTO and other International Organisations in Geneva signing the guest book with Head of International Relations F. Pauss and Adviser E. Tsesmelis, visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela.

14 November 2013 - Director of Indian Institute of Technology Indore P. Mathur with members of the Indian community working at CERN; visiting the LHC tunnel at Point 2, the ALICE experimental area and SM18 with ALICE Collaboration Spokesperson, Istituto Nazionale Fisica Nucleare P. Giubellino and Technology Department, Accelerator Beam Transfer Group Leader V. Mertens

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

14 November 2013 - Director of Indian Institute of Technology Indore P. Mathur with members of the Indian community working at CERN; visiting the LHC tunnel at Point 2, the ALICE experimental area and SM18 with ALICE Collaboration Spokesperson, Istituto Nazionale Fisica Nucleare P. Giubellino and Technology Department, Accelerator Beam Transfer Group Leader V. Mertens

High Surface Area Tunnels in Hexagonal WO₃.

Science.gov (United States)

Sun, Wanmei; Yeung, Michael T; Lech, Andrew T; Lin, Cheng-Wei; Lee, Chain; Li, Tianqi; Duan, Xiangfeng; Zhou, Jun; Kaner, Richard B

2015-07-08

High surface area in h-WO3 has been verified from the intracrystalline tunnels. This bottom-up approach differs from conventional templating-type methods. The 3.67 Å diameter tunnels are characterized by low-pressure CO2 adsorption isotherms with nonlocal density functional theory fitting, transmission electron microscopy, and thermal gravimetric analysis. These open and rigid tunnels absorb H(+) and Li(+), but not Na(+) in aqueous electrolytes without inducing a phase transformation, accessing both internal and external active sites. Moreover, these tunnel structures demonstrate high specific pseudocapacitance and good stability in an H2SO4 aqueous electrolyte. Thus, the high surface area created from 3.67 Å diameter tunnels in h-WO3 shows potential applications in electrochemical energy storage, selective ion transfer, and selective gas adsorption.

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system.Photos 01, 02: Pictured with the newly installed magnet and transport system in the transfer line tunnel are LHC project leader Lyn Evans (second left, white helmet); Volker Mertens, responsible for the LHC injecti...

18 December 2012 -Portuguese President of FCT M. Seabra visiting the Computing Centre with IT Department Head F. Hemmer, ATLAS experimental area with Collaboration Spokesperson F. Gianotti and A. Henriques Correia, in the LHC tunnel at Point 2 and CMS experimental area with Deputy Spokesperson J. Varela, signing an administrative agreement with Director-General R. Heuer; LIP President J. M. Gago and Delegate to CERN Council G. Barreia present.

CERN Multimedia

Samuel Morier-Genoud

2012-01-01

18 December 2012 -Portuguese President of FCT M. Seabra visiting the Computing Centre with IT Department Head F. Hemmer, ATLAS experimental area with Collaboration Spokesperson F. Gianotti and A. Henriques Correia, in the LHC tunnel at Point 2 and CMS experimental area with Deputy Spokesperson J. Varela, signing an administrative agreement with Director-General R. Heuer; LIP President J. M. Gago and Delegate to CERN Council G. Barreia present.

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. The first installation phase will continue until mid-April. In addition to the magnets, a beam dump facility also has to be installed. The second installation phase will take place later this year and should be completed in 2004, when the TI 8 transfer line is due to be tested. The second transfer line, in tunnel TI 2, should be ready in April 2007, once the LHC magnets have been transported through the downstream section of this tunnel.Pho...

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. The first installation phase will continue until mid-April. In addition to the magnets, a beam dump facility also has to be installed. The second installation phase will take place later this year and should be completed in 2004, when the TI 8 transfer line is due to be tested. The second transfer line, in tunnel TI 2, should be ready in April 2007, once the LHC magnets have been transported through the downstream section of this tunnel. Th...

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. The first installation phase will continue until mid-April. In addition to the magnets, a beam dump facility also has to be installed. The second installation phase will take place later this year and should be completed in 2004, when the TI 8 transfer line is due to be tested. The second transfer line, in tunnel TI 2, should be ready in April 2007, once the LHC magnets have been transported through the downstream section of this tunnel. We...

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

Engineers win award for Swiss tunnel

CERN Multimedia

2003-01-01

A Derby engineering consultancy has won the Tunnelling Industry Award 2003 for Excellence in Tunnel Design, offered by the British Tunnelling Society, for its work on the LHC in Geneva, Switzerland (1/2 page).

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...

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...

Precision transport of LHC superconducting magnet

CERN Multimedia

Maximilien Brice

2003-01-01

These photos show tests of the first convoy with a prototype short straight section (SSS) quadrupole in the LHC tunnel. There is little free space in the tunnel as the SSS convoy passes alongside a dipole vacuum vessel. These convoys feature infrared guidance, which offsets the minimal clearance in the tunnel and limits vibration, both of which could damage the fragile magnets.

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)

15 February 2012 - Geneva United Nations Office Director-General K.-J. Tokayev in the LHC tunnel with Adviser for Relations with international organisations M. Bona and Technology Department Head F. Bordry.

CERN Multimedia

Jean-claude Gadmer

2012-01-01

Kassym-Jomart Tokayev, director-general of the United Nations Office at Geneva, (centre picture 02), visited CERN on 15 February. He toured the LHC tunnel with Maurizio Bona, CERN’s adviser to the director-general, relations with international organizations, left, and Frédérick Bordry, CERN’s technology department head. He also visited the ATLAS underground experimental area, as well as the exhibition at the Globe of Science and Innovation.

Successful test of SPS-to-LHC beamline

CERN Multimedia

Maximilien Brice

2004-01-01

On 23 October there was great excitement in the Prevessin control room when, on the first attempt, a beam passed over 2.5 km down the new SPS-to-LHC transfer line, TI8, to within a few metres of the LHC tunnel.

Demineralised water cooling in the LHC accelerator

CERN Document Server

Peón-Hernández, G

2002-01-01

In spite of the LHC accelerator being a cryogenic machine, it remains nevertheless a not negligible heat load to be removed by conventional water-cooling. About 24MW will be taken away by demineralised water cooled directly by primary water from the LHC cooling towers placed at the even points. This paper describes the demineralised water network in the LHC tunnel including pipe diameters, lengths, water speed, estimated friction factor, head losses and available supply and return pressures for each point. It lists all water cooled equipment, highlights the water cooled cables as the most demanding equipment followed by the radio frequency racks and cavities, and by the power converters. Their main cooling requirements and their positions in the tunnel are also presented.

Some of the QRL team in UJ22 of the LHC tunnel, where the last sector of the cryogenic distribution line was installed.

CERN Multimedia

Viviane Li

2006-01-01

The cryogenic distribution line "the QRL" is a circle built in 8 sectors, each approximately 3 km in length. It will circulate helium in liquid and gas phases, at different temperatures and pressures, to provide the cryogenic conditions for the superconducting magnets in the LHC tunnel.

19 January 2011 - Korean Vice Minister II of Education, Science and Technology K.Chang-Kyung with Adviser R. Voss, Director-General R. Heuer and head of International Relations F. Pauss; in the LHC tunnel at Point 5 and CMS experimental cavern with Collaboration Spokesperson G. Tonelli.

CERN Multimedia

Maximilien Brice

2011-01-01

Korean vice-minister II of education, science and technology, Kim Chang-Kyung, visiting the CMS experimental area at CERN on 19 January. He also had the opportunity to view part of the LHC tunnel, as well as to visit the CERN Control Centre.

Work on a transfer tunnel access shaft

CERN Multimedia

Laurent Guiraud

2000-01-01

Civil engineers work on one of the access shafts from the SPS to the LHC transfer tunnel, which will allow components and equipment to be lowered directly so that minimal transport is required. The transfer tunnel will take a proton beam from the SPS pre-accelerator and inject it into the clockwise circulating ring in the LHC where the beam will be accelerated to a final energy of 7 TeV.

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system.Photo 01: Pictured with the newly installed magnet and transport system in the transfer line tunnel are (left to right) Volker Mertens, responsible for the LHC injection and transfer lines; personnel involved in tr...

3rd May 2009 - Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda, visiting ATLAS experimental area, LHC tunnel and CERN Control Centre with CERN Director-General R. Heuer, Collaboration Spokesperson F. Gianotti and Beams Department Head P. Collier.

CERN Document Server

Maximilien Brice

2009-01-01

090506101-08: signature of the guest book and exchange of gifts; 090506109 + 46-64: Japanese Ambassador to the United Nations Office S. Kitajima, Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda, CERN Director-General R. Heuer, Non Member-State relations Adviser J. Ellis and ATLAS Collaboration Spokesperson F. Gianotti visiting the LHC tunnel at Point 1; 090506110-11 + 28-45: Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda and his delegation visiting ATLAS experimental area with CERN Japanese users and Management; 090506112 + 86-94: Japanese Minister of State for Science and Technology Policy, Food Safety, Minister of Consumer Affairs, Minister of Space Policy S. Noda, CERN Director-General R. Heuer and Japanese users in front of an LHC superconducting magnet; sLHC Project Leader also present. 090506113-19: Arrival of Japanese Min...

Robert Aymar seals the last interconnect in the LHC

CERN Multimedia

Maximilien Brice

2007-01-01

The LHC completes the circle. On 7 November, in a brief ceremony in the LHC tunnel, CERN Director General Robert Aymar (Photo 1) sealed the last interconnect between the main magnets of the Large Hadron Collider (LHC). Jean-Philippe Tock, leader of the Interconnections team, tightens the last bolt (Photos 4-8).

Strategy and issues for the LHC upgrades and fair, including longer-term prospects

CERN Document Server

Zimmermann, F

2013-01-01

This report discusses the time line, goals and key ingredients for the next ten years of LHC operation, including injector upgrade, for the following High Luminosity LHC (HL-LHC), and for the FAIR project. Results from pertinent EuCARD-WP4 workshops on optics, space charge, crab cavities, crystal collimation, and electron cloud are summarized in this context. A Large Hadron electron Collider, LHeC, would be an additional upgrade, further expanding the physics scope of the LHC, to eventually include both ep and γγ Higgs factories (LHeC-HF and SAPPHiRE). Results from relevant topical WP4 workshops are highlighted. The development of magnet and cable technology based on Nb$_{3}$Sn, and HTS, for the HL-LHC prepares the ground for a future higher-energy hadron collider, either in the LHC tunnel, “HELHC” (33 TeV c.m.), or in a new 80- or 100-km tunnel, “VHE-LHC” (100 TeV c.m.). A large new tunnel could also host an ultimate highest-precision e+e- Higgs factory collider, “TLEP,” exhibiting many synergi...

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.

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'

Successful test of SPS-to-LHC beamline

CERN Multimedia

Maximilien Brice

2004-01-01

On 23 October there was great excitement in the Prevessin control room when, on the first attempt, a beam passed over 2.5 km down the new SPS-to-LHC transfer line, TI8, to within a few metres of the LHC tunnel. Members of the AB, AT and TS departments involved in the beamline and its test, celebrate their success with the Director General, Robert Aymar, and the LHC Project Leader, Lyn Evans.

Successful test of SPS-to-LHC beamline

CERN Multimedia

2004-01-01

On 23 October there was great excitement in the Prevessin control room when, on the first attempt, a beam passed over 2.5 km down the new SPS-to-LHC transfer line, TI8, to within a few metres of the LHC tunnel. Above: members of the AB, AT and TS departments involved in the beamline and its test, celebrate their success with the Director General, Robert Aymar, and the LHC Project Leader, Lyn Evans.

Energy Deposition and DPA in the Superconducting Links for the HILUMI LHC Project at the LHC Interaction Points

CERN Document Server

AUTHOR|(CDS)2092158; Broggi, Francesco; Santini, C; Ballarino, Amalia; Cerutti, Francesco; Esposito, Luigi Salvatore

2015-01-01

In the framework of the upgrade of the LHC machine, the powering of the LHC magnets foresees the removal of the power converters and distribution feedboxes from the tunnel and its location at the surface[1]. The Magnesium Diboride (MgB2) connecting lines in the tunnel will be exposed to the debris from 7+7 TeV p-p interaction. The Superconducting (SC) Links will arrive from the surface to the tunnel near the separation dipole, at about 80 m from the Interaction Point at IP1 and IP5. The Connection Box (where the cables of the SC Links are connected to the NbTi bus bar) will be close to the beam pipe. The debris and its effect on the MgB2 SC links in the connection box (energy deposition and displacement per atom) are presented. The effect of thermal neutrons on the Boron consumption and the contribution of the lithium nucleus and the alpha particle on the DPA are evaluated. The results are normalized to an integrated luminosity of 3000 fb-1, value that represents the LHC High Luminosity lifetime. The dose de...

Installation of the LHC transfer lines begins

CERN Multimedia

2003-01-01

On 19 February, the very first magnet was installed in one of the two tunnels that will house the transfer lines leading to the LHC. This magnet, recycled from a previous facility, was transported and positioned using a novel system designed for conveying large objects through narrow tunnels.

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.

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

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...

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.

End of the road for the LHC magnets...well, above ground that is!

CERN Multimedia

2003-01-01

The first LHC dipole cryomagnet has been delivered to the SMI2 building for final assembly prior to lowering it into the LHC tunnel. Over the next 3 years, all LHC cryomagnets will pass through these doors before starting their journey underground.

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.

Quantum dot resonant tunneling diode single photon detector with aluminum oxide aperture defined tunneling area

DEFF Research Database (Denmark)

Li, H.W.; Kardynal, Beata; Ellis, D.J.P.

2008-01-01

Quantum dot resonant tunneling diode single photon detector with independently defined absorption and sensing areas is demonstrated. The device, in which the tunneling is constricted to an aperture in an insulating layer in the emitter, shows electrical characteristics typical of high quality res...

Luminosity Optimization for a Higher-Energy LHC

CERN Document Server

Dominguez, O

2011-01-01

A Higher-Energy Large Hadron Collider (HE-LHC) is an option to further push the energy frontier of particle physics beyond the present LHC. A beam energy of 16.5 TeV would require 20 T dipole magnets in the existing LHC tunnel, which should be compared with 7 TeV and 8.33 T for the nominal LHC. Since the synchrotron radiation power increases with the fourth power of the energy, radiation damping becomes significant for the HE-LHC. It calls for transverse and longitudinal emittance control vis-a-vis beam-beam interaction and Landau damping. The heat load from synchrotron radiation, gas scattering, and electron cloud also increases with respect to the LHC. In this paper we discuss the proposed HE-LHC beam parameters; the time evolution of luminosity, beam-beam tune shifts, and emittances during an HE-LHC store; the expected heat load; and luminosity optimization schemes for both round and flat beams.

The LHC machine Exhibition Lepton-Photon 2001

CERN Multimedia

2001-01-01

The LHC will enable the study of proton-proton and ion-ion collisions. The existing chain of injectors (LINAC, booster, PS, SPS) will provide the necessary particles. The LHC superconducting magnets will generate the highest magnetic fields ever reached in an accelerator of this scale. The dipoles and quadrupoles will be interconnected so as to form a continuous cryogenic "pipe" installed in the 27 km-long LEP/LHC tunnel with its separate cryoline. The superconducting RF accelerating cavities, along with the beam cleaning and beam dump systems, will complete the machine.

Preliminary Design of the HiLumi-LHC Triplet Area Beam Screen

CERN Document Server

Kersevan, R; Kos, N

2014-01-01

The so-called beam screen (BS) is a proven solution for intercepting the thermal loads caused by the circulating beams in the cryogenically-cooled sections of the LHC and minimizing dynamic vacuum effects [1]. The new triplet area foreseen for the HiLumi-LHC (HL-LHC) machine upgrade [2] has the additional feature of needing internal tungsten shields to reduce the amount of collision debris which is deflected by the high-gradient triplet magnets towards the superconducting magnets' cold masses and coils. The very aggressive optics design, based on large beam separations, calls for a maximum of physical space to remain available to the counter rotating beams in the common BS. This places severe constraints to the fabrication and installation tolerances of the BS itself, in addition to affecting the design and routing of the cryogenic lines in the area. The latest version of the BS design will be shown and discussed, together with future plans for testing materials, fabrication procedures, and installation.

Golden Jubilee Photos: Laying the Ground for the LHC

CERN Multimedia

2004-01-01

In 1997, a prototype of the LHC dipole magnet, with the two beampipes running through the centre. Even before digging the LEP tunnel, in the early eighties CERN scientists began laying the plans for the second-generation collider to go in the tunnel. From the beginning, physicists had their eyes fixed on certain goals such as finding the Higgs boson and signs of supersymmetric particles. To reach the desired energies within the LEP tunnel, instead of LEP's electrons and positrons, the next collider would need to use more massive particles that radiate away less energy as they travel around the circular tunnel. Also, since the United States was planning the Superconducting Super Collider (SSC) with a circumference even larger than LEP's, CERN scientists conceived of their next collider as a "high-luminosity" machine that would excel at producing a high number of collisions. But since making a strong antiproton beam is laborious, this collider would have to smash together two proton beams. Thus the LHC project ...

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).

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.

28 August 2013 - Director of Technical Quality Management Head of ESTEC Establishment European Space Agency F. Ongaro visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and Technology Department J.-P. Tock; visiting the ATLAS experimental area with ATLAS Deputy Spokesperson T. Wengler and signing the guest book with CERN Director-General R. Heuer. Accompanied throughout by F. Bordry and V. Parma.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

28 August 2013 - Director of Technical Quality Management Head of ESTEC Establishment European Space Agency F. Ongaro visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and Technology Department J.-P. Tock; visiting the ATLAS experimental area with ATLAS Deputy Spokesperson T. Wengler and signing the guest book with CERN Director-General R. Heuer. Accompanied throughout by F. Bordry and V. Parma.

28 August 2013 - Ambassador Extraordinary and Plenipotentiary Permanent Representative of Ireland to the United Nations Office and specialized institutions in Geneva Mr G. Corr signing the guest book with CERN Director-General R. Heuer; visiting the LHCb experimental area with LHCb Collaboration Spokesperson P. Campana and visiting the LHC tunnel at Point 8 with International Relations Adviser for Ireland E. Tsesmelis. Accompanied throughout by R. McNulty.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

28 August 2013 - Ambassador Extraordinary and Plenipotentiary Permanent Representative of Ireland to the United Nations Office and specialized institutions in Geneva Mr G. Corr signing the guest book with CERN Director-General R. Heuer; visiting the LHCb experimental area with LHCb Collaboration Spokesperson P. Campana and visiting the LHC tunnel at Point 8 with International Relations Adviser for Ireland E. Tsesmelis. Accompanied throughout by R. McNulty.

6 January 2011 - Extraordinary and plenipotentiary Ambassador M. Kovačič, Permanent Representative of the Republic of Slovenia to the United Nations Office and other international Organisations at Geneva (and Permanent Mission Staff)signing the guest book with CERN Director-General R. Heuer; in the ATLAS visitor centre, ATLAS underground area and LHC tunnel with Collaboration Spokesperson F. Gianotti and Adviser T. Kurtyka.

CERN Multimedia

Jean-Claude Gadmer

2011-01-01

6 January 2011 - Extraordinary and plenipotentiary Ambassador M. Kovačič, Permanent Representative of the Republic of Slovenia to the United Nations Office and other international Organisations at Geneva (and Permanent Mission Staff)signing the guest book with CERN Director-General R. Heuer; in the ATLAS visitor centre, ATLAS underground area and LHC tunnel with Collaboration Spokesperson F. Gianotti and Adviser T. Kurtyka.

Radiation tolerance assurance of technical equipment in the LHC radiation monitoring for technical equipment at the LHC

CERN Document Server

Wijnands, Thijs; CERN. Geneva. TS Department

2005-01-01

In contrast with other accelerators at CERN, a large amount of technical equipment will be located in the LHC tunnel, the underground areas and in the experimental caverns where they will be exposed to radiation. Nearly all this equipment makes, to a certain extent, use of commercial microelectronics which is extremely sensitive to radiation damage, both instantaneous damage and cumulative damage. Examples in the TS Department are the electronics for the position sensors of the low beta quadrupoles, the access system, the cooling and ventilation units, the electronics for the electrical distribution, the oxygen deficiency monitors and fire detection systems. The basic effects of radiation on electronic systems and components are well understood because similar problems with radiation are encountered in the aerospace and aviation industry. Since 1998, an efficient and original Radiation Tolerance Assurance approach for the LHC machine has been established. Its aim is to minimise the effects of radiation damage...

Commissioning of the 400 MHz LHC RF System

CERN Document Server

Ciapala, Edmond; Baudrenghien, P; Brunner, O; Butterworth, A; Linnecar, T; Maesen, P; Molendijk, J; Montesinos, E; Valuch, D; Weierud, F

2008-01-01

The installation of the 400 MHz superconducting RF system in LHC is finished and commissioning is under way. The final RF system comprises four cryo-modules each with four cavities in the LHC tunnel straight section round IP4. Also underground in an adjacent cavern shielded from the main tunnel are the sixteen 300 kW klystron RF power sources with their high voltage bunkers, two Faraday cages containing RF feedback and beam control electronics, and racks containing all the slow controls. The system and the experience gained during commissioning will be described. In particular, results from conditioning the cavities and their movable main power couplers and the setting up of the low level RF feedbacks will be presented.

Precision-guided vehicle for transport and installation of LHC cryomagnets

CERN Multimedia

Maximilien Brice

2003-01-01

LHC quadrupoles and dipoles are heavier, longer and more fragile than the magnets used in CERN s former LEP collider. Therefore, an innovative solution for their transport and installation in the tunnel has been developed. It consists of convoys of two tractors, a trailer and unloading equipment. The convoys feature infrared optical guidance, which offsets the minimal clearance inside the tunnel, and are designed to minimize vibration of the magnets during transport. Operations will be monitored by a technician, who will take over the controls to unload and install the magnets. The first such convoy is now undergoing testing in the tunnel. The people who have contributed to the new transport system are pictured here at Point 4 in the LHC tunnel where tests on the first convoy are being conducted. The optical guidance system uses the white lines on the floor (Photos 01 and 03) to steer the vehicle in the tunnel. The prototype quadrupole magnet used in the tests is visible in Photos 02 and 04.

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.

HL-LHC kicker magnet (MKI)

CERN Multimedia

Brice, Maximilien

2018-01-01

HL-LHC kicker magnet (MKI): last vacuum test, preparation for transport to LHC transfer line in underground tunnel.The LHC injection kicker systems (MKIs) generate fast field pulses to inject the clockwise rotating beam at Point 2 and the anti-clockwise rotating beam at Point 8: there are eight MKI magnets installed in total. Each MKI magnet contains a high purity alumina tube: if an MKI magnet is replaced this tube requires conditioning with LHC beam: until it is properly conditioned, there can be high vacuum pressure due to the beam. This high pressure can also cause electrical breakdowns in the MKI magnets. A special coating (Cr2O3) has been applied to the inside of the alumina tube of an upgraded MKI magnet – this is expected to greatly reduce the pressure rise with beam. In addition, HL-LHC beam would result in excessive heating of the MKI magnets: the upgraded design includes modifications that will reduce heating, and move the power deposition to parts that will be easier to cool. Experience during 2...

LHC Report: Preparing for 4 TeV

CERN Multimedia

Edited by Katarina Anthony based on regular reports by Mike Lamont, the Bulletin's correspondent from Chamonix

2012-01-01

After more than two months since its stop in December, the LHC is slowly coming back from its hibernation - even if the temperature of the magnets in the tunnel has actually been getting lower and lower in recent days. The tunnel has been crowded with hundreds of people, busy with maintenance activities and preparations for the restart. The end of most activities (and the access to the tunnel) is scheduled for 21 February. On this date, the Operations team will take back ownership of the machine from the Programmed Stops Coordination team and push forward the preparations for the beam.   The cool-down of all LHC sectors (left floating at around 80 K during the Christmas break) restarted three weeks ago. At present, more than half of the machine is at nominal cryogenic temperature and the completion of the cool-down is expected by 27 February. As soon as a sector is cold, the Electrical Quality Assurance (ElQA) team starts the high-voltage qualification of the superconducting circuits, to check ins...

Large Cryogenic Infrastructure for LHC Superconducting Magnet and Cryogenic Component Tests: Layout, Commissioning and Operational Experience

International Nuclear Information System (INIS)

Calzas, C.; Chanat, D.; Knoops, S.; Sanmarti, M.; Serio, L.

2004-01-01

The largest cryogenic test facility at CERN, located at Zone 18, is used to validate and to test all main components working at cryogenic temperature in the LHC (Large Hadron Collider) before final installation in the machine tunnel. In total about 1300 main dipoles, 400 main quadrupoles, 5 RF-modules, eight 1.8 K refrigeration units will be tested in the coming years.The test facility has been improved and upgraded over the last few years and the first 18 kW refrigerator for the LHC machine has been added to boost the cryogenic capacity for the area via a 25,000 liter liquid helium dewar. The existing 6 kW refrigerator, used for the LHC Test String experiments, will also be employed to commission LHC cryogenic components.We report on the design and layout of the test facility as well as the commissioning and the first 10,000 hours operational experience of the test facility and the 18 kW LHC refrigerator

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...

New magnet transport system for the LHC beam transfer lines

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system (pictured here in one of the tunnels) is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. The lead vehicle is powered by an electric rail set into the roof of the tunnel. The system is backed up by electrical batteries that enable it to operate in the absence of an outside power source or in the event of power failure. Last but not least, for the long-distance transport of magnets, it can be optically guided by a line traced on the tunnel floor. The convoy moves through the particularly narr...

Mechanical Behaviour of the LHC Cryodipoles

CERN Document Server

Buenaventura, A; Skoczen, Blazej

2000-01-01

The LHC cryodipoles are slender and heavy objects more than 15-m long. The major components of the cryodipole assembly are the 28-tonne cold mass, supported on its three Glass-Fibre-Reinforced-Epoxy support posts and the 4-tonne vacuum vessel. The performance of the LHC depends very much upon the accurate positioning of the dipoles and the beam tubes, in particular to maximise the useful beam apertures. The cryodipoles will be conditioned and measured in surface assembly buildings, then handled and transported to their positions in the tunnel and, finally, aligned. This paper presents the static and dynamic studies of the cryodipole in different configurations. The tests and analyses carried out have led to a thorough understanding of the mechanical behaviour of the cryodipoles. From the static analysis, an hyperstatic supporting system is proposed in order to minimise the systematic deflections and the effects due to changing temperature conditions in the tunnel. The dynamic analysis has shown that the cryod...

Digging in one last time for the LHC

CERN Multimedia

2003-01-01

A landmark event occurred during the second week of March, when the final cubic metres of earth were cleared away, completing the excavation phase for the entire LHC project . The event took place at Point 5, where the CMS detector will be installed, as civil engineering teams finished digging the cavern that connects the LHC tunnel with the bypass tunnel around the experimental cavern. Two new access shafts, two large caverns, two ancillary caverns, as well as the connecting tunnels have been excavated by the civil engineering teams. "The engineers heaved a huge sigh of relief when the work was done, because the excavations were quite risky. Anything can happen, and the risk of delays was far from zero," explains Jean Luc Baldy Head of ST Division's civil engineering group. This was especially true around Point 5, where unusual geology created some problems. The moraine-molasse interface lies 50 metres beneath the surface, or just about 18 metres above the roof of the caverns. Because the moraine consists of...

High-precision performance testing of the LHC power converters

CERN Document Server

Bastos, M; Dreesen, P; Fernqvist, G; Fournier, O; Hudson, G

2007-01-01

The magnet power converters for LHC were procured in three parts, power part, current transducers and control electronics, to enable a maximum of industrial participation in the manufacturing and still guarantee the very high precision (a few parts in 10-6) required by LHC. One consequence of this approach was several stages of system tests: factory reception tests, CERN reception tests, integration tests , short-circuit tests and commissioning on the final load in the LHC tunnel. The majority of the power converters for LHC have now been delivered, integrated into complete converter and high-precision performance testing is well advanced. This paper presents the techniques used for high-precision testing and the results obtained.

A word from the DG - Major progress for the LHC

CERN Multimedia

2006-01-01

The return to work after the summer holiday period has been marked by significant progress in the installation of the LHC machine and its detectors. At the beginning of the month, the one thousandth superconducting magnet was positioned in the accelerator tunnel. Passing this symbolic milestone is a testament to the successful efforts of the hundreds of LHC collaborators who are working day and night to install the machine in time, and I would like to take this opportunity to congratulate them. Despite the significant technical and organisational difficulties associated with different types of activities being carried out in parallel in a tunnel where space is limited, the LHC installation teams have achieved remarkable feats. As a result, the delays incurred owing to the problems encountered with the cryogenic distribution line in 2004 have been partly recouped. The cryoline is almost complete, with seven out of eight sectors accepted while installation of the eighth is expected to be completed at the...

Electromagnetic and mechanical design of a 56 mm aperture mode dipole for the LHC

International Nuclear Information System (INIS)

Ahlbaeck, J.; Ikaeheimo, J.; Jaervi, J.

1994-01-01

The Large Hadron Collider (LHC) project is proposed as the future extension of the CERN accelerator complex. The LHC requires twin aperture superconducting dipoles of highest possible field to guide the proton beams in the existing LEP tunnel of 26.7 km circumference. This paper describes the electromagnetic and mechanical design of a 56 mm aperture model dipole for the LHC

The surveyors get the measure of the LHC

CERN Multimedia

2002-01-01

The first to start work in the LHC tunnel, the surveyors are precisely marking out the positions of the future accelerator's magnets. A total of 7000 reference points will have to be marked out over two years.

3 May 2014 - His Excellency Dr Karolos Papoulias President of the Hellenic Republic in the LHC tunnel at Point 1 and in ATLAS experimental cavern with Director-General R. Heuer.

CERN Multimedia

Brice, Maximilien

2014-01-01

In the LHC tunnel at Point 1: Beams Department, Controls Group Leader E. Hatziangeli and Technology Department, Cryogenics Group Deputy Leader D. Delikaris. In the ATLAS cavern: ATLAS Deputy Spokesperson B. Heinemann and ATLAS Collaboration National contact person and CAST Collaboration National Technical University of Athens Team Leader E. Gazis.

20 January 2014 - Members of the Regional Assemblies and Parliaments United Kingdom of Great Britain and Northern Ireland visiting the LHC tunnel at Point 8 with Technology Department, Vacuum, Surfaces and Coatings Group P. Cruikshank.

CERN Document Server

Pantelia, Anna

2014-01-01

20 January 2014 - Members of the Regional Assemblies and Parliaments United Kingdom of Great Britain and Northern Ireland visiting the LHC tunnel at Point 8 with Technology Department, Vacuum, Surfaces and Coatings Group P. Cruikshank.

4 April 2013 - Spanish State Secretary of Science, Development and Innovation C. Vela Olmo in the LHC tunnel with Technology Department Head F. Bordry and signing the guest book with CERN Director-General R. Heuer.

CERN Multimedia

Anna Pantelia

2013-01-01

4 April 2013 - Spanish State Secretary of Science, Development and Innovation C. Vela Olmo in the LHC tunnel with Technology Department Head F. Bordry and signing the guest book with CERN Director-General R. Heuer.

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)

Installation of the LHC transfer lines begins

CERN Multimedia

Patrice Loïez

2003-01-01

The first of 700 magnets has been installed in one of the two transfer tunnels built to transfer the SPS beam into the LHC. The start of this first installation phase of the LHC transfer lines provides the opportunity to launch a new and highly original modular system for transporting and installing all kinds of magnets in very narrow tunnels. The system is based on very compact bogies, up to four of which can be coupled together to form a convoy. The wheels are fitted with individual motors enabling them to swivel through an angle of 90° and the convoy to move laterally. In this way the magnet is delivered directly to its installation point, but beneath the beamline. It is then raised into its final position in the beamline using air cushions, which form an integrated part of the transport system. Here we see the transport vehicle alongside the magnet supports. Visible in the background is the first magnet in place.

QCD-instantons at LHC. Theoretical aspects; QCD-Instantonen am LHC. Theoretische Aspekte

Energy Technology Data Exchange (ETDEWEB)

Petermann, M.

2007-06-15

Instantons are nonperturbative, topologically nontrivial field configurations, which occur in every nonabelian gauge theory. They can be understood as tunneling processes between topologically distinct vacua. Although being a basic theoretical aspect of the Standard Model, a direct experimental verification of instanton processes is still lacking. In this thesis the general discovery potential for QCD-instantons at the LHC is studied in detail by means of instanton perturbation theory. In this context the close correspondence between the leading instanton induced processes at HERA and at LHC becomes important. Essential aspects and differences to deep inelastic scattering can already be revealed by studying the simplest process. Based on these results inclusive cross sections are calculated including the emission of final state gluons. Compared to deep inelastic scattering, a large enhancement of the cross section is found. (orig.)

