Layout and Optics Solution for the LHC Insertion Upgrade Phase I

CERN Document Server

Fartoukh, S

2010-01-01

The main guidelines of the LHC IR upgrade Phase I project are the development of wider aperture (120 mm) and lower gradient (120 T/m) quadrupoles using the wellcharacterized Nb-Ti technology in order to build new inner triplets (IT) for the ATLAS and CMS experimental insertions, while minimizing the hardware modifications in the other parts of these insertions, in particular leaving unchanged the so-called "matching section" (MS) and "dispersion suppressor" (DS). While one of the initial goal was to squeeze the optics down to a B* of 25 cm, optics solutions with a B* of 30 cm are already at the edge of feasibility, both in terms of the IT and MS mechanical acceptance, gradients of the MS and DS quadrupole magnets, and correctability by the arc sextupoles of the huge chromatic aberrations generated at low B*. The layout of the new inner triplet and the corresponding injection and collision optics will be presented and analyzed in terms of aperture and chromatic correction.

Calculation of Residual Dose Rates and Intervention Scenarios for the LHC Beam Cleaning Insertions-Constraints and Optimization

CERN Document Server

Brugger, Markus; Assmann, R W; Forkel-Wirth, Doris; Menzel, Hans Gregor; Roesler, Stefan; Vincke, Helmut H

2005-01-01

Radiation protection of the personnel who will perform interventions in the LHC Beam Cleaning Insertions is mandatory and includes the design of equipment and the establishment of work procedures. Residual dose rates due to activated equipment are expected to reach significant values such that any maintenance has to be planned and optimized in advance. Three-dimensional maps of dose equivalent rates at different cooling times after operation of the LHC have been calculated with FLUKA. The simulations are based on an explicit calculation of induced radioactivity and of the transport of the radiation from the radioactive decay. The paper summarizes the results for the Beam Cleaning Insertions and discusses the estimation of individual and collective doses received by personnel during critical interventions, such as the exchange of a collimator or the installation of Phase 2. The given examples outline the potential and the need to optimize, in an iterative way, the design of components as well as the layout of ...

LHC Interaction Region Upgrade Phase I

CERN Document Server

Ostojic, R

2009-01-01

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

US-LHC IR magnet error analysis and compensation

International Nuclear Information System (INIS)

Wei, J.; Ptitsin, V.; Pilat, F.; Tepikian, S.; Gelfand, N.; Wan, W.; Holt, J.

1998-01-01

This paper studies the impact of the insertion-region (IR) magnet field errors on LHC collision performance. Compensation schemes including magnet orientation optimization, body-end compensation, tuning shims, and local nonlinear correction are shown to be highly effective

Optimization of the LHC interaction region with respect to beam-induced energy deposition

International Nuclear Information System (INIS)

Mokhov, N.V.; Strait, J.B.

1996-06-01

Energy deposition in the superconducting magnets by particles from p- p collisions is a significant challenge for the design of the LHC high luminosity insertions. We have studies the dependence of the energy deposition on the apertures and strengths of insertion magnets and on the placement of absorbers in front of and within the quadrupoles. Monte Carlo simulations were made using the code DTUJET to generate 7x7 TeV p-p events and the code MARS to follow hadronic and electromagnetic cascades induced in the insertion components. The 3D geometry and magnetic field descriptions of the LHC-4.1 lattice were used. With a quadrupole coil aperture ≥70 mm, absorbers can be placed within the magnet bore which reduce the peak power density, at full luminosity, below 0.5 mW/g, a level that should allow the magnets to operate at their design field. The total heat load can be removed by a cooling system similar to that used in the main magnets

Proposal for the award of two contracts for the supply of fine-blanked austenitic steel yoke laminations and inserts for the cold masses of the LHC superconducting dipole magnets

CERN Document Server

1999-01-01

This document concerns the award of two contracts for the total supply of 642 000 fine-blanked austenitic steel yoke laminations, of two different types, and 642 000 inserts for the cold masses of the LHC superconducting dipole magnets. Following a market survey carried out among 70 firms in sixteen Member States and one firm in Japan, a call for tenders (IT-2700/LHC/LHC) was sent on 3 June 1999 to seven firms in four Member States and one firm in Japan. By the closing date, CERN had received five tenders. The Finance Committee is invited to agree to the negotiation of two contracts with: - ELAY INDUSTRIAL (ES) for the supply of 324 000 fine-blanked austenitic steel yoke laminations of the first type and the corresponding number of inserts, which represents the total required quantity of laminations of the first type and of corresponding inserts for the cold masses of the LHC superconducting dipole magnets, for a total amount of 481 814 euros, which at the exchange rate given in the tender correspond to 770 8...

Normal Conducting Separation Dipoles for the LHC Beam Cleaning Insertions

CERN Document Server

Bidon, S; Hans, O; Kalbreier, Willi; Kiselev, O; Petrov, V; Protopopov, I V; Pupkov, Yu A; Ramberger, S; de Rijk, G; Ruvinsky, E; Sukhanov, A

2004-01-01

In the Large Hadron Collider (LHC), two straight sections, IR3 and IR7, will be dedicated to beam cleaning. These cleaning insertions will be equipped with normal conducting magnets. MBW magnets are dipole magnets used to increase the separation of the two beams. They have a core length of 3.4 m and a gap height of 52 mm and will operate at a magnetic field ranging from 0.09 T to 1.53 T. Limitations on the dimensions and total weight of the magnet resulted in a special design with a common yoke for the two beams. The orbits of the two beams will be separated horizontally by a distance between 194 mm and 224 mm in the gap of the magnet. The magnet was designed in collaboration between CERN and BINP. The report presents the main design issues and results of the pre-series acceptance tests including mechanical, electrical and magnetic field measurements.

HL-LHC (High-Luminosity LHC) first stone ceremony June 2018

CERN Document Server

Brice, Maximilien

2018-01-01

The first two pictures: Point 1 of the LHC. The Director-General of CERN inserts the time capsule containing a document submitted by France submits a document which is inserted in a time capsule at Point 1 of the LHC. This is the article "Geneva" of the Encyclopedia de Diderot and d'Alembert. In August 1756, during his stay in Geneva, Voltaire stayed in a property called Les Délices, many visitors including d'Alembert were involved in writing this article. Today, that location is the Library of Geneva's centre of research for the Enlightenment period. The following two pictures: Point 5 of the LHC. The Director-General of CERN inserts the time capsule containing a document submitted by the Republic and Canton of Geneva. This historic document from 1952 is the telegram by which the President of the Council of State at the time, Mr. Louis Casai, announced to his fellow members of the Government of Geneva the news of the decision taken by the signatory states of the convention for the establishment of a Europea...

Status of the LHC low-$\\beta$ insertion quadrupole magnet development at KEK

CERN Document Server

Ogitsu, T; Ohuchi, N; Ajima, Y; Burkhardt, E E; Higashi, N; Hirano, H; Lida, M; Kimura, N; Ohhata, H; Tanaka, K; Shintomi, T; Terashima, A; Tsuchiya, K; Yamamoto, A; Orikasa, T; Murai, S; Oosaki, O

2002-01-01

The development of the LHC low-beta insertion quadrupole magnets has been conducted at KEK since 1996. After the successful development of short model magnets, the first prototype magnet has been built by Toshiba and is tested at KEK. Although the quench performance and the field quality of the magnet are satisfactory, a design problem is found in one of the end spacers. The problem increases the risk of a turn-to-turn and in fact causes shorts in the second prototype magnet, and in the trial coil of the first production magnet. The design is modified and the problem appears to be resolved. The construction of the production magnets is now started and lasts till the summer of 2004. (9 refs).

The team responsible for testing and measuring the LHC insertion quadrupoles

CERN Multimedia

Patrice Loïez

2003-01-01

The LHC main magnet system includes about 600 superconducting quadrupoles for beam focusing. Superconducting Matching Quadrupole Magnets (MQMs) are just one of several varieties of quadrupole; they will be installed in the accelerator´s eight ´insertion zones´, four of which are also experimental areas, where the beams will intersect to produce proton-proton collisions. The first MQM, built by the UK firm Tesla Engineering, has passed its acceptance tests. The team responsible for the tests is pictured here with the 3.5-metre-long magnet. Photo 01: Bottom row, left to right, Michäel Ky, Antoine Dias Goncalves, Gilles Rittaud, Yannick Riva; middle row, left to right, Vladimir Bretin, Noël Dalexandro, Bert Lust, Patrick Viret; top row, left to right, Christian Giloux, Ranko Ostojic, Walter Venturini Delsolaro, Lassaâd Gharsallah.

Normal-Conducting Separation and Compensation Dipoles for the LHC Experimental Insertions

CERN Document Server

Ramberger, S; Cornuet, D; Gérard, D; Gurov, D; Hans, O; Kalbreier, Willi; Kiselev, O; Morozov, I; Ogurtsov, A; Petrov, V; de Rijk, G; Ruvinsky, E; Sukhanov, A; Zhilayev, K

2006-01-01

The experimental insertions of the LHC make use of normal-conducting magnets to provide for part of the beam separation and to compensate the effect of two large spectrometer dipoles. Three different types with respect to the length were designed and are based on the same type of lamination. The main type of magnet MBXW has a core length of 3.4 m while the MBXWT and MBXWS magnets are 1.5 m and 0.75 m long versions respectively. The magnet design was done in collaboration between CERN and BINP and the dipole magnets are produced by BINP. So far all three MBXWS magnets, all three MBXWT magnets and fifteen of twenty-nine MBXW magnets have been manufactured and delivered to CERN. The report presents the main design issues and results of the acceptance tests including mechanical, electrical and magnetic field measurements.

Report from LHC MDs 1391 and 1483: Tests of new methods for study of nonlinear errors in the LHC experimental insertions

CERN Document Server

Maclean, Ewen Hamish; Fuchsberger, Kajetan; Giovannozzi, Massimo; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

2017-01-01

Nonlinear errors in experimental insertions can pose a significant challenge to the operability of low-β∗ colliders. Previously such errors in the LHC have been studied via their feed-down to tune and coupling under the influence of the nominal crossing angle bumps. This method has proved useful in validating various components of the magnetic model. To understand and correct those errors where significant discrepancies exist with the magnetic model however, will require further development of this technique, in addition to the application of novel methods. In 2016 studies were performed to test new methods for the study of the IR-nonlinear errors.

Nonlinear Correction Schemes for the Phase 1 LHC Insertion Region Upgrade and Dynamic Aperture Studies

CERN Document Server

de Maria, R; Tomás, R

2009-01-01

The Phase 1 LHC Interaction Region (IR) upgrade aims at increasing the machine luminosity essentially by reducing the beam size at the Interaction Point (IP). This requires a total redesign of the full IR. A large set of options has been proposed with conceptually different designs. This paper reports on a general approach for the compensation of the multipolar errors of the IR magnets in the design phase. The goal is to use the same correction approach for the different designs. The correction algorithm is based on the minimization of the differences between the IR transfer map with errors and the design IR transfer map. Its performance is tested using the dynamic aperture as figure of merit. The relation between map coefficients and resonance terms is also given as a way to target particular resonances by selecting the right map coefficients. The dynamic aperture is studied versus magnet aperture using recently established relations between magnetic errors and magnet aperture.

Construction and Qualification of the Pre-Series MQM Superconducting Quadrupoles for the LHC Insertions

CERN Document Server

Ostojic, R; Lucas, J; Venturini-Delsolaro, W; Landgrebe, D

2004-01-01

The LHC insertions will be equipped with individually powered MQM superconducting quadrupoles, produced in three versions with magnetic lengths of 2.4 m, 3.4 m, and 4.8 m. The quadrupoles feature a 56 mm aperture coil, designed on the basis of an 8.8 mm wide Rutherford-type NbTi cable for a nominal gradient of 200 T/m at 1.9 K and 5390 A. A total of 96 quadrupoles are in production in Tesla Engineering, UK. In this report we describe the construction of the pre-series MQM quadrupoles and present the results of the qualification tests.

Conceptual Design of the LHC Interaction Region Upgrade Phase-I

CERN Document Server

Ostojic, R; Baglin, V; Ballarino, A; Cerutti, F; Denz, R; Fartoukh, S; Fessia, P; Foraz, K; Fürstner, M; Herr, Werner; Karppinen, M; Kos, N; Mainaud-Durand, H; Mereghetti, A; Muttoni, Y; Nisbet, D; Prin, H; Tock, J P; Van Weelderen, R; Wildner, E

2008-01-01

The LHC is starting operation with beam. The primary goal of CERN and the LHC community is to ensure that the collider is operated efficiently and that it achieves nominal performance in the shortest term. Since several years the community has been discussing the directions for maximizing the physics reach of the LHC by upgrading the experiments, in particular ATLAS and CMS, the LHC machine and the CERN proton injector complex, in a phased approach. The first phase of the LHC interaction region upgrade was approved by Council in December 2007. This phase relies on the mature Nb-Ti superconducting magnet technology with the target of increasing the LHC luminosity to 2 to 3 10^34 cm^-2s^-1, while maximising the use of the existing infrastructure. In this report, we present the goals and the proposed conceptual solutions for the LHC IR Upgrade Phase-I which include the recommendations of the conceptual design review.

Insertion and crossing region design

International Nuclear Information System (INIS)

Wienands, U.; Beloshitsky, P.

2001-01-01

This article is the summary of the 5-afternoon tutorial on insertions for circular machines. Roughly half the course (Part 1) was spent discussing interaction regions, We start by recapitulating basic beam optics including building blocks. This provides the tools to analyze the basic structure of interaction regions and explore the parameter space. This simple example is then successively refined and made more realistic. Examples of realized interaction regions for both hadron and electron machines are shown and their salient features and differences explained. A brief discussion of solenoid-decoupling brings Part 1 to a close. In Part 2 we discussed various utility sections. Dispersion suppressors are presented in detail discussing the principles as well as the practical implementation of flexible suppressors using LEP as an example. Injection schemes, both single-turn and multi-turn stacking, are presented in depth. The matching of wiggler and undulator insertions and a discussion of the impact of these devices on beam parameters closes out Part 2

Upgrade of the ATLAS Muon Barrel Trigger for HL-LHC

CERN Document Server

Romano, Marino; The ATLAS collaboration

2015-01-01

The present ATLAS muon trigger in the barrel region (|eta|<1.05) is based on three layers of RPC chambers. It was designed to run for 10 years at the LHC luminosity of 10^{34} cm^{-2}s^{-1} and operated successfully and with high selectivity during the first run of the LHC. In order to ensure a stable performance of the RPCs until 2035 at the higher rates and at luminosities of 5-7x10^{34} cm^{-2}s^{-1} provided by HL-LHC, the chambers will have to be operated with reduced gas gain to respect the original design limits on currents and integrated charge. The ATLAS muon collaboration proposes an upgrade of the system by installing an inner layer of new generation RPCs during the LHC shutdown expected for the year 2023. This new layer will increase the system redundancy and therefore allow operation with high efficiency and high selectivity during the HL-LHC phase. The insertion of this new layer will also increase the geometrical acceptance in the barrel region from 75% to 95%. Moreover, the additional measu...

Upgrade of the ATLAS Muon Barrel Trigger for HL-LHC.

CERN Document Server

Biondi, Silvia; The ATLAS collaboration

2015-01-01

The present ATLAS muon trigger in the barrel region (|η | < 1.05) is based on three layers of RPC chambers. It was designed to run for 10 years at the LHC luminosity of 1034cm−2s−1 and operated successfully and with high selectivity during the first run of the LHC. In order to ensure a stable performance of the RPCs until 2035 at the higher rates and at luminosities of 5−7x1034cm−2s−1 provided by HL-LHC, the chambers will have to be operated with reduced gas gain to respect the original design limits on currents and integrated charge. The ATLAS muon collaboration proposes an upgrade of the system by installing an inner layer of new generation RPCs during the LHC shutdown expected for the year 2023. This new layer will increase the system redundancy and therefore allow operation with high efficiency and high selectivity during the HL-LHC phase. The insertion of this new layer will also increase the geometrical acceptance in the barrel region from 75% to 95%. Moreover, the additional measurements ...

Report from LHC MD 2158: IR-nonlinear studies

CERN Document Server

Maclean, Ewen Hamish; Cruz Alaniz, Emilia; Dalena, Barbara; Dilly, Joschua Werner; Fol, Elena; Giovannozzi, Massimo; Hofer, Michael; Malina, Lukas; Persson, Tobias Hakan Bjorn; Coello De Portugal - Martinez Vazquez, Jaime Maria; Skowronski, Piotr Krzysztof; Solfaroli Camillocci, Matteo; Tomas Garcia, Rogelio; Garcia-Tabares Valdivieso, Ana; Wegscheider, Andreas; CERN. Geneva. ATS Department

2018-01-01

For the first time the LHC is running for luminosity-production with local corrections for nonlinear errors in the ATLAS and CMS insertions. While a major step forward in LHC optics commissioning strategy (and one which has yielded clear operational benefits) considerable challenges remain to be overcome, both in regard to the optimization of LHC optics and in order to ensure successful commissioning of the High-Luminosity LHC. MD 2158 sought to follow up several aspects of the 2017 nonlinear optics commissioning which are not yet understood, and by enhancing sextupole and dodecapole sources in the ATLAS and CMS insertions explore the prospects for linear and nonlinear optics commissioning in the HL-LHC.

Optics Challenges and Solutions for the LHC Insertion Upgrade Phase I

CERN Document Server

Fartoukh, S

2010-01-01

The goal of the LHC Insertion (IR) Upgrade Phase-I is to enable a reliable operation of the machine with a performance at least doubled with respect to its design luminosity. One key ingredient is ideally a reduction of Beta* down to 25 cm, using a new inner triplet (IT) with longer Nb-Ti quadrupoles operating at a lower gradient (~ 120 T/m) and therefore offering a larger aperture (120 mm). Reducing Beta*, but also operating at a lower IT gradient (which, at a given Beta*, further increases the size of the Beta-functions all over the long straight section), has however a certain number of drawbacks which cannot be solved by only increasing the aperture of the new low-beta quadrupoles. Without modifying the current layout of the matching section (MS) and assuming that the arc sextupoles cannot safely operate above nominal current (550A), optics solutions with a Beta* of 30 cm are already at the edge of feasibility, both in terms of mechanical aperture in the MS and new IT (assuming 120 mm aperture), in terms ...

LHC interaction region quadrupole cryostat design

International Nuclear Information System (INIS)

Nicol, T.H.; Darve, Ch.; Huang, Y.; Page, T.M.

2002-01-01

The cryostat of a Large Hadron Collider (LHC) Interaction Region (IR) quadrupole magnet consists of all components of the inner triplet except the magnet assembly itself. It serves to support the magnet accurately and reliably within the vacuum vessel, to house all required cryogenic piping, and to insulate the cold mass from heat radiated and conducted from the environment. It must function reliably during storage, shipping and handling, normal magnet operation, quenches, and seismic excitations, and must be able to be manufactured at low cost. The major components of the cryostat are the vacuum vessel, thermal shield, multi-layer insulation system, cryogenic piping, and suspension system. The overall design of a cryostat for superconducting accelerator magnets requires consideration of fluid flow, proper selection of materials for their thermal and structural performance at both ambient and operating temperature, and knowledge of the environment to which the magnets will be subjected over the course of their expected operating lifetime. This paper describes the current LHC IR inner triplet quadrupole magnet cryostats being designed and manufactured at Fermilab as part of the US-LHC collaboration, and includes discussions on the structural and thermal considerations involved in the development of each of the major systems

Proposal for the award of two contracts for the supply of fine-blanked low-carbon steel yoke laminations and inserts for the cold masses of the LHC superconducting dipole magnets

CERN Document Server

1999-01-01

This document concerns the award of two contracts for the supply of 5 812 000 fine-blanked low-carbon steel yoke laminations, of two different types, and 5 800 000 inserts for the cold masses of the LHC superconducting dipole magnets. Following a market survey carried out among 70 firms in sixteen Member States and one firm in Japan, a call for tenders (IT-2467/LHC/LHC) was sent on 3 June 1999 to seven firms in four Member States. By the closing date, CERN had received five tenders. The Finance Committee is invited to agree to the negotiation of two contracts with: - FUG (DE) for the supply of 3 632 000 fine-blanked low-carbon steel yoke laminations and 3 625 000 inserts, which represents 5/8 of the total quantity required for the cold masses of the LHC superconducting dipole magnets, for a total amount of 2 525 563 euros, which at the exchange rate given in the tender correspond to 4 019 038 Swiss francs, subject to revision for contractual deliveries after 31 December 2001, with an option for the supply of ...

Accelerator physics studies on the effects from an asynchronous beam dump onto the LHC experimental region collimators

CERN Document Server

Lari, L; Boccone, V; Bruce, R; Cerutti, F; Rossi, A; Vlachoudis, V; Mereghetti, A; Faus-Golfe, A

2012-01-01

Asynchronous beam aborts at the LHC are estimated to occur on average once per year. Accelerator physics studies of asynchronous dumps have been performed at different beam energies and beta-stars. The loss patterns are analyzed in order to identify the losses in particular on the Phase 1 Tertiary Collimators (TCT), since their tungsten-based active jaw insert has a lower damage threshold than the carbon-based other LHC collimators. Settings of the tilt angle of the TCTs are discussed with the aim of reducing the thermal loads on the TCT themselves.

Preliminary proposal of a Nb3Sn quadrupole model for the low β insertions of the LHC

International Nuclear Information System (INIS)

Ambrosio, G.; Ametrano, F.; Bellomo, G.; Broggi, F.; Rossi, L.; Volpini, G.

1995-09-01

In recent years Nb 3 Sn based conductors have shown wide applicability for superconducting magnets in many research areas like high field solenoids for laboratory experiment, for NMR spectroscopy and high field magnets for fusion. Nb 3 Sn technology is progressing fast, increasing both technical reliability and availability. The Nb 3 Sn technology, which has a higher critical field than NbTi, seems attractive for IR (Insertion Region) quadrupoles of large colliders . In this paper it is proposed the construction of a superconducting quadrupole wound with Nb 3 Sn cable for a second generation IR inner triplet low β quadrupoles, for the Large Hadron Collider at CERN. The low β quadrupoles, control the beam focusing at collision points, therefore a gain in term of focus strength and/or coil aperture can increase significantly machine performance. Two are the main steps for the whole project: 1) design and construction of a 1 metre long quadrupole to demonstrate the actual feasibility, which is the subject of this proposal; 2) study for integration of the quadrupole in the machine and final design of 5 m long quadrupoles finalized to the LHC

Machine Protection Challenges for HL-LHC

CERN Document Server

Schmidt, R; Wenninger, J; Wollmann, D; Zerlauth, M

2014-01-01

LHC operation requires the flawless functioning of the machine protection systems. The energy stored in the beam was progressively increased beyond the 140 MJ range at the end of 2012 at 4 TeV/c. The further increase to more than 300 MJ expected for 2015 at 6.5 TeV/c should be possible with the existing protection systems. For HL-LHC additional failure modes need to be considered. The stored beam energy will increase by another factor of two with respect to nominal and a factor of five more than experienced so far. The maximum beta function in the high luminosity insertion regions will increase. It is planned to install crab cavities in the LHC to compensate for the loss in luminosity due to the crossing-angle. With crab cavities, sudden voltage decays within 100 µs after e.g. cavity quenches can lead to large transverse beam oscillations. Tracking simulations predict trajectory distortions of up to 1.5 σ after a sudden drop of the deflecting voltage in a single cavity. Protons in the halo with an energy of...