Open Access to the LHC takes on a new meaning

CERN Multimedia

2008-01-01

Complete scientific documentation on the LHC machine and detectors is now freely available on the Web. The ATLAS collaboration, shown here, contributed to the 1,600-page scientific documentation of the LHC, along with staff from the other five detectors and the LHC machine.Now that the LHC tunnel and the experimental caverns are shut down for public visits, "Open Access to the LHC" has taken on an entirely new meaning. Last Thursday, 14 August, seven major articles were published electronically in a special issue of the Journal of Instrumentation (JINST). Together they form the complete scientific documentation on the design and construction of the LHC machine and the six detectors (ALICE, ATLAS, CMS, LHCb, LHCf and TOTEM), and thus on the entire LHC project, well before start-up on 10 September. For many years to come, these papers will serve as key references for the stream of scientific results that will begin to emerge from the ...

7 March 2013 -Stanford University Professor N. McKeown FREng, Electrical Engineering and Computer Science and B. Leslie, Creative Labs visiting CERN Control Centre and the LHC tunnel with Director for Accelerators and Technology S. Myers.

CERN Multimedia

Anna Pantelia

2013-01-01

7 March 2013 -Stanford University Professor N. McKeown FREng, Electrical Engineering and Computer Science and B. Leslie, Creative Labs visiting CERN Control Centre and the LHC tunnel with Director for Accelerators and Technology S. Myers.

Dipoles for High-Energy LHC

CERN Document Server

Todesco, E; De Rijk, G; Rossi, L

2014-01-01

For the High Energy LHC, a study of a 33 TeV center of mass collider in the LHC tunnel, main dipoles of 20 T operational field are needed. In this paper we first review the conceptual design based on block coil proposed in the Malta workshop, addressing the issues related to coil fabrication and assembly. We then propose successive simplifications of this design, associating a cost estimate of the conductor. We then analyse a block layout for a 15 T magnet. Finally, we consider two layouts based on the D20 and HD2 short models built by LBL. A first analysis of the aspects related to protection of these challenging magnets is given.

Facility Closure Report for T-Tunnel (U12T), Area 12, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

2008-01-01

This Facility Closure Report (FCR) has been prepared to document the actions taken to permanently close the remaining accessible areas of U12t-Tunnel (T-Tunnel) in Area 12 of the Nevada Test Site (NTS). The closure of T-Tunnel was a prerequisite to transfer facility ownership from the Defense Threat Reduction Agency (DTRA) to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO). Closure of the facility was accomplished with the cooperation and concurrence of both NNSA/NSO and the Nevada Division of Environmental Protection (NDEP). The purpose of this FCR is to document that the closure of T-Tunnel complied with the closure requirements specified in the Facility Closure Plan for N- and T-Tunnels Area 12, Nevada Test Site (Appendix D) and that the facility is ready for transfer to NNSA/NSO. The Facility Closure Plan (FCP) is provided in Appendix D. T-Tunnel is located approximately 42 miles north of Mercury in Area 12 of the NTS (Figure 1). Between 1970 and 1987, T-Tunnel was used for six Nuclear Weapons Effects Tests (NWETs). The tunnel was excavated horizontally into the volcanic tuffs of Rainier Mesa. The T-Tunnel complex consists of a main access drift with two NWET containment structures, a Gas Seal Plug (GSP), and a Gas Seal Door (GSD) (Figure 2). The T-Tunnel complex was mothballed in 1993 to preserve the tunnel for resumption of testing, should it happen in the future, to stop the discharge of tunnel effluent, and to prevent unauthorized access. This was accomplished by sealing the main drift GSD

Snapshots to shed light on LHC performance

CERN Multimedia

2006-01-01

With the impressive size and unprecedented power of the LHC, it is all too easy to overlook the smaller devices that have the difficult task of monitoring the new accelerator. You don't have to stand too far back from the big picture to see examples of clever technology inside the LHC. One of the undulators installed in the LHC tunnel can be seen on the right of the photo. From right to left, back row: Lucio Rossi (group leader, MCS), Davide Tommasini (conceptual design, MCS), Thierry Tenaglia (integration design,TS-MME), Remo Maccaferri (project leader, MCS) and Hans Kummer (MCS/ME); front row: Gilles Trachez (MCS-ME) and Bruno Meunier (FSU-AT12). In contrast to the usual articles about the LHC's big number statistics, examples of clever problem-solving found in beam monitoring machinery show that smaller things can be beautiful too. The design of the LHC accelerator brought new challenges for monitoring the shape of the particle beam, known as the beam profile. The size of the beam shrinks as higher energi...

The last stage of LHC construction

International Nuclear Information System (INIS)

Serin, L.

2006-01-01

A few months ago the setting of the LHC (large hadron collider) machine began in the Lep's tunnel at CERN. The LHC is composed of 1200 dipole magnets that are progressively installed in the 27 km long underground circular facility, 2 universal experiments ATLAS and CMS, huge by the size of their respective detector: 40 x 20 x 20 m as well as by their number of participants: 1500 people for each one are being built in gigantic carves. All the efforts are concentrated to make every component of the machine fully installed by summer 2007 in order to get the first collisions before 2008

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

9 February 2012 - Permanent Representative of the Kingdom of Spain to the United Nations Office at Geneva and other International Organisations, Ambassador A. Santos Maraver signing the guest book with CERN Director-General; in the CERN Control Centre with N. Catalan; visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela; throughout accompanied by Adviser J. Salicio Diez and Former Physics Deputy Department Head L. Alvarez Gaumé.

CERN Multimedia

Visual Media Office

2012-01-01

9 February 2012 - Permanent Representative of the Kingdom of Spain to the United Nations Office at Geneva and other International Organisations, Ambassador A. Santos Maraver signing the guest book with CERN Director-General; in the CERN Control Centre with N. Catalan; visiting the LHC tunnel at Point 5 and CMS underground experimental area with Collaboration Spokesperson J. Incandela; throughout accompanied by Adviser J. Salicio Diez and Former Physics Deputy Department Head L. Alvarez Gaumé.

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.)

Transport and installation of the LHC cryo-magnets

CERN Document Server

Artoos, K; Capatina, O; Chevalley, JM; Foraz, K; Guinchard, M; Hauviller, Claude; Kershaw, K; Prodon, S; Rühl, Ingo; Trinquart, G; Weisz, S; Ponsot, P

2007-01-01

Eleven years have passed between the beginning of transport and handling studies in 1996 and the completion of the LHC cryo-magnets installation in 2007. More than 1700 heavy, long and fragile cryo-magnets had to be transported and installed in the 27 km long LHC tunnel with very restricted available space. The size and complexity of the project involved challenges in the field of equipment design and manufacturing, maintenance, training and follow-up of operators and logistics. The paper presents the milestones, problems to be overcome and lessons learned during this project.

30 March 2009 - Representatives of the Danish Council for Independent Research Natural Sciences visiting the LHC tunnel at Point 1 with Collaboration Spokesperson F. Gianotti, Former Spokesperson P. Jenni and Transition Radiation Tracker Project Leader C. Rembser.

CERN Document Server

Maximilien Brice

2009-01-01

30 March 2009 - Representatives of the Danish Council for Independent Research Natural Sciences visiting the LHC tunnel at Point 1 with Collaboration Spokesperson F. Gianotti, Former Spokesperson P. Jenni and Transition Radiation Tracker Project Leader C. Rembser.

The Fire Brigade is training for the LHC

CERN Multimedia

2007-01-01

Rescue exercise at Point 8: the CERN Fire Brigade works to save a virtual victim trapped under scaffolding in the LHCb cavern.The CERN Fire Brigade really is unique. Its mission is made even more difficult by the fact that it must be capable of responding to situations underground, in many kilometres of tunnels and dozens of shafts. These specialist skills have to be honed in preparation for LHC commissioning. With a view to meeting these requirements, the "Preparing for the LHC" training course was held for the second time on 23 and 24 May. "The aim of the course is to allow the Fire Brigade to familiarise itself with and use all the resources available in the event of a problem in the tunnel", explains Gilles Colin, who is in charge of training for the CERN Fire Brigade. The two-day programme is designed to train fire Brigade members in the techniques used to free and release trapped victims. Through a series of theoretical sess...

LEP sees the end of the tunnel

CERN Multimedia

2002-01-01

After 14 months, which have seen the removal of 30,000 tonnes of material from the tunnel, the LEP dismantling operation has now been completed. LHC installation, which will be subject to new safety rules, can go ahead.

20 Novemnber 2013 - Ambassador of the Kingdom of the Netherlands to Switzerland B. Twaalfhoven in the LHC tunnel with CERN scientists G. De Rijk and H. Ten Kate; signing the guest book with CERN Director-General R. Heuer.

CERN Multimedia

Anna Pantelia

2013-01-01

20 Novemnber 2013 - Ambassador of the Kingdom of the Netherlands to Switzerland B. Twaalfhoven in the LHC tunnel with CERN scientists G. De Rijk and H. Ten Kate; signing the guest book with CERN Director-General R. Heuer.

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...

Concrete Walls Crumble as Tunnel TI8 Breaks Through

CERN Multimedia

2001-01-01

On Wednesday, October 3rd, the excitement in the tunnels deep beneath CERN was high as an exuberant crowd watched the second and last transfer tunnel (TI8) from the SPS break through to the LHC. The Director-General with the Mayors of Meyrin and Prévessin at the breakthrough point. The area where the break through was to occur did not look particularly special, just a concrete wall with bright orange paint sprayed in the centre. But the austere surroundings quickly faded from importance as a tremendous ruckus filled the corridor. Just minutes later the first pieces of the wall started popping off. The suspense in the room grew and eventually the spinning drill became readily visible to the entire crowd.... and that's when the real noise started, the noise of applause! 'This is the second time I have seen this happen but it is always moving because it shows our steps forward.' said Prof. Luciano Maiani. Technicians, physicists, and engineers chatted excitedly as the tunnel team climbed through...

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...

Technical basis for removal of 221-T tunnel from airborne radiological area status

International Nuclear Information System (INIS)

Geuther, W.J.

1996-01-01

This document provides the technical basis for removal of the 221-T Tunnel from airborne radiological control. T Plant Radiological Control has evaluated air sampling data and engineering controls, and determined the necessary administrative controls to make this transition. With these administrative controls (specified within document) in place, the tunnel can be removed from Airborne Radioactive Area status. The removal of the tunnel from airborne status will allow work to be performed within the tunnel under controlled conditions, as outlined in this technical basis, without the use of respiratory protection equipment

The LHC enters a new phase

CERN Document Server

CERN Bulletin

2010-01-01

After achieving the world record energy of 1.18 TeV per proton beam last November, the LHC is now preparing for higher energy and luminosity.   The teams are working in the tunnel to improve the electrical reliability of the magnet protection system.   Before the 2009 running period began, all the necessary preparations to run the LHC at the collision energy of 1.18 TeV per beam had been carried out. The goal of the technical stop, which will end mid-February, is to prepare the machine for running at 3.5 TeV per beam. In order to achieve that, a current as high as 6 kAmps will have to flow into the LHC magnets. The main work is taking place on the new quench protection system (nQPS) where teams are improving the electrical reliability of the connection between the Instrumentation Feedthrough Systems (IFS) on the magnets and the nQPS equipment. There are around 500 of these connectors for each of the eight sectors in the LHC that need to be repaired. These operations are necessary to en...

ORBIT FEEDBACK CONTROL FOR THE LHC Prototyping at the SPS

CERN Document Server

Steinhagen, Ralph J

2004-01-01

The Large Hadron Collider (LHC) is the next generation proton collider that is presently built at CERN. The LHC will be installed in the former LEP (Large Electron Positron Collider) tunnel. The presence of a high intensity beam in an environment of cryogenic magnets requires an excellent control of particle losses from the beam. Eventually the performance of the LHC may be limited by the ability to control the beam losses. The performance of the LHC cleaning system depends critically on the beam position stability. Ground motion, field and alignment imperfections and beam manipulations may cause orbit movements. The role of the future LHC Orbit Feedback System is the minimisation of closed orbit perturbations by periodically measuring and steering the transverse beam position back to its reference position. This diploma thesis focuses on the design and prototyping of an orbit feedback system at the SPS. The design is based on a separation of the steering problem into space and time. While the correction in s...

Super and ferric: the first HL-LHC component is ready

CERN Multimedia

Antonella Del Rosso

2016-01-01

Although the actual installation phase in the tunnel will only start in 2024, the first magnet – a sextupole – of the High-Luminosity LHC (HL-LHC) is ready and working according to specifications. This first component is also rather unique as, unlike the superconducting magnets currently used in the LHC, it relies on a “superferric” heart.   An expert in the LASA Laboratory (INFN Milan, Italy) works on assembling the first sextupole corrector of the HL-LHC. (Image: INFN Milan) Although the name might sound completely unfamiliar, superferric magnets were first proposed in the 1980s as a possible solution for high-energy colliders. However, many technical problems had to be overcome before the use of superferric magnets could become a reality. In its final configuration, the HL-LHC will have 36 superferric corrector magnets, of which 4 will be quadrupoles, 8 sextupoles and 24 higher order magnets. In superferric (or “iron-dominated”) magne...

Experience with the Quality Assurance of the Superconducting Electrical Circuits of the LHC Machine

CERN Document Server

Bozzini, D; Kotarba, A; Mess, Karl Hubert; Olek, S; Russenschuck, Stephan

2006-01-01

The coherence between the powering reference database for the LHC and the Electrical Quality Assurance (ELQA) is guaranteed on the procedural level. However, a challenge remains the coherence between the database, the magnet test and assembly procedures, and the connection of all superconducting circuits in the LHC machine. In this paper, the methods, tooling, and procedures for the ELQA during the assembly phase of the LHC will be presented in view of the practical experience gained in the LHC tunnel. Some examples of detected polarity errors and electrical non-conformities will be presented. The parameters measured at ambient temperature, such as the dielectric insulation of circuits, will be discussed.

Mechanical Design of the LHC Standard Half-Cell

Science.gov (United States)

Poncet, A.; Brunet, J. C.; Cruikshank, P.; Genet, M.; Parma, V.; Rohmig, P.; Saban, R.; Tavian, L.; Veness, R.; Vlogaert, J.; Williams, L. R.

1997-05-01

The LHC Conceptual Design Report issued on 20th October 1995 (CERN/AC/95-05 (LHC) - nicknamed "Yellow Book") introduced significant changes to some fundamental features of the LHC standard half-cell, composed of one quadrupole, 3 dipoles and a set of corrector magnets. A separate cryogenic distribution line was introduced, which was previously inside the main cryostat. The dipole length has been increased from 10 to 15 m and independent powering of the focusing and defocusing quadrupole magnets was chosen. Individual quench protection diodes were introduced in magnets interconnects and many auxiliary bus bars were added to feed in series the various families of correcting superconducting magnets. The various highly intricate basic systems such as: cryostats and cryogenics feeders, superconducting magnets and their electrical feeding and protection, vacuum beam screen and its cooling, support and alignment devices have been redesigned, taking into account the very tight space available. These space constraints are given by the necessity to have maximum integral bending field strength for maximum LHC energy, and the existing LHC tunnel. Finally, cryogenic and vacuum sectorisation have been introduced to reduce downtimes and facilitate commissioning.

30th August 2010 - Permanent Representative of the People's Republic of China to the United Nations Office at Geneva, Ambassador Y. He visiting the CMS underground experimental area and LHC tunnel with CERN Director-General R. Heuer and Collaboration Spokesperson G. Tonelli.

CERN Multimedia

Maximilien Brice

2010-01-01

CERN-HI-1008197 01: in the LHC tunnel at Point 5: CMS Collaboaration Spokesperson G. Tonelli, Mrs L. Jianping (Ambassador's spouse), Mrs B. Heuer, Permanent Representative of the People's Republic of China to the United Nations Office at Geneva, Ambassador Y. He, CERN Director-General R. Heuer and Adviser R. Voss; CERN-HI-1008197 57: in front of the CMS experiment at LHC point 5: CMS technical Coordinator A. Ball, Mrs L. Jianping (Ambassador's spouse), Permanent Representative of the People's Republic of China to the United Nations Office at Geneva, Ambassador Y. He; Mrs B. Heuer, CERN Director-General R. Heuer, CMS Collaboaration Spokesperson G. Tonelli and Adviser R. Voss. CERN-HI-1008197 02 - 14: Welcome in front of building 3562 at CMS. Head of International relations F: Pauss gives the introduction talk to the delegation. CERN-HI-1008197 15 - 25: visiting CMS control room at Point 5 with Collaboration Spokesperson G. Tonelli; CERN-HI-1008197 26 - 29: visiting the service cavern in the CMS underground ar...

LHC - latest in a long line of rings

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-12-15

The LHC - Large Hadron Collider - ring in CERN's 27-kilometre LEP tunnel is the natural next link in an accelerator chain first forged in the mid-1950s with the decision to build Europe's first state-of-the-art high energy synchrotron at CERN. A lot of ground has been covered since the LHC idea was launched over a decade ago. While the basic machine design has moved through several iterations, preparations for the experimental programme are well underway. CERN is now responding to the December 1991 request from its governing body, Council, to supply detailed information on the technical feasibility of the machine, its costs, and its experimental programme. In the late 1970s, when plans for CERN's LEP electron-positron collider were being pieced together, far-sighted people were already looking further ahead. With the LEP tunnel itself a major investment for the future, the circumference of the ring and the tunnel cross-section were kept as large as possible, so that another ring could be fitted in when the time came. On the physics front, the ultimate quest was the mysterious higgs mechanism which controls electroweak symmetry breaking. The symmetry of the vacuum is broken by the higgs field. Somewhere along the line, this fundamental field has to show itself as one or more higgs particles.

LHC - latest in a long line of rings

International Nuclear Information System (INIS)

Anon.

1993-01-01

The LHC - Large Hadron Collider - ring in CERN's 27-kilometre LEP tunnel is the natural next link in an accelerator chain first forged in the mid-1950s with the decision to build Europe's first state-of-the-art high energy synchrotron at CERN. A lot of ground has been covered since the LHC idea was launched over a decade ago. While the basic machine design has moved through several iterations, preparations for the experimental programme are well underway. CERN is now responding to the December 1991 request from its governing body, Council, to supply detailed information on the technical feasibility of the machine, its costs, and its experimental programme. In the late 1970s, when plans for CERN's LEP electron-positron collider were being pieced together, far-sighted people were already looking further ahead. With the LEP tunnel itself a major investment for the future, the circumference of the ring and the tunnel cross-section were kept as large as possible, so that another ring could be fitted in when the time came. On the physics front, the ultimate quest was the mysterious higgs mechanism which controls electroweak symmetry breaking. The symmetry of the vacuum is broken by the higgs field. Somewhere along the line, this fundamental field has to show itself as one or more higgs particles

Acoustic measurements in the collimation region of the LHC

CERN Document Server

Deboy, D; Baccigalupi, C; Burkart, F; Cauchi, M; Derrez, C S; Lendaro, J; Masi, A; Spiezia, G; Wollmann, D

2011-01-01

The LHC accelerator at CERN has the most advanced collimation system ever being installed. The collimators intercept unavoidable particle losses and therefore are essential to avoid beam induced quenches of the superconducting magnets. In addition, they provide passive machine protection against mis-kicked beams. During material robustness tests on a LHC collimator prototype in 2004 and 2006, vibration and acoustic measurements have shown that a beam impact detection system should be feasible using accelerometers and microphones as sensors in the LHC. Recently, such sensors have been installed close to the primary collimators in the LHC tunnel. First analyses of raw data show that the system is sensitive enough to detect beam scraping on collimators. Therefore, the implementation of a sophisticated acousticmonitoring system is under investigation. It may be useful not only to detect beam impacts on primary collimators in case of failure, but also to derive further information on beam losses that occur during ...

18 December 2013 - P. Kron Chairman and Chief Executive Officer of ALSTOM signing the Guest Book with the Director-General R. Heuer and visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry. Accompanied by P. Fassnacht throughout.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

18 December 2013 - P. Kron Chairman and Chief Executive Officer of ALSTOM signing the Guest Book with the Director-General R. Heuer and visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry. Accompanied by P. Fassnacht throughout.

Senior Senator from Florida and Chairman, Senate Committee on Space, Aeronautics and Related Sciences W. Nelson, visiting the ATLAS cavern and LHC tunnel with ATLAS Collaboration Spokesperson P. Jenni and AMS Collaboration Spokesperson S.C.C.Ting, 16 March 2008.

CERN Multimedia

Maximilien Brice

2008-01-01

Senior Senator from Florida and Chairman, Senate Committee on Space, Aeronautics and Related Sciences W. Nelson, visiting the ATLAS cavern and LHC tunnel with ATLAS Collaboration Spokesperson P. Jenni and AMS Collaboration Spokesperson S.C.C.Ting, 16 March 2008.

7 May 2013 - Ambassador of the Federal Republic of Germany to Switzerland and Liechtenstein P. Gottwald and Mrs Gottwald in the ATLAS experimental cavern and LHC tunnel with Collaboration Deputy Spokesperson T. Wengler and German Scientists A. Schopper and V. Mertens.

CERN Multimedia

Maximilien Brice

2013-01-01

7 May 2013 - Ambassador of the Federal Republic of Germany to Switzerland and Liechtenstein P. Gottwald and Mrs Gottwald in the ATLAS experimental cavern and LHC tunnel with Collaboration Deputy Spokesperson T. Wengler and German Scientists A. Schopper and V. Mertens.

Rock samples from LEP/LHC tunnel excavation

CERN Multimedia

1985-01-01

Rock samples taken from 0 to 170 m below ground on the CERN site when the LEP (Large Electron Positron collider) pit number 6 was drilled in Bois-chatton (Versonnex). The challenges of LHC civil engineering: A mosaic of works, structures and workers of differents crafts and origins. Three consulting consortia for the engineering and the follow-up of the works. Four industrial consortia for doing the job. A young team of 25 CERN staff, 30 surface buildings, 32 caverns of all sizes, 170 000 m3 of concrete, 420 000 m3 excavated. 1998-2004 : six years of work and 340 millions Swiss Francs.

Quench Performance of the LHC Insertion Magnets

CERN Document Server

Lasheras, N C; Siemko, A; Ostojic, R; Kirby, G

2009-01-01

After final installation in the LHC tunnel, the MQM and MQY quadrupole magnets of the LHC insertions are now being commissioned to their nominal currents. These two types of magnets operate at 1.9 K and 4.5 K and with nominal currents ranging from 3600 A to 5390 A. From the very first acceptance tests of the bare magnets coming from the manufacturers, they have been powered using different cycles, in different configurations, at different temperatures and in different tests facilities. In this paper we present the global results of these powering tests. We aim at separating common from individual features of these groups of magnets. Temperature dependence of the training, temperature margin, and ultimate current can be extracted from these tests. As these magnets are used to match the optics and the dispersion in the machine, the projected ultimate current at which they can be operated is critical in view of operation of LHC.

A bit of the LHC in the mairies

CERN Multimedia

2008-01-01

As partners in the Organization’s Open Days, the communes will be given a present that is very symbolic of CERN. On Saturday, 5 April, CERN will be offering its personnel and their families preview visits to the LHC before the general public is admitted the following day. The mayors and deputy mayors of each partner commune will inaugurate the various tour routes. A CERN delegation will take the opportunity to offer the mayors a unique present to thank them for their invaluable cooperation: a 60 cm diameter section of a dipole magnet weighing almost 10 kg. The choice of present is no coincidence. It is highly symbolic since the dipoles are at the very heart of the LHC project. Each section is a faithful replica of a slice of one of the 1232 LHC dipole magnets which will be used to guide the particles around the ring. The dipoles alone occupy almost 18 km of the 27 km LHC tunnel. They are composed of superconducting cables, consisting of niobium-titanium strands with ...

14 February 2012 - Vice-President of the Senate of the Parliament of the Czech Republic A. Gajduskova signing the guest book with CERN Director-General R. Heuer; visiting ATLAS experimental area with Collaboration Spokesperson F. Gianotti. Ambassador Sequensova to the UN accompanies the Vice-President.

CERN Document Server

Maximilien Brice

2012-01-01

Vice-president of the Senate of the Parliament of the Czech Republic, Alena Gajduskova was welcomed to CERN by Rolf Heuer, CERN’s director-general, on 14 and 15 February. Her time at CERN included the ATLAS Visitor Centre and underground experimental area, the LHC tunnel, the LHC superconducting-magnet test hall and the ALICE underground experimental area. She also heard a presentation on the LHC Computing Grid Project at CERN’s Computer Centre.

LHC un defi technologique sans precedent

CERN Document Server

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 detect...

QCD-instantons at LHC. Theoretical aspects

International Nuclear Information System (INIS)

Petermann, M.

2007-06-01

Instantons are nonperturbative, topologically nontrivial field configurations, which occur in every nonabelian gauge theory. They can be understood as tunneling processes between topologically distinct vacua. Although being a basic theoretical aspect of the Standard Model, a direct experimental verification of instanton processes is still lacking. In this thesis the general discovery potential for QCD-instantons at the LHC is studied in detail by means of instanton perturbation theory. In this context the close correspondence between the leading instanton induced processes at HERA and at LHC becomes important. Essential aspects and differences to deep inelastic scattering can already be revealed by studying the simplest process. Based on these results inclusive cross sections are calculated including the emission of final state gluons. Compared to deep inelastic scattering, a large enhancement of the cross section is found. (orig.)

Remote Qualification of HLS and WPS Systems in the LHC Tunnel

CERN Document Server

Mainaud Durand, Helene; Marin, Antonio; Rousseau, Michel; Sosin, Mateusz

2014-01-01

The position of the inner triplets of the LHC is monitored using Hydrostatic Levelling System (HLS) and Wire Positioning System (WPS). A regulation of these systems is needed to guarantee the sensors’ function. Such a regulation was done in-situ up to now, but the level of residual radiation at the level of the inner triplets will significantly increase with the next steps of LHC operation. Two systems have been designed to perform such a remote qualification: a filling/purging system for the HLS system and a wire displacer system for the WPS. In the paper, the requirements and the solutions proposed are described, with the emphasis on the conceptual design and the results obtained.

The beam dump tunnels

CERN Multimedia

Patrice Loïez

2002-01-01

In these images workers are digging the tunnels that will be used to dump the counter-circulating beams. Travelling just a fraction under the speed of light, the beams at the LHC will each carry the energy of an aircraft carrier travelling at 12 knots. In order to dispose of these beams safely, a beam dump is used to extract the beam and diffuse it before it collides with a radiation shielded graphite target.

Graphene-Molybdenum Disulfide-Graphene Tunneling Junctions with Large-Area Synthesized Materials.

Science.gov (United States)

Joiner, Corey A; Campbell, Philip M; Tarasov, Alexey A; Beatty, Brian R; Perini, Chris J; Tsai, Meng-Yen; Ready, William J; Vogel, Eric M

2016-04-06

Tunneling devices based on vertical heterostructures of graphene and other 2D materials can overcome the low on-off ratios typically observed in planar graphene field-effect transistors. This study addresses the impact of processing conditions on two-dimensional materials in a fully integrated heterostructure device fabrication process. In this paper, graphene-molybdenum disulfide-graphene tunneling heterostructures were fabricated using only large-area synthesized materials, unlike previous studies that used small exfoliated flakes. The MoS2 tunneling barrier is either synthesized on a sacrificial substrate and transferred to the bottom-layer graphene or synthesized directly on CVD graphene. The presence of graphene was shown to have no impact on the quality of the grown MoS2. The thickness uniformity of MoS2 grown on graphene and SiO2 was found to be 1.8 ± 0.22 nm. XPS and Raman spectroscopy are used to show how the MoS2 synthesis process introduces defects into the graphene structure by incorporating sulfur into the graphene. The incorporation of sulfur was shown to be greatly reduced in the absence of molybdenum suggesting molybdenum acts as a catalyst for sulfur incorporation. Tunneling simulations based on the Bardeen transfer Hamiltonian were performed and compared to the experimental tunneling results. The simulations show the use of MoS2 as a tunneling barrier suppresses contributions to the tunneling current from the conduction band. This is a result of the observed reduction of electron conduction within the graphene sheets.

Geochemical study of acid mine drainage of the Big Lick Tunnel area, Williamstown, PA

International Nuclear Information System (INIS)

Tollin, S.

1993-01-01

Acid mine drainage in the anthracite region of Pennsylvania continues to be a significant environmental problem. This study examines the acid mine outflow from the Big Lick Tunnel, north of Williamstown, Dauphin County, Pennsylvania. The tunnel drains abandoned mines on the north side of the Big Lick Mountain. Mining ceased in the area circa 1940, and the tunnel has been in operation since that time. The water, soil and stream bed sediment geochemistry has been studied to determine their changes in chemistry over distance. The pH, TDS and metal concentrations were the primary focus. Metal concentrations were determined using an ICP unit. Data indicates the pH of the outflow to range between 6.7 and 7.3 Fe and Mn concentrations are as high as 9.7 ppb. Extensive metal precipitation (''yellow boy'') occurs within the tunnel and for several hundred meters from the mouth of the tunnel. The combination of near neutral pH and high metal concentration suggest that the drainage is in contact with highly alkaline materials prior to discharge from the tunnel. The geology of the area does not suggest bedrock as the possible source of alkaline material. One hypothesis is that the acidic water is reacting with the concrete tunnel and being neutralized. Data also suggests that the Fe precipitates much quicker than the Mn, resulting in a zonation between Fe-rich and Mn-rich sediments along the length of the drainage

Vacuum vessels for the LHC magnets arrive at CERN

CERN Multimedia

2001-01-01

The first batch of pre-series vacuum vessels for the LHC dipole magnets has just been delivered to CERN. The vessels are components of the cryostats and will provide the thermal insulation for the superconducting magnets. The first batch of vacuum vessels for the LHC dipole magnets with the team taking part at CERN in ordering and installing them. Left to right : Claude Hauviller, Monique Dupont, Lloyd Williams, Franck Gavin, Alain Jacob, Christophe Vuitton, Davide Bozzini, Laure Sandri, Mikael Sjoholm and André de Saever. In 2006 all that will be seen of the LHC superconducting dipoles in the LHC tunnel will be a line of over 1230 blue cylindrical vacuum vessels. Ten vessels, each weighing 4 tonnes, are already at CERN. On 6 July the first batch of pre-series vessels reached the Lab-oratory from the firm SIMIC Spa whose works are near Savona in north-western Italy. Despite appearances, these 15-metre long, 1-metre diameter blue tubes are much more sophisticated than sections of a run-of-the-mill...

Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

Science.gov (United States)

Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

2018-03-01

In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

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...

Task Force Report, Safety of Personnel in LHC underground areas following the accident of 19th September 2008

CERN Document Server

Delille, B; Inigo-Golfin, J; Lindell, G; Roy, G; Tavian, L; Thomas, E; Trant, R; Völlinger, C

2009-01-01

In January 2009, the Task Force on Safety of Personnel in the LHC underground areas following the accident in sector 3-4 of 19th September 2008 (Safety Task Force) received from the CERN Director General the mandate to investigate the impact of the accident of 19th September 2008 on the safety of personnel working in the LHC underground areas. This mandate includes the elaboration of preventive and/or corrective measures, if deemed necessary. This report gives the conclusions and recommendations of the Safety Task Force which have been reviewed by an external advisory committee of safety experts.

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...

Theoretical Modeling and Experimental Investigation of the Thermal Performance of the LHC Prototype Lattice Cryostats

CERN Document Server

Riddone, G

1997-01-01

This thesis presents the thermal performance of the LHC (Large Hadron Collider) prototype cryostats both in steady-state and in transient conditions. LHC will be built in the 27 km LEP tunnel and will provide proton-proton collisions. It will make use of superconducting magnets operating in static bath of superfluid helium at 1.9 K. The thesis is mainly divided in three parts. The first part cont ains three chapters which present a brief overview of the LHC project. Part 1-Chapter 1 gives a short introduction to the LHC design layout and performance. Part 1-Chapter 2 refers to LHC cryogenic s ystem and describes the general architecture of the cryogenic plants, the temperature levels and the heat loads. The 50 m long LHC prototype half-cell contains one twin-bore quadrupole and four twin-a perture dipoles. In Part 1-Chapter 3 the design and construction of the prototype dipole and quadrupole cryostats are presented. The LHC prototype cryostats have integrated cryogenic lines, while the final LHC cryostats hav...

Using permanent magnets to boost the dipole field for the High-Energy LHC

CERN Document Server

Zimmermann, Frank

2012-01-01

The High-Energy LHC (HE-LHC) will be a new accelerator in the LHC tunnel based on novel dipole magnets, with a field up to 20 T, which are proposed to be realized by a hybrid-coil design, comprising blocks made from Nb- Ti, Nb$_{3}$Sn and HTS, respectively. Without the HTS the field would be only 15 T. In this note we propose and study the possibility of replacing the inner HTS layer by (weaker) permanent magnets that might contribute a field of 1-2 T, so that the final field would reach 16-17 T. Advantages would be the lower price of permanent magnets compared with HTS magnets and their availability in principle.

Dose calculations for the concrete water tunnels at 190-C Area, Hanford Site

International Nuclear Information System (INIS)

Kamboj, S.; Yu, C.