Preliminary proposal of a Nb{sub 3}Sn quadrupole model for the low {beta} insertions of the LHC

Energy Technology Data Exchange (ETDEWEB)

Ambrosio, G; Ametrano, F; Bellomo, G; Broggi, F; Rossi, L; Volpini, G [Milan Univ. (Italy). Dip. di Fisica; [INFN, Sezione di Milano (Italy). Laboratorio Acceleratori e Superconduttivita` Applicata

1995-09-01

In recent years Nb{sub 3}Sn based conductors have shown wide applicability for superconducting magnets in many research areas like high field solenoids for laboratory experiment, for NMR spectroscopy and high field magnets for fusion. Nb{sub 3}Sn technology is progressing fast, increasing both technical reliability and availability. The Nb{sub 3}Sn technology, which has a higher critical field than NbTi, seems attractive for IR (Insertion Region) quadrupoles of large colliders . In this paper it is proposed the construction of a superconducting quadrupole wound with Nb{sub 3}Sn cable for a second generation IR inner triplet low {beta} quadrupoles, for the Large Hadron Collider at CERN. The low {beta} quadrupoles, control the beam focusing at collision points, therefore a gain in term of focus strength and/or coil aperture can increase significantly machine performance. Two are the main steps for the whole project: (1) design and construction of a 1 metre long quadrupole to demonstrate the actual feasibility, which is the subject of this proposal; (2) study for integration of the quadrupole in the machine and final design of 5 m long quadrupoles finalized to the LHC.

FLUKA Monte Carlo simulations and benchmark measurements for the LHC beam loss monitors

International Nuclear Information System (INIS)

Sarchiapone, L.; Brugger, M.; Dehning, B.; Kramer, D.; Stockner, M.; Vlachoudis, V.

2007-01-01

One of the crucial elements in terms of machine protection for CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. On-line loss measurements must prevent the superconducting magnets from quenching and protect the machine components from damages due to unforeseen critical beam losses. In order to ensure the BLM's design quality, in the final design phase of the LHC detailed FLUKA Monte Carlo simulations were performed for the betatron collimation insertion. In addition, benchmark measurements were carried out with LHC type BLMs installed at the CERN-EU high-energy Reference Field facility (CERF). This paper presents results of FLUKA calculations performed for BLMs installed in the collimation region, compares the results of the CERF measurement with FLUKA simulations and evaluates related uncertainties. This, together with the fact that the CERF source spectra at the respective BLM locations are comparable with those at the LHC, allows assessing the sensitivity of the performed LHC design studies

FLUKA Monte Carlo simulations and benchmark measurements for the LHC beam loss monitors

Science.gov (United States)

Sarchiapone, L.; Brugger, M.; Dehning, B.; Kramer, D.; Stockner, M.; Vlachoudis, V.

2007-10-01

One of the crucial elements in terms of machine protection for CERN's Large Hadron Collider (LHC) is its beam loss monitoring (BLM) system. On-line loss measurements must prevent the superconducting magnets from quenching and protect the machine components from damages due to unforeseen critical beam losses. In order to ensure the BLM's design quality, in the final design phase of the LHC detailed FLUKA Monte Carlo simulations were performed for the betatron collimation insertion. In addition, benchmark measurements were carried out with LHC type BLMs installed at the CERN-EU high-energy Reference Field facility (CERF). This paper presents results of FLUKA calculations performed for BLMs installed in the collimation region, compares the results of the CERF measurement with FLUKA simulations and evaluates related uncertainties. This, together with the fact that the CERF source spectra at the respective BLM locations are comparable with those at the LHC, allows assessing the sensitivity of the performed LHC design studies.

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.

Performance of the Totem Detectors at the LHC

CERN Document Server

INSPIRE-00062364; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Bagliesi, M.G.; Berardi, V.; Berretti, M.; Bossini, E.; Bottigli, U.; Bozzo, M.; Brücken, E.; Buzzo, A.; Cafagna, F.S.; Catanesi, M.G.; Cecchi, R.; Covault, C.; Csanád, M.; Csörgő, T.; Deile, M.; Doubek, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Karev, A.; Kašpar, J.; Kopal, J.; Kundrát, V.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lippmaa, J.; Lokajíček, M.; Losurdo, L.; Lo Vetere, M.; Lucas Rodríguez, F.; Macrí, M.; Mäki, T.; Mercadante, A.; Minafra, N.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Österberg, K.; Palazzi, P.; Pedreschi, E.; Procházka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Scribano, A.; Smajek, J.; Snoeys, W.; Spinella, F.; Sziklai, J.; Taylor, C.; Thys, A.; Turini, N.; Vacek, V.; Vítek, M.; Welti, J.; Whitmore, J.; Wyszkowski, P.

2013-01-01

The TOTEM Experiment is designed to measure the total proton-proton cross-section with the luminosity-independent method and to study elastic and diffractive pp scattering at the LHC. To achieve optimum forward coverage for charged particles emitted by the pp collisions in the interaction point IP5, two tracking telescopes, T1 and T2, are installed on each side of the IP in the pseudorapidity region 3.1 $\\le |\\eta| \\le $6.5, and special movable beam-pipe insertions – called Roman Pots (RP) – are placed at distances of ±147m and ±220m from IP5. This article describes in detail the working of the TOTEM detector to produce physics results in the first three years of operation and data taking at the LHC.

Performance Studies for Protection Against Asynchronous Dumps in the LHC

CERN Document Server

Kramer, T; Bracco, C; Goddard, B; Meddahi, M

2010-01-01

The LHC beam dump system has to safely dispose all beams in a wide energy range of 450 GeV to 7 TeV. A 3 ms abort gap in the beam structure for the switch-on of the extraction kicker field ideally allows a loss-free extraction under normal operating conditions. However, a low number of asynchronous beam aborts is to be expected from reliability calculations and from the first year's operational experience with the beam dump kickers. For such cases, MAD-X simulations including all optics and alignment errors have been performed to determine loss patterns around the LHC as a function of the position of the main protection elements in interaction region six. Special attention was paid to the beam load on the tungsten collimators which protect the triplets in the LHC experimental insertions, and the tracking results compared with semi-analytical numerical estimates. The simulations are also compared to the results of beam commissioning of these protection devices.

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)

Investigations on a Q0 Doublet Optics for the LHC Luminosity Upgrade

CERN Document Server

Laface, E; Scandale, Walter; Wildner, E

2008-01-01

The Q0 scheme of the LHC insertion region is based on the introduction of a doublet of quadrupoles at 13 m from the IP. We present here the doublet optics and the magnets layout such as gradients, lengths, positions and apertures. In this scheme we show the gain in luminosity and chromaticity, with respect to a nominal layout with $\\beta^{*}$ = 0.25 m (i.e. LHC phase 1 upgrade) and $\\beta^{*} = 0.15 m, due to a smaller beta-max. We show the alignment tolerance and the energy deposition issues, in Q0A-Q0B. We also consider shielding the magnets with liners. The capability of Q0 optics to limit the b function could be exploited after the LHC Phase 1 upgrade in order to reduce the $\\beta^{*}$ below 0.25 m, leaving the upgraded triplet unchanged

The LHC Transverse Damper (ADT) Performance Specification

CERN Document Server

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

1997-01-01

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

US Department of Energy Secretary Bill Richardson (centre) at an LHC interaction region quadrupole test cryostat. part of the US contribution to LHC construction and built by the US-LHC collaboration (hence the Fermilab logo)

CERN Multimedia

Barbara Warmbein

2000-01-01

Photo 01 : September 2000 - Mr Bill Richardson, Secretary of Energy, United States of America (centre) at an LHC interaction region quadrupole test cryostat, part of the US contribution to LHC construction and built by the US-LHC collaboration (hence the Fermilab logo); with l. to r. Dr Mildred Dresselhaus, Dr Carlo Wyss, CERN Director General, Profesor Luciano Maiani, Professor Roger Cashmore, Ambassador George Moose, Dr Peter Rosen, Dr John Ellis. Photo 02 : Mr. Bill Richardson (right), Secretary of Energy United States of America with Prof. Luciano Maiani leaning over one of the LHC magnets produced at Fermilab during his visit to CERN on 16th September 2000.

PROCEEDINGS OF THE WORKSHOP ON LHC INTERACTION REGION CORRECTION SYSTEMS

International Nuclear Information System (INIS)

FISCHER, W.; WEI, J.

1999-01-01

The Workshop on LHC Interaction Region Correction Systems was held at Brookhaven National Laboratory, Upton, New York, on 6 and 7 May 1999. It was attended by 25 participants from 5 institutions. The performance of the Large Hadron Collider (LHC) at collision energy is limited by the field quality of the interaction region quadrupoles and dipoles. In three sessions the workshop addressed the field quality of the these magnets, reviewed the principles and efficiency of global and local correction schemes and finalized a corrector layout. The session on Field Quality Issues, chaired by J. Strait (FNAL), discussed the progress made by KEK and FNAL in achieving the best possible field quality in the interaction region quadrupoles. Results of simulation studies were presented that assess the effects of magnetic field errors with simulation studies. Attention was given to the uncertainties in predicting and measuring field errors. The session on Global Correction, chaired by J.-P. Koutchouk (CERN), considered methods of reducing the nonlinear detuning or resonance driving terms in the accelerator one-turn map by either sorting or correcting. The session also discussed the crossing angle dependence of the dynamic aperture and operational experience from LEP. The session on Local Correction, chaired by T. Taylor (CERN), discussed the location, strength and effectiveness of multipole correctors in the interaction regions for both proton and heavy ion operation. Discussions were based on technical feasibility considerations and dynamic aperture requirements. The work on linear corrections in the interaction regions was reviewed

Regional insertion: an emergent approach

International Nuclear Information System (INIS)

Serra, M.T.F.; Nascimento Teixeira, P. do

1989-01-01

The Brazilian Electrical Sector incorporates new variables that expressing the extensive spectrum of environmental impacts in the take of decisions, referring to the viability of realizing a electrical undertaking, attends the several restrictions that are important by the sector and by the society in the environment area and promotes the adequate generation of liquid benefits, consequential of the electrical undertaking. Due to these factors, the Electrical Sector is improving the concept of regional insertion, with the sectorial expansion in long-dated and the created demand in the environmental and social area, focalizing the solution for these questions. (C.G.C.). 1 fig, 2 tabs

Design Challenges for a Wide-Aperture Insertion Quadrupole Magnet

CERN Document Server

Russenschuck, S; Perez, J C; Ramos, D; Fessia, P; Karppinen, M; Kirby, G; Sahner, T; Schwerg, N

2011-01-01

The design and development of a superconducting (Nb-Ti) quadrupole with 120 mm aperture, for an upgrade of the LHC insertion region, faces challenges arising from the LHC beam optics requirements and the heat-deposition. The first triggered extensive studies of coil alternatives with four and six coil-blocks in view of field quality and operation margins. The latter requires more porous insulation schemes for both the cables and the ground-plane. This in turn necessitates extensive heatpropagation and quench-velocity studies, as well as more efficient quench heaters. The engineering design of the magnet includes innovative features such as self-locking collars, which will enable the collaring to be performed with the coils on a horizontal assembly bench, a spring-loaded and collapsible assembly mandrel, tuning-shims for field quality, porous collaring-shoes, and coil end-spacer design based on differential geometry methods. The project also initiated code extensions in the quench-simulation and CAD/CAM module...

Increased native T1-values at the interventricular insertion regions in precapillary pulmonary hypertension.

Science.gov (United States)

Spruijt, Onno A; Vissers, Loek; Bogaard, Harm-Jan; Hofman, Mark B M; Vonk-Noordegraaf, Anton; Marcus, J Tim

2016-03-01

Cardiac magnetic resonance imaging of the pressure overloaded right ventricle (RV) of precapillary pulmonary hypertension (PH) patients, exhibits late gadolinium enhancement at the interventricular insertion regions, a phenomenon which has been linked to focal fibrosis. Native T1-mapping is an alternative technique to characterize myocardium and has the advantage of not requiring the use of contrast agents. The aim of this study was to characterize the myocardium of idiopathic pulmonary arterial hypertension (IPAH), systemic scleroderma related PH (PAH-Ssc) and chronic thromboembolic PH (CTEPH) patients using native T1-mapping and to see whether native T1-values were related to disease severity. Furthermore, we compared native T1-values between the different precapillary PH categories. Native T1-mapping was performed in 46 IPAH, 14 PAH-SSc and 10 CTEPH patients and 10 control subjects. Native T1-values were assessed using regions of interest at the RV and LV free wall, interventricular septum and interventricular insertion regions. In PH patients, native T1-values of the interventricular insertion regions were significantly higher than the native T1-values of the RV free wall, LV free wall and interventricular septum. Native T1-values at the insertion regions were significantly related to disease severity. Native T1-values were not different between IPAH, PAH-Ssc and CTEPH patients. Native T1-values of the interventricular insertion regions are significantly increased in precapillary PH and are related to disease severity. Native T1-mapping can be developed as an alternative technique for the characterization of the interventricular insertion regions and has the advantage of not requiring the use of contrast agents.

Power Load from Collision Debris on the LHC Point 8 Insertion Magnets implied by the LHCB Luminosity Increase

CERN Document Server

Esposito, L S; Lechner, A; Mereghetti, A; Vlachoudis, V; Patapenka, A

2013-01-01

LHCb is aiming to upgrade its goal peak luminosity up to a value of 2 × 1033 cm−2 s−1 after LS2. We investigate the collision debris impact on the machine elements by extensive FLUKA simulations, showing that the present machine layout is substantially compatible with such a luminosity goal. In particular the installation of a TAS (Target Absorber of Secondaries, installed in front of the final focus Q1-Q3 quadrupole triplet in the LHC high luminosity insertions) turns out not to be necessary on the basis of the expected peak power deposition in the Q1 superconducting coils. A warm protection may be desirable to further reduce heat load and dose on the D2 recombination dipole, due to the absence of the TAN (Target Absorber of Neutrals, present in Point 1 and 5).

Instrumentation status of the low-b magnet systems at the Large Hadron Collider (LHC)

CERN Document Server

Darve, C.; Casas-Cubillos, J.; Perin, A.; Vauthier, N.

2011-01-01

The low-beta magnet systems are located in the Large Hadron Collider (LHC) insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process allowing proton collisions at luminosity up to 10**34/cm**2s. Those systems are a contribution of the US-LHC Accelerator project. The systems are mainly composed of the quadrupole magnets (triplets), the separation dipoles and their respective electrical feed-boxes (DFBX). The low-beta magnet systems operate in an environment of extreme radiation, high gradient magnetic field and high heat load to the cryogenic system due to the beam dynamic effect. Due to the severe environment, the robustness of the diagnostics is primordial for the operation of the triplets. The hardware commissioning phase of the LHC was completed in February 2010. In the sake of a safer and more user-friendly operation, several consolidations and instrumentation modifications were implemented during this commissioning phase. This paper presents ...

Instrumentation Status of the Low-β Magnet Systems at the Large Hadron Collider (LHC)

CERN Document Server

Darve, C; Casas-Cubillos, J; Perin, A; Vauthier, N

2011-01-01

The low-β magnet systems are located in the Large Hadron Collider (LHC) insertion regions around the four interaction points. They are the key elements in the beams focusing/defocusing process allowing proton collisions at luminosity up to 1034cm-2s-1. Those systems are a contribution of the US-LHC Accelerator project. The systems are mainly composed of the quadrupole magnets (triplets), the separation dipoles and their respective electrical feed-boxes (DFBX). The low-β magnet systems operate in an environment of extreme radiation, high gradient magnetic field and high heat load to the cryogenic system due to the beam dynamic effect. Due to the severe environment, the robustness of the diagnostics is primordial for the operation of the triplets. The hardware commissioning phase of the LHC was completed in February 2010. In the sake of a safer and more user-friendly operation, several consolidations and instrumentation modifications were implemented during this commissioning phase. This paper presents the in...

Quench Propagation in the Superconducting 6 kA Flexible Busbars of the LHC

OpenAIRE

Calvi, M; Herzog, R; Pelegrin-Carcelen, J M; Sonnemann, F

2001-01-01

Flexible superconducting cables with currents up to 6 kA will be used to power magnets individually in the insertion regions of the LHC. In case of a quench, the currents in these circuits will decay very fast (with time constants of about 200 ms) such that relatively small copper cross sections are sufficient for these busbars. Quench propagation experiments on a prototype cable and corresponding simulations led to a detailed understanding of the quench behavior of these busbars and to recom...

Proposal to negotiate an amendment to an existing contract for the supply of MQY-type superconducting quadrupole magnets for the LHC insertions

CERN Document Server

2005-01-01

This document concerns the proposal to negotiate an amendment to an existing contract for the supply of MQY-type superconducting quadrupole magnets for the LHC insertions. For the reasons explained in this document, the Finance Committee is invited to approve an amendment to an existing contract with the firm ACCEL (DE) for the supply of four additional MQY-type superconducting quadrupole magnets for an amount of 569 000 euros (881 950 Swiss francs), subject to revision for inflation, bringing the total to a maximum amount of up to 3 198 656 euros (4 957 917 Swiss francs), subject to revision for inflation. The amounts in Swiss francs have been calculated using the present rate of exchange.

LHC gets the ball rolling

CERN Multimedia

2007-01-01

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

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...

An Improved Cllimation System for the LHC

CERN Document Server

Assmann, R W; Bertarelli, A; Braun, H; Brugger, M; Brüning, Oliver Sim; Bruno, L; Calatroni, S; Chiaveri, Enrico; Dehning, Bernd; Ferrari, A; Goddard, B; Holzer, E B; Jeanneret, J B; Jiménez, M; Kain, V; Lamont, M; Mayer, M; Métral, Elias; Perret, R; Redaelli, S; Risselada, Thys; Robert-Démolaize, G; Sösler, S; Ruggiero, F; Schmidt, R; Schulte, Daniel; Sievers, P; Vlachoudis, V; Vos, L; Vossenberg, Eugène B; Wenninger, J; Ajguirei, I L; Baishev, I S; Kurochkin, I; Tsutsui, H; Kaltchev, D I

2004-01-01

The handling of the high-intensity LHC beams in a super-conducting environment requires a high-robustness collimation system with unprecedented cleaning efficiency. For gap closures down to 2.2 mm no beam instabilities must be induced from the collimator impedance. A difficult trade-off between collimator robustness, cleaning efficiency and collimator impedance is encountered. The conflicting LHC requirements are resolved with a phased approach, relying on low Z collimators for maximum robustness and hybrid metallic collimators for maximum performance. Efficiency is further enhanced with an additional cleaning close to the insertion triplets. The machine layouts have been adapted to the new requirements. The LHC collimation hardware is presently under design and has entered into the prototyping and early testing phase. Plans for collimator tests with beam are presented.

Design and construction of a one-metre model of the 70 mm aperture quadrupole for the LHC low-β insertions

International Nuclear Information System (INIS)

Ostojic, R.; Taylor, T.M.; Kirby, G.A.

1994-01-01

In order to achieve high field quality and low current rating of the 250 T/m quadrupoles for the LHC low-β insertions, a design based on a graded four-layer coil with an aperture of 70 mm, wound from NbTi conductor cooled at 1.8 K, has been proposed. Its mechanical structure is based on the collar-spacer concept, where a thin collar serves for coil assembly only. The iron yoke has both important magnetic and structural functions, since the magnetic forces are taken by the rigidity of the iron lamination pack. The coil and cable parameters are derived for this particular structure, and the results of the structural analysis of the magnet are presented. A one-meter model of the quadrupole is presently under construction; its features are described and some initial cable tests reported

Elastic cross-section and luminosity measurement in Atlas at LHC

Energy Technology Data Exchange (ETDEWEB)

Efthymiopoulos, I. [Conseil Europeen pour la recherche nucleaire, AB Dept., Geneve (Switzerland)

2005-07-01

Recently the Atlas experiment was complemented with a set of ultra-small-angle detectors located in 'Roman Pot' inserts at 240 m on either side of the interaction point, aiming at the absolute determination of the LHC luminosity by measuring the elastic scattering rate at the Coulomb Nuclear Interference region. Details of the proposed measurement the detector construction and the expected performance as well as the challenges involved are discussed here. Our aim is to determine the luminosity within a 2% error and give a competitive measurement on other parameters like the {rho}-parameter, the total cross-section and the nuclear slope.

Regional insertion: an emergent approach; Insercao regional: uma abordagem emergente

Energy Technology Data Exchange (ETDEWEB)

Serra, M T.F.; Nascimento Teixeira, P do [ELETROBRAS, Rio de Janeiro, RJ (Brazil). Dept. de Meio Ambiente

1990-12-31

The Brazilian Electrical Sector incorporates new variables that expressing the extensive spectrum of environmental impacts in the take of decisions, referring to the viability of realizing a electrical undertaking, attends the several restrictions that are important by the sector and by the society in the environment area and promotes the adequate generation of liquid benefits, consequential of the electrical undertaking. Due to these factors, the Electrical Sector is improving the concept of regional insertion, with the sectorial expansion in long-dated and the created demand in the environmental and social area, focalizing the solution for these questions. (C.G.C.). 1 fig, 2 tabs.

LHC progress report

CERN Multimedia

CERN Bulletin

2010-01-01

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

Copper Heat Exchanger for the External Auxiliary Bus-Bars Routing Line in the LHC Insertion Regions

CERN Document Server

Garion, C; Seyvet, F; Sitko, M; Skoczen, B; Tock, J P

2006-01-01

The corrector magnets and the main quadrupoles of the LHC dispersion suppressors are powered by a special superconducting line (called auxiliary bus-bars line N), external to the cold mass and housed in a 50 mm diameter stainless steel tube fixed to the cold mass. As the line is periodically connected to the cold mass, the same gaseous and liquid helium cools both the magnets and the line. The final sub-cooling process (from around 4.5 K down to 1.9 K) consists in the phase transformation from liquid to superfluid helium. Heat is extracted from the line through the magnets via their point of junction. In dispersion suppressor zones, approximately 40 m long, the sub-cooling of the line is slightly delayed with respect to the magnets. This might have an impact on the readiness of the accelerator for operation. In order to accelerate the process, a special heat exchanger has been designed. It is located in the middle of the dispersion suppressor portion of the line. Its main function consists in providing a loca...

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 ...

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...

LHC Inner Triplet Powering Strategy

CERN Document Server

Bordry, Frederick

2001-01-01

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

LHCb: Numerical Analysis of Machine Background in the LHCb Experiment for the Early and Nominal Operation of LHC

CERN Multimedia

Lieng, M H; Corti, G; Talanov, V

2010-01-01

We consider the formation of machine background induced by proton losses in the long straight section of the LHCb experiment at LHC. Both sources showering from the tertiary collimators located in the LHCb insertion region as well as local beam-gas interaction are taken into account. We present the procedure for, and results of, numerical studies of such background for various conditions. Additionally expected impact and on the experiment and signal characteristics are discussed.

Study on off-momentum tail scraping in the LHC

CERN Document Server

Mirarchi, D; Bruce, R; CERN. Geneva. ATS Department

2014-01-01

A study on o-momentum tail population in the LHC was performed through collimator scraping at high dispersion region. High intensity measurements at the end of a physics ll with 25ns bunch spacing were carried out on 16th December 2012, using primary collimators (TCPs) in the momentum cleaning insertion (IR3) as scrapers. The o-momentum cuts were applied up to the level where the IR3 primary collimator is the aperture bottleneck for all particles outside the bucket, and the TCPs in the betatron cleaning insertion (IR7) are still the primary restriction of aperture of the machine in the transverse plane for particles inside the bucket. This because whether a particle is lost in IR3 or IR7 is not given only by the momentum oset but also by the betatron amplitude, as explained in the text. A signicant decay of the abort gap (AG) population was observed, while moving in the collimator jaw on the side where particles with negative o-momentum are expected. The level of the AG popupation achieved was at a similar le...