1997-01-01

The RESRAD-BUILD code was used to calculate the radiological dose from the contaminated concrete water tunnels at the 190-C Area at the Hanford Site. Two exposure scenarios, recreationist and maintenance worker, were considered. A residential scenario was not considered because the material was assumed to be left intact (i.e., the concrete would not be rubbleized because the location would not be suitable for construction of a house). The recreationist was assumed to use the tunnel for 8 hours per day for 1 week as an overnight shelter. The maintenance worker was assumed to spend 20 hours per year working in the tunnel. Six exposure pathways were considered in calculating the dose. Three external exposure pathways involved penetrating radiation emitted directly from the contaminated tunnel floor, emitted from radioactive particulates deposited on the tunnel floor, and resulting from submersion in airborne radioactive particulates. Three internal exposure pathways involved inhalation of airborne radioactive particulates; inadvertent direct ingestion of removable, contaminated material on the tunnel floor; and inadvertent indirect ingestion of airborne particulates deposited on the tunnel floor. The gradual removal of surface contamination over time and the ingrowth of decay products were considered in calculating the dose at different times. The maximum doses were estimated to be 1.5 mrem/yr for the recreationist and 0.34 mrem/yr for the maintenance worker

First Experience with the LHC Cryogenic Instrumentation

CERN Document Server

Vauthier, N; Balle, Ch; Casas-Cubillos, J; Ciechanowski, M; Fernandez-Penacoba, G; Fortescue-Beck, E; Gomes, P; Jeanmonod, N; Lopez-Lorente, A; Suraci, A

2008-01-01

The LHC under commissioning at CERN will be the world's largest superconducting accelerator and therefore makes extensive use of cryogenic instruments. These instruments are installed in the tunnel and therefore have to withstand the LHC environment that imposes radiation-tolerant design and construction. Most of the instruments require individual calibration; some of them exhibit several variants as concerns measuring span; all relevant data are therefore stored in an Oracle® database. Those data are used for the various quality assurance procedures defined for installation and commissioning, as well as for generating tables used by the control system to configure automatically the input/output channels. This paper describes the commissioning of the sensors and the corresponding electronics, the first measurement results during the cool-down of one machine sector; it discusses the different encountered problems and their corresponding solutions.

The Evolving Wide Area Network Infrastructure in the LHC era

CERN Multimedia

CERN. Geneva

2004-01-01

The global network is more than ever taking its role as the great "enabler" for many branches of science and research. Foremost amongst such science drivers is of course the LHC/LCG programme, although there are several other sectors with growing demands of the network. Common to all of these is the realisation that a straightforward over provisioned best efforts wide area IP service is probably not enough for the future. This talk will summarise the needs of several science sectors, and the advances being made to exploit the current best efforts infrastructure. It will then describe current projects aimed as provisioning "better than best efforts" services (such bandwidth on demand), the global optical R&D testbeds and the strategy of the research network providers to move towards hybrid multi-service networks for the next generation of the global wide area production network.

5 June 2013 - Sri Lankan Senior Minister of Scientific Affairs T. Vitharana signing the guest book with Director-General R. Heuer, in the LHC tunnel at Point 5 with International Relations Adviser R. Voss and in the CMS cavern with CERN Team leader A. Petrilli.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

5 June 2013 - Sri Lankan Senior Minister of Scientific Affairs T. Vitharana signing the guest book with Director-General R. Heuer, in the LHC tunnel at Point 5 with International Relations Adviser R. Voss and in the CMS cavern with CERN Team leader A. Petrilli.

31 Jannuary 2012 - Pakistan COMSATS Executive Director I. E. Qureshi visiting the LHC tunnel at Point 2 with ALICE Collaboration Spokesperson P. Giubellino and International Relations Adviser R. Voss; Exchange of gifts and signature of the guest book with CERN Director-General R. Heuer.

CERN Multimedia

Maximilien Brice

2012-01-01

31 Jannuary 2012 - Pakistan COMSATS Executive Director I. E. Qureshi visiting the LHC tunnel at Point 2 with ALICE Collaboration Spokesperson P. Giubellino and International Relations Adviser R. Voss; Exchange of gifts and signature of the guest book with CERN Director-General R. Heuer.

Exergy Analysis of the Cryogenic Helium Distribution System for the Large Hadron Collider (LHC)

CERN Document Server

Claudet, S; Tavian, L; Wagner, U

2010-01-01

The Large Hadron Collider (LHC) at CERN features the world’s largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility..

EXERGY ANALYSIS OF THE CRYOGENIC HELIUM DISTRIBUTION SYSTEM FOR THE LARGE HADRON COLLIDER (LHC)

International Nuclear Information System (INIS)

Claudet, S.; Lebrun, Ph.; Tavian, L.; Wagner, U.

2010-01-01

The Large Hadron Collider (LHC) at CERN features the world's largest helium cryogenic system, spreading over the 26.7 km circumference of the superconducting accelerator. With a total equivalent capacity of 145 kW at 4.5 K including 18 kW at 1.8 K, the LHC refrigerators produce an unprecedented exergetic load, which must be distributed efficiently to the magnets in the tunnel over the 3.3 km length of each of the eight independent sectors of the machine. We recall the main features of the LHC cryogenic helium distribution system at different temperature levels and present its exergy analysis, thus enabling to qualify second-principle efficiency and identify main remaining sources of irreversibility.

Stability of the Horizontal Curvature of the LHC Cryodipoles During Cold Tests

CERN Document Server

Cano, E D Fernandez; García-Pérez, J; Jeanneret, Jean Bernard; Poncet, A; Seyvet, F; Tovar-Gonzalez, A; Wildner, E; IEEE Trans. Nucl. Sci.

2006-01-01

The LHC will be composed of 1232 horizontally curved, 15 meter long, superconducting dipole magnets cooled at 1.9 K. They are supported within their vacuum vessel by three Glass Fiber Reinforced Epoxy (GFRE) support posts. Each cryodipole is individually cold tested at CERN before its installation and interconnection in the LHC 27 km circumference tunnel. As the magnet geometry under cryogenic operation is extremely important for the LHC machine aperture, a new method has been developed at CERN in order to monitor the magnet curvature change between warm and cold states. It enabled us to conclude that there is no permanent horizontal curvature change of the LHC dipole magnet between warm and cold states, although a systematic horizontal transient deformation during cool-down was detected. This deformation generates loads in the dipole supporting system; further investigation permitted us to infer this behavior to the asymmetric thermal contraction of the rigid magnet thermal shield during cool-down. Controlli...

Transport and handling LHC components A permanent challenge

CERN Document Server

Bertone, C

2004-01-01

The LHC project, collider and experiments, is an assembly of thousands of elements, large or small, heavy or light, fragile or robust. Each element has its own transport requirements that constitute a real challenge to handle. Even simple manoeuvres could lead to difficulties in integration, routing and execution due to the complex environment and confined underground spaces. Examples of typical LHC elements transport and handling will be detailed such as the 16-m long, 34-t heavy, fragile cryomagnets from the surface to the final destination in the tunnel, or the delicate cryogenic cold-boxes down to pits and detector components. This challenge did not only require a lot of imagination but also a close cooperation between all the involved parties, in particular with colleagues from safety, cryogenics, civil engineering, integration and logistics.

Quantum Diaries Blog: Is the moon full? Just ask the LHC operators

CERN Multimedia

Pauline Gagnon

2012-01-01

Corrections to proton orbits in the LHC appear as regular dips in the instantaneous luminosity measured by CMS (beige) and ATLAS (green).   The LHC is so large that the gravitational force exerted by the moon is not the same at all points, which creates small distortions of the tunnel. And the machine is sensitive enough to detect minute deformations created by the small differences in gravitational force across its diameter. Therefore, the orbits of protons in the accelerator have to be adjusted regularly to account for the gravitational effect of the moon. Read more on the Quantum Diaries Blog post.

3 October 2013 - Ukrainian Vice Prime Minister Ukraine K. I. Gryschenko welcomed by CERN Director-General R. Heuer who introduces Head of International Relations R. Voss; Head of Technology Department F. Bordry; Deputy Head of International Relations E. Tsesmelis; Deputy Legal Counsel M. Wilbers; Adviser for Ukraine T. Kurtyka; Signing of the Agreement between Ukraine and CERN concerning the granting of the status of Associate Member at CERN; in the LHC tunnel at Point 5 and visiting CMS experimental area with CERN Team Leader A. Petrilli.

CERN Multimedia

Anna Pantelia

2013-01-01

3 October 2013 - Ukrainian Vice Prime Minister Ukraine K. I. Gryschenko welcomed by CERN Director-General R. Heuer who introduces Head of International Relations R. Voss; Head of Technology Department F. Bordry; Deputy Head of International Relations E. Tsesmelis; Deputy Legal Counsel M. Wilbers; Adviser for Ukraine T. Kurtyka; Signing of the Agreement between Ukraine and CERN concerning the granting of the status of Associate Member at CERN; in the LHC tunnel at Point 5 and visiting CMS experimental area with CERN Team Leader A. Petrilli.

Experimental Study on RFID Antenna Reading Areas in a Tunnel System

Directory of Open Access Journals (Sweden)

Kai Kordelin

2017-01-01

Full Text Available We study optimized antenna reading area mappings for a radiofrequency identification- (RFID- based access monitoring system, used in an underground nuclear waste storage facility. We shortly introduce the access monitoring system developed for the ONKALO tunnel in Finland and describe the antenna mounting points as well as the research area. Finally, we study the measurement results of the antenna reading areas and factors that affect the reading area size. Based on our results, in addition to antenna location and direction, absorption to obstacles, reflections, diffraction, scattering, and refraction affect the antenna reading area.

Contact area between femoral tunnel and interference screw in anatomic rectangular tunnel ACL reconstruction: a comparison of outside-in and trans-portal inside-out techniques.

Science.gov (United States)

Hiramatsu, Kunihiko; Mae, Tatsuo; Tachibana, Yuta; Nakagawa, Shigeto; Shino, Konsei

2018-02-01

The purpose of this study was to compare the femoral tunnel length, the femoral graft bending angle at the femoral tunnel aperture, and the contact area between the femoral tunnel wall and an interference screw used for fixation in anatomic rectangular tunnel anterior cruciate ligament (ACL) reconstruction (ART ACLR). The study included 149 patients with primary ACL injury who underwent ART ACLR. Preoperatively, flexion angle of the index knee was checked under general anaesthesia. Those of less than 130° of passive flexion were assigned to the outside-in (OI) technique (78 patients), while the others to the trans-portal inside-out (TP) technique (71 patients). The patients underwent computed tomography with multiplanar reconstruction at 3-5 weeks post-operatively. Femoral tunnel length, graft bending angle, and contact ratio between the IFS and femoral tunnel were assessed. P contact ratio in the OI technique was significantly larger than that in the TP technique at every point in the femoral tunnel (P contact ratio than the TP technique after ART ACLR. Retrospective comparative study, Level III.

The Interconnections of the LHC Cryomagnets

CERN Document Server

Jacquemod, A; Skoczen, Blazej; Tock, J P

2001-01-01

The main components of the LHC, the next world-class facility in high-energy physics, are the twin-aperture high-field superconducting cryomagnets to be installed in the existing 26.7-km long tunnel. After installation and alignment, the cryomagnets have to be interconnected. The interconnections must ensure the continuity of several functions: vacuum enclosures, beam pipe image currents (RF contacts), cryogenic circuits, electrical power supply, and thermal insulation. In the machine, about 1700 interconnections between cryomagnets are necessary. The interconnections constitute a unique system that is nearly entirely assembled in the tunnel. For each of them, various operations must be done: TIG welding of cryogenic channels (~ 50 000 welds), induction soldering of main superconducting cables (~ 10 000 joints), ultrasonic welding of auxiliary superconducting cables (~ 20 000 welds), mechanical assembly of various elements, and installation of the multi-layer insulation (~ 200 000 m2). Defective junctions cou...

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...

The value of MRI iniIdiopathic tarsal tunnel syndrome by measuring the cross-sectional area of tarsal tunnel

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Jung; Jeong, Yu Mi; Lee, Sheen Woo; Choi Seung; Kim, Jeong Ho; Park, Hong Gi [Gachon University, Gil Hospital, Incheon (Korea, Republic of)

2015-03-15

The purpose of this study was to evaluate the use of MRI as a diagnostic test in tarsal tunnel syndrome. There are no published reports with this aim and no diagnostic standard for idiopathic tarsal tunnel syndrome (TTS) using imaging modalities. We retrospectively searched our Picture Archiving and Communication System data and medical records to identify patients who were clinically and electomyographically diagnosed with idiopathic TTS without space-occupying lesion on MRI. Twenty five patients were included in the patient group. Another twenty-five patients who underwent ankle MRI for Achilles tendon disease were selected and included in the control group. Cross-sectional areas (CSA) of tarsal tunnel were manually measured independently by two radiologists who were blinded to clinical and surgical results, using three-dimensional reconstruction software in our hospital. Measurements were done on axial images at three levels (level 1, tibiotalar joint level; level 2, medial malleolar tip level; level 3, sustentaculum tali level). Patient and control group data were statistically analyzed by the Mann-Whitney test. The mean values of CSA at levels 1, 2, and 3 of the tarsal tunnel were 87.8 mm2, 98.2 mm2, and 105.2 mm2, respectively in the patient group; and 100.0 mm2, 113.8 mm2, and 127.9 mm2 in the control group, respectively, in reader 1; and 86.2 mm2, 97.6 mm2, 105.2 mm2, respectively in the patient group; and 99.7 mm2, 112.3 mm2, 124.4 mm2, respectively, in the control group, in reader 2. The mean CSA in the patient group was significantly less than that of the control group at all three levels (p < 0.05). Intra-class correlation coefficient value between reader 1 and reader 2 were 0.98 in group 1, and 0.97 in group 2, respectively. MRI can be helpful in the assessment of idiopathic tarsal tunnel syndrome. CSA measurements of tarsal tunnel at each level may predict TTS even though there are no space occupying lesions in the tarsal tunnel on MRI.

Fast Automatic Beam-Based Alignment of the LHC Collimator Jaws

CERN Document Server

AUTHOR|(CDS)2080813; Assmann, R W

2014-01-01

The CERN Large Hadron Collider (LHC) in Geneva, Switzerland is the largest and most powerful particle accelerator ever built. With a circumference of 27 km, it is designed to collide particles in two counter-rotating beams at a centre-of-mass energy of 14 TeV to explore the fundamental forces and constituents of matter. Due to its potentially destructive high energy particle beams, the LHC is equipped with several machine protection systems. The LHC collimation system is tasked with scattering and absorbing beam halo particles before they can quench the superconducting magnets. The 108 collimators also protect the machine from damage in the event of very fast beam losses, and shields sensitive devices in the tunnel from radiation over years of operation. Each collimator is made up of two blocks or ‘jaws’ of carbon, tungsten or copper material. The collimator jaws need be placed symmetrically on either side of the beam trajectory, to clean halo particles with maximum efficiency. The beam orbit and beam siz...

Steel septum magnets for the LHC beam injection and extraction

CERN Document Server

Bidon, S; Guinand, M; Gyr, Marcel; Sassowsky, M; Weisse, E; Weterings, W; Abramov, A; Ivanenko, A I; Kolatcheva, E; Lapyguina, O; Ludmirsky, E; Mishina, N; Podlesny, P; Riabov, A; Tyurin, N

2002-01-01

The Large Hadron Collider (LHC) will be a superconducting accelerator and collider to be installed in the existing underground LEP ring tunnel at CERN. It will provide proton-proton collisions with a centre of mass energy of 14 TeV. The proton beams coming from the SPS will be injected into the LHC at 450 GeV by vertically deflecting kicker magnets and horizontally deflecting steel septum magnets (MSI). The proton beams will be dumped from the LHC with the help of two extraction systems comprising horizontally deflecting kicker magnets and vertically deflecting steel septum magnets (MSD). The MSI and MSD septa are laminated iron-dominated magnets using an all welded construction. The yokes are constructed from two different half cores, called coil core and septum core. The septum cores comprise circular holes for the circulating beams. This avoids the need for careful alignment of the usually wedge-shaped septum blades used in classical Lambertson magnets. The MSI and MSD septum magnets were designed and buil...

Vehicle autonomous localization in local area of coal mine tunnel based on vision sensors and ultrasonic sensors.

Directory of Open Access Journals (Sweden)

Zirui Xu

Full Text Available This paper presents a vehicle autonomous localization method in local area of coal mine tunnel based on vision sensors and ultrasonic sensors. Barcode tags are deployed in pairs on both sides of the tunnel walls at certain intervals as artificial landmarks. The barcode coding is designed based on UPC-A code. The global coordinates of the upper left inner corner point of the feature frame of each barcode tag deployed in the tunnel are uniquely represented by the barcode. Two on-board vision sensors are used to recognize each pair of barcode tags on both sides of the tunnel walls. The distance between the upper left inner corner point of the feature frame of each barcode tag and the vehicle center point can be determined by using a visual distance projection model. The on-board ultrasonic sensors are used to measure the distance from the vehicle center point to the left side of the tunnel walls. Once the spatial geometric relationship between the barcode tags and the vehicle center point is established, the 3D coordinates of the vehicle center point in the tunnel's global coordinate system can be calculated. Experiments on a straight corridor and an underground tunnel have shown that the proposed vehicle autonomous localization method is not only able to quickly recognize the barcode tags affixed to the tunnel walls, but also has relatively small average localization errors in the vehicle center point's plane and vertical coordinates to meet autonomous unmanned vehicle positioning requirements in local area of coal mine tunnel.

Vehicle autonomous localization in local area of coal mine tunnel based on vision sensors and ultrasonic sensors.

Science.gov (United States)

Xu, Zirui; Yang, Wei; You, Kaiming; Li, Wei; Kim, Young-Il

2017-01-01

This paper presents a vehicle autonomous localization method in local area of coal mine tunnel based on vision sensors and ultrasonic sensors. Barcode tags are deployed in pairs on both sides of the tunnel walls at certain intervals as artificial landmarks. The barcode coding is designed based on UPC-A code. The global coordinates of the upper left inner corner point of the feature frame of each barcode tag deployed in the tunnel are uniquely represented by the barcode. Two on-board vision sensors are used to recognize each pair of barcode tags on both sides of the tunnel walls. The distance between the upper left inner corner point of the feature frame of each barcode tag and the vehicle center point can be determined by using a visual distance projection model. The on-board ultrasonic sensors are used to measure the distance from the vehicle center point to the left side of the tunnel walls. Once the spatial geometric relationship between the barcode tags and the vehicle center point is established, the 3D coordinates of the vehicle center point in the tunnel's global coordinate system can be calculated. Experiments on a straight corridor and an underground tunnel have shown that the proposed vehicle autonomous localization method is not only able to quickly recognize the barcode tags affixed to the tunnel walls, but also has relatively small average localization errors in the vehicle center point's plane and vertical coordinates to meet autonomous unmanned vehicle positioning requirements in local area of coal mine tunnel.

Successful beam test of the SPS-to-LHC transfer line TI2

CERN Multimedia

2007-01-01

Image of the first beam spot on the last BTV screen traversed by the beam during the TI 2 test.At 12:03:47 on 28 October a beam passed down the 2.7 km of the new SPS-to-LHC transfer line TI 2 at the first attempt, to within some 50 m of the LHC tunnel. After initial tuning, a range of measurements was carried out with a low intensity proton beam and preliminary analyses look good. After the test, no increase in radiation levels was found in either the LHC or ALICE, and the zones were rapidly opened again for access. As from next year TI 2 will regularly transport a beam from the SPS to the LHC injection point of Ring 1, near Point 2 (ALICE). The TI 8 transfer line, which will bring particles from the SPS to the injection point in Ring 2, near Point 8 (LHCb), was commissioned successfully with low intensity beam in 2004. The two LHC injection lines have a combined length of 5.6 km and comprise some seven hundred warm magnets. While a...

1 October 2013 - British Minister of State for Trade and Investment Lord Green of Hurstpierpoint signing the guest book with Head of Internationals Relations R. Voss; visiting the LHC tunnel at Point 1 and the ATLAS experimental cavern with ATLAS Collaboration Members K. Behr and J. Catmore.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

1 October 2013 - British Minister of State for Trade and Investment Lord Green of Hurstpierpoint signing the guest book with Head of Internationals Relations R. Voss; visiting the LHC tunnel at Point 1 and the ATLAS experimental cavern with ATLAS Collaboration Members K. Behr and J. Catmore.

LHC train control system for autonomous inspections and measurements

OpenAIRE

Di Castro, Mario; Baiguera Tambutti, Maria Laura; Gilardoni, Simone; Losito, Roberto; Lunghi, Giacomo; Masi, Alessandro

2018-01-01

Intelligent robotic systems are becoming essential for inspection and measurements in harsh environments, such as the European Organization for Nuclear Research (CERN) accelerators complex. Aiming at increasing safety and machine availability, robots can help to perform repetitive or dangerous tasks, reducing the risk for the personnel as the exposure to radiation. The Large Hadron Collider (LHC) tunnel at CERN has been equipped with fail-safe trains on monorail able to perform autonomously d...

Measurements of very forward particles production spectra at LHC: the LHCf experiment

CERN Document Server

Berti, Eugenio; Bonechi, Lorenzo; Bongi, Massimo; Castellini, Guido; D'Alessandro, Raffaello; Haguenauer, Maurice; Itow, Yoshitaka; Iwata, Taiki; Kasahara, Katsuaki; Makino, Yuya; Masuda, Kimiaki; Matsubayashi, Eri; Menjo, Hiroaki; Muraki, Yasushi; Papini, Paolo; Ricciarini, Sergio; Sako, Takashi; Suzuki, Takuya; Tamura, Tadahisa; Tiberio, Alessio; Torii, Shoji; Tricomi, Alessia; Turner, W C; Ueno, Mana; Zhou, Qi Dong

2017-01-01

Thanks to two small sampling calorimeters installed in the LHC tunnel at ±140 m from IP1, the LHC forward (LHCf) experiment is able to detect neutral particles produced by high energy proton-ion collisions in the very forward region (pseudo-rapidity η > 8.4). The main aim of LHCf is to provide precise measurements of the production spectra relative to these particles, in order to tune hadronic interaction models used by ground-based cosmic rays experiments. In this paper we will present the current status of the LHCf experiment, regarding in particular collected data and analysis results, as well as future prospects

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...

Co-operation Agreement relating to LHC Commissioning

CERN Multimedia

2005-01-01

CERN Director-General Robert Aymar and Ryszard Tadeusiewicz, the Rector of the AGH University of Science and Technology in Cracow, after signing the agreement. On 29 July, the Rector of the AGH University of Science and Technology in Cracow, Ryszard Tadeusiewicz, and CERN Director-General Robert Aymar signed a collaboration agreement relating to the commissioning of the instrumentation and monitoring equipment for the LHC cryogenic system. Under the agreement, a team consisting of a dozen physicists, engineers and technicians from the AGH University in Cracow will lend a helping hand to the teams at CERN for the commissioning of the cryogenic system in the tunnel. This is the first in what will be a series of agreements relating to the commissioning of the LHC's various systems. From the end of this year until the summer of 2007, CERN will require reinforcements of physicists, engineers and technicians in order to complete the many tasks associated with the start-up of the accelerator. CERN is therefore pre...

6. workshop on electronics for LHC experiments. Proceedings

International Nuclear Information System (INIS)

2000-01-01

The purpose of the workshop was to review the electronics for LHC experiments and to identify areas and encourage common efforts for the development of electronics within and between the different LHC experiments and to promote collaboration in the engineering and physics communities involved in the LHC activities. (orig.)

6. workshop on electronics for LHC experiments. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-10-25

The purpose of the workshop was to review the electronics for LHC experiments and to identify areas and encourage common efforts for the development of electronics within and between the different LHC experiments and to promote collaboration in the engineering and physics communities involved in the LHC activities. (orig.)

Completion of the Series Fabrication of the Main Superconducting Quadrupole Magnets of LHC

CERN Document Server

Tortschanoff, Theodor; Papaphilippou, Y; Rossi, L; Schirm, K M; Burgmer, R; Klein, H U; Krischel, D; Schellong, B; Schmidt, P; Durante, M; Payn, A; Rifflet, J M; Simon, F

2007-01-01

By end of November 2006, the last main superconducting quadrupole cold mass needed for the installation was delivered by ACCEL Instruments to CERN. In total, 360 cold masses for the arc regions of the machine and 32 special units dedicated to the dispersion suppressor regions are installed in the LHC ring. The latter ones contain the same main magnet but different types of correctors and are of increased length with respect to the regular arc ones. The end of the fabrication of these magnets coincided with the end of the main dipole deliveries allowing a parallel assembly into their cryostats and installation into the LHC tunnel. The positioning into the tunnel was optimized using the warm field measurements performed in the factory. On the other hand, the correct slot assignment of the quadrupoles was complicated due to the multitude of variants and to the fact that a number of units needed to be replaced by spares which were customized for other slots. The paper gives some final data about the successful fa...

CERN moves into the LHC era

CERN Multimedia

2001-01-01

Dr Hans Eschelbacher (on the left), President of the CERN Council for the last three years, hands over to his successor Maurice Bourquin.  The CERN Council, where the representatives of the 20 Member States of the Organization decide on scientific programmes and financial resources, held its 116th session on 15 December under the chairmanship of Dr. Hans C. Eschelbacher (DE). 'Le Roi est mort. Vive le Roi !' The Large Electron Positron Collider (LEP) era has ended and CERN's future is the Large Hadron Collider (LHC), stated Director General, Prof. Luciano Maiani. He opened his report to Council with a 'homage to LEP', which reached the end of its career during 2000 and is now being dismantled to make way for CERN's next major machine, the LHC collider, in the same 27-kilometre tunnel. The strong indications of a Higgs boson at 115 GeV found during the year were the culmination of LEP's long and distinguished physics career, during which the machine opened up new regimes of precision physics, involvi...

The Development of the Control System for the Cryogenics in the LHC Tunnel

CERN Document Server

Fluder, C; Casas-Cubillos, J; Dubert, P; Gomes, P; Pezzetti, M; Tovar-Gonzalez, A; Zwalinski, L

2011-01-01

The Large Hadron Collider (LHC) was commissioned at CERN and started operation with beams in 2008. The LHC makes extensive use of superconductors, in magnets, electrical feed boxes and accelerating cavities, which are operated at cryogenic temperatures. The process automation for the cryogenic distribution around the 27 km accelerator circumference is based on 18 Programmable Logic Controllers (PLCs); overall, they handle 4 000 control loops and 8 000 alarms and interlocks; 16 000 cryogenic sensors and actuators are accessed through industrial field networks. This paper reviews the control system architecture and the main hardware and software components; presents the hardware commissioning and software production methodologies; and illustrates some of the problems faced during development, commissioning and nominal cryogenics operation, together with the solutions applied.

The commissioning of the instrumentation for the LHC tunnel cryogenics

CERN Document Server

Avramidou, R; Bamis, C; Casas-Cubillos, J; Dragoneas, A; Fampris, X; Fernandez-Penacoba, G; Gomes, P; Gousiou, E; Jeanmonod, N; Karagiannis, F; Koumparos, A; Leontsinis, S; Lopez-Lorente, A; Patsouli, A; Polychroniadis, I; Suraci, A; Theodoropoulos, G; Vauthier, N; Vottis, C

2007-01-01

The Large Hadron Collider (LHC) at CERN is a superconducting accelerator and proton-proton collider of circumference of 27 km, lying about 100 m underground. Its operation relies on 1232 superconducting dipoles with a field of 8.3 T and 392 superconducting quadrupoles with a field gradient of 223 T/m powered at 11.8 kA and operating in superfluid helium at 1.9 K. This paper describes the cryogenic instrumentation commissioning, the challenges and the project organization based on our 2.5 years experience.

Software Tools for Electrical Quality Assurance in the LHC

CERN Document Server

Bednarek, Mateusz

2011-01-01

There are over 1600 superconducting magnet circuits in the LHC machine. Many of them consist of a large number of components electrically connected in series. This enhances the sensitivity of the whole circuits to electrical faults of individual components. Furthermore, circuits are equipped with a large number of instrumentation wires, which are exposed to accidental damage or swapping. In order to ensure safe operation, an Electrical Quality Assurance (ELQA) campaign is needed after each thermal cycle. Due to the complexity of the circuits, as well as their distant geographical distribution (tunnel of 27km circumference divided in 8 sectors), suitable software and hardware platforms had to be developed. The software combines an Oracle database, LabView data acquisition applications and PHP-based web follow-up tools. This paper describes the software used for the ELQA of the LHC.

Software tools for electrical quality assurance in the LHC

International Nuclear Information System (INIS)

Bednarek, M.; Ludwin, J.

2012-01-01

There are over 1600 superconducting magnet circuits in the LHC machine. Many of them consist of a large number of components electrically connected in series. This enhances the sensitivity of the whole circuits to electrical faults of individual components. Furthermore, circuits are equipped with a large number of instrumentation wires, which are exposed to accidental damage or swapping. In order to ensure safe operation, an Electrical Quality Assurance (ELQA) campaign is needed after each thermal cycle. Due to the complexity of the circuits, as well as their distant geographical distribution (tunnel of 27 km circumference divided in 8 sectors), suitable software and hardware platforms had to be developed. The software combines an Oracle database, LabView data acquisition applications and PHP-based web follow-up tools. This paper describes the software used for the ELQA of the LHC. (authors)

Reliability review of the LHC collimators low level control system

International Nuclear Information System (INIS)

Masi, A.; Donze, M.; Losito, R.

2011-01-01

The LHC collimators' low level control system is responsible for the positioning, with an accuracy of a few um, of more than 500 motor axes located around the entire LHC tunnel and synchronized at us level,The collimators' axes position is verified in Real Time, monitoring at 100 Hz more than 700 LVDT positioning sensors. Apart from the challenging requirements of timing and positioning accuracy, the system is characterized by a high level of reliability since the collimators have the crucial function of machine protection. In this paper we focus on the architectural and technical choices adopted to guarantee the level of reliability required by the application. We also present the tools and solutions developed to manage this huge control system making the support easier and faster for its operation. (authors)

Cryogenic Risk Assessments before Works in the LHC Tunnel

CERN Multimedia

CERN. Geneva

2016-01-01

Tests conducted in 2013/4 demonstrated that a small, residual risk to expose personnel to a helium spill exists in the LHC. Helium spills with a mass flow of less than 100 g s^-1 could be caused by workers accidentally damaging sensitive equipment in the cryogenic distribution system, such as instrumentation feedthroughs. In order to control this risk, a cryogenic risk assessment for all works taking place in the vicinity of such sensitive equipment is mandatory. The risk assessment and its recommendations are approved by the hierarchy and the complex manager before work can start. After introducing the risk assessment procedure, I will give some feedback on its implementation and present status.

Inductive Soldering of the Junctions of the Main Superconducting Busbars of the LHC

CERN Document Server

Jacquemod, A; Schauf, F; Skoczen, Blazej; Tock, J P

2004-01-01

The Large Hadron Collider (LHC) is the next world-facility for the high energy physics community, presently under construction at CERN, Geneva. The LHC will bring into collisions intense beams of protons and ions. The main components of the LHC are the twin-aperture high-field superconducting cryomagnets that will be installed in the existing 26.7-km long tunnel. They are powered in series by superconducting Nb-Ti cables. Along the machine, about 60 000 joints between superconducting cables must be realised in-situ during the installation. Ten thousands of them, rated at 13 000 A, are involved in the powering scheme of the main dipoles and quadrupoles. To meet the requirements of the cryogenic budget, an electrical resistance at operating temperature (1.9 K) lower than 0.6 nW has to be achieved. The induction soldering technology was selected for this purpose. After a brief introduction to the LHC project, the constraints and requirements are listed. Then, the applied solution is detailed. The splices of the ...

12 December 2013 - Sir Konstantin Novoselov, Nobel Prize in Physics 2010, signing the guest book with International Relations Adviser E. Tsesmelis; visiting the ATLAS experimental cavern with Spokesperson D. Charlton; in the LHC tunnel with Technology Department Head F. Bordry. I. Antoniadis, CERN Theory Group Leader, accompanies throughout.

CERN Multimedia

Anna Pantelia

2013-01-01

12 December 2013 - Sir Konstantin Novoselov, Nobel Prize in Physics 2010, signing the guest book with International Relations Adviser E. Tsesmelis; visiting the ATLAS experimental cavern with Spokesperson D. Charlton; in the LHC tunnel with Technology Department Head F. Bordry. I. Antoniadis, CERN Theory Group Leader, accompanies throughout.

Design approach for the development of a cryomodule for compact crab cavities for Hi-Lumi LHC

Science.gov (United States)

Pattalwar, Shrikant; Jones, Thomas; Templeton, Niklas; Goudket, Philippe; McIntosh, Peter; Wheelhouse, Alan; Burt, Graeme; Hall, Ben; Wright, Loren; Peterson, Tom

2014-01-01

A prototype Superconducting RF (SRF) cryomodule, comprising multiple compact crab cavities is foreseen to realise a local crab crossing scheme for the "Hi-Lumi LHC", a project launched by CERN to increase the luminosity performance of LHC. A cryomodule with two cavities will be initially installed and tested on the SPS drive accelerator at CERN to evaluate performance with high-intensity proton beams. A series of boundary conditions influence the design of the cryomodule prototype, arising from; the complexity of the cavity design, the requirement for multiple RF couplers, the close proximity to the second LHC beam pipe and the tight space constraints in the SPS and LHC tunnels. As a result, the design of the helium vessel and the cryomodule has become extremely challenging. This paper assesses some of the critical cryogenic and engineering design requirements and describes an optimised cryomodule solution for the evaluation tests on SPS.

Interaction between groundwater and TBM (Tunnel Boring Machine) excavated tunnels

OpenAIRE

Font Capó, Jordi

2012-01-01

A number of problems, e.g. sudden inflows are encountered during tunneling under the piezometric level, especially when the excavation crosses high transmissivity areas. These inflows may drag materials when the tunnel crosses low competent layers, resulting in subsidence, chimney formation and collapses. Moreover, inflows can lead to a decrease in head level because of aquifer drainage. Tunnels can be drilled by a tunnel boring machine (TBM) to minimize inflows and groundwater impacts, restr...

Radiation Tests on the Complete System of the Instrumentation of the LHC Cryogenics at the CERN Neutrinos to Gran Sasso (CNGS) Test Facility

CERN Document Server

Gousiou, E; Casas Cubillos, J; de la Gama Serrano, J

2009-01-01

There are more than 6000 electronic cards for the instrumentation of the LHC cryogenics, housed in crates and distributed around the 27 km tunnel. Cards and crates will be exposed to a complex radiation field during the 10 years of LHC operation. Rad-tol COTS and rad-hard ASIC have been selected and individually qualified during the design phase of the cards. The test setup and the acquired data presented in this paper target the qualitative assessment of the compliance with the LHC radiation environment of an assembled system. It is carried out at the CNGS test facility which provides exposure to LHC-like radiation field.

2nd report from the LHC performance workshop

CERN Multimedia

Bulletin's correspondent from Chamonix

2012-01-01

Tuesday's sessions were spent looking ahead to the possibilities for 2012. The morning started with the experiments' desiderata for the year with the key requirement being either discovery of Higgs or exclusion at the 95% confidence level down to 115 GeV. To achieve this Atlas and CMS will need an integrated luminosity in the order of 15 fb-1.   Potential improvements to performance and machine availability were then discussed with presentations on maximising the time the LHC is delivering collisions to the experiments, and the potential of the injectors to provide bunches with higher intensities and the smallest possible beam size (these fold directly into higher collision rates). Machine performance will also be improved in 2012 thanks to a number of mitigation measures taken during the Christmas stop aimed at reducing the effects of radiation on the electronics situated in the LHC tunnel. The possibility for running at a beam energy of 4 TeV was put on the table. Discussions w...

Radiation protection considerations in the design of the LHC, CERN's large hadron collider

International Nuclear Information System (INIS)

Hoefert, M.; Huhtinen, M.; Moritz, L.E.; Nakashima, H.; Potter, K.M.; Rollet, S.; Stevenson, G.R.; Zazula, J.M.

1996-01-01

This paper describes the radiological concerns which are being taken into account in the design of the LHC (CERN's future Large Hadron Collider). The machine will be built in the 27 km circumference ring tunnel of the existing LEP collider at CERN. The high intensity of the circulating beams (each containing more than 10 14 protons at 7 TeV) determines the thickness specification of the shielding of the main-ring tunnel, the precautions to be taken in the design of the beam dumps and their associated caverns and the radioactivity induced by the loss of protons in the main ring by inelastic beam-gas interactions. The high luminosity of the collider is designed to provide inelastic collision rates of 10 9 per second in each of the two principal detector installations, ATLAS and CMS. These collisions determine the shielding of the experimental areas, the radioactivity induced in both the detectors and in the machine components on either side of the experimental installations and, to some extent, the radioactivity induced in the beam-cleaning (scraper) systems. Some of the environmental issues raised by the project will be discussed. (author)

Fabrication of nanometer flat areas onto YBa2Cu3O7-x thin film surfaces by scanning tunneling microscope

International Nuclear Information System (INIS)

Virtanen, J.A.; Suketu, P.; Huth, G.C.; Cho, Z.H.

1991-01-01

A scanning tunneling microscope was used to mechanically ''mill'' nanometer flat areas of up to 1600 μm 2 on high temperature superconducting (HTS) films of YBa 2 Cu 3 O 7-x which were originally formed by laser ablation. Flatness to a standard deviation of 2 nm in height was found to be characteristic of milled areas. It was subsequently possible to mill trenches and ditches onto these flat areas. Scanning tunneling measurements of the exposed layered structure of the milled HTS surface are also reported. Surface modifications are also possible by the application of voltage pulse to the tunneling tip. The combination of electrical pulses and milling offer a possibility of mixed electromechanical patterning of the film

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

The Control System for the Cryogenics in the LHC Tunnel [First Experience and Improvements

CERN Document Server

Gomes, P; Casas, J; Fluder, C; Fortescue, E; Le Roux, P; Penacoba, G; Pezzetti, M; Soubiran, M; Tovar, A; Zwalinski, L

2010-01-01

The Large Hadron Collider (LHC) was commissioned at CERN and started operation with beams in 2008. Several months of operation in nominal cryogenic conditions have triggered an optimisation of the process functional analysis. This lead to a few revisions of the control logic, which were realised on-the-fly. During the 2008-09 shut-down, and in order to enhance the safety, availability and operability of the LHC cryogenics, a major rebuild of the logic and several hardware modifications were implemented. The databases, containing instruments and controls in-formation, are being rationalized; the automatic tool, that extracts data for the control software, is being simplified. This paper describes the main improvements and sug-gests perspectives of further developments.

The Large Hadron Collider in the LEP tunnel

International Nuclear Information System (INIS)

Brianti, G.; Huebner, K.

1987-01-01

The status of the studies for the CERN Large Hadron Collider (LHC) is described. This collider will provide proton-proton collisions with 16 TeV centre-of-mass energy and a luminosity exceeding 10 33 cm -2 s -1 per interaction point. It can be installed in the tunnel of the Large Electron-Positron Storage Ring (LEP) above the LEP elements. It will use superconducting magnets of a novel, compact design, having two horizontally separated channels for the two counter-rotating bunched proton beams, which can collide in a maximum of seven interaction points. Collisions between protons of the LHC and electrons of LEP are also possible with a centre-of-mass energy of up to 1.8 TeV and a luminosity of up to 2 x 10 32 cm -2 s -1 . (orig.)

Reliability analysis for the quench detection in the LHC machine

CERN Document Server

Denz, R; Vergara-Fernández, A

2002-01-01

The Large Hadron Collider (LHC) will incorporate a large amount of superconducting elements that require protection in case of a quench. Key elements in the quench protection system are the electronic quench detectors. Their reliability will have an important impact on the down time as well as on the operational cost of the collider. The expected rates of both false and missed quenches have been computed for several redundant detection schemes. The developed model takes account of the maintainability of the system to optimise the frequency of foreseen checks, and evaluate their influence on the performance of different detection topologies. Seen the uncertainty of the failure rate of the components combined with the LHC tunnel environment, the study has been completed with a sensitivity analysis of the results. The chosen detection scheme and the maintainability strategy for each detector family are given.

LHC Report: Summertime and the living is ZZ (and WW etc.)

CERN Document Server

Mike Lamont for the LHC Team

2012-01-01

The LHC had a rocky recovery from the extended luminosity calibration runs, and on Saturday 21 July a number of fills were lost due to beam instabilities. The situation was stabilised by temporarily backing off increasing bunch intensity and, in fact, the next 24 hours saw a record delivery of around 260 pb-1 to each of the ATLAS and CMS experiments.   This good performance continued the following week with around 55% of the time spent in "stable beams". Over 1 fb-1 was delivered to ATLAS and CMS. This was despite some timeouts for access and operational development. Peak luminosity is down about 10% from the highs earlier in the year, but the LHC is regularly enjoying long fills in the 12 to 15 hour range. Here we are seeing the benefits of the extensive consolidation work to mitigate the effects of radiation to electronics in the LHC tunnel and the continuing efforts to improve overall reliability. Combining data runs from 2011 and 2012, LHCb crossed the 2 fb-1 mark last Mond...

LHC Report: The shutdown work nearing completion

CERN Multimedia

CERN Bulletin

2011-01-01

The work planned for the LHC injector chain during the winter shutdown is nearing completion. The PS Booster (PSB) and PS will be closed to access next week, and the control of machine access will be transferred to the CERN Control Centre in preparation for the resumption of machine operation. Hardware tests are being performed in all the machines.   Tests are under way in the LHC tunnel. The technical teams are putting the finishing touches to the work planned for the winter shutdown. At the Linac2, the PS Booster and the PS, work will be completed next week and hardware tests will be carried out soon after. POPS, the new powering system for the PS, will be commissioned for the first time in the coming days after the necessary preliminary tests have been carried out. At the SPS, various magnets have been replaced over recent weeks and the performance tests on the main power supply and other hardware tests will be able to start shortly. After that, the machine will be ready for operation with b...

Upgrade of the LHC magnet interconnections thermal shielding

Energy Technology Data Exchange (ETDEWEB)

Musso, Andrea; Barlow, Graeme; Bastard, Alain; Charrondiere, Maryline; Deferne, Guy; Dib, Gaëlle; Duret, Max; Guinchard, Michael; Prin, Hervé; Craen, Arnaud Vande; Villiger, Gilles [CERN European Organization for Nuclear Research, Meyrin 1211, Geneva 23, CH (Switzerland); Chrul, Anna [The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, ul.Radzikowskiego 152, 31-324 Krakow (Poland); Damianoglou, Dimitrios [NTUA National Technical University of Athens, Heeron Polytechniou 9, 15780 Zografou (Greece); Strychalski, Michał [Wroclaw University of Technology, Faculty of Mechanical and Power Engineering, Wyb. Wyspianskiego 27, Wroclaw, 50-370 (Poland); Wright, Loren [Lancaster University, Bailrigg, Lancaster, LA1 4YW (United Kingdom)

2014-01-29

The about 1700 interconnections (ICs) between the Large Hadron Collider (LHC) superconducting magnets include thermal shielding at 50-75 K, providing continuity to the thermal shielding of the magnet cryostats to reduce the overall radiation heat loads to the 1.9 K helium bath of the magnets. The IC shield, made of aluminum, is conduction-cooled via a welded bridge to the thermal shield of the adjacent magnets which is actively cooled. TIG welding of these bridges made in the LHC tunnel at installation of the magnets induced a considerable risk of fire hazard due to the proximity of the multi-layer insulation of the magnet shields. A fire incident occurred in one of the machine sectors during machine installation, but fortunately with limited consequences thanks to prompt intervention of the operators. LHC is now undergoing a 2 years technical stop during which all magnet's ICs will have to be opened to consolidate the magnet electrical connections. The IC thermal shields will therefore have to be removed and re-installed after the work is completed. In order to eliminate the risk of fire hazard when re-welding, it has been decided to review the design of the IC shields, by replacing the welded bridges with a mechanical clamping which also preserves its thermal function. An additional advantage of this new solution is the ease in dismantling for maintenance, and eliminating weld-grinding operations at removal needing radioprotection measures because of material activation after long-term operation of the LHC. This paper describes the new design of the IC shields and in particular the theoretical and experimental validation of its thermal performance. Furthermore a status report of the on-going upgrade work in the LHC is given.

Upgrade of the LHC magnet interconnections thermal shielding

Science.gov (United States)

Musso, Andrea; Barlow, Graeme; Bastard, Alain; Charrondiere, Maryline; Chrul, Anna; Damianoglou, Dimitrios; Deferne, Guy; Dib, Gaëlle; Duret, Max; Guinchard, Michael; Prin, Hervé; Strychalski, Michał; Craen, Arnaud Vande; Villiger, Gilles; Wright, Loren

2014-01-01

The about 1700 interconnections (ICs) between the Large Hadron Collider (LHC) superconducting magnets include thermal shielding at 50-75 K, providing continuity to the thermal shielding of the magnet cryostats to reduce the overall radiation heat loads to the 1.9 K helium bath of the magnets. The IC shield, made of aluminum, is conduction-cooled via a welded bridge to the thermal shield of the adjacent magnets which is actively cooled. TIG welding of these bridges made in the LHC tunnel at installation of the magnets induced a considerable risk of fire hazard due to the proximity of the multi-layer insulation of the magnet shields. A fire incident occurred in one of the machine sectors during machine installation, but fortunately with limited consequences thanks to prompt intervention of the operators. LHC is now undergoing a 2 years technical stop during which all magnet's ICs will have to be opened to consolidate the magnet electrical connections. The IC thermal shields will therefore have to be removed and re-installed after the work is completed. In order to eliminate the risk of fire hazard when re-welding, it has been decided to review the design of the IC shields, by replacing the welded bridges with a mechanical clamping which also preserves its thermal function. An additional advantage of this new solution is the ease in dismantling for maintenance, and eliminating weld-grinding operations at removal needing radioprotection measures because of material activation after long-term operation of the LHC. This paper describes the new design of the IC shields and in particular the theoretical and experimental validation of its thermal performance. Furthermore a status report of the on-going upgrade work in the LHC is given.

Median nerve cross-sectional area and MRI diffusion characteristics: normative values at the carpal tunnel

International Nuclear Information System (INIS)

Yao, Lawrence; Gai, Neville

2009-01-01

Enlargement of the median nerve is an objective potential imaging sign of carpal tunnel syndrome. Diffusion tensor MRI (DTI) may provide additional structural information that may prove useful in characterizing median neuropathy. This study further examines normal values for median nerve cross-sectional area (CSA), apparent diffusion coefficient (ADC), and fractional anisotropy (FA). Twenty-three wrists in 17 healthy volunteers underwent MRI of the wrist at 3 T. In 13 subjects, DTI was performed at a B value of 600 mm 2 /s. Median nerve CSA, ADC, and FA were analyzed at standardized anatomic levels. Mean (SD) median nerve CSA within the proximal carpal tunnel was 10.0 (3.4) mm 2 . The mean (SD) FA of the median nerve was 0.71 (0.06) and 0.70 (0.13) proximal to and within the carpal tunnel, respectively. There was a significant difference between nerve CSA and ADC, but not FA, at the distal forearm and proximal carpal tunnel. Nerve CSA, ADC, and FA did not differ between men and women or between dominant and non-dominant wrists. Nerve CSA at the proximal carpal tunnel was positively correlated with subject age and body mass index. Our results suggest a 90% upper confidence limit for normal median nerve CSA of 14.4 mm 2 at the proximal carpal tunnel, higher than normal limits reported by many ultrasound studies. We observed a difference between the CSA and ADC, but not the FA, of the median nerve at the distal forearm and proximal carpal tunnel levels. (orig.)

27 June 2012 - Ambassador K. Pierce, Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations Office and other international organisations in Geneva visiting the LHC tunnel at Point 5 with Department Head P. Collier and CMS control room with Former Collaboration Spokesperson J. Virdee.

CERN Multimedia

Laurent Egli

2012-01-01

27 June 2012 - Ambassador K. Pierce, Permanent Representative of the United Kingdom of Great Britain and Northern Ireland to the United Nations Office and other international organisations in Geneva visiting the LHC tunnel at Point 5 with Department Head P. Collier and CMS control room with Former Collaboration Spokesperson J. Virdee.

8 April 2013 - Indian Hon'ble Minister for Ministry of Science & Technology and Ministry of Earth Sciences Shri Sudini Jaipal Reddy in the LHC tunnel with K. Foraz, visiting the CMS cavern with Technical Coordinator A. Ball and Former Spokesperson T. Virdee, signing the guest book with Director-General R. Heuer.

CERN Multimedia

Samuel Morier-Genoud

2013-01-01

8 April 2013 - Indian Hon'ble Minister for Ministry of Science & Technology and Ministry of Earth Sciences Shri Sudini Jaipal Reddy in the LHC tunnel with K. Foraz, visiting the CMS cavern with Technical Coordinator A. Ball and Former Spokesperson T. Virdee, signing the guest book with Director-General R. Heuer.

17 January 2014 - Y. Sakurada Japanese Senior Vice Minister of Education, Culture, Sports, Science and Technology signing the Guest book with CERN Director-General R. Heuer and visiting the LHC tunnel at Point 1 with Technology Department Head J.M. Jiménez. Head of International Relations R. Voss present throughout.

CERN Multimedia

Pantelia, Anna

2014-01-01

17 January 2014 - Y. Sakurada Japanese Senior Vice Minister of Education, Culture, Sports, Science and Technology signing the Guest book with CERN Director-General R. Heuer and visiting the LHC tunnel at Point 1 with Technology Department Head J.M. Jiménez. Head of International Relations R. Voss present throughout.

CERN Open Days The LHC demystified!

CERN Multimedia

2008-01-01

Lots of surprises are being planned for the CERN Open Days scheduled for 5 and 6 April (see 21 January edition of the Bulletin). Fred’s itinerary on 6 April 20089.00 a.m\tDeparture from SM12 at CERN (the pit down which all the LHC magnets were lowered into the tunnel)9.15 a.m. Saint-Genis theatre10.00 a.m.\tRoussillon communal hall in Crozet 10.50 a.m. La Chenaille communal hall in Echenevex 11.40 a.m. CMS Building SX5 at Cessy 2.30 p.m. La Forge communal hall in Versonnex 3.30 p.m. Le Levant communal hall in Ferney Voltaire4.40 Forum in Meyrin 5.30 p.m. Main Auditorium at CERN For instance, Fred, who fronts the French television programme "C’est pas sorcier" on France 3 will be taking part in the Open Day for the general public on Sunday, 6 April. He will be on board a CERN lorry carrying a 35 tonne 15 m long dipole magnet and will make halts at eight Swiss and French communes around the LHC Ring to meet the local inhabitants (see...

20 September 2013 - Ambassador Z. Akram , Permanent Representative of the Islamic Republic of Pakistan to the United Nations Office and other international organisations in Geneva (3rd) with Mechanical and Materials Engineering Group Leader F. Bertinelli, Head of International Relations R. Voss, CMS Collaboration, Quaid-i-Azam University H. Hoorani, Permanent Mission First Secretary U. Iqbal Jadoon and LHC Consolidation, Industrial Services, Technology Department JP. Tock in front of the lift to the LHC tunnel at Point 1. Site Manager M. Décombaz on the back.

CERN Multimedia

Anna Pantelia

2013-01-01

20 September 2013 - Ambassador Z. Akram , Permanent Representative of the Islamic Republic of Pakistan to the United Nations Office and other international organisations in Geneva (3rd) with Mechanical and Materials Engineering Group Leader F. Bertinelli, Head of International Relations R. Voss, CMS Collaboration, Quaid-i-Azam University H. Hoorani, Permanent Mission First Secretary U. Iqbal Jadoon and LHC Consolidation, Industrial Services, Technology Department JP. Tock in front of the lift to the LHC tunnel at Point 1. Site Manager M. Décombaz on the back.

Typical Underwater Tunnels in the Mainland of China and Related Tunneling Technologies

Directory of Open Access Journals (Sweden)

Kairong Hong

2017-12-01

Full Text Available In the past decades, many underwater tunnels have been constructed in the mainland of China, and great progress has been made in related tunneling technologies. This paper presents the history and state of the art of underwater tunnels in the mainland of China in terms of shield-bored tunnels, drill-and-blast tunnels, and immersed tunnels. Typical underwater tunnels of these types in the mainland of China are described, along with innovative technologies regarding comprehensive geological prediction, grouting-based consolidation, the design and construction of large cross-sectional tunnels with shallow cover in weak strata, cutting tool replacement under limited drainage and reduced pressure conditions, the detection and treatment of boulders, the construction of underwater tunnels in areas with high seismic intensity, and the treatment of serious sedimentation in a foundation channel of immersed tunnels. Some suggestions are made regarding the three potential great strait-crossing tunnels—the Qiongzhou Strait-Crossing Tunnel, Bohai Strait-Crossing Tunnel, and Taiwan Strait-Crossing Tunnel—and issues related to these great strait-crossing tunnels that need further study are proposed. Keywords: Underwater tunnel, Strait-crossing tunnel, Shield-bored tunnel, Immersed tunnel, Drill and blast

There are those who call it...TIM

CERN Multimedia

2007-01-01

To boldly go where people can't... The Train Inspection Monorail, affectionately referred to as 'TIM,' will allow scientists, technicians and engineers to view and take measurements in the LHC tunnel when it is inaccessible to humans. TIM in the tunnel.Jean-Louis Grenard, who designed TIM's mechanical components, uses the portable remote control station to put the TIM through its paces at Point 1 in the LHC. Imagine being able to view parts of the LHC before people are allowed into the tunnel after the beam has been circulating...or to accurately measure the position of equipment in areas with the highest levels of radiation without risking human exposure. The Train Inspection Monorail, or 'TIM' to its closer friends, is a modular train that will run along the ceiling of the LHC tunnel, helping many groups on site to address the problems of inspecting, measuring and even handling equipment in the LHC when radiation levels and cryogenic hazards will restrict personnel access to the tunnel. TIM was developed ...

Fabrication and dc characteristics of small-area tantalum and niobium superconducting tunnel junctions

International Nuclear Information System (INIS)

Face, D.W.; Prober, D.E.

1987-01-01

We discuss the fabrication and dc electrical characteristics of small-area (1--6 μm 2 ) superconducting tunnel junctions with Ta or Nb base electrodes and Pb or Pb/sub 0.9/Bi/sub 0.1/ counterelectrodes. These junctions have very small subgap leakage currents, a ''sharp'' current rise at the sum-gap voltage, and show strong quantum effects when used as microwave mixers. The use of a low-energy (--150 eV) ion cleaning process and a novel step-defined fabrication process that eliminates photoresist processing after base electrode deposition are discussed. Tunnel barriers formed by dc glow discharge oxidation were the most successful. Tunnel barrier formation by thermal oxidation and ion-beam oxidation is also discussed. An oxidized Ta overlayer (--7 nm thick) was found to improve the characteristics of Nb-based junctions. The electrical characteristics of junctions with different electrode and barrier materials are presented and discussed in terms of the physical mechanisms that lead to excess subgap current and to a width of the current rise at the sum-gap voltage

Tunneling current between graphene layers

OpenAIRE

Poklonski, Nikolai A.; Siahlo, Andrei I.; Vyrko, Sergey A.; Popov, Andrey M.; Lozovik, Yurii E.

2013-01-01

The physical model that allows to calculate the values of the tunneling current be-tween graphene layers is proposed. The tunneling current according to the pro-posed model is proportional to the area of tunneling transition. The calculated value of tunneling conductivity is in qualitative agreement with experimental data.

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)

Work on the LHC new Quench Protection System (nQPS), January 2010

CERN Multimedia

Maximilien Brice

2010-01-01

Teams working on improving the electrical reliability of the connection between the Instrumentation Feedthrough Systems (IFS) on the magnets and the nQPS equipment. These operations are necessary to ensure that higher currents can be safely handled. Wearing of helmets in the LHC tunnel is obligatory However, people performing delicate tasks at a fixed position where there is no danger of falling objects are authorised to remove them for the duration of their work.

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

2nd workshop on Heavy Flavour Production at the LHC

CERN Document Server

2017-01-01

The second HF@LHC workshop for experimenters and theorists to discuss successes and failures in measurement and simulation of heavy quark production at the LHC and relevant aspects of their decays. The workshop will bring together experts in areas of LHC physics sensitive to top, bottom, and charm quark production, from both the theory and experimental communities. Focus will be placed on areas where new experimental data is needed as modelling input, and where experimental studies are currently limited by theory uncertainties. Lively discussion is strongly encouraged!

Load test with the mobile telescopic crane (160 T) for handling LHC magnets

CERN Multimedia

Patrice Loïez

2002-01-01

CERN has taken delivery of a new telescopic mobile crane. The new crane will be required to load LHC dipole magnets made in Building SM18 onto a trailer that will take them to the Prévessin site, where they will be put in storage until they can be lowered into the tunnel. It has passed its first operating tests, which consisted of lifting a 37-tonne concrete block.

STATISTICAL CHALLENGES FOR SEARCHES FOR NEW PHYSICS AT THE LHC.

Energy Technology Data Exchange (ETDEWEB)

CRANMER, K.

2005-09-12

Because the emphasis of the LHC is on 5{sigma} discoveries and the LHC environment induces high systematic errors, many of the common statistical procedures used in High Energy Physics are not adequate. I review the basic ingredients of LHC searches, the sources of systematics, and the performance of several methods. Finally, I indicate the methods that seem most promising for the LHC and areas that are in need of further study.

21 May 2013 - Slovakian State Secretary, Ministry of Health V. Čislák signing the Guest Book with CERN Director-General R. Heuer; in the LHC tunnel at Point 2 with V. Senaj (Technology Department); in the ALICE experimental cavern with P. Chochula (Physics Department). M. Cirilli (Knowledge Transfer Group) present.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

21 May 2013 - Slovakian State Secretary, Ministry of Health V. Čislák signing the Guest Book with CERN Director-General R. Heuer; in the LHC tunnel at Point 2 with V. Senaj (Technology Department); in the ALICE experimental cavern with P. Chochula (Physics Department). M. Cirilli (Knowledge Transfer Group) present.

29 November 2013 - U. Humphrey Orjiako Nigerian Ambassador Extraordinary and Plenipotentiary Permanent Mission to the United Nations Office and other international organisations in Geneva signing the Guest Book with Head of International Relations R. Voss, visiting the LHC tunnel at Point 2 and the ALICE cavern with ALICE Collaboration Deputy Spokesperson Y. Schutz.

CERN Multimedia

Noemi Caraban

2013-01-01

29 November 2013 - U. Humphrey Orjiako Nigerian Ambassador Extraordinary and Plenipotentiary Permanent Mission to the United Nations Office and other international organisations in Geneva signing the Guest Book with Head of International Relations R. Voss, visiting the LHC tunnel at Point 2 and the ALICE cavern with ALICE Collaboration Deputy Spokesperson Y. Schutz.

16 Augur 2013 -Bulgarian Minister of Education and Sciences A. Klisarova visiting the LHC tunnel with S. Russenschuck and CMS experimental cavern with Deputy Spokesperson T. Camporesi and V. Genchev ; signing the guest book with CERN Director-General R. Heuer. Accompanied throughout by P. Hristov, L. Litov, R. Voss and Z. Zaharieva.

CERN Multimedia

Anna Pantelia

2013-01-01

16 Augur 2013 -Bulgarian Minister of Education and Sciences A. Klisarova visiting the LHC tunnel with S. Russenschuck and CMS experimental cavern with Deputy Spokesperson T. Camporesi and V. Genchev ; signing the guest book with CERN Director-General R. Heuer. Accompanied throughout by P. Hristov, L. Litov, R. Voss and Z. Zaharieva.

1 April 2014 - President of the Parliament of the Principality of Liechtenstein A. Frick and his delegation visiting the LHC tunnel at Point 1 with Technology Department Head J.M. Jiménez and signing the Guest book with CERN Director-General R. Heuer. Deputy Head of International Relations E. Tsesmelis present throughout.

CERN Multimedia

Pantelia, Anna

2014-01-01

1 April 2014 - President of the Parliament of the Principality of Liechtenstein A. Frick and his delegation visiting the LHC tunnel at Point 1 with Technology Department Head J.M. Jiménez and signing the Guest book with CERN Director-General R. Heuer. Deputy Head of International Relations E. Tsesmelis present throughout.

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...

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)

Contract Management of LHC Civil Engineering at Point 5

CERN Document Server

Osborne, J A

1999-01-01

Civil engineering work commenced in August 1998 at LEP Point 5 for the underground and surface works necessary to accommodate the CMS detector for the LHC project. The principal underground works consist of two parallel caverns, separated by a support pillar, two new shafts, a number of smaller connection and service galleries and tunnel enlargements on the existing LEP tunnel. The surface works consist of the 140 m long SX building for the detector assembly and numerous other steel and concrete structures necessary for the installation and operation of CMS. The civil engineering design and supervision has been awarded to a joint venture of Gibb (UK), SGI (Switzerland) and Geoconsult (Austria), and the contracting to a joint venture of Dragados (Spain) and Seli (Italy) for 112 MCHF. The aim of this paper is to discuss the management of this contract and in particular how the various parties interact in order to work most efficiently.

LS1 to LHC Report: LHC key handed back to Operations

CERN Multimedia

CERN Bulletin

2015-01-01

This week, after 23 months of hard work involving about 1000 people every day, the key to the LHC was symbolically handed back to the Operations team. The first long shutdown is over and the machine is getting ready for a restart that will bring its beam to full energy in early spring.   Katy Foraz, LS1 activities coordinator, symbolically hands the LHC key to the operations team, represented, left to right, by Jorg Wenninger, Mike Lamont and Mirko Pojer. All the departments, all the machines and all the experimental areas were involved in the first long shutdown of the LHC that began in February 2013. Over the last two years, the Bulletin has closely followed  all the work and achievements that had been carefully included in the complex general schedule drawn up and managed by the team led by Katy Foraz from the Engineering Department. “The work on the schedule began two years before the start of LS1 and one of the first things we realised was that there was no commercial...

A new crane for the LHC magnets

CERN Multimedia

2002-01-01

Last Friday CERN took delivery of the new crane that will be used for handling the LHC magnets. CERN took delivery of its new telescopic mobile crane on Friday, 22 February. It underwent its first operating tests, which consisted of lifting a 37-tonne concrete block. Five drive-steer axles, two engines with a capacity of 544 and 203 hp respectively, a telescopic boom with a 60-metre reach and a lifting capacity of 160 tonnes at 3 metres: these are the impressive characteristics of CERN's new 160-tonne crane. And the handling of the LHC magnets, each weighing a 'trifling' 33 tonnes, demands no less than this. The new crane will be required to load the magnets made in Building SM18 onto a trailer that will take them to the Prévessin site, where they will be put in storage until they can be lowered into the tunnel. The telescopic mobile crane arrived at CERN last Friday and has passed its first operating tests with flying colours. Until now, CERN had two cranes, with a maximum capacity of 40 and 60...

SEU tests performed on the digital communication system for LHC cryogenic instrumentation

International Nuclear Information System (INIS)

Casas-Cubillos, J.; Faccio, F.; Gomes, P.; Martin, M.A.; Rodriguez-Ruiz, M.A.

2002-01-01

The future LHC particle accelerator will use a large number of cryogenic sensors and actuators, most of which are located inside the machine tunnel and therefore in a radiation environment. These elements will communicate through a fieldbus. This paper reports the irradiation study carried out on WorldFIP fieldbus communication system. A digital communication system based on WorldFIP fieldbus protocol has been implemented and single event effects and total ionizing dose radiation tests have been performed on it

The dance of the LHC magnets

CERN Multimedia

2003-01-01

The dance of the blue magnets has begun. On 25 April, the first superconducting dipole magnet for the LHC made the trip from Building SM18, where it had been tested and assembled, to the Prévessin site, where it is now being stored. The next few months will see many of these exceptional convoys - in more ways than one - bringing the magnets along the Route de l'Europe to Prévessin for storage before they are lowered into the tunnel. CERN's impressive overhead travelling crane loading the 15-metre-long magnet onto a lorry.The start of the 10-km-an-hour journey to the Prévessin site. Infinite care is taken with the loading, transportation and unloading of these precious magnets.

Pollutant Plume Dispersion over Hypothetical Urban Areas based on Wind Tunnel Measurements

Science.gov (United States)

Mo, Ziwei; Liu, Chun-Ho

2017-04-01

Gaussian plume model is commonly adopted for pollutant concentration prediction in the atmospheric boundary layer (ABL). However, it has a number of limitations being applied to pollutant dispersion over complex land-surface morphology. In this study, the friction factor (f), as a measure of aerodynamic resistance induced by rough surfaces in the engineering community, was proposed to parameterize the vertical dispersion coefficient (σz) in the Gaussian model. A series of wind tunnel experiments were carried out to verify the mathematical hypothesis and to characterize plume dispersion as a function of surface roughness as well. Hypothetical urban areas, which were assembled in the form of idealized street canyons of different aspect (building-height-to-street-width) ratios (AR = 1/2, 1/4, 1/8 and 1/12), were fabricated by aligning identical square aluminum bars at different separation apart in cross flows. Pollutant emitted from a ground-level line source into the turbulent boundary layer (TBL) was simulated using water vapour generated by ultrasonic atomizer. The humidity and the velocity (mean and fluctuating components) were measured, respectively, by humidity sensors and hot-wire anemometry (HWA) with X-wire probes in streamwise and vertical directions. Wind tunnel results showed that the pollutant concentration exhibits the conventional Gaussian distribution, suggesting the feasibility of using water vapour as a passive scalar in wind tunnel experiments. The friction factor increased with decreasing aspect ratios (widening the building separation). It was peaked at AR = 1/8 and decreased thereafter. Besides, a positive correlation between σz/xn (x is the distance from the pollutant source) and f1/4 (correlation coefficient r2 = 0.61) was observed, formulating the basic parameterization of plume dispersion over urban areas.