Elastic scattering of protons at the TOTEM experiment at the LHC

CERN Document Server

AUTHOR|(CDS)2080719; Csanád, Máté; Niewiadomski, Hubert

The TOTEM experiment at the LHC at CERN is optimized to measure elastic and diffractive scattering at the LHC and measures the total proton-proton cross-section with\tthe luminosity-independent method. The TOTEM experiment uses the special technique of movable beam pipe insertions -- called Roman Pots -- to detect very forward protons. The reconstruction of the forward proton kinematics requires the precise understanding of the LHC beam optics. A new method of LHC optics determination is reported, which exploits kinematical distributions of elastically scattered proton-proton data measured by the Roman Pots of the TOTEM experiment. The method has been successfully applied to data samples recorded since 2010. The interpretation of the proton-proton elastic differential cross-section is a challenging task. The geometrical model of proton-proton elastic scattering of Bialas and Bzdak is fitted to ISR data and to data measured by the TOTEM experiment at LHC energy of $\\sqrt{s}=7$~TeV. The Bialas-Bzdak model is g...

Inclusive production at LHC energies

International Nuclear Information System (INIS)

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

2011-01-01

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

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...

Results of 3-dimensional structural FE-modeling of the coil end-regions of the LHC main dipoles

CERN Document Server

Hoeck, U; Schillo, M; Perini, D; Siegel, N

2000-01-01

The transition region between the straight part and the ends of the coils of the LHC model and prototype dipole magnets are often identified as the origin of training quenches. In order to study how the discontinuities in the material properties of these regions affect coil pre-stress and possibly gain more insight in the quench behavior, a program was set up at CERN to analyze by 3D-FEM these particular regions. The ACCEL team, who performed a similar analysis for the main quadrupoles of the Superconducting Supercollider SSC, is entrusted with this program. In this paper we report on the results of 3D-modeling and analysis of the coil return end region, including the complete coil mass, of a 1-m single bore model magnet. This magnet represents all relevant features of the "two-in-one" LHC main dipole design concerning the winding configuration, the collar pack, the yoke, and the outer shell representing the He-vessel. The transition region between coil ends and straight section is modeled by slicing the magn...

OVERVIEW OF THE RHIC INSERTION REGION, SEXTUPOLE, AND SNAKE POWER SUPPLY SYSTEMS

International Nuclear Information System (INIS)

BRUNO, D.; ENG, W.; GANETIS, G.; LAMBIASE, R.F.; SANDBERG, J.

2001-01-01

The Relativistic Heavy Ion Collider (RHIC) was commissioned in 1999 and 2000. RHIC requires power supplies to supply currents to highly inductive superconducting magnets. The RHIC Insertion Region (IR) contains many shunt power supplies to trim the current of different magnet elements in a large superconducting magnet circuit. There are a total of 237 Insertion Region power supplies in both RHIC rings. RHIC also requires sextupole power supplies. One sextupole power supply is connected across 12 sextupole magnets. There are a total of 24 sextupole power supplies in both rings. Snake magnets are also a part of the RHIC ring, and these snake magnets also require power supplies. There shall be a total of 24 snake power supplies in both rings. Power supply technology, connections, control systems and interfacing with the Quench Protection System will be presented

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 ...

Development of a high gradient quadrupole for the LHC Interaction Regions

International Nuclear Information System (INIS)

Bossert, R.; Feher, S.; Gourlay, S.A.

1997-04-01

A collaboration of Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory is engaged in the design of a high gradient quadrupole suitable for use in the LHC interaction regions. The cold iron design incorporates a two-layer, cos(2θ) coil geometry with a 70 mm aperture operating in superfluid helium. This paper summarizes the progress on a magnetic, mechanical and thermal design that meets the requirements of maximum gradient above 250 T/m, high field quality and provision for adequate cooling in a high radiation environment

Design of a High Gradient Quadrupole for the LHC Interaction Regions

International Nuclear Information System (INIS)

Bossert, R.; Gourlay, S.A.; Heger, T.; Huang, Y.; Kerby, J.; Lamm, M.J.; Limon, P.J.; Mazur, P.O.; Nobrega, F.; Ozelis, J.P.; Sabbi, G.; Strait, J.; Zlobin, A.V.; Caspi, S.; Dell'orco, D.; McInturff, A.D.; Scanlan, R.M.; Van Oort, J.M.; Gupta, R.C.

1997-03-01

A collaboration of Fermilab, Lawrence Berkeley National Laboratory and Brookhaven National Laboratory is currently engaged in the design of a high gradient quadrupole suitable for use in the LHC interaction regions. The cold iron design incorporates a two-shell, cos2θ coil geometry with a 70 mm aperture. This paper summarizes the progress on a magnetic and mechanical design that meets the requirements of maximum gradient ≥250 T/m, operation at 1.8K, high field quality and provision for adequate cooling in a high radiation environment

Double diffractive cross-section measurement in the forward region at LHC

CERN Document Server

Antchev, G.; Atanassov, I.; Baechler, J.; Avati, V.; Berardi, V.; Bossini, E.; Berretti, M.; Bottigli, U.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.S.; Catanesi, M.G.; Csanad, M.; Csorgo, T.; Deile, M.; Eggert, K.; Eremin, V.; Ferro, F.; Fiergolski, A.; Garcia, F.; Giani, S.; Greco, V.; Grzanka, L.; Heino, J.; Hilden, T.; Karev, A.; Kaspar, J.; Kopal, J.; Kundrat, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Leszko, T.; Lippmaa, E.; Lippmaa, J.; Lokajicek, M.; Losurdo, L.; Lo Vetere, M.; Lucas Rodriguez, F.; Macri, M.; Maki, T.; Mercadante, A.; Minafra, N.; Minutoli, S.; Nemes, F.; Niewiadomski, H.; Oliveri, E.; Orava, R.; Oljemark, F.; Oriunno, M.; Osterberg, K.; Palazzi, P.; Prochazka, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Saarikko, H.; Scribano, A.; Smajek, J.; Snoeys, W.; Sziklai, J.; Taylor, C.; Turini, N.; Vacek, V.; Vitek, M.; Welti, J.; Whitmore, J.; Wyszkowski, P.

2013-12-26

The first double diffractive cross-section measurement in the very forward region has been carriedout by the TOTEM experiment at the LHC with center-of-mass energy of √s = 7 TeV. By utilizingthe very forward TOTEM tracking detectors T1 and T2, which extend up to pseudo rapidity |$\\eta$|=6.5, a clean sample of double diffractive pp events was extracted. From these events, we measured the cross-section $\\sigma_{DD}$ = (116±25) mb for events where both diffractive systems have 4.7 < |$\\eta$|$_{min}$ < 6.5.

BPM Tolerances for HL-LHC Orbit Correction in the Inner Triplet Area

CERN Document Server

AUTHOR|(CDS)2075212

2015-01-01

For the HL-LHC beam spot sizes as small as 7 mum are considered for the high luminosity insertions IR1 and IR5. In addition, the luminosity has to be levelled over several hours by changing beta* resulting in constant changes of the optics and thus orbit changes. The small beam size and the continuous optics changes in general make the alignment of the beams at the IP challenging. In order to avoid continuous luminosity scans for the alignment of the beams at the IP, the orbit correction has to rely on the readings of the BPMs in the IT region. In this paper we review the requirements on resolution and accuracy of the BPMs and compare different options for the placement of the BPMs in the IT region

The TOTEM project at LHC

International Nuclear Information System (INIS)

Buenerd, M.

1996-01-01

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

Beam-induced heat loads on the beam screens of the inner triplets for the HL-LHC

CERN Document Server

Skripka, Galina; CERN. Geneva. ATS Department

2018-01-01

The expected heat load induced on the beam screens has been evaluated for the triplet assemblies in the four experimental Insertion Regions (IRs) of the HL-LHC. The contribution from electron cloud effects has been estimated using PyECLOUD macroparticle simulations. The presence of a surface treatment for the reduction of the Secondary Electron Yield has been taken into account. The contribution from the impedance of the beam screen has been evaluated taking into account the impact of the temperature and of the magnetic field on the resistivity of the surface.

The DFBX cryogenic distribution boxes for the LHC straight sections

International Nuclear Information System (INIS)

Zbasnik, Jon P.; Corradi, Carol A.; Green, Michael A.; Kajiyama, Y.; Knolls, Michael J.; LaMantia, Roberto F.; Rasson, Joseph E.; Reavill, Dulie; Turner, William C.

2002-01-01

The DFBX distribution boxes are designed to connect the LHC cryogenic distribution system to the interaction region quadrupoles [1] and dipoles for the Large Hadron Collider (LHC). The DFBX distribution boxes also have the current leads for the superconducting interaction region magnets and the LHC interaction region correction coils. The DFBX boxes also connect the magnet and cryogenic instrumentation to the CERN data collection system. The DFBX boxes serve as the cryogenic circulation center and the nerve center for four of the LHC straight sections. This report describes primarily the cryogenic function of the DFBXs

Influence of mechanical vibrations on the field quality measurements of LHC interaction region quadrupole magnets

CERN Document Server

Di Marco, J; Schlabach, P; Sylvester, C D; Tompkins, J C; Krzywinski, J

2000-01-01

The high gradient quadrupole magnets being developed by the US-LHC Accelerator Project for the LHC Interaction Regions have stringent field quality requirements. The field quality of these magnets will be measured using a rotating coil system presently under development. Mechanical vibrations of the coil during field quality measurements are of concern because such vibrations can introduce systematic errors in measurement results. This paper presents calculations of the expected influence of vibrations on field quality measurements and a technique to measure vibrations present in data acquired with standard "tangential-style" probes. Measured vibrations are reported and compared to simulations. Limits on systematic errors in multipole measurements are discussed along with implications for probe and measurement system design. (3 refs).

High bandwidth pixel detector modules for the ATLAS Insertable B-Layer

International Nuclear Information System (INIS)

Backhaus, Malte

2014-01-01

The investigation of the nature of the recently discovered electro-weak symmetry breaking mechanism of the standard model of particle physics as well as the search for physics beyond the standard model with the LHC require to collect even more data. To achieve this goal, the luminosity of the LHC will be increased in two steps. The increased luminosity results in serious challenges for the inner tracking systems of the experiments at the LHC. The ATLAS pixel detector will also be upgraded in a two stage program. During the shutdown in 2013 and 2014 a fourth hybrid pixel detector layer, the socalled Insertable B-Layer (IBL) is inserted inside the existing pixel detector. This thesis focuses on the characterization, performance measurement, and production quality assurance of the central sensitive elements of the IBL, the modules. This includes a full characterization of the readout chip (FE-I4) and of the assembled modules. A completely new inner tracking system is mandatory in ATLAS after the second luminosity increase in the shutdown of 2022 and 2023. The final chapter of this thesis introduces a new module concept that uses an industrial high voltage CMOS technology as sensor layer, which is capacitively coupled to the FE-I4 readout chip.

Electrons identification in the forward region of the ATLAS electromagnetic calorimeter at the LHC and first data analysis

International Nuclear Information System (INIS)

Chareyre, E.

2010-09-01

The start up of the ATLAS experiment at the CERN LHC has been done during the autumn 2009. During the construction and integration of the detector, combined beam tests grouping several subsystems have been carried out. In the forward region of the detector (η > 2.5), a combined beam test with electromagnetic and hadronic calorimeters has been done, whose data (pions and electrons) has been analyzed. Identification of electrons in this region can be used to study decays of Z and W bosons and also to develop some tools to understand the background noises. A method to estimate rejection of pions and electrons identification efficiency is presented using a discriminant analysis based on the methods of Fisher discriminant and on Boosted Decision Trees. It is shown that a pion rejection higher than 200 with an efficiency of electron identification of 50% can be obtained. Moreover the tools and methods developed during the beam tests have been applied on the first data of the LHC with collisions at 7 TeV. Since the present luminosity of the LHC is not yet sufficient to study precisely production of Z and W bosons by using data, a study using the Pythia generator has been done on electrons physics in the forward region. (author)

On the LHC observation of gluinos from the Egret-preferred region

International Nuclear Information System (INIS)

Bednyakov, V. A.; Budagov, Ju. A.; Gladyshev, A. V.; Kazakov, D. I.; Khramov, E. V.; Khubua, D. I.