Installation and Quality Assurance of the Interconnections between Cryo-assemblies of the LHC Long Straight Sections

CERN Document Server

Garion, C; Tock, J P

2006-01-01

The interconnections between the cryomagnets and cryogenic utilities in the LHC long Straight Sections constitute the last machine installation activity. They are ensuring continuity of the beam and insulation vacuum systems, cryogenic fluid and electrical circuits and thermal insulation. The assembly is carried out in a constraining tunnel environment with restricted space. Therefore, the assembly sequence has to be well defined and specific tests have to be performed during the interconnection work to secure the reliability of the system and thus to ensure the global accelerator availability. The LHC has 8 long straight insertion zones composed of special cryomagnets involving specific interconnection procedures and QA plans. The aim of this paper is to present the installation and quality assurance procedures implemented for the LHC LSS interconnections. Technologies such as manual and automatic welding and resistive soldering will be described as well as the different quality controls, such as visual and ...

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...

Cryogenic Infrastructure for Testing of LHC Series Superconducting Magnets

CERN Document Server

Axensalva, J; Herblin, L; Lamboy, J P; Tovar-Gonzalez, A; Vuillerme, B

2005-01-01

The ~1800 superconducting magnets for the LHC machine shall be entirely tested at reception before their installation in the tunnel. For this purpose and in order to reach the reliability and efficiency at the nominal load required for an industrial operation for several years, we have gradually upgraded and retrofitted the cryogenic facilities installed in the early nineties for the testing at CERN of prototypes and preseries magnets. The final infrastructure of the test station, dedicated to check industrially the quality of the series magnets, is now nearly complete. We present the general layout and describe the overall performance of the system.

Ultralarge area MOS tunnel devices for electron emission

DEFF Research Database (Denmark)

Thomsen, Lasse Bjørchmar; Nielsen, Gunver; Vendelbo, Søren Bastholm

2007-01-01

density. Oxide thicknesses have been extracted by fitting a model based on Fermi-Dirac statistics to the C-V characteristics. By plotting I-V characteristics in a Fowler plot, a measure of the thickness of the oxide can be extracted from the tunnel current. These apparent thicknesses show a high degree......A comparative analysis of metal-oxide-semiconductor (MOS) capacitors by capacitance-voltage (C-V) and current-voltage (I-V) characteristics has been employed to characterize the thickness variations of the oxide on different length scales. Ultralarge area (1 cm(2)) ultrathin (similar to 5 nm oxide......) MOS capacitors have been fabricated to investigate their functionality and the variations in oxide thickness, with the use as future electron emission devices as the goal. I-V characteristics show very low leakage current and excellent agreement to the Fowler-Nordheim expression for the current...

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...

GIF++: A new CERN Irradiation Facility to test large-area particle detectors for the High-Luminosity LHC program

CERN Document Server

Guida, Roberto

2016-01-01

The high-luminosity LHC (HL-LHC) upgrade is setting a new challenge for particle detector technologies. The increase in luminosity will produce a higher particle background with respect to present conditions. To study performance and stability of detectors at LHC and future HL-LHC upgrades, a new dedicated facility has been built at CERN: the new Gamma Irradiation Facility (GIF++). The GIF++ is a unique place where high energy charged particle beams (mainly muons) are combined with gammas from a 14 TBq 137Cesium source which simulates the background radiation expected at the LHC experiments. Several centralized services and infrastructures are made available to the LHC detector community to facilitate the different R&D; programs.

Defining the value of injection current and effective electrical contact area for EGaIn-based molecular tunneling junctions.

Science.gov (United States)

Simeone, Felice C; Yoon, Hyo Jae; Thuo, Martin M; Barber, Jabulani R; Smith, Barbara; Whitesides, George M

2013-12-04

Analysis of rates of tunneling across self-assembled monolayers (SAMs) of n-alkanethiolates SCn (with n = number of carbon atoms) incorporated in junctions having structure Ag(TS)-SAM//Ga2O3/EGaIn leads to a value for the injection tunnel current density J0 (i.e., the current flowing through an ideal junction with n = 0) of 10(3.6±0.3) A·cm(-2) (V = +0.5 V). This estimation of J0 does not involve an extrapolation in length, because it was possible to measure current densities across SAMs over the range of lengths n = 1-18. This value of J0 is estimated under the assumption that values of the geometrical contact area equal the values of the effective electrical contact area. Detailed experimental analysis, however, indicates that the roughness of the Ga2O3 layer, and that of the Ag(TS)-SAM, determine values of the effective electrical contact area that are ~10(-4) the corresponding values of the geometrical contact area. Conversion of the values of geometrical contact area into the corresponding values of effective electrical contact area results in J0(+0.5 V) = 10(7.6±0.8) A·cm(-2), which is compatible with values reported for junctions using top-electrodes of evaporated Au, and graphene, and also comparable with values of J0 estimated from tunneling through single molecules. For these EGaIn-based junctions, the value of the tunneling decay factor β (β = 0.75 ± 0.02 Å(-1); β = 0.92 ± 0.02 nC(-1)) falls within the consensus range across different types of junctions (β = 0.73-0.89 Å(-1); β = 0.9-1.1 nC(-1)). A comparison of the characteristics of conical Ga2O3/EGaIn tips with the characteristics of other top-electrodes suggests that the EGaIn-based electrodes provide a particularly attractive technology for physical-organic studies of charge transport across SAMs.

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.

TOTEM: Discoveries may go “forward” at the LHC

CERN Multimedia

TOTEM Collaboration

2015-01-01

After two very intense years of activity during which the TOTEM apparatus has gone through an extensive upgrade programme, the collaboration is now ready to explore the new territories in forward physics that will open at 13 TeV.   One vertical TOTEM Roman Pot and a tilted one, in the LHC tunnel. The rotation of the Roman Pots was one of the operations performed by the TOTEM collaboration during the LS1 upgrade programme. The TOTEM experimental apparatus that will operate during Run 2 of the LHC will be significantly better than before: the Roman Pot detectors have been re-configured to resolve pile-up and prepared for the addition in the near future of high-precision time-of-flight detectors. In addition, their impedance characteristics have been significantly improved to allow the beam to be approached safely at higher intensities. Finally, following up on the Memorandum of Understanding signed in 2014 by TOTEM and CMS, the two experiments have worked on upgrading their data acquisition an...

East Area Irradiation Test Facility: Preliminary FLUKA calculations

CERN Document Server

Lebbos, E; Calviani, M; Gatignon, L; Glaser, M; Moll, M; CERN. Geneva. ATS Department

2011-01-01

In the framework of the Radiation to Electronics (R2E) mitigation project, the testing of electronic equipment in a radiation field similar to the one occurring in the LHC tunnel and shielded areas to study its sensitivity to single even upsets (SEU) is one of the main topics. Adequate irradiation test facilities are therefore required, and one installation is under consideration in the framework of the PS East area renovation activity. FLUKA Monte Carlo calculations were performed in order to estimate the radiation field which could be obtained in a mixed field facility using the slowly extracted 24 GeV/c proton beam from the PS. The prompt ambient dose equivalent as well as the equivalent residual dose rate after operation was also studied and results of simulations are presented in this report.

20 December 2013 - R. M. Cordeiro Dunlop Ambassador Permanent Representative of Brazil to the United Nations Office and other international organisations in Geneva visiting the LHC tunnel at Point 5 with CMS Collaboration, CERN Team Leader A. Petrilli and signing the Guest Book with CERN Director-General. Accompanied by J. Salicio and R. Voss throughout.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

20 December 2013 - R. M. Cordeiro Dunlop Ambassador Permanent Representative of Brazil to the United Nations Office and other international organisations in Geneva visiting the LHC tunnel at Point 5 with CMS Collaboration, CERN Team Leader A. Petrilli and signing the Guest Book with CERN Director-General. Accompanied by J. Salicio and R. Voss throughout.

30 August 2013 - Senior Vice Minister for Foreign Affairs in Japan M. Matsuyama signing the guest book with CERN Director-General; visit the ATLAS experimental cavern with ATLAS Spokesperson D. Charlton and visiting the LHC tunnel at Point 1 with former ATLAS Japan national contact physicist T. Kondo. R. Voss and K. Yoshida present throughout.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

30 August 2013 - Senior Vice Minister for Foreign Affairs in Japan M. Matsuyama signing the guest book with CERN Director-General; visit the ATLAS experimental cavern with ATLAS Spokesperson D. Charlton and visiting the LHC tunnel at Point 1 with former ATLAS Japan national contact physicist T. Kondo. R. Voss and K. Yoshida present throughout.

LHC beam stability and feedback control

International Nuclear Information System (INIS)

Steinhagen, Ralph

2007-01-01

This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a proportional

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...

An intelligent and networking solution of radiation monitoring system for LHC

International Nuclear Information System (INIS)

Shao Beibei; Gong Guanghua

2001-01-01

The LHC (the Large Hadron Collider), the largest accelerator in the world, is under designing and construction at CERN. It shares the 27 km LEP tunnel and is expected to be on the air in 2005. The Radiation Monitoring System of LEP was a central system with non-intelligent detectors. While as the proposed new RMS for LHC is a distributing intelligent networked system. Around 350 detectors will be employed. To save the cost, the design should make the old LEP's non-intelligent detectors reusable. To allow the detector controller automatic reports the detector database and net location through the world Fip bus, 1 wire components are embedded into the detectors and the network sockets. The radiation tolerance and the reliability of the communication of the wire components have been tested in a strong radiation field at CERN. The low cost components based position detection technique is valuable for most networked control system

Mobile CT-System for In-situ Inspection in the LHC at CERN

CERN Document Server

Sauerwein, C; Caspers, F; Dalin, J M; Haemmerle, V; Tiseanu, I; Tock, J P

2010-01-01

For the inspection of certain critical elements of the LHC machine a mobile computed tomography system has been developed and built. This instrument has to satisfy stringent space, volume and weight requirements in order to be transportable and usable to any interconnection location in the LHC tunnel. Particular regions of interest in the interconnection zones between adjacent magnets are the plug in modules (PIM), the soldered splices in the superconducting bus-bars and the interior of the quench diode container. This system permits detailed inspection of these regions without needing to break the insulation vacuum. Limited access for the x-ray tube and the detector required the development of a special type of partial tomography, together with suitable reconstruction techniques for 3 D volume generation from radiographic projections. The layout of the complete machine, the limited angle tomography, as well as a number of radiographic and tomographic inspection results is presented.

Installation of the cryo-magnets for the LHC passed the symbolic 1000 mark at the beginning of the month

CERN Multimedia

2006-01-01

At 10.30 am on 5 September, the 1000th cryo-magnet was installed in the LHC tunnel in the arc between point 3 and point 4. The same week also saw the completion of the cryo-magnet installation between point 8 and point 1, making this the first sector where all the magnets have been installed. Three other sectors (7-8, 4-5 and 5-6) are very close to completion with only a very few magnets missing, and installation work is now concentrated on sectors 3-4 and 6-7. There are a total of 1746 cryo-magnets altogether, of which 1232 are the well known blue dipoles. The remaining 746 cryo-magnets should be transported and installed by March 2007.  Installation in the LHC tunnel is only one of many successive steps in the life of a cryo-magnet: cold mass manufacturing, cryostating, magnet testing at low temperature, preparation before lowering, transport, interconnecting, pumping down, cooling down and commissioning before injecting the first protons beams. Hundreds of collaborators, both from CERN and from the contra...

Large area thinned planar sensors for future high-luminosity-LHC upgrades

International Nuclear Information System (INIS)

Wittig, T.; Lawerenz, A.; Röder, R.

2016-01-01

Planar hybrid silicon sensors are a well proven technology for past and current particle tracking detectors in HEP experiments. However, the future high-luminosity upgrades of the inner trackers at the LHC experiments pose big challenges to the detectors. A first challenge is an expected radiation damage level of up to 2⋅ 10 16 n eq /cm 2 . For planar sensors, one way to counteract the charge loss and thus increase the radiation hardness is to decrease the thickness of their active area. A second challenge is the large detector area which has to be built as cost-efficient as possible. The CiS research institute has accomplished a proof-of-principle run with n-in-p ATLAS-Pixel sensors in which a cavity is etched to the sensor's back side to reduce its thickness. One advantage of this technology is the fact that thick frames remain at the sensor edges and guarantee mechanical stability on wafer level while the sensor is left on the resulting thin membrane. For this cavity etching technique, no handling wafers are required which represents a benefit in terms of process effort and cost savings. The membranes with areas of up to ∼ 4 × 4 cm 2 and thicknesses of 100 and 150 μm feature a sufficiently good homogeneity across the whole wafer area. The processed pixel sensors show good electrical behaviour with an excellent yield for a suchlike prototype run. First sensors with electroless Ni- and Pt-UBM are already successfully assembled with read-out chips.

Large area thinned planar sensors for future high-luminosity-LHC upgrades

Science.gov (United States)

Wittig, T.; Lawerenz, A.; Röder, R.

2016-12-01

Planar hybrid silicon sensors are a well proven technology for past and current particle tracking detectors in HEP experiments. However, the future high-luminosity upgrades of the inner trackers at the LHC experiments pose big challenges to the detectors. A first challenge is an expected radiation damage level of up to 2ṡ 1016 neq/cm2. For planar sensors, one way to counteract the charge loss and thus increase the radiation hardness is to decrease the thickness of their active area. A second challenge is the large detector area which has to be built as cost-efficient as possible. The CiS research institute has accomplished a proof-of-principle run with n-in-p ATLAS-Pixel sensors in which a cavity is etched to the sensor's back side to reduce its thickness. One advantage of this technology is the fact that thick frames remain at the sensor edges and guarantee mechanical stability on wafer level while the sensor is left on the resulting thin membrane. For this cavity etching technique, no handling wafers are required which represents a benefit in terms of process effort and cost savings. The membranes with areas of up to ~ 4 × 4 cm2 and thicknesses of 100 and 150 μm feature a sufficiently good homogeneity across the whole wafer area. The processed pixel sensors show good electrical behaviour with an excellent yield for a suchlike prototype run. First sensors with electroless Ni- and Pt-UBM are already successfully assembled with read-out chips.

Scanning tunneling microscopy

International Nuclear Information System (INIS)

Binnig, G.; Rohrer, H.

1983-01-01

Based on vacuum tunneling, a novel type of microscope, the scanning tunneling microscope (STM) was developed. It has an unprecedented resolution in real space on an atomic scale. The authors review the important technical features, illustrate the power of the STM for surface topographies and discuss its potential in other areas of science and technology. (Auth.)

Scanning tunneling microscope nanoetching method

Science.gov (United States)

Li, Yun-Zhong; Reifenberger, Ronald G.; Andres, Ronald P.

1990-01-01

A method is described for forming uniform nanometer sized depressions on the surface of a conducting substrate. A tunneling tip is used to apply tunneling current density sufficient to vaporize a localized area of the substrate surface. The resulting depressions or craters in the substrate surface can be formed in information encoding patterns readable with a scanning tunneling microscope.

The radiation monitoring system for the LHC experiments and experimental areas

CERN Document Server

Ilgner, C

2004-01-01

With the high energies stored in the beams of the LHC, special attention needs to be paid to accident scenarios involving beam losses which may have an impact on the installed experiments. Among others, an unsynchronized beam abort and a D1 magnet failure are considered serious cases. According to simulations, the CMS inner tracker in such accident scenarios can be damaged by instantaneous rates which are many orders of magnitude above normal conditions. Investigations of synthetic diamond as a beam condition monitor sensor, capable of generating a fast beam dump signal, will be presented. Furthermore, a system to monitor the radiation fields in the experimental areas is being developed. It must function in the radiation fields inside and around the experiments, over a large dynamic range. Several new active and passive sensors, such as RadFET, OSL (Optically Stimulated Luminescence) sensors, p-i-n diodes, Polymer-Alanine Dosimeters and TLDs (Thermoluminescent Dosimeters) are under investigation. Recent resul...

Mechanism of water inrush in tunnel construction in karst area

Directory of Open Access Journals (Sweden)

Liping Li

2016-05-01

Full Text Available With the rapid developing trend of long, large and deep construction characteristics for underground engineering in the world, China has the largest number of karst tunnels with the wide scales and great difficulties. As the hydrogeological conditions are becoming unprecedentedly complex, water inrush disaster becomes the bottleneck problem for the further development of traffic tunnels. Based on the statistical analysis of a large number of cases of water inrush in karst tunnels, influence factors of water inrush have been put forward from the view of karst hydrogeological factors and engineering disturbance of human factors. Karst hydrogeological factors include geological defect, strata dip, formation lithology, landform and underground level. Human factors of engineering disturbance include excavation and reinforcement geological prediction, monitoring and measurement of surrounding rock. It also introduces some geological disasters caused by the water inrush in tunnel excavation. In terms of the formation of water inrush channel, water inrush types are divided into geological defects inrush, non-geological defects inrush and the combination. Conclusions will be beneficial to further research on hazards control of underground construction.

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.

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.

The metrology of the LHC project: what news?

International Nuclear Information System (INIS)

Chambardon, M.; Missiaen, D.; Quesnel, J.P.; Scandale, W.; Naegely, A.V.; Naegely, P.

1999-01-01

The Large Hadron Collider (LHC), under construction at CERN, uses superconducting magnets operating at a temperature of 1.9 K to guide the circulating particles. A specific feature of the main magnets (dipoles and quadrupoles) is the two-in-one design with two magnetic channels in one common retaining structure. Indeed, the accelerator is made of two rings, mechanically linked, that have to be simultaneously aligned during the installation in the already existing LEP tunnel. The assembly tolerances of the LHC main magnets have been reconsidered to take into account the tight constraints on geometry. The dipoles are bent to follow closely the curvature of the circulating particles and to make a larger mechanical aperture available for the circulating particles. In order to minimise the geometrical errors the dipole assembly procedure is assisted by high precision survey measurements based on laser trackers. By this we hope to reduce to ± 1 mm the positioning error along the axis of the magnets. In addition the ends of the dipoles and quadrupoles should be aligned with even better precision to reduce to below ± 0.3 mm the displacement of the bellows in the magnet-to-magnet interconnection. All these precautions are expected to make easier the installation and to improve the LHC machine operation. In Section 2, we discuss the survey activity related to the civil engineering work. In section 3 we discuss the alignment of the dipoles in their cryostats. In Section 4 we present our geodetic network and in Section 5 we draw our conclusions. (authors)

The LHC machine-experiment interface

CERN Multimedia

CERN. Geneva; Tsesmelis, Emmanuel; Brüning, Oliver Sim

2002-01-01

This series of three lectures will provide an overview of issues arising at the interface between the LHC machine and the experiments, which are required for guiding the interaction between the collider and the experiments when operation of the LHC commences. A basic description of the LHC Collider and its operating parameters, such as its energy, currents, bunch structure and luminosity, as well as variations on these parameters, will be given. Furthermore, the optics foreseen for the experimental insertions, the sources and intensities of beam losses and the running-in scenarios for the various phases of operation will be discussed. A second module will cover the specific requirements and expectations of each experiment in terms of the layout of experimental areas, the matters related to radiation monitoring and shielding, the design of the beam pipe and the vacuum system, alignment issues and the measurement of the total cross-section and absolute luminosity by the experiments. Finally an analysis of infor...

Supersymmetry and the LHC (Lectures CANCELLED)

CERN Multimedia

CERN. Geneva

2006-01-01

I will first give a pedagogical motivation for, and introduction to, supersymmetric extensions of the Standard Model. The biggest obstacle that prevents theorists from making clear-cut predictions for the production of superparticles at the LHC is our lack of knowledge of how supersymmetry is broken. I will review the most promising SUSY breaking mechanisms that have been suggested so far, and outline the resulting signatures for LHC experiments. Finally, I will try to make contact with other areas of particle physics and cosmology, where supersymmetry also might play a role.

17 October 2013 - C. Ashton High Representative of the European Union for Foreign Affairs and Security Policy, Vice-President of the European Commission visiting the ATLAS cavern with ATLAS Collaboration Spokesperson D. Charlton; visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and signing the Guest book with CERN Director-General R. Heuer.

CERN Multimedia

Maximilien Brice

2013-01-01

17 October 2013 - C. Ashton High Representative of the European Union for Foreign Affairs and Security Policy, Vice-President of the European Commission visiting the ATLAS cavern with ATLAS Collaboration Spokesperson D. Charlton; visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and signing the Guest book with CERN Director-General R. Heuer.

5 June 2013 - European Union Ambassador to Switzerland and the Principality of Liechtenstein R. Jones in the ATLAS cavern with ATLAS Collaboration Deputy Spokesperson T. Wengler, in the LHC tunnel at Point 1 with Technology Department Head F. Bordry and signing the guest book with Director-General R. Heuer. Head of the EU Projects Office S. Stavrev present.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

5 June 2013 - European Union Ambassador to Switzerland and the Principality of Liechtenstein R. Jones in the ATLAS cavern with ATLAS Collaboration Deputy Spokesperson T. Wengler, in the LHC tunnel at Point 1 with Technology Department Head F. Bordry and signing the guest book with Director-General R. Heuer. Head of the EU Projects Office S. Stavrev present.

16 December 2013 - P. Lavie President of the Technion Institute of Technology in Israel visiting the ATLAS cavern with ATLAS Deputy Spokesperson T. Wengler; visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and signing the Guest Book with CERN Director-General R. Heuer. G. Mikenberg, E. Rabinovici, Y. Rozen and S. Tarem present throughout.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

16 December 2013 - P. Lavie President of the Technion Institute of Technology in Israel visiting the ATLAS cavern with ATLAS Deputy Spokesperson T. Wengler; visiting the LHC tunnel at Point 1 with Technology Department Head F. Bordry and signing the Guest Book with CERN Director-General R. Heuer. G. Mikenberg, E. Rabinovici, Y. Rozen and S. Tarem present throughout.

16 July 2013 - Israel Ministry of Education Director-General D. Stauber in the LHC tunnel at Point 1 with L. Tavian, visiting the ATLAS experimental cavern with Senior Physicist G. Mikenberg; Israeli Delegate to CERN Council E. Rabinovici and CERN Adviser for Israel E. Tsesmelis present; signing the guest book with CERN Director-General R. Heuer.

CERN Multimedia

Anna Pantelia

2013-01-01

16 July 2013 - Israel Ministry of Education Director-General D. Stauber in the LHC tunnel at Point 1 with L. Tavian, visiting the ATLAS experimental cavern with Senior Physicist G. Mikenberg; Israeli Delegate to CERN Council E. Rabinovici and CERN Adviser for Israel E. Tsesmelis present; signing the guest book with CERN Director-General R. Heuer.

24 May 2013 - Rector of the Polish Stanislaw Staszic AGH University of Science and Technology T. Slomka in the LHC tunnel at Point 8 with Senior Polish Staff Member A. Siemko, in LHCb experimental cavern with LHCb Collaboration Spokesperson P. Campana and signing the guest book with Director-General R. Heuer. Adviser for Eastern Europe T. Kurtyka present.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

24 May 2013 - Rector of the Polish Stanislaw Staszic AGH University of Science and Technology T. Slomka in the LHC tunnel at Point 8 with Senior Polish Staff Member A. Siemko, in LHCb experimental cavern with LHCb Collaboration Spokesperson P. Campana and signing the guest book with Director-General R. Heuer. Adviser for Eastern Europe T. Kurtyka present.

Design and fabrication of the prototype superconducting tuning quadrupole and octupole correction winding for the LHC project

International Nuclear Information System (INIS)

Perin, R.; Siegel, N.; Bidaurrazaga, H.; Garcia Tabares, L.

1992-01-01

CERN is preparing for the construction of the Large Hadron Collider (LHC) to be installed in the LEP tunnel. The magnetic lattice of the LHC will consist of a ring of twin aperture dipoles and quadrupoles, connected electrically in series. To adjust the working point of the machine, so called tuning quadrupoles will be installed in pairs in each regular cell, next to the main quadrupoles. Also, to correct multipolar field errors in the LHC, an octupole correction winding is required near each lattice quadrupole. A nested construction of these two magnets is foreseen. As part of the LHC R and D program, CERN and ACICA (a group of five Spanish industries: Abengoz, Canzler, Indar, Cenemesa and AME; since June 1990 Cenemesa is part of ABB Spain), signed a common development agreement for the design, fabrication and testing of a prototype tuning quadrupole and octupole corrector. This paper describes the design of these magnets, giving details of magnetic and mechanical calculations, including results from existing and specially developed computer codes, and model work. Further, the construction procedures are described, including the facilities and tooling developed by ACICA for this work

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...

Coupled Simulations of the Synchrotron Radiation and Induced Desorption Pressure Profiles for the HL-LHC Triplet Area and Interaction Points

CERN Document Server

Kersevan, R; Bregliozzi, G

2014-01-01

The HiLumi-LHC machine upgrade has officially started as an approved LHC project (see dedicated presentations at this conference on the subject). One important feature of the upgrade is the installation of very high-gradient triplet magnets for focusing the beams at the collision points of the two high-luminosity detectors ATLAS and CMS. Other important topics are new superconducting D1 and D2 magnets, installation of crab cavities and new tertiary collimators, and re-shuffling of the dispersion suppression area. Based on the current magnetic lattice set-up and beam orbits, a detailed study of the emission of synchrotron radiation (SR) and related photon-induced desorption (PID) has been carried out. A significant amount of SR photons are generated by the two off-axis beams in the common vacuum chamber of the triplet area, about 57 m in length. Ray-tracing Montecarlo codes Synrad+ and Molflow+ have been employed in this study. The related PID pressure profiles are shown, together with simulations using the co...

Plastic Zone Analysis of Deep-Buried, Noncircular Tunnel and Application on the High-Speed Railway in the Karst Area

Directory of Open Access Journals (Sweden)

Hai Shi

2017-01-01

Full Text Available With the conformal mapping function provided by Verruijt, the outland of a noncircular tunnel can be mapped to a circular unit in the complex plane and then spread the analytic function into a Laurent series. The stress unified solution of oval and horseshoe cross section can be determined using Muskhelishvili’s complex variables function method. Subsequently, the solution can be taken into the Griffith strength failure criterion and determine the scale and shape of plastic zone in the tunnel surrounding rock. Aiming at the critical safety thickness between a concealed cave and tunnel in the karst area and determining whether the plastic zone of tunnel surrounding rock is connected with the plastic zone of cave as a judgment standard, the model of critical safety thickness among the concealed caves and tunnels is established. The numerical model is established in comparison with the computing method of rock plate critical safety thickness in actual engineering based on the Doumo tunnel engineering of Shanghai-Kunming (Guizhou segment high-speed railway. The following conclusions can be drawn: the analytical approximation method has less indexes, and the output of this method is approximately close to actual engineering and numerical analysis, in which it is reliable and rational.

Large hadron collider in the LEP tunnel. Proceedings. Vol. 2

International Nuclear Information System (INIS)

1984-01-01

A Workshop, jointly organized by ECFA and CERN, took place at Lausanne and at CERN in March 1984 to study various options for a pp (or panti p) collider which might be installed at a later data alongside LEP in the LEP tunnel. Following the exploration of e + e - physics up to the highest energy now foreseeable, this would open up the opportunity to investigate hadron collisions in the new energy range of 10 to 20 TeV in the centre of mass. These proceedings put together the documents prepared in connection with this Workshop. They cover possible options for a Large Hadron Collider (LHC) in the LEP tunnel, the physics case as it stands at present, and studies of experimental possibilities in this energy range with luminosities as now considered. See hints under the relevant topics. (orig./HSI)

Large hadron collider in the LEP tunnel. Proceedings. Vol. 1

International Nuclear Information System (INIS)

1984-01-01

A Workshop, jointly organized by ECFA and CERN, took place at Lausanne and at CERN in March 1984 to study various options for a pp (or panti p) collider which might be installed at a later date alongside LEP in the LEP tunnel. Following the exploration of e + e - physics up to the highest energy now foreseeable, this would open up the opportunity to investigate hadron collisions in the new energy range of 10 to 20 TeV in the centre of mass. These proceedings put together the documents prepared in connection with this Workshop. They cover possible options for a Large Hadron Collider (LHC= in the LEP tunnel, the physics case at it stands at present, and studies of experimental possibilities in this energy range with luminosities as now considered. See hints under the relevant topics. (orig.)

Rock mechanical conditions at the Aespoe HRL. A study of the correlation between geology, tunnel maintenance and tunnel shape

International Nuclear Information System (INIS)

Andersson, Christer; Soederhaell, Joergen

2001-12-01

Maintenance records including scaling, shotcreting and bolting have been kept since the excavation start of Aespoe HRL 1990 together with records of groundwater flow and all other activities taking place in the tunnels. When the facility was constructed one objective was to limit the rock support as much as possible. The reason for this was that it should be possible to go back and easily study the exposed rock surface. Support during the operational phase has only been carried out where and when necessary. This type of maintenance and its location is documented in the digital database each time. The maintenance records have been compiled and areas requiring more maintenance than average noted. An interview has also been held with one of the miners conducting scaling and bolting in the tunnel. His experiences together with the study of the database maintenance records led to the selection of certain areas in the tunnel to be studied by numerical modelling. The probable reason for the need of additional maintenance in all areas, not only these numerically modelled, has been investigated. Almost all maintenance in the main tunnel both during construction and the operational phase has been located in the widened curves of the access tunnel. The maintenance is also located in areas containing veins or intrusions of Smaaland granite or fine-grained granite. These areas are often located in fracture zones of different sizes or show an increasing fracture frequency. The areas numerically modelled indicate stress concentrations or unloaded stress conditions. The stress concentrations are created by the geometry of the niches and side-tunnels in relation to the in situ stress field. The angle between the tunnel and the major principal stress has an impact on the need for maintenance. The areas with the largest angles towards the principal stress direction need more maintenance than the areas almost parallel to the major principal stress direction. The maintenance work in

78 FR 46117 - National Tunnel Inspection Standards

Science.gov (United States)

2013-07-30

... busiest vehicular tunnel in the world. The Fort McHenry Tunnel handles a daily traffic volume of more than... vehicular, transit, and rail tunnels in the New York City metropolitan area. Although it is still too early... congestion along alternative routes, and save users both dollars and fuel. If these tunnels were closed due...

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...

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...

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.

Design of a 0-50 mbar pressure measurement channel compatible with the LHC tunnel radiation environment

Science.gov (United States)

Casas, Juan; Jelen, Dorota; Trikoupis, Nikolaos

2017-02-01

The monitoring of cryogenic facilities often require the measurement of pressure in the sub 5’000 Pa range that are used for flow metering applications, for saturated superfluid helium, etc. The pressure measurement is based on the minute displacement of a sensing diaphragm often through contactless techniques by using capacitive or inductive methods. The LHC radiation environment forbid the use of standard commercial sensors because of the embedded electronics that are affected both by radiation induced drift and transient Single Event Effects (SEE). Passive pressure sensors from two manufacturers were investigated and a CERN designed radiation-tolerant electronics has been developed for measuring variable-reluctance sensors. During the last maintenance stop of the LHC accelerator, four absolute pressure sensors were installed in some of the low pressure bayonet heat exchangers and four differential pressure sensors on the venturi flowmeters that monitor the cooling flow of the 20.5 kA current leads of the ATLAS end-cap superconducting toroids. The pressure sensors operating range is about 1000 to 5000 Pa and the targeted uncertainty is +/- 50 Pa which would permit to measure the equivalent saturation temperature at 1.8 K within better than 0.01 K. This paper describes the radiation hard measuring head that is based on an inductive bridge, its associated radiation-tolerant electronics that is installed under the LHC superconducting magnets or the ATLAS detector cavern; and the first operational experience.

Commissioning of the LHC Cryogenic System Subsystems Cold Commissioning in Preparation of Full Sector Tests

CERN Document Server

Serio, L; Ferlin, G; Gilbert, N; Gruehagen, Henning; Knoops, S; Parente, C; Sanmartí, M

2006-01-01

The cryogenic system for the Large Hadron Collider accelerator is presently in its final phase of installation and commissioning at nominal operating temperatures. The refrigeration capacity for the LHC will be produced using eight large cryogenic plants installed on five technical sites and distributed around the 26.7-km circumference ring located in a deep underground tunnel. The status of the cryogenic system commissioning is presented together with the experience gained in operating and commissioning it.

Conceptual design of the cryostat for the new high luminosity (HL-LHC) triplet magnets

Science.gov (United States)

Ramos, D.; Parma, V.; Moretti, M.; Eymin, C.; Todesco, E.; Van Weelderen, R.; Prin, H.; Berkowitz Zamora, D.

2017-12-01

The High Luminosity LHC (HL-LHC) is a project to upgrade the LHC collider after 2020-2025 to increase the integrated luminosity by about one order of magnitude and extend the physics production until 2035. An upgrade of the focusing triplets insertion system for the ATLAS and CMS experiments is foreseen using superconducting magnets operating in a pressurised superfluid helium bath at 1.9 K. This will require the design and construction of four continuous cryostats, each about sixty meters in length and one meter in diameter, for the final beam focusing quadrupoles, corrector magnets and beam separation dipoles. The design is constrained by the dimensions of the existing tunnel and accessibility restrictions imposing the integration of cryogenic piping inside the cryostat, thus resulting in a very compact integration. As the alignment and position stability of the magnets is crucial for the luminosity performance of the machine, the magnet support system must be carefully designed in order to cope with parasitic forces and thermo-mechanical load cycles. In this paper, we present the conceptual design of the cryostat and discuss the approach to address the stringent and often conflicting requirements of alignment, integration and thermal aspects.