2009-01-01

Prospects for observation of a SUSY-like signal from two gluinos g-bar g-bar are investigated within a certain region of the mSUGRA parameter space, where the cross section of the two-gluino production in pp-collisions at the LHC (√s = 14 TeV) is estimated at a rather high level of 17.3 pb. In this so-called EGRET-preferred region, the lightest stable neutralinos χ 1 0 can serve as cold-dark-matter particles and can naturally explain the excess of diffuse Galactic gamma rays observed by the EGRET space apparatus. The g-bar g-bar-event selection relies on a clear signature when decay products of each gluino contain one bb-bar pair, one or two ll-bar pair(s) or one or two light qq-bar pair(s), and a neutralino. Rather high transverse missing energy carried away by the two neutralinos is the essential signature of the events using of which allows the relevant Standard Model background to be reduced significantly. Furthermore, distributions of the reconstructed invariant masses of two opposite-charged-lepton or light-jet pairs produced by the χ 2 0 → χ 1 0 l + l - and χ 2 0 → χ 1 0 qq-bar three-body decays have kinematic end points which measure the difference between masses of χ 2 0 and χ 1 0 . In particular, it was found that these signatures of selected processes demonstrate good prospects for discovery of gluinos at the LHC. These signatures allow one to distinguish different mSUGRA parameters m 1/2 within the EGRET-preferred region (at a higher than 6σ confidence level with 300 fb -1 data).

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...

Crystals channel high-energy beams in the LHC

CERN Multimedia

CERN Bulletin

2015-01-01

Bent crystals can be used to deflect particle beams, as suggested by E. Tsyganov in 1976. Experimental demonstrations have been carried out for four decades in various laboratories worldwide. In recent tests, a bent crystal inserted into the LHC beam halo successfully channelled and deflected 6.5 TeV protons into an absorber, with reduced secondary irradiation.    Quasimosaic crystal for the LHC (developed by PNPI). Bent crystal technology was introduced at CERN and further developed for the LHC by the UA9 Collaboration. For about ten years, experts from CERN, INFN (Italy), Imperial College (UK), LAL (France), and PNPI, IHEP and JINR (Russia) have been investigating the advantages of using bent crystals in the collimation systems of high-energy hadron colliders. A bent crystal replacing the primary collimator can deflect the incoming halo deeply inside the secondary collimators, improving their absorption efficiency. “The bent crystals we have just tested at the world-record en...

Detector and System Developments for LHC Detector Upgrades

CERN Document Server

Mandelli, Beatrice; Guida, Roberto; Rohne, Ole; Stapnes, Steinar

2015-05-12

The future Large Hadron Collider (LHC) Physics program and the consequent improvement of the LHC accelerator performance set important challenges to all detector systems. This PhD thesis delineates the studies and strategies adopted to improve two different types of detectors: the replacement of precision trackers with ever increasingly performing silicon detectors, and the improvement of large gaseous detector systems by optimizing their gas mixtures and operation modes. Within the LHC tracker upgrade programs, the ATLAS Insertable B-layer (IBL) is the first major upgrade of a silicon-pixel detector. Indeed the overall ATLAS Pixel Detector performance is expected to degrade with the increase of luminosity and the IBL will recover the performance by adding a fourth innermost layer. The IBL Detector makes use of new pixel and front-end electronics technologies as well as a novel thermal management approach and light support and service structures. These innovations required complex developments and Quality Ass...

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)

Analysis of generic insertions made of two symmetric triplets

CERN Document Server

D'Amico, T E

1998-01-01

This paper reports on the study undertaken to explore the capabilities of a symmetric triplet to achieve the optics constraints required by the inner triplet of an insertion and more generally of a co mplete insertion made of two symmetric triplets to match a double focus to a FODO lattice. It is based on analytical treatment formulating a number of constraints equal to the parameters available. Th is thorough and systematic analysis made it possible to establish for an inner triplet as well as for a complete insertion the existence of solutions and to explicitly find out all the solutions, with out resorting to unguided numerical searches. As a by-product, a lattice transformer, made of a single triplet, that matches two different FODO cells has been singled out and studied in details. The r esults should be profitable in a number of cases. Here, the method is applied to an insertion of the type of an experimental LHC insertion in order to investigate its domain of validity and tunability .

Elastic scattering at the LHC

CERN Document Server

Kaspar, Jan; Deile, M

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

Gluon saturation and baryon stopping in the SPS, RHIC, and LHC energy regions

International Nuclear Information System (INIS)

Li Shuang; Feng Shengqin

2012-01-01

A new geometrical scaling method with a gluon saturation rapidity limit is proposed to study the gluon saturation feature of the central rapidity region of relativistic nuclear collisions. The net-baryon number is essentially transported by valence quarks that probe the saturation regime in the target by multiple scattering. We take advantage of the gluon saturation model with geometric scaling of the rapidity limit to investigate net baryon distributions, nuclear stopping power and gluon saturation features in the SPS and RHIC energy regions. Predictions for net baryon rapidity distributions, mean rapidity loss and gluon saturation feature in central Pb + Pb collisions at the LHC are made in this paper. (authors)

New magnets for the IR: How far are we from the HL-LHC target?

International Nuclear Information System (INIS)

Sabbi, G.L.

2012-01-01

Insertion quadrupoles with large aperture and high gradient are required to upgrade the luminosity of the Large Hadron Collider (LHC). The US LHC Accelerator Research Program (LARP) is a collaboration of US DOE National Laboratories aiming at demonstrating the feasibility of Nb 3 Sn magnet technology for this application. Several series of magnets with increasing performance and complexity have been fabricated, with particular emphasis on addressing length scale-up issues. Program results and future directions are discussed. (author)

Regional fibrocartilage variations in human anterior cruciate ligament tibial insertion: a histological three-dimensional reconstruction.

Science.gov (United States)

Dai, Can; Guo, Lin; Yang, Liu; Wu, Yi; Gou, Jingyue; Li, Bangchun

2015-02-01

We studied anterior cruciate ligament (ACL) tibial insertion architecture in humans and investigated regional differences that could suggest unequal force transmission from ligament to bone. ACL tibial insertions were processed histologically. With Photoshop software, digital images taken from the histological slides were collaged, contour lines were drawn, and different gray values were filled based on the structure. The data were exported to Amira software for three-dimensional reconstruction. The uncalcified fibrocartilage (UF) layer was divided into three regions: lateral, medial and posterior according to the architecture. The UF zone was significantly thicker laterally than medially or posteriorly (p fibrocartilage (CF) thickness was significantly greater in the lateral part of the enthesis compared to the medial and posterior parts (p < 0.05). The UF quantity (more UF laterally) corresponding to the CF quantity (more CF laterally) at the ACL tibial insertion provides further evidence suggesting that the load transferred from the ACL to the tibia was greater laterally than medially and posteriorly.

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.

Impedance Studies for VMTSA Module of LHC Equipped with RF Fingers

CERN Document Server

Kononenko, O; Métral, E; Grudiev, A; Caspers, F

2013-01-01

During the 2011 LHC run it was found that beam-induced heating causes many issues for accelerator components. Particularly some of the double-bellow modules, called VMTSA modules, were found to have deformed RF fingers and a broken spring, which had ensured good contact between them and a central insert. Impedance studies have been performed for different types of nonconformities. It was found that even a small gap between the fingers and a central insert could be fatal for the VMTSA operation. Results of this study were an input for the further thermal analysis.

Protecting LHC IP1/IP5 Components Against Radiation Resulting from Colliding Beam Interactions

CERN Document Server

Mokhov, N V; Kerby, J S; Strait, J B

2003-01-01

Beam-induced energy deposition in the LHC high luminosity interaction region (IR) components due to both pp collisions and beam loss in the IR vicinity is a significant challenge for the design of the high luminosity insertions. It was shown in our previous studies that a set of absorbers would reduce both the peak power density and total heat load to tolerable levels. In this paper the results of further optimization and comprehensive MARS calculations are summarized for the LHC lattice, version 6.4, for the updated IP1 and IP5 layouts and a baseline pp-collision source term. Power density, power dissipation, particle fluxes and spectra, accumulated dose and residual dose rates are studied in the components of the inner triplets including their TAS absorbers, the TAN neutral beam absorbers, separation dipoles, and quadrupoles of the outer triplets and possible collimators there. Results are given for the nominal luminosity of 1034 cm-2 s-1. The current design is proved to provide the best safety margin under...

LHC related projects and studies - Part (II)

International Nuclear Information System (INIS)

Rossi, L.; De Maria, R.

2012-01-01

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

Lessons Learnt and Mitigation Measures for the CERN LHC Equipment with RF fingers

CERN Document Server

Métral, E; Assmann, R W; Baglin, V; Barnes, M J; Berrig, O E; Bertarelli, A; Bregliozzi, G; Calatroni, S; Carra, F; Caspers, F; Day, H A; Ferro-Luzzi, M; Gallilee, M A; Garion, C; Garlasche, M; Grudiev, A; Jimenez, J M; Jones, R; Kononenko, O; Losito, R; Nougaret, J L; Parma, V; Redaelli, S; Salvant, B; Strubin, P; Veness, R; Vollinger, C; Weterings, W

2013-01-01

Beam-induced RF heating has been observed in several LHC components when the bunch/beam intensity was increased and/or the bunch length reduced. In particular eight bellows, out of the ten double-bellow modules present in the machine in 2011, were found with the spring, which should keep the RF fingers in good electrical contact with the central insert, broken. Following these observations, the designs of all the components of the LHC equipped with RF fingers have been reviewed. The lessons learnt and mitigation measures are presented in this paper.

Designing and Building a Collimation System for the High-Intensity LHC Beam

CERN Document Server

Assmann, R W; Baishev, I S; Bruno, L; Brugger, M; Chiaveri, Enrico; Dehning, Bernd; Ferrari, A; Goddard, B; Jeanneret, J B; Jiménez, M; Kain, V; Kaltchev, D I; Lamont, M; Ruggiero, F; Schmidt, R; Sievers, P; Uythoven, J; Vlachoudis, V; Vos, L; Wenninger, J

2003-01-01

The Large Hadron Collider (LHC) will collide proton beams at 14 TeV c.m. with unprecedented stored intensities. The transverse energy density in the beam will be about three orders of magnitude larger than previously handled in the Tevatron or in HERA, if compared at the locations of the betatron collimators. In particular, the population in the beam halo is much above the quench level of the superconducting magnets. Two LHC insertions are dedicated to collimation with the design goals of preventing magnet quenches in regular operation and preventing damage to accelerator components in case of irregular beam loss. We discuss the challenges for designing and building a collimation system that withstands the high power LHC beam and provides the required high cleaning efficiency. Plans for future work are outlined.

Magnetic Frequency Response of HL-LHC Beam Screens

Energy Technology Data Exchange (ETDEWEB)

Morrone, M. [CERN; Martino, M. [CERN; De Maria, R. [CERN; Fitterer, M. [Fermilab; Garion, C. [CERN

2017-10-12

Magnetic fields used to control particle beams in accelerators are usually controlled by regulating the electrical current of the power converters. In order to minimize lifetime degradation and ultimately luminosity loss in circular colliders, current-noise is a highly critical figure of merit of power converters, in particular for magnets located in areas with high beta-function, like the High Luminosity Large Hadron Collider (HL-LHC) insertions. However, what is directly acting upon the beam is the magnetic field and not the current of the power converter, which undergoes several frequency-dependent transformations until the desired magnetic field, seen by the beam, is obtained. Beam screens are very rarely considered when assessing or specifying the noise figure of merit, but their magnetic frequency response is such that they realize relatively effective low pass filtering of the magnetic field produced by the system magnet-power converter. This work aims at filling this gap by quantifying the expected impact of different beam screen layouts for the most relevant HL-LHC insertion magnets. A welldefined post-processing technique is used to derive the frequency response of the different multipoles from multi-physics Finite Element Method (FEM) simulation results. In addition, a well approximated analytical formula for the low-frequency range of multi-layered beam screens is presented.