CERN Council pauses for effect (LHC approval a step nearer)

International Nuclear Information System (INIS)

Anon.

1994-01-01

Aweek of intense diplomatic activity which had high level telephones ringing across Europe culminated in an imaginative and unexpected move on 24 June, when delegates adjourned the 100th session of CERN's governing body, Council, to be reconvened at a later date. On the Council table was the vote for CERN's next major machine, now universally agreed as the world focus of particle physics research for the start of the 21st century, the LHC proton-proton collider, to be built in CERN's 27-kilometre LEP tunnel, and the largest and most complex scientific joint effort ever undertaken in Europe

Characterization of magnetic tunnel junction test pads

DEFF Research Database (Denmark)

Østerberg, Frederik Westergaard; Kjær, Daniel; Nielsen, Peter Folmer

2015-01-01

We show experimentally as well as theoretically that patterned magnetic tunnel junctions can be characterized using the current-in-plane tunneling (CIPT) method, and the key parameters, the resistance-area product (RA) and the tunnel magnetoresistance (TMR), can be determined. The CIPT method...

LHC beam stability and feedback control

Energy Technology Data Exchange (ETDEWEB)

Steinhagen, Ralph

2007-07-20

This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a

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)

LHC@home is ready to support HiLumi LHC: take part!

CERN Multimedia

CERN Bulletin

2011-01-01

Recently relaunched, the LHC@home volunteer computing project is now ready to support the HiLumi LHC project, the design phase of the planned upgrade of the LHC that will increase its luminosity by a factor of 5 to 10 beyond its original design value. HiLumi will need massive simulations to test the beam dynamics. Whether you are at home or at work, you can help experts design the future LHC by connecting your computer to LHC@home. Go for it!   LHC@home is aimed at involving the public in real science. If you have a computer that is connected to the Internet, you can join the large team of volunteers who are already supporting its two main projects: Test4Theory, which runs computer simulations of high-energy particle collisions, and SixTrack, which is aimed at optimizing the LHC performance by performing beam dynamics simulations. In both cases, the software is designed to run only when your computer is idle and causes no disruption to your normal activities. To the simulations run by the Six...

Demonstrating the utility of boron based precursor molecules for selective area deposition in a scanning tunneling microscope

International Nuclear Information System (INIS)

Perkins, F.K.; Onellion, M.; Lee, S.; Bowben, T.A.

1992-01-01

The scanning tunneling microscope (STM) can be used to selectively deposit material from a gaseous precursor compound. Ultrasmall (less than a 100 nm across) spatial dimensions for selective area deposition may be achieved by this means. In this paper the authors outline a scheme foreselecting and designing main group cluster compounds and organometallics for this type of selective area deposition using nido-decaborane(14) as an example

CERN database services for the LHC computing grid

International Nuclear Information System (INIS)

Girone, M

2008-01-01

Physics meta-data stored in relational databases play a crucial role in the Large Hadron Collider (LHC) experiments and also in the operation of the Worldwide LHC Computing Grid (WLCG) services. A large proportion of non-event data such as detector conditions, calibration, geometry and production bookkeeping relies heavily on databases. Also, the core Grid services that catalogue and distribute LHC data cannot operate without a reliable database infrastructure at CERN and elsewhere. The Physics Services and Support group at CERN provides database services for the physics community. With an installed base of several TB-sized database clusters, the service is designed to accommodate growth for data processing generated by the LHC experiments and LCG services. During the last year, the physics database services went through a major preparation phase for LHC start-up and are now fully based on Oracle clusters on Intel/Linux. Over 100 database server nodes are deployed today in some 15 clusters serving almost 2 million database sessions per week. This paper will detail the architecture currently deployed in production and the results achieved in the areas of high availability, consolidation and scalability. Service evolution plans for the LHC start-up will also be discussed

CERN database services for the LHC computing grid

Energy Technology Data Exchange (ETDEWEB)

Girone, M [CERN IT Department, CH-1211 Geneva 23 (Switzerland)], E-mail: maria.girone@cern.ch

2008-07-15

Physics meta-data stored in relational databases play a crucial role in the Large Hadron Collider (LHC) experiments and also in the operation of the Worldwide LHC Computing Grid (WLCG) services. A large proportion of non-event data such as detector conditions, calibration, geometry and production bookkeeping relies heavily on databases. Also, the core Grid services that catalogue and distribute LHC data cannot operate without a reliable database infrastructure at CERN and elsewhere. The Physics Services and Support group at CERN provides database services for the physics community. With an installed base of several TB-sized database clusters, the service is designed to accommodate growth for data processing generated by the LHC experiments and LCG services. During the last year, the physics database services went through a major preparation phase for LHC start-up and are now fully based on Oracle clusters on Intel/Linux. Over 100 database server nodes are deployed today in some 15 clusters serving almost 2 million database sessions per week. This paper will detail the architecture currently deployed in production and the results achieved in the areas of high availability, consolidation and scalability. Service evolution plans for the LHC start-up will also be discussed.

Mechanical stability of repository tunnels and factors to be considered for determining tunnel spacing

International Nuclear Information System (INIS)

Takeuchi, Kunifumi

1994-01-01

Kristallin-1 organized by Nagra is currently advanced as a synthetic project regarding a high level radioactive waste (HLW) repository in Switzerland. Its host rock is granitic rocks, and the potential siting area is located in northern Switzerland. The objective of this project is to demonstrate the long term safety of a HLW repository under more site-specific conditions than before. As the detailed geological data were investigated, the average size of undisturbed crystalline rock blocks is limited horizontally to about several hundred meter, therefore, the HLW repository area must be divided into several panels to avoid fracture zones. It is necessary to make tunnel spacing as small as possible for the purpose of reasonably designing the entire layout of repository tunnels. The main factors to be considered for determining repository tunnel spacing are listed. Rock mass modeling, rock mass material properties, the analysis model and parameters, the numerical analysis of repository tunnel stability and its main conclusion are reported. The numerical analysis of the temperature distribution in near field was carried out. Tunnel spacing should be set more than 20 m in view of the maximum temperature. (K.I.)

Tunnel magnetoresistance in alumina, magnesia and composite tunnel barrier magnetic tunnel junctions

International Nuclear Information System (INIS)

Schebaum, Oliver; Drewello, Volker; Auge, Alexander; Reiss, Guenter; Muenzenberg, Markus; Schuhmann, Henning; Seibt, Michael; Thomas, Andy

2011-01-01

Using magnetron sputtering, we have prepared Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions with tunnel barriers consisting of alumina, magnesia, and magnesia-alumina bilayer systems. The highest tunnel magnetoresistance ratios we found were 73% for alumina and 323% for magnesia-based tunnel junctions. Additionally, tunnel junctions with a unified layer stack were prepared for the three different barriers. In these systems, the tunnel magnetoresistance ratios at optimum annealing temperatures were found to be 65% for alumina, 173% for magnesia, and 78% for the composite tunnel barriers. The similar tunnel magnetoresistance ratios of the tunnel junctions containing alumina provide evidence that coherent tunneling is suppressed by the alumina layer in the composite tunnel barrier. - Research highlights: → Transport properties of Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions. → Tunnel barrier consists of MgO, Al-Ox, or MgO/Al-Ox bilayer systems. → Limitation of TMR-ratio in composite barrier tunnel junctions to Al-Ox values. → Limitation indicates that Al-Ox layer is causing incoherent tunneling.

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...

Timing, Trigger and Control Systems for LHC Detectors

CERN Multimedia

2002-01-01

\\\\ \\\\At the LHC, precise bunch-crossing clock and machine orbit signals must be broadcast over distances of several km from the Prevessin Control Room to the four experiment areas and other destinations. At the LHC experiments themselves, quite extensive distribution systems are also required for the transmission of timing, trigger and control (TTC) signals to large numbers of front-end electronics controllers from a single location in the vicinity of the central trigger processor. The systems must control the detector synchronization and deliver the necessary fast signals and messages that are phased with the LHC clock, orbit or bunch structure. These include the bunch-crossing clock, level-1 trigger decisions, bunch and event numbers, as well as test signals and broadcast commands. A common solution to this TTC system requirement is expected to result in important economies of scale and permit a rationalization of the development, operational and support efforts required. LHC Common Project RD12 is developi...

Manufacturing and QA of adaptors for LHC

International Nuclear Information System (INIS)

Madhu Murthy, V.; Dwivedi, J.; Goswami, S.G.; Soni, H.C.; Mainaud Durand, H.; Quesnel, J.P.; )

2006-01-01

The LHC low beta quadrupoles, have very tight alignment tolerances and are located in areas with strong radiation field. They require remote re-alignment, by motorized jacks, based on the feedback of alignment sensors of each magnet. Jacks designed to support arc cryomagnets of LHC are modified and motorized with the help of adaptors. Two types of adapters, for vertical and transverse axes of the jacks, were developed and supplied through collaboration between RRCAT, DAE, India and CERN, Geneva. This paper describes their functional requirements, manufacture and quality assurance (QA). (author)

Tunneling through landsliding zone; Jisuberi chitainai no tunnel seko

Energy Technology Data Exchange (ETDEWEB)

Konbu, A; Hatabu, K; Kano, T [Tekken Corp., Tokyo (Japan)

1994-08-01

At the new tunnel construction site of the Shirakata tunnel on the Obama line in Yamaguchi Prefecture, a landsliding occurred at about 60 meters to the upper portion obliquely to the right hand side of the shaft when the excavation progressed to about 10 meters from the starting side. The landslide caused displacement at the shaft opening and change in the supports. As a result of the re-investigation, it was confirmed that the slide face went through the tunnel cross section. The measures taken were removal of the upper soil and an adoption of the all ground fastening (AGF) method (injection type long tip fastening method) as an auxiliary construction to stop loosening of the natural ground associated with the tunnel excavation. The result was a completion of tunneling the landsliding zone without a problem. This paper reports the AGF method adopted in the above construction, together with the construction works and natural ground conditions. The AGF method is about the same as the pipe roof method with regard to the natural ground accepting mechanism and the materials used. The difference is building an improved body in a limited area in the natural ground around the steel pipes by injecting the fixing material. The use of this method caused no problems in subsidence and displacement in the surrounding ground, and completed the tunneling construction without an unusual event. 1 ref., 7 figs., 2 tabs.

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 

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

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...

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.)

Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

International Nuclear Information System (INIS)

Cleland, A.N.

1991-01-01

Experiments investigated the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very-small-capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson-phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters. The experiments on small-capacitance tunnel junctions extend the measurements on the large-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wave function has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias

Geological Prediction Ahead of Tunnel Face in the Limestone Formation Tunnel using Multi-Modal Geophysical Surveys

Science.gov (United States)

Zaki, N. F. M.; Ismail, M. A. M.; Hazreek Zainal Abidin, Mohd; Madun, Aziman

2018-04-01

Tunnel construction in typical karst topography face the risk which unknown geological condition such as abundant rainwater, ground water and cavities. Construction of tunnel in karst limestone frequently lead to potentially over-break of rock formation and cause failure to affected area. Physical character of limestone which consists large cavity prone to sudden failure and become worsen due to misinterpretation of rock quality by engineer and geologists during analysis stage and improper method adopted in construction stage. Consideration for execution of laboratory and field testing in rock limestone should be well planned and arranged in tunnel construction project. Several tests including Ground Penetration Radar (GPR) and geological face mapping were studied in this research to investigate the performances of limestone rock in tunnel construction, measured in term of rock mass quality that used for risk assessment. The objective of this study is to focus on the prediction of geological condition ahead of tunnel face using short range method (GPR) and verified by geological face mapping method to determine the consistency of actual geological condition on site. Q-Value as the main indicator for rock mass classification was obtained from geological face mapping method. The scope of this study is covering for tunnelling construction along 756 meters in karst limestone area which located at Timah Tasoh Tunnel, Bukit Tebing Tinggi, Perlis. For this case study, 15% of GPR results was identified as inaccurate for rock mass classification in which certain chainage along this tunnel with 34 out of 224 data from GPR was identified as incompatible with actual face mapping.

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/

Enabling technologies for silicon microstrip tracking detectors at the HL-LHC

International Nuclear Information System (INIS)

Feld, L.; Karpinski, W.; Klein, K.

2016-04-01

While the tracking detectors of the ATLAS and CMS experiments have shown excellent performance in Run 1 of LHC data taking, and are expected to continue to do so during LHC operation at design luminosity, both experiments will have to exchange their tracking systems when the LHC is upgraded to the high-luminosity LHC (HL-LHC) around the year 2024. The new tracking systems need to operate in an environment in which both the hit densities and the radiation damage will be about an order of magnitude higher than today. In addition, the new trackers need to contribute to the first level trigger in order to maintain a high data-taking efficiency for the interesting processes. Novel detector technologies have to be developed to meet these very challenging goals. The German groups active in the upgrades of the ATLAS and CMS tracking systems have formed a collaborative ''Project on Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC'' (PETTL), which was supported by the Helmholtz Alliance ''Physics at the Terascale'' during the years 2013 and 2014. The aim of the project was to share experience and to work together on key areas of mutual interest during the R and D phase of these upgrades. The project concentrated on five areas, namely exchange of experience, radiation hardness of silicon sensors, low mass system design, automated precision assembly procedures, and irradiations. This report summarizes the main achievements.

Enabling technologies for silicon microstrip tracking detectors at the HL-LHC

Energy Technology Data Exchange (ETDEWEB)

Feld, L.; Karpinski, W.; Klein, K. [RWTH Aachen Univ. (Germany). 1. Physikalisches Institut B; Collaboration: The PETTL Collaboration; and others

2016-04-15

While the tracking detectors of the ATLAS and CMS experiments have shown excellent performance in Run 1 of LHC data taking, and are expected to continue to do so during LHC operation at design luminosity, both experiments will have to exchange their tracking systems when the LHC is upgraded to the high-luminosity LHC (HL-LHC) around the year 2024. The new tracking systems need to operate in an environment in which both the hit densities and the radiation damage will be about an order of magnitude higher than today. In addition, the new trackers need to contribute to the first level trigger in order to maintain a high data-taking efficiency for the interesting processes. Novel detector technologies have to be developed to meet these very challenging goals. The German groups active in the upgrades of the ATLAS and CMS tracking systems have formed a collaborative ''Project on Enabling Technologies for Silicon Microstrip Tracking Detectors at the HL-LHC'' (PETTL), which was supported by the Helmholtz Alliance ''Physics at the Terascale'' during the years 2013 and 2014. The aim of the project was to share experience and to work together on key areas of mutual interest during the R and D phase of these upgrades. The project concentrated on five areas, namely exchange of experience, radiation hardness of silicon sensors, low mass system design, automated precision assembly procedures, and irradiations. This report summarizes the main achievements.

Application of diamond based beam loss monitors at LHC

International Nuclear Information System (INIS)

Hempel, Maria

2013-04-01

The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus(ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments to study the questions: ''What is mass?'', ''What is the universe made of?'' and ''Why is there no antimatter?''. The four experiments take data of the collision products and try to answer the fundamental questions of physics. The two larger detectors, CMS and ATLAS, are looking for the Higgs boson to study the electroweak symmetry breaking. Both detectors were built with contrasting concepts to exclude potential error sources and to rea rm the results. The smaller experiment LHCb studies the matter-antimatter asymmetry with a focus of the beauty quark. Another smaller experiment is ALICE that studies the conditions right after the Big Bang by colliding heavy ions. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150 km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due to deviations of the beam parameters. Several systems called beam loss monitors (BLMs) can measure beam losses. This thesis concentrates on two of them, ionization chambers and diamond detectors. Over 3600 ionization chambers are installed in the LHC, especially near each quadrupole and next to

13 September 2013 - Chairman of the Board of Directors of the von Karman Institute Kingdom of Belgium J.-P. Contzen visiting the ATLAS experimental cavern with ATLAS Former Spokesperson P. Jenni; visiting the LHC tunnel at Point 1 with Technology Department N. Delruelle and signing the guest book with Technology Department Head F. Bordry. International Relations Adviser T. Kurtyka present.

CERN Multimedia

Laurent Egli (visit)

2013-01-01

13 September 2013 - Chairman of the Board of Directors of the von Karman Institute Kingdom of Belgium J.-P. Contzen visiting the ATLAS experimental cavern with ATLAS Former Spokesperson P. Jenni; visiting the LHC tunnel at Point 1 with Technology Department N. Delruelle and signing the guest book with Technology Department Head F. Bordry. International Relations Adviser T. Kurtyka present.

17 September 2013 - Estonian Minister of Education and Research J. Aaviksoo signing the guest book with CERN Director-General R- Heuer; visiting the TOTEM facility with TOTEM Collaboration Spokesperson S. Giani; in the LHC tunnel at Point 5 with International Relations Adviser T. Kurtyka and visiting the CMS cavern with CMS Collaboration Spokesperson J. Incandela. International Relations Adviser R. Voss present.

CERN Multimedia

Anna Pantelia

2013-01-01

17 September 2013 - Estonian Minister of Education and Research J. Aaviksoo signing the guest book with CERN Director-General R- Heuer; visiting the TOTEM facility with TOTEM Collaboration Spokesperson S. Giani; in the LHC tunnel at Point 5 with International Relations Adviser T. Kurtyka and visiting the CMS cavern with CMS Collaboration Spokesperson J. Incandela. International Relations Adviser R. Voss present.

The LHC dipole test control architecture

International Nuclear Information System (INIS)

Gorskaya, E.; Samojlov, V.; Raimondo, A.; Rijllart, A.

2003-01-01

The next large accelerator project at CERN is the Large Hadron Collider, which is foreseen to be installed in the existing LEP tunnel, and scheduled to be commissioned in 2007. For this project, 1200 15-metre long dipole magnets need to be tested at CERN in warm and cold conditions on dedicated test benches that are under development. The final LHC dipole series test set-up will consist of 12 benches organized in 6 clusters of two benches sharing the largest and most expensive devices. This sharing is made possible by a deliberate de-phasing of the tests among magnets, ensuring an optimum use of resources, such as cryogenics and power equipment, without limiting the total throughput. An offered two-level control architecture includes: 1) the Test 'Master' that drives the test for a cluster; 2) the Resource 'Manager' that allocates common devices and central resources. The implementation of this architecture is done in the LabVIEW environment

The Beginner's Guide to Wind Tunnels with TunnelSim and TunnelSys

Science.gov (United States)

Benson, Thomas J.; Galica, Carol A.; Vila, Anthony J.

2010-01-01

The Beginner's Guide to Wind Tunnels is a Web-based, on-line textbook that explains and demonstrates the history, physics, and mathematics involved with wind tunnels and wind tunnel testing. The Web site contains several interactive computer programs to demonstrate scientific principles. TunnelSim is an interactive, educational computer program that demonstrates basic wind tunnel design and operation. TunnelSim is a Java (Sun Microsystems Inc.) applet that solves the continuity and Bernoulli equations to determine the velocity and pressure throughout a tunnel design. TunnelSys is a group of Java applications that mimic wind tunnel testing techniques. Using TunnelSys, a team of students designs, tests, and post-processes the data for a virtual, low speed, and aircraft wing.

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)

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.

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”...

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,...

Ground penetrating radar measurements at the ONKALO research tunnel and eastern part of the Olkiluoto investigation area at July 2006

International Nuclear Information System (INIS)

Sipola, V.; Tarvainen, A.-M.

2007-04-01

Ground Penetrating Radar (GPR) measurements were carried out at ONKALO research site in summer 2006. Measurements included 400 metres of measurements inside ONKALO access tunnel and about 1800 metres of measurements on the ground, at the eastern parts of Olkiluoto investigation area. The purpose of the measurements done inside the access tunnel was to investigate, whether it would be possible to locate deformation structures or long fractures in the rock mass below the tunnel. The purpose of the measurements made on top of the ground was to investigate, whether it would be possible to locate glacio-isostatic faults from the soils. A secondary target was to try and locate the rock surface. The chosen part of ONKALO tunnel was measured using five different frequencies, which enabled comparing the results to each other. It also enabled getting a higher resolution picture of the top rock, than what would have been possible using only one low-frequency antenna. The on-the-ground measurements were measured using only one frequency. (orig.)

Acceleration and support post deformation measurements during surface and tunnel transport of a LHC Short Straight Section

CERN Document Server

Capatina, O; CERN. Geneva. TS Department

2004-01-01

This technical note is a complement to the technical note [1]. The former technical note dealt with the experimental modal analysis and the road transport with transport restraints and special suspension. The present note describes the measured accelerations and support post deformations during road transport at reduced speed without end restraints or special suspension. This note also reports the accelerations and support post deformations during handling and tunnel transport with the dedicated tunnel vehicle. The measured accelerations are compared with the specified acceleration limits.

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...

A new magnet for the LHC mock-up

CERN Multimedia

HSE Unit

2013-01-01

This year, the safety training centre on the Prévessin site acquired a mock-up of the LHC, which simulates the work and safety conditions in the tunnel.   Photo: Christoph Balle. A new dummy quadrupole has just been added to the magnet chain, making the mock-up even more realistic. The new facility, which was a joint endeavour by the TE, GS, BE and EN Departments, will significantly improve the quality of the various training courses held at the centre, particularly the course on the use of self-rescue masks. To consult the safety training catalogue and/or sign up for radiation protection training, please go to: https://cta.cern.ch. For further information, please contact the Safety Training and Awareness service by telephone on 73811 or 79935 or by e-mail to safety-training@cern.ch.  

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...

Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

International Nuclear Information System (INIS)

Cleland, A.N.

1991-04-01

Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q ∼ 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement

CERN Open Days 2013, Point 4: LHC Radio Frequency

CERN Multimedia

CERN Photolab

2013-01-01

Stand description: At Point 4 visitors will descend into the LHC tunnel to see the "engine" of the collider: the accelerating cavities where the circulating particles get a small kick of energy as they pass by 11,000 times each second. During your visit underground, you will see the superconducting magnets as well as instruments for observing the beams. You will also walk through the huge cavern containing the Radio Frequency power plants which provide the particle beams with energy. On surface no restricted access  Above ground, you will see the cryogenics installations which keep the accelerator at a just few degrees above absolute zero. Lots of fascinating information and exhibits about CERN's accelerators and experiments will be on display, with CERN engineers and physicists on hand all day to answer your questions.

Thermodynamics of phonon-modulated tunneling centers

International Nuclear Information System (INIS)

Junker, W.; Wagner, M.

1989-01-01

In recent years tunneling centers have frequently been used to explain the unusual thermodynamic properties of disordered materials; in these approaches, however, the effect of the tunneling-phonon interaction is neglected. The present study considers the archetype model of phono-assisted tunneling, which is well known from other areas of tunneling physics (quantum diffusion, etc.). It is shown that the full thermodynamic information can be rigorously extracted from a single Green function. An extended factorization procedure beyond Hartree-Fock is introduced, which is checked by sum rules as well as by exact Goldberger-Adams expansions. The phonon-modulated internal energy and specific heat are calculated for different power-law coupling setups

Excavation of the Surikamigawa dam diversion tunnel. Surikamigawa dam karihaisui tunnel kantsu

Energy Technology Data Exchange (ETDEWEB)

Ikeda, T.; Konno, T. (Ministry of Construction, Tokyo (Japan))

1994-04-01

A bypass tunnel construction has been completed at the Surikamigawa dam (Japan). This paper describes the summary of the construction. The full-swing dam construction work is scheduled to begin in 1995. The soils distributed near the dam site consist of lapillus tuff containing andesite-based light stones and tuff-based conglomerates containing large gravels. Excavation of the dam diversion tunnel has used a blasting method, and the tunnel construction has adopted an automatic tunnel cross section marking system and a non-electric explosion method. This marking system is a system to irradiate a laser beam onto the facing to depict excavation lines that realizes labor saving and high-accuracy excavation. The error at the tunnel completion was found 20 mm. The non-electric explosion method ignites a coated explosive layer with an impact wave, which is electrostatically safe, and reduces blasting vibration. Electric detonators have also been used because of using ANFO explosives. The result obtained from measurements of inner space displacement necessary for the blasting process has indicated that the area near the dam site consists of stable mountains. 6 figs., 4 tabs.

Application of diamond based beam loss monitors at LHC

Energy Technology Data Exchange (ETDEWEB)

Hempel, Maria

2013-04-15

The Large Hadron Collider (LHC) was conceived in the 1980s and started the operation in 2008. It needed more than 20 years to plan and construct this accelerator and its experiments. Four main experiments are located around the ring, Compact Muon Solenoid (CMS), A Toroidal LHC Apparatus(ATLAS), A Large Ion Collider Experiment (ALICE) and LHC beauty (LHCb). Two beams that traveling in opposite direction in the LHC tunnel, collide in each of the experiments to study the questions: ''What is mass?'', ''What is the universe made of?'' and ''Why is there no antimatter?''. The four experiments take data of the collision products and try to answer the fundamental questions of physics. The two larger detectors, CMS and ATLAS, are looking for the Higgs boson to study the electroweak symmetry breaking. Both detectors were built with contrasting concepts to exclude potential error sources and to rea rm the results. The smaller experiment LHCb studies the matter-antimatter asymmetry with a focus of the beauty quark. Another smaller experiment is ALICE that studies the conditions right after the Big Bang by colliding heavy ions. The navigation of the beams is done by over 10000 magnets and each beam has a stored energy of 362MJ which correspond to the kinetic energy of a train like the TGV travelling of 150 km/h. Only a small percentage of that energy can damage the material in the LHC ring or the magnets. This would mean a repair time of months or years, without taking any data. To avoid such a scenario, it is important to monitor the beam condition and measure the amount of losses of the beam. Such losses can for example happen due to dust particles in the vacuum chambers or due to deviations of the beam parameters. Several systems called beam loss monitors (BLMs) can measure beam losses. This thesis concentrates on two of them, ionization chambers and diamond detectors. Over 3600 ionization chambers are installed in

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)

Tunnel support design by comparison of empirical and finite element analysis of the Nahakki tunnel in mohmand agency, pakistan

Directory of Open Access Journals (Sweden)

Riaz Asif

2016-03-01

Full Text Available The paper analyses the geological conditions of study area, rock mass strength parameters with suitable support structure propositions for the under construction Nahakki tunnel in Mohmand Agency. Geology of study area varies from mica schist to graphitic marble/phyllite to schist. The tunnel ground is classified and divided by the empisical classification systems like Rock mass rating (RMR, Q system (Q, and Geological strength index (GSI. Tunnel support measures are selected based on RMR and Q classification systems. Computer based finite element analysis (FEM has given yet another dimension to design approach. FEM software Phase2 version 7.017 is used to calculate and compare deformations and stress concentrations around the tunnel, analyze interaction of support systems with excavated rock masses and verify and check the validity of empirically determined excavation and support systems.

Facility Closure Report for Tunnel U16a, Area 16, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

2009-01-01

U16a is not listed in the Federal Facility Agreement and Consent Order. The closure of U16a was sponsored by the Defense Threat Reduction Agency (DTRA) and performed with the cooperation of the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office and the Nevada Division of Environmental Protection. This report documents closure of this site as identified in the DTRA Fiscal Year 2008 Statement of Work, Task 6.3. Closure activities included: (1) Removing and disposing of a shack and its contents; (2) Disposing of debris from within the shack and in the vicinity of the tunnel entrance; (3) Verifying that the tunnel is empty; (4) Welding screened covers over tunnel vent holes to limit access and allow ventilation; and (5) Constructing a full-tunnel cross-section fibercrete bulkhead to prevent access to the tunnel Field activities were conducted from July to August 2008.

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 ...

Tunnel oxide passivated rear contact for large area n-type front junction silicon solar cells providing excellent carrier selectivity

Directory of Open Access Journals (Sweden)

Yuguo Tao

2016-01-01

Full Text Available Carrier-selective contact with low minority carrier recombination and efficient majority carrier transport is mandatory to eliminate metal-induced recombination for higher energy conversion efficiency for silicon (Si solar cells. In the present study, the carrier-selective contact consists of an ultra-thin tunnel oxide and a phosphorus-doped polycrystalline Si (poly-Si thin film formed by plasma enhanced chemical vapor deposition (PECVD and subsequent thermal crystallization. It is shown that the poly-Si film properties (doping level, crystallization and dopant activation anneal temperature are crucial for achieving excellent contact passivation quality. It is also demonstrated quantitatively that the tunnel oxide plays a critical role in this tunnel oxide passivated contact (TOPCON scheme to realize desired carrier selectivity. Presence of tunnel oxide increases the implied Voc (iVoc by ~ 125 mV. The iVoc value as high as 728 mV is achieved on symmetric structure with TOPCON on both sides. Large area (239 cm2 n-type Czochralski (Cz Si solar cells are fabricated with homogeneous implanted boron emitter and screen-printed contact on the front and TOPCON on the back, achieving 21.2% cell efficiency. Detailed analysis shows that the performance of these cells is mainly limited by boron emitter recombination on the front side.

Physics perspectives with AFTER@LHC (A Fixed Target ExpeRiment at LHC

Directory of Open Access Journals (Sweden)

Massacrier L.

2018-01-01

Full Text Available AFTER@LHC is an ambitious fixed-target project in order to address open questions in the domain of proton and neutron spins, Quark Gluon Plasma and high-x physics, at the highest energy ever reached in the fixed-target mode. Indeed, thanks to the highly energetic 7 TeV proton and 2.76 A.TeV lead LHC beams, center-of-mass energies as large as sNN = 115 GeV in pp/pA and sNN = 72 GeV in AA can be reached, corresponding to an uncharted energy domain between SPS and RHIC. We report two main ways of performing fixed-target collisions at the LHC, both allowing for the usage of one of the existing LHC experiments. In these proceedings, after discussing the projected luminosities considered for one year of data taking at the LHC, we will present a selection of projections for light and heavy-flavour production.

Electronics and readout of a large area silicon detector for LHC

International Nuclear Information System (INIS)

Borer, K.; Munday, D.J.; Parker, M.A.; Anghinolfi, F.; Aspell, P.; Campbell, M.; Chilingarov, A.; Jarron, P.; Heijne, E.H.M.; Santiard, J.C.; Scampoli, P.; Verweij, H.; Goessling, C.; Lisowski, B.; Reichold, A.; Spiwoks, R.; Tsesmelis, E.; Benslama, K.; Bonino, R.; Clark, A.G.; Couyoumtzelis, C.; Kambara, H.; Wu, X.; Fretwurst, E.; Lindstroem, G.; Schultz, T.; Bardos, R.A.; Gorfine, G.W.; Moorhead, G.F.; Taylor, G.N.; Tovey, S.N.; Bibby, J.H.; Hawkings, R.J.; Kundu, N.; Weidberg, A.; Campbell, D.; Murray, P.; Seller, P.; Teiger, J.

1994-01-01

The purpose of the RD2 project is to evaluate the feasibility of a silicon tracker and/or preshower detector for LHC. Irradiation studies with doses equivalent to those expected at LHC have been performed to determine the behavior of operational parameters such as leakage current, depletion voltage and charge collection during the life of the detector. The development of fast, dense, low power and low cost signal processing electronics is one of the major activities of the collaboration. We describe the first fully functional integrated analog memory chip with asynchronous read and write operations and level 1 trigger capture capabilities. A complete test beam system using this analog memory chip at 66 MHz has been successfully operated with RD2 prototype silicon detectors during various test runs. The flexibility of the electronics and readout have allowed us to easily interface our set-up to other data acquisition systems. Mechanical studies are in progress to design a silicon tracking detector with several million channels that may be operated at low (0-10 C) temperature, while maintaining the required geometrical precision. Prototype readout boards for such a detector are being developed and simulation studies are being performed to optimize the readout architecture. (orig.)

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.

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.

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)

Optimization of the powering tests of the LHC superconducting circuits

CERN Document Server

Bellesia, B; Denz, R; Fernandez-Robles, C; Pojer, M; Saban, R; Schmidt, R; Solfaroli Camillocci, M; Thiesen, H; Vergara Fernández, A

2010-01-01

The Large Hadron Collider has (LHC) 1572 superconducting circuits which are distributed along the eight 3.5 km LHC sectors [1]. Time and resources during the commissioning of the LHC technical systems were mostly consumed by the powering tests of each circuit. The tests consisted in carrying out several powering cycles at different current levels for each superconducting circuit. The Hardware Commissioning Coordination was in charge of planning, following up and piloting the execution of the test program. The first powering test campaign was carried out in summer 2007 for sector 7-8 with an expected duration of 12 weeks. The experience gained during these tests was used by the commissioning team for minimising the duration of the following powering campaigns to comply with the stringent LHC project deadlines. Improvements concerned several areas: strategy, procedures, control tools, automatization, and resource allocation led to an average daily test rate increase from 25 to 200 tests per day. This paper desc...

Industrial tooling and methods for the junctions of the superconducting busbars in the interconnections between the LHC cryomagnets

International Nuclear Information System (INIS)

Balaguer, J M; Colombet, T; Jacquemod, A; Laurent, F; Nambride, C; Taffard, Y; Tock, J Ph

2006-01-01

The Large Hadron Collider (LHC) is the next world-facility for the high energy physics community, presently under installation at CERN, Geneva. The main components of the LHC are the twin-aperture high-field superconducting cryomagnets that are powered in series by superconducting Nb-Ti busbars. Along the machine, about 60 000 splices between the superconducting busbars have to be performed in-situ during the interconnection activities. They are carrying a nominal current varying from 600 A to 13 kA depending upon the magnets, at an operating temperature of 1.9 K. Three specific techniques have been developed and optimised for the splicing of the three main types of cables: inductive and resistive soldering, ultrasonic welding. After a brief presentation of the constraints and requirements applying to these junctions, the tooling is described, highlighting the industrialisation aspects. Before their use to interconnect actual cryomagnets in the LHC tunnel, the equipments and procedures follow rigorous qualification to ensure that all the characteristics of the junctions (electrical, mechanical, reliability, ...) are within the specifications. The assessment of the tooling performance is obtained via sample testing of superconducting busbars. Initial results are presented

Development of the System Test for the LHC Tune Measurement and Abort Gap Monitoring

CERN Document Server

Beccati, B

2008-01-01

The Large Hadron Collider (LHC) is the largest accelerator in the world and it will collide opposing beams of 7 TV protons together. It is built inside a 27km tunnel on the border between France and Switzerland. Within the framework of the project IUSS- Ferrara, I collaborated with the members of the AB-BI section at CERN: Accelerator Beam - Beam Instrumentation. My degree thesis is the result of this cooperation. My project is made of two sections, one for each themes analyzed during this year at CERN: the first one concerns the Tune, the second one is about the Abort gap. LHC is a synchrotron, an accelerator using dipole magnets to bending and quadrupole magnets to transverse focusing. Passing through this pattern of magnets, particles make oscillations. We refer to these ones as Betatron oscillations. The number of such oscillations/turn is called Tune. The ability tomeasure the tune is important for many kinds of diagnostic. In the base band tune (BBQ) measurement system developed at CERN the signal is di...

The etiology of idiopathic carpal tunnel syndrome. Evaluation from the viewpoint of magnetic resonance imaging

International Nuclear Information System (INIS)

Ikeda, Jun

2003-01-01

The etiology of idiopathic carpal tunnel syndrome has not been clarified. A cross sectional area of carpal tunnel, flexor tendons, median nerve, and thickness of transverse carpal ligament were evaluated by MRI. Twenty-six patients who were electrophysiologically diagnosed with idiopathic carpal tunnel syndrome were tested by MRI. All patients were females; the mean age was sixty-four years old. The cross sectional area of carpal tunnel, the median nerve area, the area of the flexor tendons and its synovium in carpal tunnel, and thickness of the transverse carpal ligament were calculated. The following are of a seuere type carpal tunnel syndrome: Mean area of the flexor tendons and its synovium in carpal tunnel, 110.5±25.5 mm 2 (control group; 79.3±13.8 mm 2 ); ratio of flexor tendons and its synovium area to carpal tunnel area, 51.6±8.8% (control; 40.5±2.3%); and thickness of the transverse carpal ligament, 3.3±0.4 mm (control; 2.4±0.4 mm). These mean areas in severe carpal tunnel syndrome were significantly greater than those in mild type (p<0.05 or p<0.01). From the viewpoint of this result, it is possible that tenosynovitis is strongly to the etiology of idiopathic carpal tunnel syndrome. In other words, synovium edema causes chronic high pressure environment in carpal tunnel. Moreover, we classified these MRI findings into the following subgroups: enlargement of cross sectional area of flexor tendon and its synovia (n=8; 25.8%), thickened transverse carpal ligament (n=11; 35.5%), and combined type (n=7; 22.6%). This classification by MRI imaging was related to a clinical course and electro-physiologic severity. The present study suggests that to evaluate the cross sectional, area of an MRI image is useful for diagnosis and cure of idiopathic carpal tunnel syndrome. (author)

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...

Off-momentum collimation and cleaning in the energy ramp in the LHC

CERN Document Server

Quaranta, Elena; Giulini Castiglioni Agosteo, Stefano Luigi Maria

This Master thesis work has been carried out at CERN in the framework of the LHC (Large Hadron Collider) Collimation project. The LHC is a two-beam proton collider, built to handle a stored energy of 360MJ for each beam. Since the energy deposition from particle losses could quench the superconducting magnets, a system of collimators has been installed in two cleaning insertions in the ring and in the experimental areas. The achievable LHC beam intensity is directly coupled to the beam loss rate and, consequently, to the cleaning eciency of the collimation system. This study analyses the collimation cleaning performance in dierent scenarios inside the accelerator. First, simulations are performed of the transverse losses in the LHC collimation system during the acceleration process. The results are compared with data taken during a dedicated session at the LHC machine. Simulations are also performed to predict the collimation eciency during future operation at higher energy. Furthermore, an investigation of t...

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

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.

28 November 2013 - N. N. Kudryavtsev, Russian Rector of the Moscow Institute of Physics and Technology signing an Agreement and the Guest Book with CERN Director-General R. Heuer; visiting the ATLAS cavern with ATLAS Deputy Spokesperson B. Heinemann and visiting the LHC tunnel at Point 1 with AGH University of Science and Technology A. Erokhin. M. Savino, Physics Department, Joint Institute for Nuclear Research also present.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

28 November 2013 - N. N. Kudryavtsev, Russian Rector of the Moscow Institute of Physics and Technology signing an Agreement and the Guest Book with CERN Director-General R. Heuer; visiting the ATLAS cavern with ATLAS Deputy Spokesperson B. Heinemann and visiting the LHC tunnel at Point 1 with AGH University of Science and Technology A. Erokhin. M. Savino, Physics Department, Joint Institute for Nuclear Research also present.

29 October 2013 - Former Director-General of IAEA H. Blix on the occasion of the Thorium Energy Conference at CERN with Chair of the ThEC13 Organization Committee E. Lillestol and Author of the book “Atome Vert” (Green Atom) J.-C. de Mestral; in the LHC tunnel at Point 1 with Technology Department, Machine Protection & Electrical Integrity Group, Performance Evaluation Section Member A. Verweij.

CERN Multimedia

Anna Pantelia

2013-01-01

29 October 2013 - Former Director-General of IAEA H. Blix on the occasion of the Thorium Energy Conference at CERN with Chair of the ThEC13 Organization Committee E. Lillestol and Author of the book “Atome Vert” (Green Atom) J.-C. de Mestral; in the LHC tunnel at Point 1 with Technology Department, Machine Protection & Electrical Integrity Group, Performance Evaluation Section Member A. Verweij.

9 April 2013 - Minister for Universities and Science United Kingdom of Great Britain and Northern Ireland D. Willetts in the ATLAS experimental cavern with ATLAS Collaboration Spokesperson D. Charlton and in the LHC tunnel at Point 1 with Beams Department Head P. Collier. Director for Accelerators and Technology S. Myers, Editor at the Communication Group K. Kahle and Beams Department Engineer R. Veness present.

CERN Multimedia

Jean-Claude Gadmer

2013-01-01

9 April 2013 - Minister for Universities and Science United Kingdom of Great Britain and Northern Ireland D. Willetts in the ATLAS experimental cavern with ATLAS Collaboration Spokesperson D. Charlton and in the LHC tunnel at Point 1 with Beams Department Head P. Collier. Director for Accelerators and Technology S. Myers, Editor at the Communication Group K. Kahle and Beams Department Engineer R. Veness present.

The ATLAS computing challenge for HL-LHC

CERN Document Server

Campana, Simone; The ATLAS collaboration

2016-01-01

The ATLAS experiment successfully commissioned a software and computing infrastructure to support the physics program during LHC Run 2. The next phases of the accelerator upgrade will present new challenges in the offline area. In particular, at High Luminosity LHC (also known as Run 4) the data taking conditions will be very demanding in terms of computing resources: between 5 and 10 KHz of event rate from the HLT to be reconstructed (and possibly further reprocessed) with an average pile-up of up to 200 events per collision and an equivalent number of simulated samples to be produced. The same parameters for the current run are lower by up to an order of magnitude. While processing and storage resources would need to scale accordingly, the funding situation allows one at best to consider a flat budget over the next few years for offline computing needs. In this paper we present a study quantifying the challenge in terms of computing resources for HL-LHC and present ideas about the possible evolution of the ...

Single Electron Tunneling

International Nuclear Information System (INIS)

Ruggiero, Steven T.

2005-01-01

Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have

Radiation protection at the LHC, CERN's large hadron collider

International Nuclear Information System (INIS)

Potter, K.M.; Hoefert, M.; Stevenson, G.R.

1996-01-01

After a brief description of the Large Hadron Collider (LHC), which will produce 7 TeV on 7 TeV proton collisions, some of the radiological questions it raises will be discussed. The machine will be built in the 27 km circumference ring-tunnel of an existing collider at CERN. It aims to achieve collision rates of 10 9 per second in two of its high-energy particle detectors. This requires two high-intensity beams of more than 10 14 protons each. Shielding, access control and activation in addition to the high power in the proton-proton collisions must be taken into account. The detectors and local electronics of the particle physics experiments, which will surround these collisions, will have to be radiation resistant. Some of the environmental issues raised by the project will be discussed. (author)

The LHC magnet system and its status of development

Science.gov (United States)

Bona, Maurizio; Perin, Romeo; Vlogaert, Jos

1995-01-01

CERN is preparing for the construction of a new high energy accelerator/collider, the Large Hadron Collider (LHC). This new facility will mainly consist of two superconducting magnetic beam channels, 27 km long, to be installed in the existing LEP tunnel. The magnetic system comprises about 1200 twin-aperture dipoles, 13.145 m long, with an operational field of 8.65 T, about 600 quadrupoles, 3 m long, and a very large number of other superconducting magnetic components. A general description of the system is given together with the main features of the design of the regular lattice magnets. The paper also describes the present state of the magnet R & D program. Results from short model work, as well as from full scale prototypes will be presented, including the recently tested 10 m long full-scale prototype dipole manufactured in industry.

Tunneling technologies for the collider ring tunnels

International Nuclear Information System (INIS)

Frobenius, P.

1989-01-01

The Texas site chosen for the Superconducting Super Collider has been studied, and it has been determined that proven, conventional technology and accepted engineering practice are suitable for constructing the collider tunnels. The Texas National Research Laboratory Commission report recommended that two types of tunneling machines be used for construction of the tunnels: a conventional hard rock tunnel boring machine (TBM) for the Austin chalk and a double shielded, rotary TBM for the Taylor marl. Since the tunneling machines usually set the pace for the project, efficient planning, operation, and coordination of the tunneling system components will be critical to the schedule and cost of the project. During design, tunneling rate prediction should be refined by focusing on the development of an effective tunneling system and evaluating its capacity to meet or exceed the required schedules. 8 refs., 13 figs

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...

Three-dimensional scanning force/tunneling spectroscopy at room temperature

International Nuclear Information System (INIS)

Sugimoto, Yoshiaki; Ueda, Keiichi; Abe, Masayuki; Morita, Seizo

2012-01-01

We simultaneously measured the force and tunneling current in three-dimensional (3D) space on the Si(111)-(7 × 7) surface using scanning force/tunneling microscopy at room temperature. The observables, the frequency shift and the time-averaged tunneling current were converted to the physical quantities of interest, i.e. the interaction force and the instantaneous tunneling current. Using the same tip, the local density of states (LDOS) was mapped on the same surface area at constant height by measuring the time-averaged tunneling current as a function of the bias voltage at every lateral position. LDOS images at negative sample voltages indicate that the tip apex is covered with Si atoms, which is consistent with the Si-Si covalent bonding mechanism for AFM imaging. A measurement technique for 3D force/current mapping and LDOS imaging on the equivalent surface area using the same tip was thus demonstrated. (paper)

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...

Mark the date! LHC inauguration and LHC-Fest CERN, Tuesday 21 October 2008

CERN Document Server

2008-01-01

"For a long time we will remember the year 2008, an important year for CERN. as it marks the achievement of the LHC, a great tool for future discoveries, and the completion of exceptional works that demanded the commitment and motivation of many… a remarkable motivation," declared Director-General Robert Aymar during a recent interview. To celebrate this historical milestone in this very important "Big Science" project, CERN has organised two events on October 21: the LHC official inauguration and the LHC-fest. The LHC official inauguration will take place from 14h00 to 18h00, at Point 18 of the Laboratory, in the presence of the highest representatives from the member states of CERN and representatives from the other communities and authorities of the countries participating in the LHC adventure. 300 members from the international press are also expected, giving a total of 1500 guests. The ceremony will be broadcast live in the Lab...

Impedance measurements and simulations for the LHC and HL-LHC injection protection collimator

CERN Document Server

AUTHOR|(CDS)2125995; Biancacci, Nicolò

This thesis focuses on the study and the data analysis of the Injection Protection Collimator (also Injection Protection Target Dump or TDI), one of the Large Hadron Collider (LHC) collimators at CERN, in Geneva. The last chapters also deal with the Segmented TDI (TDIS), the TDI upgrade for High Luminosity-LHC (HL-LHC). Going more into details, measurements on the TDI - hexagonal Boron Nitride (TDI - hBN, installed in the LHC during run 2015) were carried out. Using the obtained results as an input, two derivations followed: one evaluating the layer resistivity and the other one for its thickness, in order to consider all the possible coating degradations that could occur. The whole range of data obtained from both the derivations was then fed to Impedance Wake 2D (IW2D), a code performing numerical simulations, to attain impedances. Finally, the resulting longitudinal impedance was compared to some measurements performed on the real TDIs, immediately after they were removed from the LHC. The TDI - Graphite, ...

The tunneling magnetoresistance current dependence on cross sectional area, angle and temperature

Directory of Open Access Journals (Sweden)

Z. H. Zhang

2015-03-01

Full Text Available The magnetoresistance of a MgO-based magnetic tunnel junction (MTJ was studied experimentally. The magnetoresistance as a function of current was measured systematically on MTJs for various MgO cross sectional areas and at various temperatures from 7.5 to 290.1 K. The resistance current dependence of the MTJ was also measured for different angles between the two ferromagnetic layers. By considering particle and angular momentum conservation of transport electrons, the current dependence of magnetoresistance can be explained by the changing of spin polarization in the free magnetic layer of the MTJ. The changing of spin polarization is related to the magnetoresistance, its angular dependence and the threshold current where TMR ratio equals zero. A phenomenological model is used which avoid the complicated barrier details and also describes the data.

Underlying Event Studies for LHC Energies

International Nuclear Information System (INIS)

Barnafoeldi, Gergely Gabor; Levai, Peter; Agocs, Andras G.

2011-01-01

Underlying event was originally defined by the CDF collaboration decades ago. Here we improve the original definition to extend our analysis for events with multiple-jets. We introduce a definition for surrounding rings/belts and based on this definition the jet- and surrounding-belt-excluded areas will provide a good underlying event definition. We inverstigate our definition via the multiplicity in the defined geometry. In parallel, mean transverse momenta of these areas also studied in proton-proton collisions at √(s) = 7 TeV LHC energy.

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.

Tunneling path toward spintronics

International Nuclear Information System (INIS)

Miao Guoxing; Moodera, Jagadeesh S; Muenzenberg, Markus

2011-01-01

The phenomenon of quantum tunneling, which was discovered almost a century ago, has led to many subsequent discoveries. One such discovery, spin polarized tunneling, was made 40 years ago by Robert Meservey and Paul Tedrow (Tedrow and Meservey 1971 Phys. Rev. Lett. 26 192), and it has resulted in many fundamental observations and opened up an entirely new field of study. Until the mid-1990s, this field developed at a steady, low rate, after which a huge increase in activity suddenly occurred as a result of the unraveling of successful spin tunneling between two ferromagnets. In the past 15 years, several thousands of papers related to spin polarized tunneling and transport have been published, making this topic one of the hottest areas in condensed matter physics from both fundamental science and applications viewpoints. Many review papers and book chapters have been written in the past decade on this subject. This paper is not exhaustive by any means; rather, the emphases are on recent progress, technological developments and informing the reader about the current direction in which this topic is moving.

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.

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

Scaling Projections on Spin-Transfer Torque Magnetic Tunnel Junctions

Science.gov (United States)

Das, Debasis; Tulapurkar, Ashwin; Muralidharan, Bhaskaran

2018-02-01

We investigate scaling of technologically relevant magnetic tunnel junction devices in the trilayer and pentalayer configurations by varying the cross-sectional area along the transverse direction using the non-equilibrium Green's function spin transport formalism. We study the geometry dependence by considering square and circular cross-sections. As the transverse dimension in each case reduces, we demonstrate that the transverse mode energy profile plays a major role in the resistance-area product. Both types of devices show constant tunnel magnetoresistance at larger cross-sectional areas but achieve ultra-high magnetoresistance at small cross-sectional areas, while maintaining low resistance-area products. We notice that although the critical switching voltage for switching the magnetization of the free layer nanomagnet in the trilayer case remains constant at larger areas, it needs more energy to switch at smaller areas. In the pentalayer case, we observe an oscillatory behavior at smaller areas as a result of double barrier tunneling. We also describe how switching characteristics of both kinds of devices are affected by the scaling.

D Modelling of Tunnel Excavation Using Pressurized Tunnel Boring Machine in Overconsolidated Soils

Science.gov (United States)

Demagh, Rafik; Emeriault, Fabrice

2013-06-01

The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

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

Evaluation of the source area of rooftop scalar measurements in London, UK using wind tunnel and modelling approaches.

Science.gov (United States)

Brocklehurst, Aidan; Boon, Alex; Barlow, Janet; Hayden, Paul; Robins, Alan

2014-05-01

The source area of an instrument is an estimate of the area of ground over which the measurement is generated. Quantification of the source area of a measurement site provides crucial context for analysis and interpretation of the data. A range of computational models exists to calculate the source area of an instrument, but these are usually based on assumptions which do not hold for instruments positioned very close to the surface, particularly those surrounded by heterogeneous terrain i.e. urban areas. Although positioning instrumentation at higher elevation (i.e. on masts) is ideal in urban areas, this can be costly in terms of installation and maintenance costs and logistically difficult to position instruments in the ideal geographical location. Therefore, in many studies, experimentalists turn to rooftops to position instrumentation. Experimental validations of source area models for these situations are very limited. In this study, a controlled tracer gas experiment was conducted in a wind tunnel based on a 1:200 scale model of a measurement site used in previous experimental work in central London. The detector was set at the location of the rooftop site as the tracer was released at a range of locations within the surrounding streets and rooftops. Concentration measurements are presented for a range of wind angles, with the spread of concentration measurements indicative of the source area distribution. Clear evidence of wind channeling by streets is seen with the shape of the source area strongly influenced by buildings upwind of the measurement point. The results of the wind tunnel study are compared to scalar concentration source areas generated by modelling approaches based on meteorological data from the central London experimental site and used in the interpretation of continuous carbon dioxide (CO2) concentration data. Initial conclusions will be drawn as to how to apply scalar concentration source area models to rooftop measurement sites and

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.

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

Mitigation of landslide area around railway tunnel, South Sumatra Province, Indonesia

Science.gov (United States)

Toha, M. Taufik; Setiabudidaya, Dedi; Komar, Syamsul; Bochori, Ghadafi, Moamar A.; Adiwarman, Mirza; Rahim, S. E.

2017-09-01

Adequate and safe railway line infrastructures as well as facilities are required to support the rail transport system in South Sumatra. The slope stability along railway line of Lahat-Lubuk Linggau South Sumatra were studied during landslide that occured on January 23th, 2016. The landslide occurred on the mouth of railway tunnel in Gunung Gajah Village, Lahat District that causing the railway transportation system had to be stopped for a few days. A comprehensive research was conducted to analyze the causes of the landslide and to identify other landslide risky areas along the railway line Lahat-Lubuk Linggau. The research activities included surveying, sampling, laboratory testing, investigating condition of geology, geotechnics, hydrogeology/hydrology, morphology and land use. The factors that cause landslide in the past studies were found to be morphology, structural geology, physical and mechanical characteristics, hydrogeology, hydrology, external forces (train vibration, earthquake). Results back analysis of slope stability when the landslide occurred showed that the value Safety Factor (SF) = 1, angle of friction = 0°, and cohesion = 0.49 kg/cm2 (49 kPa). Based on the observation and analysis of the condition of the morphology and orientation of the structure of the rock layers, there was a location prone to landslide (labile) in the surrounding area of the landslide. Mitigations to potential landslide in adjacent area were building a retaining wall, draining channels, and shortcrete at the rock wall after landslides and maintaining the land use around the slopes.

Monitoring and Analysis of Ground Settlement Induced by Tunnelling with Slurry Pressure-Balanced Tunnel Boring Machine

Directory of Open Access Journals (Sweden)

Hyunku Park

2018-01-01

Full Text Available A case study of monitoring and analysis of ground settlement caused by tunnelling of stacked twin tunnels for underground metro line construction through the densely populated area using the slurry pressure-balanced TBM is presented. Detailed ground settlement monitoring was carried out for the initial stage of down-track tunnelling in order to estimate trough width factor and volume losses including face, shield, and tail losses. In addition, using the gap model, prediction of volume loss and ground settlement was carried out with consideration of the ground condition, TBM configurations, and actual operation data. The predictions of the gap model were compared with the observed results, and adjustment factors were determined for volume loss estimation. The adjusted factors were applied to predict ground settlement of the up-track tunnel, and its results were compared with the field measurements.

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 ...

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...

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...

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...

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...

Enhanced MRI in carpal tunnel syndrome

International Nuclear Information System (INIS)

Hayakawa, Katsuhiko; Nakane, Takashi; Kobayashi, Shigeru; Asai, Takahiro; Wada, Kunio; Yoshizawa, Hidezo

1998-01-01

In this study, we performed contrast-enhanced MRI in patients with idiopathic carpal tunnel syndrome and examined the morphologic change in the carpal tunnel. In the transverse section of the opening of carpal tunnel where scaphoid and pisiform bones are figured out, we measured and examined 4 items, viz. the soft carpal tunnel volume, flat rate of median nerve, position of median nerve and thickness of palmer ligaments composing the base of carpal tunnel, with an image analyzer attached to the MRI apparatus. Whereas the average carpal tunnel volume in 12 hands of normal controls was 166.8 mm 2 , that in 74 hands of carpal tunnel syndrome was 207.2 mm 2 , a significant increase compared with the normal controls. The flat rate of median nerve was 46% in the controls, but that was 37.5% in the carpal tunnel syndrome, a significant flattening was noted. We connected the peaks of the scaphoid node and pisiform bone with a line and named it standard line. When we observed the position of median nerve in the carpal tunnel, the nerve in 9 of 12 hands, 75%, lay below the standard line in the controls, but the nerve in 65 of 74 hands, 87.8%, lay above the standard line in the carpal tunnel syndrome, clearly showing that the median nerve had shifted to the palmar side. Regarding these morphologic changes of the carpal tunnel, the internal pressure of the carpal tunnel is considered to be raised with swelling of the soft tissues mainly composing the inside of carpal tunnel, thus the area of cross section of carpal tunnel to be increased, the median nerve to be shifted to the palmar side and the median nerve to be compressed by the transverse carpal ligament at that time. Although we can observe these morphological changes readily in MRI images, these images show only the results of carpal tunnel syndrome after all, and do not specify the direct causes. However, we believe that these facts are important factors in the manifestation of idiopathic carpal tunnel syndrome. (author)

Rock mass evaluation for predicting tunnel constructability in the preliminary investigation stage. Phenomena causing difficult tunneling and rockburst prediction

International Nuclear Information System (INIS)

Shin, Koichi; Sawada, Masataka; Inohara, Yoshiki; Shidahara, Takumi; Hatano, Teruyoshi

2011-01-01

For the selection of the Detailed Investigation Areas for HLW disposal, predicting the tunnel constructability is one of the requirements together with assessing long-term safety. This report is the 1st of the three papers dealing with the evaluation of tunnel constructability. This paper deals with the geological factors relating to difficult tunneling such as squeezing, rockburst, and others. Also it deals with the prediction of rockburst. The 2nd paper will deal with the prediction of squeezing. The 3rd paper deals with the engineering characteristics of rock mass through rock mass classification. This paper about difficult tunneling has been based upon analysis of more than 500 tunneling reports about 280 tunnel constructions. The causes of difficult tunneling are related to (1) underground water, (2) mechanical properties of the rock, or (3) others such as gas. The geological factors for excessive water inflow are porous volcanic product of Quarternary, fault crush zone and hydrothermally altered zone of Green Tuff area, and degenerated mixed rock in accretionary complex. The geological factors for squeezing are solfataric clay at Quarternary volcanic zone, fault crush zone and hydrothermally altered zone of Green Tuff area, mudstone and fault crush zone of sedimentary rock of Neogene and later. Information useful for predicting rockburst has been gathered from previous reports. In the preliminary investigation stage, geological survey, geophysical survey and borehole survey from the surface are the source of information. Therefore rock type, P-wave velocity from seismic exploration and in-situ rock stress from hydrofracturing have been considered. Majority of rockburst events occurred at granitic rock, excluding coal mine where different kind of rockburst occurred at pillars. And P-wave velocity was around 5 km/s at the rock of rockburst events. Horizontal maximum and minimum stresses SH and Sh have been tested as a criterion for rockburst. It has been

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.

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

The Real-Time Data Analysis and Decision System for Particle Flux Detection in the LHC Accelerator at CERN.

CERN Document Server

Zamantzas, C; Dehning, B

2006-01-01

The superconducting Large Hadron Collider (LHC) under construction at the European Organisation for Nuclear Research (CERN) is an accelerator unprecedented in terms of beam energy, particle production rate and also in the potential of self-destruction. Its operation requires a large variety of instrumentation, not only for the control of the beams, but also for the protection of the complex hardware systems. The Beam Loss Monitoring (BLM) system has to prevent the superconducting magnets from becoming normal conducting and protect the machine components against damages making it one of the most critical elements for the protection of the LHC. For its operation, the system requires 3600 detectors to be placed at various locations around the 27 km ring. The measurement system is sub-divided to the tunnel electronics, which are responsible for acquiring, digitising and transmitting the data, and the surface electronics, which receive the data via 2 km optical data links, process, analyze, store and issue warning...

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 ...

Augmented reality aiding collimator exchange at the LHC

International Nuclear Information System (INIS)

Martínez, Héctor; Fabry, Thomas; Laukkanen, Seppo; Mattila, Jouni; Tabourot, Laurent

2014-01-01

Novel Augmented Reality techniques have the potential to have a large positive impact on the way remote maintenance operations are carried out in hazardous areas, e.g. areas where radiation doses that imply careful planning and optimization of maintenance operations are present. This paper describes an Augmented Reality strategy, system and implementation for aiding the remote collimator exchange in the LHC, currently the world's largest and highest-energy particle accelerator. The proposed system relies on marker detection and multi-modal augmentation in real-time. A database system has been used to ensure flexibility. The system has been tested in a mock-up facility, showing real time performance and great potential for future use in the LHC. The technical-scientific difficulties identified during the development of the system and the proposed solutions described in this paper may help the development of future Augmented Reality systems for remote handling in scientific facilities

Augmented reality aiding collimator exchange at the LHC

Energy Technology Data Exchange (ETDEWEB)

Martínez, Héctor, E-mail: hector.martinez@sensetrix.com [SenseTrix, PL 20 FI-00101 Helsinki (Finland); Fabry, Thomas [European Organization for Nuclear Research, CERN, CH-1211 Genève 23 (Switzerland); Laukkanen, Seppo [SenseTrix, PL 20 FI-00101 Helsinki (Finland); Mattila, Jouni [Tampere University of Technology, PO Box 527, FI-33101 Tampere (Finland); Tabourot, Laurent [SYMME, Université de Savoie, Polytech Annecy-Chambéry, 5 chemin de Bellevue, 74944 Annecy le Vieux (France)

2014-11-01

Novel Augmented Reality techniques have the potential to have a large positive impact on the way remote maintenance operations are carried out in hazardous areas, e.g. areas where radiation doses that imply careful planning and optimization of maintenance operations are present. This paper describes an Augmented Reality strategy, system and implementation for aiding the remote collimator exchange in the LHC, currently the world's largest and highest-energy particle accelerator. The proposed system relies on marker detection and multi-modal augmentation in real-time. A database system has been used to ensure flexibility. The system has been tested in a mock-up facility, showing real time performance and great potential for future use in the LHC. The technical-scientific difficulties identified during the development of the system and the proposed solutions described in this paper may help the development of future Augmented Reality systems for remote handling in scientific facilities.

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 ...

Snow and ice blocking of tunnels

Energy Technology Data Exchange (ETDEWEB)

Lia, Leif

1998-12-31

Hydroelectric power development in cold regions causes much concern about operational reliability and dam safety. This thesis studies the temperature distribution in tunnels by means of air temperature measurements in six tunnel spillways and five diversion tunnels. The measurements lasted for two consecutive winters. The air through flow tunnel is used as it causes cooling of both rock and water. In open spillway tunnels, frost reaches the entire tunnel. In spillway tunnels with walls, the frost zones reach about 100 m from the downstream end. In mildly-inclined diversion tunnels, a frost free zone is located in the middle of the tunnel and snow and ice problems were only observed in the inlet and outlet. Severe aufeis is accumulation is observed in the frost zones. The heat transfer from rock to air, water and ice is calculated and used in a prediction model for the calculation of aufeis build-up together with local field observation data. The water penetration of snow plugs is also calculated, based on the heat balance. It takes 20 to 50 days for water to enter the blocked tunnel. The empirical values are 30 to 60 days, but only 1 day if the temperature of the snow pack is 0{sup o}C. Sensitivity analyses are carried out for temperature variations in rock, snow, water and ice. Systematic field observation shows that it is important for hydropower companies to know about the effects of snow and ice blocking in an area. A risk analysis of dam safety is presented for a real case. Finally, the thesis proposes solutions which can reduce the snow and ice problems. 79 refs., 63 figs., 11 tabs.

The LHC Tier1 at PIC: Experience from first LHC run

International Nuclear Information System (INIS)

Flix, J.; Perez-Calero Yzquierdo, A.; Accion, E.; Acin, V.; Acosta, C.; Bernabeu, G.; Bria, A.; Casals, J.; Caubet, M.; Cruz, R.; Delfino, M.; Espinal, X.; Lanciotti, E.; Lopez, F.; Martinez, F.; Mendez, V.; Merino, G.; Pacheco, A.; Planas, E.; Porto, M. C.; Rodriguez, B.; Sedov, A.

2013-01-01

This paper summarizes the operational experience of the Tier1 computer center at Port d'Informacio Cientifica (PIC) supporting the commissioning and first run (Run1) of the Large Hadron Collider (LHC). The evolution of the experiment computing models resulting from the higher amounts of data expected after there start of the LHC are also described. (authors)

Energy Deposition in Adjacent LHC Superconducting Magnets from Beam Loss at LHC Transfer Line Collimators

CERN Document Server

Beavan, S; Kain, V

2006-01-01

Injection intensities for the LHC are over an order of magnitude above the damage threshold. The collimation system in the two transfer lines is designed to dilute the beam sufficiently to avoid damage in case of accidental beam loss or mis-steered beam. To maximise the protection for the LHC most of the collimators are located in the last 300 m upstream of the injection point where the transfer lines approach the LHC machine. To study the issue of possible quenches following beam loss at the collimators part of the collimation section in one of the lines, TI 8, together with the adjacent part of the LHC has been modeled in FLUKA. The simulated energy deposition in the LHC for worst-case accidental losses and as well as for losses expected during a normal filling is presented.

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

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.

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. &...

Cost comparison between Subterrene and current tunneling methods. Final report

International Nuclear Information System (INIS)

Bledsoe, J.D.; Hill, J.E.; Coon, R.F.

1975-05-01

A study was made to compare tunnel construction costs between the Subterrene tunneling system and methods currently in use. Three completed tunnels were selected for study cases to represent finished diameters ranging from 3.05 meters (10 feet) to 6.25 meters (20.5 feet). The study cases were normalized by deleting extraneous work and assigning labor, equipment, and materials costs for the Southern California area in 1974. Detailed cost estimates (shown in Appendix A) were then made for the three tunnels for baseline. A conceptual nuclear powered Subterrene tunneling machine (NSTM) was designed. It was assumed that NSTM's were available for each of the three baseline tunnels. Costs were estimated (shown in Appendix B) for the baseline tunnels driven by NSTM

Sonographic diagnosis of carpal tunnel syndrome: a study in 200 hospital workers

Directory of Open Access Journals (Sweden)

Adham do Amaral e Castro

2015-10-01

Full Text Available AbstractObjective:To describe the prevalence of carpal tunnel syndrome in a sample of 200 healthy hospital workers, establishing the respective epidemiological associations.Materials and Methods:Two hundred individuals were submitted to wrist ultrasonography to measure the median nerve area. They were questioned and examined for epidemiological data, body mass index, carpal tunnel syndrome signs and symptoms, and submitted to the Boston carpal tunnel questionnaire (BCTQ to evaluate the carpal tunnel syndrome severity. A median nerve area ≥ 9 mm2 was considered to be diagnostic of carpal tunnel syndrome.Results:Carpal tunnel syndrome was diagnosed by ultrasonography in 34% of the sample. It was observed the association of carpal tunnel syndrome with age (p < 0.0001, paresthesia (p < 0.0001, Tinel's test (p < 0.0001, Phalen's test (p< 0.0001, BCTQ score (p < 0.0001, and years of formal education (p < 0.0001. Years of formal education was the only variable identified as an independent risk factor for carpal tunnel syndrome (95% CI = 1.03 to 1.24.Conclusion:The prevalence of carpal tunnel syndrome in a population of hospital workers was of 34%. The number of years of formal education was the only independent risk factor for carpal tunnel syndrome.