The LHC can probe small x PDFs; the treatment of the infrared region

International Nuclear Information System (INIS)

Martin, A. D.; De Oliveira, E. G.; Ryskin, M. G.

2013-01-01

First, we show how to reduce the sensitivity of the NLO predictions of the Drell-Yan production of low-mass, lepton-pairs, at high rapidity, to the choice of factorization scale. In this way, observations of this process at the LHC can make direct measurements of parton distribution functions in the low x domain; x≲10 −4 . Second, we find an inconsistency in the conventional NLO treatment of the infrared region. We illustrate the problem using the NLO coefficient function of Drell-Yan production.

Fast loss analysis with LHC diamond detectors in 2017

CERN Document Server

Gorzawski, Arkadiusz; Fuster Martinez, Nuria; Garcia Morales, Hector; Mereghetti, Alessio; Cai, Xu; Valentino, Gianluca; Appleby, Robert Barrie; CERN. Geneva. ATS Department

2018-01-01

We presented some applications of the diamond BLM system installed in the LHC betatron collimation insertion. A selection of results illustrates the potential of this measurement system to understand better the losses at the LHC. Measurements range from the bunch-by-bunch analysis in different phases of the operational cycle, to the frequency analysis of fast losses. This work will continue in 2018, in collaboration with the various teams at CERN. New hardware is planned to improve the system. The addition of one monitor per beam will allow distinguishing the horizontal and vertical contents of losses at primary collimators, thus opening the possibility for a better understanding of loss mechanisms and for further study of correlation with other bunch-by-bunch measurements.

Regional research exploitation of the LHC a case-study of the required computing resources

CERN Document Server

Almehed, S; Eerola, Paule Anna Mari; Mjörnmark, U; Smirnova, O G; Zacharatou-Jarlskog, C; Åkesson, T

2002-01-01

A simulation study to evaluate the required computing resources for a research exploitation of the Large Hadron Collider (LHC) has been performed. The evaluation was done as a case study, assuming existence of a Nordic regional centre and using the requirements for performing a specific physics analysis as a yard-stick. Other imput parameters were: assumption for the distribution of researchers at the institutions involved, an analysis model, and two different functional structures of the computing resources.

The LHC can probe small x PDFs; the treatment of the infrared region

Energy Technology Data Exchange (ETDEWEB)

Martin, A. D.; De Oliveira, E. G.; Ryskin, M. G. [Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE (United Kingdom)

2013-04-15

First, we show how to reduce the sensitivity of the NLO predictions of the Drell-Yan production of low-mass, lepton-pairs, at high rapidity, to the choice of factorization scale. In this way, observations of this process at the LHC can make direct measurements of parton distribution functions in the low x domain; x Less-Than-Or-Equivalent-To 10{sup -4}. Second, we find an inconsistency in the conventional NLO treatment of the infrared region. We illustrate the problem using the NLO coefficient function of Drell-Yan production.

The Special LHC Interconnections Technologies, Organization and Quality Control

CERN Document Server

Tock, J P; Bozzini, D; Cruikshank, P; Desebe, O; Felip, M; Garion, C; Hajduk, L; Jacquemod, A; Kos, N; Laurent, F; Poncet, A; Russenschuck, Stephan; Slits, I; Vaudaux, L; Williams, L

2008-01-01

In addition to the standard interconnections (IC) of the continuous cryostat of the Large Hadron Collider (LHC), there exists a variety of special ones related to specific components and assemblies, such as cryomagnets of the insertion regions, electrical feedboxes and superconducting links. Though they are less numerous, their specificities created many additional IC types, requiring a larger variety of assembly operations and quality control techniques, keeping very high standards of quality. Considerable flexibility and adaptability from all the teams involved (CERN staff, collaborating institutes, contractors) were the key points to ensure the success of this task. This paper first describes the special IC and presents the employed technologies which are generally adapted from the standard work. Then, the organization adopted for this non-repetitive work is described. Examples of non-conformities that were resolved are also discussed. Figures of merit in terms of quality and productivity are given and com...

Development of LHC-IR model quadrupoles in the US

CERN Document Server

Sabbi, G

2007-01-01

Insertion quadrupoles with large aperture and high gradient are required to achieve the luminosity upgrade goal of 1035 cm-2 s-1 at the Large Hadron Collider (LHC). In 2004, the US Department of Energy established the LHC Accelerator Research Program (LARP) to develop a technology base for the upgrade. The focus of the magnet program, which is a collaboration of three US laboratories, BNL, FNAL and LBNL, is on development of high gradient quadrupoles using Nb$_{3}$Sn in order to operate at high field and with sufficient temperature margin. Other program components address issues regarding magnet design, radiation-hard materials, long magnet scale-up, quench protection, fabrication techniques and conductor and cable R&D. This paper reports on the development od model quadrupoles and outlines the long-term goals of the program.

Volunteer Clouds and Citizen Cyberscience for LHC Physics

International Nuclear Information System (INIS)

Aguado Sanchez, Carlos; Blomer, Jakob; Buncic, Predrag; Ellis, John; Harutyunyan, Artem; Marquina, Miguel; Mato, Pere; Schulz, Holger; Segal, Ben; Sharma, Archana; Skands, Peter; Chen Gang; Wu Jie; Wu Wenjing; Garcia Quintas, David; Grey, Francois; Lombrana Gonzalez, Daniel; Rantala, Jarno; Weir, David; Yadav, Rohit

2011-01-01

Computing for the LHC, and for HEP more generally, is traditionally viewed as requiring specialized infrastructure and software environments, and therefore not compatible with the recent trend in v olunteer computing , where volunteers supply free processing time on ordinary PCs and laptops via standard Internet connections. In this paper, we demonstrate that with the use of virtual machine technology, at least some standard LHC computing tasks can be tackled with volunteer computing resources. Specifically, by presenting volunteer computing resources to HEP scientists as a v olunteer cloud , essentially identical to a Grid or dedicated cluster from a job submission perspective, LHC simulations can be processed effectively. This article outlines both the technical steps required for such a solution and the implications for LHC computing as well as for LHC public outreach and for participation by scientists from developing regions in LHC research.

Beam Dynamics Requirements for the Powering Scheme of the HL-LHC Triplet

CERN Document Server

AUTHOR|(CDS)2075212; Fartoukh, Stephane; Giovannozzi, Massimo

2015-01-01

For the HL-LHC, β ∗ values as small as 15 cm are envisaged as baseline scenario for the high luminosity insertions IR1 and IR5, thus leading to an increase of the maximum β- functions in the inner triplet (IT). The larger beta-functions in the IT result in a higher sensitivity of the beam to any linear or non-linear, static or dynamic, field imperfections in the IT region. In this paper, we summarize accordingly the tolerances of the triplet power supplies in terms of current ripple, stability and reproducibility. Both the baseline IT powering scheme and other alternative schemes will be presented, the later reducing the tune shift caused by a current modulation and thus weakening its possible impact on the long term stability.

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

Concerning effects of fringe fields and longitudinal distribution of b10 in LHC low-β regions

International Nuclear Information System (INIS)

Meot, F.; Paris, A.

1997-08-01

Effects of fringe fields in separation dipoles D1/D2 and low-β quadrupoles Q1-Q3 of LHC interaction regions in collision optics are investigated by means of stepwise ray-tracing in terms of aberrations, beam envelopes and other detunings. Effects of the longitudinal distribution of b 10 error coefficient are next investigated in a similar way for assessment and comparison

The construction of the Insertable B-Layer and the $b$-tagging performance at high-\\pt of the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00362129; La Rosa, Alessandro; Ferrere, Didier

Although the recent discovery of the Higgs boson by the LHC experiments represented a major success of the Standard Model theory, several questions need still to be answered. The search of new physics particles beyond the Standard Model will require the LHC to collect a large amount of data. To achieve this goal the LHC collider went through a long shutdown, increasing both the energy and the luminosity. In particular the increase of luminosity will require the ATLAS Inner Detector to operate in a more track-dense environment, which mainly affects the ATLAS Pixel Detector. In order to cope with the high pile-up expected with the increase of luminosity the Pixel detector was then upgraded during the long shutdown with the insertion of a fourth innermost layer, the Insertable B-Layer (IBL). This thesis focuses on the construction of the IBL. This includes the loading of silicon pixel detector modules on the support staves, the quality assurance of these instrumented staves and the commissioning after the integr...

The development of diamond tracking detectors for the LHC

International Nuclear Information System (INIS)

Adam, W.; Berdermann, E.; Bergonzo, P.; Boer, W. de; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Doroshenko, J.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fischer, P.; Fizzotti, F.; Furetta, C.; Gan, K.K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kaplon, J.; Karl, C.; Kass, R.; Keil, M.; Knoepfle, K.T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Perera, L.; Pernegger, H.; Pernicka, M.; Polesello, P.; Potenza, R.; Riester, J.L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M.

2003-01-01

Chemical vapor deposition diamond has been discussed extensively as an alternate sensor material for use very close to the interaction region of the LHC where extreme radiation conditions exist. During the last few years diamond devices have been manufactured and tested with LHC electronics with the goal of creating a detector usable by all LHC experiment. Extensive progress on diamond quality, on the development of diamond trackers and on radiation hardness studies has been made. Transforming the technology to the LHC specific requirements is now underway. In this paper we present the recent progress achieved

The development of diamond tracking detectors for the LHC

CERN Document Server

Adam, W; Bergonzo, P; de Boer, Wim; Bogani, F; Borchi, E; Brambilla, A; Bruzzi, M; Colledani, C; Conway, J; D'Angelo, P; Dabrowski, W; Delpierre, P A; Doroshenko, J; Dulinski, W; van Eijk, B; Fallou, A; Fischer, P; Fizzotti, F; Furetta, C; Gan, K K; Ghodbane, N; Grigoriev, E; Hallewell, G D; Han, S; Hartjes, F; Hrubec, Josef; Husson, D; Kagan, H; Kaplon, J; Karl, C; Kass, R; Keil, M; Knöpfle, K T; Koeth, T W; Krammer, M; Lo Giudice, A; Lü, R; MacLynne, L; Manfredotti, C; Marshall, R D; Meier, D; Menichelli, D; Meuser, S; Mishina, M; Moroni, L; Noomen, J; Oh, A; Perera, L; Pernegger, H; Pernicka, M; Polesello, P; Potenza, R; Riester, J L; Roe, S; Rudge, A; Sala, S; Sampietro, M; Schnetzer, S; Sciortino, S; Stelzer, H; Stone, R; Sutera, C; Trischuk, W; Tromson, D; Tuvé, C; Vincenzo, B; Weilhammer, P; Wermes, N; Wetstein, M; Zeuner, W; Zöller, M

2003-01-01

Chemical vapor deposition diamond has been discussed extensively as an alternate sensor material for use very close to the interaction region of the LHC where extreme radiation conditions exist. During the last few years diamond devices have been manufactured and tested with LHC electronics with the goal of creating a detector usable by all LHC experiment. Extensive progress on diamond quality, on the development of diamond trackers and on radiation hardness studies has been made. Transforming the technology to the LHC specific requirements is now underway. In this paper we present the recent progress achieved.

The development of diamond tracking detectors for the LHC

Energy Technology Data Exchange (ETDEWEB)

Adam, W.; Berdermann, E.; Bergonzo, P.; Boer, W. de; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D' Angelo, P.; Dabrowski, W.; Delpierre, P.; Doroshenko, J.; Dulinski, W.; Eijk, B. van; Fallou, A.; Fischer, P.; Fizzotti, F.; Furetta, C.; Gan, K.K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H. E-mail: harris.kagan@cern.ch; Kaplon, J.; Karl, C.; Kass, R.; Keil, M.; Knoepfle, K.T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; Mac Lynne, L.; Manfredotti, C.; Marshall, R.D.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Perera, L.; Pernegger, H.; Pernicka, M.; Polesello, P.; Potenza, R.; Riester, J.L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M

2003-11-21

Chemical vapor deposition diamond has been discussed extensively as an alternate sensor material for use very close to the interaction region of the LHC where extreme radiation conditions exist. During the last few years diamond devices have been manufactured and tested with LHC electronics with the goal of creating a detector usable by all LHC experiment. Extensive progress on diamond quality, on the development of diamond trackers and on radiation hardness studies has been made. Transforming the technology to the LHC specific requirements is now underway. In this paper we present the recent progress achieved.