COOL, LCG Conditions Database for the LHC Experiments Development and Deployment Status

CERN Document Server

Valassi, A; Clemencic, M; Pucciani, G; Schmidt, S A; Wache, M; CERN. Geneva. IT Department, DM

2009-01-01

The COOL project provides common software components and tools for the handling of the conditions data of the LHC experiments. It is part of the LCG Persistency Framework (PF), a broader project set up within the context of the LCG Application Area (AA) to devise common persistency solutions for the LHC experiments. COOL software development is the result of the collaboration between the CERN IT Department and ATLAS and LHCb, the two experiments that have chosen it as the basis of their conditions database infrastructure. COOL supports conditions data persistency using several relational technologies (Oracle, MySQL, SQLite and FroNTier), based on the CORAL Common Relational Abstraction Layer. For both experiments, Oracle is the backend used for the deployment of COOL database services at Tier0 and Tier1 sites of the LHC Computing Grid. While the development of new software functionalities is being frozen as LHC operations are ramping up, the main focus for the project in 2008 has shifted to performance optimi...

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.

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.

A Vision in Aeronautics: The K-12 Wind Tunnel Project

Science.gov (United States)

1997-01-01

A Vision in Aeronautics, a project within the NASA Lewis Research Center's Information Infrastructure Technologies and Applications (IITA) K-12 Program, employs small-scale, subsonic wind tunnels to inspire students to explore the world of aeronautics and computers. Recently, two educational K-12 wind tunnels were built in the Cleveland area. During the 1995-1996 school year, preliminary testing occurred in both tunnels.

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.

10 October 2013 - D. Braun First Deputy Minister for Regional Development, Czech Republic, P. Styczeń Deputy Minister of Transport, Construction and Maritime Economy, Republic of Poland and F. Palko State Secretary, Ministry of Transport, Construction and Regional Development, Slovak Republic visiting the LHC tunnel at Point 1 with Technology Department, Vacuum, Surfaces and Coatings Group Leader J. M. Jimenez and signing the Guest book with CERN Director-General R. Heuer

CERN Multimedia

Anna Pantelia

2013-01-01

10 October 2013 - D. Braun First Deputy Minister for Regional Development, Czech Republic, P. Styczeń Deputy Minister of Transport, Construction and Maritime Economy, Republic of Poland and F. Palko State Secretary, Ministry of Transport, Construction and Regional Development, Slovak Republic visiting the LHC tunnel at Point 1 with Technology Department, Vacuum, Surfaces and Coatings Group Leader J. M. Jimenez and signing the Guest book with CERN Director-General R. Heuer

Performance of the CMS precision electromagnetic calorimeter at LHC Run II and prospects for High-Luminosity LHC

Science.gov (United States)

Zhang, Zhicai

2018-04-01

Many physics analyses using the Compact Muon Solenoid (CMS) detector at the LHC require accurate, high-resolution electron and photon energy measurements. Following the excellent performance achieved during LHC Run I at center-of-mass energies of 7 and 8 TeV, the CMS electromagnetic calorimeter (ECAL) is operating at the LHC with proton-proton collisions at 13 TeV center-of-mass energy. The instantaneous luminosity delivered by the LHC during Run II has achieved unprecedented levels. The average number of concurrent proton-proton collisions per bunch-crossing (pileup) has reached up to 40 interactions in 2016 and may increase further in 2017. These high pileup levels necessitate a retuning of the ECAL readout and trigger thresholds and reconstruction algorithms. In addition, the energy response of the detector must be precisely calibrated and monitored. We present new reconstruction algorithms and calibration strategies that were implemented to maintain the excellent performance of the CMS ECAL throughout Run II. We will show performance results from the 2015-2016 data taking periods and provide an outlook on the expected Run II performance in the years to come. Beyond the LHC, challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL-LHC) . We review the design and R&D studies for the CMS ECAL and present first test beam studies. Particular challenges at HL-LHC are the harsh radiation environment, the increasing data rates, and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. We present test beam results of hadron irradiated PbWO crystals up to fluences expected at the HL-LHC . We also report on the R&D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

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.

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 ...

Performance with lead ions of the LHC beam dump system

CERN Document Server

Bruce, R; Jensen, L; Lefèvre, T; Weterings, W

2007-01-01

The LHC beam dump system must function safely with 208Pb82+ions. The differences with respect to the LHC proton beams are briefly recalled, and the possible areas for performance concerns discussed, in particular the various beam intercepting devices and the beam instrumentation. Energy deposition simulation results for the most critical elements are presented, and the conclusions drawn for the lead ion operation. The expected performance of the beam instrumentation systems are reviewed in the context of the damage potential of the ion beam and the required functionality of the various safety and post-operational analysis requirements.

New strategies of the LHC experiments to meet the computing requirements of the HL-LHC era

CERN Document Server

Adamova, Dagmar

2017-01-01

The performance of the Large Hadron Collider (LHC) during the ongoing Run 2 is above expectations both concerning the delivered luminosity and the LHC live time. This resulted in a volume of data much larger than originally anticipated. Based on the current data production levels and the structure of the LHC experiment computing models, the estimates of the data production rates and resource needs were re-evaluated for the era leading into the High Luminosity LHC (HLLHC), the Run 3 and Run 4 phases of LHC operation. It turns out that the raw data volume will grow 10 times by the HL-LHC era and the processing capacity needs will grow more than 60 times. While the growth of storage requirements might in principle be satisfied with a 20 per cent budget increase and technology advancements, there is a gap of a factor 6 to 10 between the needed and available computing resources. The threat of a lack of computing and storage resources was present already in the beginning of Run 2, but could still be mitigated, e.g....

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...

Injection Protection Upgrade for the HL-LHC

CERN Document Server

AUTHOR|(CDS)2067108; Biancacci, Nicolo; Bracco, Chiara; Frasciello, Oscar; Gentini, Luca; Goddard, Brennan; Lechner, Anton; Maciariello, Fausto; Perillo Marcone, Antonio; Salvant, Benoit; Shetty, Nikhil Vittal; Steele, Genevieve; Velotti, Francesco; Zobov, Mikhail

2015-01-01

The injector complex of the LHC is undergoing important changes in the light of the LIU project to provide brighter beams to the LHC. For this reason and as part of the High Luminosity LHC project the injection protection system of the LHC will be upgraded in the Long Shutdown 2 (2018 - 2019) to be able to protect downstream elements against injection failures with the high brightness, high intensity HL-LHC beams. The upgraded LHC injection protection system will consist of a segmented injection protection absorber TDIS, and auxiliary collimators and masks. The layout modifications are described, and the machine element protection and absorber jaw robustness studies are presented for the new systems.

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...

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...

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/

A new home for LHC physicists

CERN Multimedia

2008-01-01

Work is about to start on a new extension to Building 40 to make extra space for 300 LHC scientists at CERN. Work on a new development to provide office space for 300 scientists at CERN will start on 5 January. Building 42, a new extension to Building 40, will provide extra space for researchers and external collaborators working on the LHC experiments. The 3160 square meters of floor space will be divided into 300 new work places and 6 meeting rooms. Located on the south side of Building 40, the extension will boast some impressive views over the vineyard to the south of CERN. The design is centred around a large courtyard garden. Once completed, there will be internal connections to Building 40 as well as a large outdoor decking area overlooking the central garden. The design was done by the same architect as for Building 40, Jacques Perret, and is planned with the environment in mind. The grass roof will provide both insulation an...

Technologies pioneered by LHC. Superconducting magnet and radiation-tolerant tracking detector

International Nuclear Information System (INIS)

Yamamoto, Akira; Unno, Yoshinobu

2007-01-01

In the LHC project of proton-proton collisions exploring the energy frontier, superconducting magnets and radiation-tolerant tracking detector play fundamental roles as key technologies. The superconducting magnets contribute to bending and focusing particle beam by using high magnetic field created with the NbTi superconductor cooled to the superfluid temperature of He (1.9 K). In order to overcome the unprecedented radiation damage and to capture the particles emerging with high energy and high density, the large area and highly radiation-tolerant silicon semiconductor tracking detector has been developed for the LHC experiment. (author)

Optical data transmission ASICs for the high-luminosity LHC (HL-LHC) experiments

International Nuclear Information System (INIS)

Li, X; Huang, G; Sun, X; Liu, G; Deng, B; Gong, D; Guo, D; Liu, C; Liu, T; Xiang, A C; Ye, J; Zhao, X; Chen, J; You, Y; He, M; Hou, S; Teng, P-K; Jin, G; Liang, H; Liang, F

2014-01-01

We present the design and test results of two optical data transmission ASICs for the High-Luminosity LHC (HL-LHC) experiments. These ASICs include a two-channel serializer (LOCs2) and a single-channel Vertical Cavity Surface Emitting Laser (VCSEL) driver (LOCld1V2). Both ASICs are fabricated in a commercial 0.25-μm Silicon-on-Sapphire (SoS) CMOS technology and operate at a data rate up to 8 Gbps per channel. The power consumption of LOCs2 and LOCld1V2 are 1.25 W and 0.27 W at 8-Gbps data rate, respectively. LOCld1V2 has been verified meeting the radiation-tolerance requirements for HL-LHC experiments

Air quality assessment in Salim Slam Tunnel

International Nuclear Information System (INIS)

El-Fadel, M.; Hashisho, Z.; Saikaly, P.

1999-01-01

Full text.Vehicle emissions constitute a serious occupational environmental hazard particularly in confined spaces such as tunnels and underground parking garages. these emissions at elevated concentrations, can cause adverse health effects, which range from nausea and eye irritation to mutagenicity, carcinogenicity and even death. This paper presents an environmental air quality assessment in a tunnel located in a highly congested urban area. For this purpose, air samples were collected and analyzed for the presence of primary air pollutants, priority metals, and volatile organic carbons. Air quality modeling was conducted to simulate variations of pollutant concentrations in the tunnel under worst case scenarios including traffic congestion and no air ventilation. Field measurements and mathematical simulation results were used to develop a strategy for proper air quality management in tunnels

Superconducting tunnel-junction refrigerator

International Nuclear Information System (INIS)

Melton, R.G.; Paterson, J.L.; Kaplan, S.B.

1980-01-01

The dc current through an S 1 -S 2 tunnel junction, with Δ 2 greater than Δ 1 , when biased with eV 1 +Δ 2 , will lower the energy in S 1 . This energy reduction will be shared by the phonons and electrons. This device is shown to be analogous to a thermoelectric refrigerator with an effective Peltier coefficient π* approx. Δ 1 /e. Tunneling calculations yield the cooling power P/sub c/, the electrical power P/sub e/ supplied by the bias supply, and the cooling efficiency eta=P/sub c//P/sub e/. The maximum cooling power is obtained for eV= +- (Δ 2 -Δ 1 ) and t 1 =T 1 /T/sub c/1 approx. 0.9. Estimates are made of the temperature difference T 2 -T 1 achievable in Al-Pb and Sn-Pb junctions with an Al 2 O 3 tunneling barrier. The performance of this device is shown to yield a maximum cooling efficiency eta approx. = Δ 1 /(Δ 2 -Δ 1 ) which can be compared with that available in an ideal Carnot refrigerator of eta=T 1 /(T 2 -T 1 ). The development of a useful tunnel-junction refrigerator requires a tunneling barrier with an effective thermal conductance per unit area several orders of magnitude less than that provided by the A1 2 O 3 barrier in the Al-Pb and Sn-Pb systems

Fire analyses in central and disposal tunnels by APROS

International Nuclear Information System (INIS)

Peltokorpi, L.; Kukkola, T.; Nieminen, J.

2012-12-01

The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m 3 /s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

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...

Large hadron collider (LHC) project quality assurance plan

Energy Technology Data Exchange (ETDEWEB)

Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

2002-09-30

The LHC Quality Assurance Plan is a set of operating principles, requirements, and practices used to support Berkeley Lab's participation in the Large Hadron Collider Project. The LHC/QAP is intended to achieve reliable, safe, and quality performance in the LHC project activities. The LHC/QAP is also designed to fulfill the following objectives: (1) The LHC/QAP is Berkeley Lab's QA program document that describes the elements necessary to integrate quality assurance, safety management, and conduct of operations into the Berkeley Lab's portion of the LHC operations. (2) The LHC/QAP provides the framework for Berkeley Lab LHC Project administrators, managers, supervisors, and staff to plan, manage, perform, and assess their Laboratory work. (3) The LHC/QAP is the compliance document that conforms to the requirements of the Laboratory's Work Smart Standards for quality assurance (DOE O 414.1, 10 CFR 830.120), facility operations (DOE O 5480.19), and safety management (DOE P 450.4).

Large hadron collider (LHC) project quality assurance plan

International Nuclear Information System (INIS)

Gullo, Lisa; Karpenko, Victor; Robinson, Kem; Turner, William; Wong, Otis

2002-01-01

The LHC Quality Assurance Plan is a set of operating principles, requirements, and practices used to support Berkeley Lab's participation in the Large Hadron Collider Project. The LHC/QAP is intended to achieve reliable, safe, and quality performance in the LHC project activities. The LHC/QAP is also designed to fulfill the following objectives: (1) The LHC/QAP is Berkeley Lab's QA program document that describes the elements necessary to integrate quality assurance, safety management, and conduct of operations into the Berkeley Lab's portion of the LHC operations. (2) The LHC/QAP provides the framework for Berkeley Lab LHC Project administrators, managers, supervisors, and staff to plan, manage, perform, and assess their Laboratory work. (3) The LHC/QAP is the compliance document that conforms to the requirements of the Laboratory's Work Smart Standards for quality assurance (DOE O 414.1, 10 CFR 830.120), facility operations (DOE O 5480.19), and safety management (DOE P 450.4)

Heavy-ion operation of HL-LHC

CERN Document Server

Jowett, J M; Versteegen, R

2015-01-01

The heavy-ion physics programme of the LHC will continue during the HL-LHC period with upgraded detectors capable of exploiting several times the design luminosity for nucleus–nucleus (Pb–Pb) collisions. For proton–nucleus (p–Pb) collisions, unforeseen in the original design of the LHC, a comparable increase beyond the 2013 luminosity should be attainable. We present performance projections and describe the operational strategies and relatively modest upgrades to the collider hardware that will be needed to achieve these very significant extensions to the physics potential of the High Luminosity LHC.

3-D metrology applied to superconducting dipole magnets for LHC

International Nuclear Information System (INIS)

Dupont, M.; Missiaen, D.; Peguiron, L.

1999-01-01

The construction of the Large Hadron Collider (LHC) requires the manufacture of 1232 superconducting dipole magnets containing two beam channels in a common mechanical structure. These dipole magnets, which produce the required magnetic field to deflect the particles along a circular trajectory, have to be bent in their horizontal plane in order to ensure the largest mechanical aperture. Very tight tolerances on the geometry of these magnets have to be imposed during their fabrication in order to minimise, during operation, the possible losses of particles, which circulate in rather small channels and to ensure the alignment of the adjacent magnets in the ring tunnel. This necessitates a thorough metrological inspection of the magnet geometry and an accurate positioning of some of its components. This paper presents the measuring system and the developed methodology to realize these operations. The results on the first 15 m long dipole magnet are shown. (author)

Tunneling behavior of the formosan subterranean termite (isoptera: rhinotermitadae) in dry soil

Science.gov (United States)

This study examines the effect of dry soil on tunnel construction by the Formosan subterranean termite, Cptotermes formosanus. Termites did not construct tunnels in dry soil in any of the treatments. Termites only constructed tunnels in moist areas in treatments where the soil was partially moistene...

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.

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...

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-...

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...

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...

A model to relate wind tunnel measurements to open field odorant emissions from liquid area sources

Science.gov (United States)

Lucernoni, F.; Capelli, L.; Busini, V.; Sironi, S.

2017-05-01

Waste Water Treatment Plants are known to have significant emissions of several pollutants and odorants causing nuisance to the near-living population. One of the purposes of the present work is to study a suitable model to evaluate odour emissions from liquid passive area sources. First, the models describing volatilization under a forced convection regime inside a wind tunnel device, which is the sampling device that typically used for sampling on liquid area sources, were investigated. In order to relate the fluid dynamic conditions inside the hood to the open field and inside the hood a thorough study of the models capable of describing the volatilization phenomena of the odorous compounds from liquid pools was performed and several different models were evaluated for the open field emission. By means of experimental tests involving pure liquid acetone and pure liquid butanone, it was verified that the model more suitable to describe precisely the volatilization inside the sampling hood is the model for the emission from a single flat plate in forced convection and laminar regime, with a fluid dynamic boundary layer fully developed and a mass transfer boundary layer not fully developed. The proportionality coefficient for the model was re-evaluated in order to account for the specific characteristics of the adopted wind tunnel device, and then the model was related with the selected model for the open field thereby computing the wind speed at 10 m that would cause the same emission that is estimated from the wind tunnel measurement furthermore, the field of application of the proposed model was clearly defined for the considered models during the project, discussing the two different kinds of compounds commonly found in emissive liquid pools or liquid spills, i.e. gas phase controlled and liquid phase controlled compounds. Lastly, a discussion is presented comparing the presented approach for emission rates recalculation in the field, with other approaches

Tunnel - history of

International Nuclear Information System (INIS)

1998-11-01

This book introduces history of tunnel in ancient times, the middle ages and modern times, survey of tunnel and classification of bedrock like environment survey of position, survey of the ground, design of tunnel on basic thing of the design, and design of tunnel of bedrock, analysis of stability of tunnel and application of the data, construction of tunnel like lattice girder and steel fiber reinforced shot crete, and maintenance control and repair of tunnel.

The new biometric access control system resembles a big electronic eye. It will be used to control access to the LHC from 2007 onwards.

CERN Multimedia

Maximilien Brice

2006-01-01

The new LHC access control systems will soon be using the latest technology: optical recognition based on iris image data. In order to gain access to the tunnel it will be your eye, not your credentials that you'll be required to show! As of September, the entrance point at Point 8 should be the first to be fitted out with iris recognition equipment. The other access shafts will then gradually be equipped one by one.

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.

The TOTEM GEM Telescope (T2) at the LHC

International Nuclear Information System (INIS)

Quinto, M.; Berretti, M.; David, E.; Garcia, F.; Greco, V.; Heino, J.; Hilden, T.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Oliveri, E.; Ropelewski, L.; Scribano, A.; Turini, N.; Stenis, M. van

2011-01-01

The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

The TOTEM GEM Telescope (T2) at the LHC

Energy Technology Data Exchange (ETDEWEB)

Quinto, M. [INFN Sezione di Bari, Via E.Orabona n 4, 70126 Bari (Italy); Berretti, M. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); David, E. [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland); Garcia, F. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Greco, V. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Heino, J.; Hilden, T.; Kurvinen, K. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Lami, S. [INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Latino, G. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Lauhakangas, R. [University of Helsinki, Institute of Physics and Department of Physical Sciences, Helsinki (Finland); Oliveri, E. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Ropelewski, L. [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland); Scribano, A.; Turini, N. [University of Siena, Physics Department, Via Roma 56, I-53100 Siena (Italy); INFN Sezione di Pisa, Largo B. Pontecorvo, 3. I-56127. Pisa (Italy); Stenis, M. van [CERN, PH Department, 1211 Geneva 23, Geneva (Switzerland)

2011-06-15

The TOTEM T2 telescope will measure inelastically produced charged particles in the forward region of the LHC Interaction Point 5. Each arm of the telescope consists in a set of 20 triple-GEM (Gas Electron Multiplier) detectors with tracking and trigger capabilities. The GEM technology has been considered for the design of TOTEM very forward T2 telescopes thanks to its characteristics: large active areas, good position and timing resolution, excellent rate capability and radiation hardness. Each of the four T2 half arms has been fully assembled and equipped with electronics at CERN and systematically tested in the SPS beam line H8 in 2008/09. After some optimization, the operation of the GEM chambers was fully satisfactory and the T2 telescopes were installed and commissioned in their final positions at the LHC interaction point. During the first LHC run (December 2009) the T2 telescopes have collected data, at 900 GeV and 2.36 TeV. We will present here the performances of the detector and the preliminary results obtained using the data collected.

A Fast CVD Diamond Beam Loss Monitor for LHC

CERN Document Server

Griesmayer, E; Dobos, D; Effinger, E; Pernegger, H

2011-01-01

Chemical Vapour Deposition (CVD) diamond detectors were installed in the collimation area of the CERN LHC to study their feasibility as Fast Beam Loss Monitors in a high-radiation environment. The detectors were configured with a fast, radiation-hard pre-amplifier with a bandwidth of 2 GHz. The readout was via an oscilloscope with a bandwidth of 1 GHz and a sampling rate of 5 GSPS. Despite the 250 m cable run from the detectors to the oscilloscope, single MIPs were resolved with a 2 ns rise time, a pulse width of 10 ns and a time resolution of less than 1 ns. Two modes of operation were applied. For the analysis of unexpected beam aborts, the loss profile was recorded in a 1 ms buffer and, for nominal operation, the histogram of the time structure of the losses was recorded in synchronism with the LHC period of 89.2 μs. Measurements during the LHC start-up (February to December 2010) are presented. The Diamond Monitors gave an unprecedented insight into the time structure of the beam losses resolving the 400...

Evaluation of tunnel seismic prediction (TSP) result using the Japanese highway rock mass classification system for Pahang-Selangor Raw Water Transfer Tunnel

Science.gov (United States)

Von, W. C.; Ismail, M. A. M.

2017-10-01

The knowing of geological profile ahead of tunnel face is significant to minimize the risk in tunnel excavation work and cost control in preventative measure. Due to mountainous area, site investigation with vertical boring is not recommended to obtain the geological profile for Pahang-Selangor Raw Water Transfer project. Hence, tunnel seismic prediction (TSP) method is adopted to predict the geological profile ahead of tunnel face. In order to evaluate the TSP results, IBM SPSS Statistic 22 is used to run artificial neural network (ANN) analysis to back calculate the predicted Rock Grade Points (JH) from actual Rock Grade Points (JH) using Vp, Vs and Vp/Vs from TSP. The results show good correlation between predicted Rock Grade points and actual Rock Grade Points (JH). In other words, TSP can provide geological profile prediction ahead of tunnel face significantly while allowing continuously TBM excavation works. Identifying weak zones or faults ahead of tunnel face is crucial for preventative measures to be carried out in advance for a safer tunnel excavation works.

Conceptual study of the cryostats for the cold powering system for the triplets of the High Luminosity LHC

Science.gov (United States)

Ballarino, A.; Giannelli, S.; Jacquemod, A.; Leclercq, Y.; Ortiz Ferrer, C.; Parma, V.

2017-12-01

The High Luminosity LHC (HL-LHC) is a project aiming to upgrade the Large Hadron Collider (LHC) after 2020-2025 in order to increase the integrated luminosity by about one order of magnitude and extend the operational capabilities until 2035. The upgrade of the focusing triplet insertions for the Atlas and CMS experiments foresees using superconducting magnets operating in a pressurised superfluid helium bath at 1.9 K. The increased radiation levels from the particle debris produced by particle collisions in the experiments require that the power converters are placed in radiation shielded zones located in a service gallery adjacent to the main tunnel. The powering of the magnets from the gallery is achieved by means of MgB2 superconducting cables in a 100-m long flexible cryostat transfer line, actively cooled by 4.5 K to 20 K gaseous helium generated close to the magnets. At the highest temperature end, the helium flow cools the High Temperature Superconducting (HTS) current leads before being recovered at room temperature. At the magnet connection side, a dedicated connection box allows connection to the magnets and a controlled boil-off production of helium for the cooling needs of the powering system. This paper presents the overall concept of the cryostat system from the magnet connection boxes, through the flexible cryostat transfer line, to the connection box of the current leads.

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.

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)

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.

Coupled Boundary and Finite Element Analysis of Vibration from Railway Tunnels

DEFF Research Database (Denmark)

Andersen, Lars; Jones, C.J.C.

2006-01-01

The analysis of vibration from railway tunnels is of growing interest as new and higher-speed railways are built under the ground to address the transport problems of growing modern urban areas around cities. Such analysis can be carried out using numerical methods but models and therefore comput...... body vibration (about 4 to 80 Hz). A coupled finite element and boundary element scheme is applied in both two and three dimensions. Two tunnel designs are considered: a cut-and-cover tunnel for a double track and a single-track tunnel dug with the New Austrian Tunnelling Method (NATM)....

Fluka studies of the Asynchronous Beam Dump Effects on LHC Point 6

CERN Document Server

Versaci, R; Goddard, B; Mereghetti, A; Schmidt, R; Vlachoudis, V; CERN. Geneva. ATS Department

2011-01-01

The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. Using FLUKA Monte Carlo simulations, we have investigated the effects of an asynchronous beam dump at the LHC Point 6 where beams, with a stored energy of 360 MJ, can instantaneously release up to a few J cm^-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm^-3. In the present paper we will describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyze the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

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...

Accelerators and storage rings. TS Workshop 2005. Book of Abstracts

International Nuclear Information System (INIS)

Ciriani, P.; Magnin, B.; Oliveira, R. de; Chevalley, J.; Artoos, K.; Bertone, C.; Minginette, P.; Corso, J.P.; Grillot, S.; Weisz, S.; Prodon, S.; Sakkinen, J.; Foraz, K.; Funken, A.; Bangert, N.; Hakulinen, T.; Boncompagni, Y.; Delamare, C.; Folch, R.; Poehler, M.; Bertarelli, A.; Martel, C.; Butin, F.; Osborne, J.; Evrard, S.; Lacarrere, D.; Gayde, J.C.; Renaglia, T.; Batz, M.; Tsesmelis, E.; Wijnands, T.; Perrot, A.L.; Gastal, M.; Atieh, S.; Cherif, A.; Costa Pinto, P.; Calatroni, S.; Ninin, P.; Battistin, M.; Arnau Izquierdo, G.; Favre, G.; Mathot, S.; Mainaud, H.; Podevin, C.; Jones, M.; Stowisek, J.; Roy, S.; Sanchez-Corral, E.; Petit, S.; Martel, P.; Colloca, C.; Van Der Bij, E.; Vadon, M.; Kahle, K.; Principe, R.; Macina, D.; Schmidt, R.; Ridewood, J.; Lopez-Hernandez, L.A.

2005-01-01

This document gathers the abstracts of the papers presented at the workshop. This workshop was dedicated to the status of the technical support of the LHC (large hadron collider) in CERN. The different issues concern: -) the installation of the equipment in the LHC tunnel (super-conducting magnets, cold boxes, PS magnets...), -) underground logistics, -) the installation of experimental areas, -) the new CERN control center, and -) special technologies. (A.C.)

Accelerators and storage rings. TS Workshop 2005. Book of Abstracts

Energy Technology Data Exchange (ETDEWEB)

Ciriani, P.; Magnin, B.; Oliveira, R. de; Chevalley, J.; Artoos, K.; Bertone, C.; Minginette, P.; Corso, J.P.; Grillot, S.; Weisz, S.; Prodon, S.; Sakkinen, J.; Foraz, K.; Funken, A.; Bangert, N.; Hakulinen, T.; Boncompagni, Y.; Delamare, C.; Folch, R.; Poehler, M.; Bertarelli, A.; Martel, C.; Butin, F.; Osborne, J.; Evrard, S.; Lacarrere, D.; Gayde, J.C.; Renaglia, T.; Batz, M.; Tsesmelis, E.; Wijnands, T.; Perrot, A.L.; Gastal, M.; Atieh, S.; Cherif, A.; Costa Pinto, P.; Calatroni, S.; Ninin, P.; Battistin, M.; Arnau Izquierdo, G.; Favre, G.; Mathot, S.; Mainaud, H.; Podevin, C.; Jones, M.; Stowisek, J.; Roy, S.; Sanchez-Corral, E.; Petit, S.; Martel, P.; Colloca, C.; Van Der Bij, E.; Vadon, M.; Kahle, K.; Principe, R.; Macina, D.; Schmidt, R.; Ridewood, J.; Lopez-Hernandez, L.A

2005-07-01

This document gathers the abstracts of the papers presented at the workshop. This workshop was dedicated to the status of the technical support of the LHC (large hadron collider) in CERN. The different issues concern: -) the installation of the equipment in the LHC tunnel (super-conducting magnets, cold boxes, PS magnets...), -) underground logistics, -) the installation of experimental areas, -) the new CERN control center, and -) special technologies. (A.C.)

Direct, coherent and incoherent intermediate state tunneling and scanning tunnel microscopy (STM)

International Nuclear Information System (INIS)

Halbritter, J.

1997-01-01

Theory and experiment in tunneling are still qualitative in nature, which hold true also for the latest developments in direct-, resonant-, coherent- and incoherent-tunneling. Those tunnel processes have recently branched out of the field of ''solid state tunnel junctions'' into the fields of scanning tunnel microscopy (STM), single electron tunneling (SET) and semiconducting resonant tunnel structures (RTS). All these fields have promoted the understanding of tunneling in different ways reaching from the effect of coherence, of incoherence and of charging in tunneling, to spin flip or inelastic effects. STM allows not only the accurate measurements of the tunnel current and its voltage dependence but, more importantly, the easy quantification via the (quantum) tunnel channel conductance and the distance dependence. This new degree of freedom entering exponentially the tunnel current allows an unique identification of individual tunnel channels and their quantification. In STM measurements large tunnel currents are observed for large distances d > 1 nm explainable by intermediate state tunneling. Direct tunneling with its reduced tunnel time and reduced off-site Coulomb charging bridges distances below 1 nm, only. The effective charge transfer process with its larger off-site and on-site charging at intermediate states dominates tunnel transfer in STM, biology and chemistry over distances in the nm-range. Intermediates state tunneling becomes variable range hopping conduction for distances larger than d > 2 nm, for larger densities of intermediate states n 1 (ε) and for larger temperatures T or voltages U, still allowing high resolution imaging

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...

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.

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.

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.

ATLAS Muon Spectrometer Upgrades for the High Luminosity LHC

CERN Document Server

Valderanis, Chrysostomos; The ATLAS collaboration

2015-01-01

ATLAS Muon Spectrometer Upgrades for the High Luminosity LHC The luminosity of the LHC will increase up to 2x10^34 cm-2s-1 after the long shutdown in 2019 (phase-1 upgrade) and up to 7x10^34 cm-2s-1 after the long shutdown in 2025 (phase-2 upgrade). In order to cope with the increased particle fluxes, upgrades are envisioned for the ATLAS muon spectrometer. At phase-1, the current innermost stations of the ATLAS muon endcap tracking system (the Small Wheels) will be upgraded with 2x4-layer modules of Micromega detectors, sandwiched by two 4 layer modules of small strip Thin Gap Chambers on either side. Each 4-layer module of the so-called New Small Wheels covers a surface area of approximately 2 to 3 m2 for a total active area of 1200 m2 each for the two technologies. On such large area detectors, the mechanical precision (30 \\mu m along the precision coordinate and 80 \\mu m along the beam) is a key point and must be controlled and monitored along the process of construction and integration. The design and re...

Magnetic Analysis of a Single-Aperture 11T Nb3Sn Demonstrator Dipole for LHC Upgrades

Energy Technology Data Exchange (ETDEWEB)

Auchmann, B. [CERN; Karppinen, M. [CERN; Kashikhin, V. [Fermilab; Zlobin, A. V. [Fermilab

2012-05-01

The planned upgrade of the LHC collimation system foresees additional collimators to be installed in the dispersion suppressor areas around points 2, 3, and 7. The necessary longitudinal space for the collimators could be provided by replacing some 8.33-T 15-m-long NbTi LHC main dipoles with shorter 11-T Nb3Sn dipoles compatible with the LHC lattice and main systems. To demonstrate this possibility, in 2011 Fermilab and CERN started a joint R&D program with the goal of building a 5.5-m-long tw in-aperture dipole prototype suitable for installation in the LHC by 2014. The first step of this program is the development of a 2-m-long single-aperture demonstration dipole with the nominal field of 11 T at the LHC nominal current of ~11.85 kA and 60-m m bore with ~20% margin. This paper presents the results of magnetic analysis of the single-aperture Nb3Sn demonstrator dipole for the LHC collimation system upgrade.

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...

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)

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.

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.

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