The development of diamond tracking detectors for the LHC

Science.gov (United States)

Adam, W.; Berdermann, E.; Bergonzo, P.; de Boer, W.; Bogani, F.; Borchi, E.; Brambilla, A.; Bruzzi, M.; Colledani, C.; Conway, J.; D'Angelo, P.; Dabrowski, W.; Delpierre, P.; Doroshenko, J.; Dulinski, W.; van Eijk, B.; Fallou, A.; Fischer, P.; Fizzotti, F.; Furetta, C.; Gan, K. K.; Ghodbane, N.; Grigoriev, E.; Hallewell, G.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kaplon, J.; Karl, C.; Kass, R.; Keil, M.; Knöpfle, K. T.; Koeth, T.; Krammer, M.; Logiudice, A.; Lu, R.; mac Lynne, L.; Manfredotti, C.; Marshall, R. D.; Meier, D.; Menichelli, D.; Meuser, S.; Mishina, M.; Moroni, L.; Noomen, J.; Oh, A.; Perera, L.; Pernegger, H.; Pernicka, M.; Polesello, P.; Potenza, R.; Riester, J. L.; Roe, S.; Rudge, A.; Sala, S.; Sampietro, M.; Schnetzer, S.; Sciortino, S.; Stelzer, H.; Stone, R.; Sutera, C.; Trischuk, W.; Tromson, D.; Tuve, C.; Vincenzo, B.; Weilhammer, P.; Wermes, N.; Wetstein, M.; Zeuner, W.; Zoeller, M.; RD42 Collaboration

2003-11-01

Chemical vapor deposition diamond has been discussed extensively as an alternate sensor material for use very close to the interaction region of the LHC where extreme radiation conditions exist. During the last few years diamond devices have been manufactured and tested with LHC electronics with the goal of creating a detector usable by all LHC experiment. Extensive progress on diamond quality, on the development of diamond trackers and on radiation hardness studies has been made. Transforming the technology to the LHC specific requirements is now underway. In this paper we present the recent progress achieved.

Beam induced heat loads on the beam-screens of the twin-bore magnets in the IRs of the HL-LHC

CERN Document Server

Iadarola, Giovanni; Rumolo, Giovanni

2016-01-01

The expected heat load induced on the beam screens has been evaluated for all the twin-bore magnets in the Insertion Regions (IRs) of the HL-LHC. The contribution from the impedance of the beam screen has been evaluated taking into account the presence of a longitudinal weld in the beam screen and the impact of the temperature and of the magnetic field on the resistivity of the surface. The contribution coming from electron cloud effects has been evaluated for different values of the Secondary Electron Yield of the surface based PyECLOUD build-up simulations.

Testing of the large bore single aperture 1-meter superconducting dipoles made with phenolic inserts

CERN Document Server

Boschmann, H; Dubbeldam, R L; Kirby, G A; Lucas, J; Ostojic, R; Russenschuck, Stephan; Siemko, A; Taylor, T M; Vanenkov, I; Weterings, W

1998-01-01

Two identical single aperture 1-metre superconducting dipoles have been built in collaboration with HMA Power Systems and tested at CERN. The 87.8 mm aperture magnets feature a single layer coil wound using LHC main dipole outer layer cable, phenolic spacer type collars, and a keyed two part structural iron yoke. The magnets are designed as models of the D1 separation dipole in the LHC experimental insertions, whose nominal field is 4.5 T at 4.5 K. In this report we present the test results of the two magnets at 4.3 K and 1.9 K.

Study of Quench Protection for the Nb$_3$Sn Low-β Quadrupole for the LHC Luminosity Upgrade (HiLumi-LHC)

CERN Document Server

Todesco, E; Bellomo, G; Sorbi, M; Ambrosio, G; Chlachidze, G; Felice, H; Marchevsky, M; Salmi, T

2015-01-01

The HiLumi program is aiming to develop and build new Nb$_{3}$Sn, high-field (12 T) and large aperture (150 mm) superconducting quadrupoles, which will be inserted in the LHC interaction regions and will provide the final focusing of the beam, in the program of the luminosity upgrade. The quench protection of these magnets is one of the most challenging aspects, mainly because of the large value of the magnet inductance (160 mH for the configuration with two 8 m long magnets in series), of the large value of the stored magnetic energy density in the coils (0.12 J/mm3, a factor 2 larger than in the conventional NbTi quadrupoles) and of the use of Nb$_{3}$Sn as conductor, which has never been used for large accelerator magnets. Previous works have demonstrated that a “standard” conservative analysis, assuming quench heaters only on the coils outer layer, gives high hot spot temperature, close to the design limit (350 K). In this paper, a new study of quench protection is presented. The benefic effects of la...

TRACKING AND VERTEXING WITH THE ATLAS INNER DETECTOR IN THE LHC RUN2 AND BEYOND

CERN Document Server

Choi, Kyungeon; The ATLAS collaboration

2017-01-01

Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, ...

Tracking and Vertexing with the ATLAS Inner Detector in the LHC Run2 and Beyond

CERN Document Server

Swift, Stewart Patrick; The ATLAS collaboration

2017-01-01

Run-2 of the LHC has provided new challenges to track and vertex reconstruction with higher centre-of-mass energies and luminosity leading to increasingly high-multiplicity environments, boosted, and highly-collimated physics objects. To achieve this goal, ATLAS is equipped with the Inner Detector tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. In addition, the Insertable B-layer (IBL) is a fourth pixel layer, which was inserted at the centre of ATLAS during the first long shutdown of the LHC. An overview of the use of each of these subdetectors in track and vertex reconstruction, as well as the algorithmic approaches taken to the specific tasks of pattern recognition and track fitting, is given. The performance of the Inner Detector tracking and vertexing will be summarised. These include a factor of three reduction in the reconstruction time, optimisation for the expected conditions, ...

LHC and the neutrino paradigm

CERN Multimedia

CERN. Geneva

2011-01-01

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

LHC Report: imaginative injectors

CERN Multimedia

Pierre Freyermuth for the LHC team

2016-01-01

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

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...

LHC project. Exploring the smallest world with the highest energy beam

International Nuclear Information System (INIS)

Kondo, Takahiko; Kobayashi, Tomio

2007-01-01

The LHC accelerator at CERN will be completed soon and the experiments are about to start, making it possible to explore the TeV energy region for the first time in human history. There exists a clear reason why the TeV region is especially important for experimental exploration. The Higgs particle, the last elusive element of the Standard Model, will be discovered with very high probability. In addition there are high chances to discover signs of new physics beyond the Standard Model such as SUSY particles. Dark matter may be discovered. As an introduction of the mini-special issue for LHC, its goals and history is briefly reviewed, followed by a description on LHC accelerator, four LHC experiments as well as the contributions by Japan. (author)

Anatomy of the inert two-Higgs-doublet model in the light of the LHC and non-LHC dark matter searches

Science.gov (United States)

Belyaev, Alexander; Cacciapaglia, Giacomo; Ivanov, Igor P.; Rojas-Abatte, Felipe; Thomas, Marc

2018-02-01

The inert two-Higgs-doublet model (i2HDM) is a theoretically well-motivated example of a minimal consistent dark matter (DM) model which provides monojet, mono-Z , mono-Higgs, and vector-boson-fusion +ETmiss signatures at the LHC, complemented by signals in direct and indirect DM search experiments. In this paper we have performed a detailed analysis of the constraints in the full five-dimensional parameter space of the i2HDM, coming from perturbativity, unitarity, electroweak precision data, Higgs data from the LHC, DM relic density, direct/indirect DM detection, and LHC monojet analysis, as well as implications of experimental LHC studies on disappearing charged tracks relevant to a high DM mass region. We demonstrate the complementarity of the above constraints and present projections for future LHC data and direct DM detection experiments to probe further i2HDM parameter space. The model is implemented into the CalcHEP and micrOMEGAs packages, which are publicly available at the HEPMDB database, and it is ready for a further exploration in the context of the LHC, relic density, and DM direct detection.

Performance Limits and IR Design Challenges of a Possible LHC Luminosity Upgrade Based on Nb-Ti SC Magnet Technology

CERN Document Server

Brüning, Oliver Sim; Ostojic, R; Rossi, L; Ruggiero, F; Scandale, Walter; Taylor, T

2004-01-01

We investigate the maximum LHC performance for a standard IR design based on classical NbTi insertion magnets. We include in our analysis a ternary Nb-based ductile allow such as NbTi(Ta), a less developed but relatively cheap superconducting material which may allow to gain about 1 T in the peak field in the coils, and discuss the corresponding luminosity reach for a possible LHC upgrade compared to that based on Nb$_{3}$Sn magnets.

Turning the LHC Ring into a New Physics Search Machine

CERN Document Server

Kalliokoski, Matti; Mieskolainen, Mikael; Orava, Risto

2016-01-01

By combining the LHC Beam Loss Monitoring (BLM) system with the LHC experiments, a powerful search machine for new physics beyond the standard model can be realised. The pair of final state protons in the central production process, exit the LHC beam vacuum chamber at locations determined by their fractional momentum losses and will be detected by the BLM detectors. By mapping out the coincident pairs of the BLM identified proton candidates around the four LHC interaction regions, a scan for centrally produced particle states can be made independently of their decay modes.

Overview of the ATLAS Insertable B-Layer (IBL) Project

CERN Document Server

Kagan, M; The ATLAS collaboration

2013-01-01

The upgrades for the ATLAS Pixel Detector will be staged in preparation for high luminosity LHC. The first upgrade for the Pixel Detector will be the construction of a new pixel layer which is currently under construction and will be installed during the first shutdown of the LHC machine, in 2013-14. The new detector, called the Insertable B-layer (IBL), will be installed between the existing Pixel Detector and a new, smaller radius beam-pipe at a radius of 3.3 cm. The IBL required the development of several new technologies to cope with increased radiation and pixel occupancy and also to improve the physics performance through reduction of the pixel size and a more stringent material budget. Two different silicon sensor technologies, planar n-in-n and 3D, will be used, connected with the new generation 130nm IBM CMOS FE-I4 readout chip via solder bump-bonds. 32 \

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...

Correction of vertical crossing induced dispersion in LHC

International Nuclear Information System (INIS)

Meot, F.

1997-11-01

Beam crossing schemes in the LHC interaction regions impose non-zero vertical closed orbit in the low-β triplets, which excite a perturbative periodic dispersion; the phenomenon is described and quantified in detail. It is shown that this dispersion reaches values at the limit of tolerances in the nominal optics of Version 5.0 of the LHC ring, and prohibitively large values in particular in the low- β quadrupoles and interaction regions in the foreseen extreme β-squeeze case (β * = 0.25 m). Such behaviour justifies including a local correction in the LHC design, in order to damp the effect and confine it as much as possible in the vicinity of the excitation sources (the low-β triplets). An optical compensation scheme based on the use of skew quadrupoles is described in detail, as well as the entailed residual dispersion

Correction of vertical crossing induced dispersion in LHC

International Nuclear Information System (INIS)

Meot, F.

1997-11-01

Beam crossing schemes in the LHC interaction regions impose non-zero vertical closed orbit in the low-β triplets, which excite a perturbative periodic dispersion; the phenomenon is described and quantified in detail. It is shown that this dispersion reaches values at the limit of tolerances in the nominal optics of Version 5.0 of the LHC ring, and prohibitively large values in particular in the low-β quadrupoles and interaction regions in the foreseen extreme β-squeeze case (β * = 0.25 m). Such behavior justifies including a local correction in the LHC design, in order to damp the effect and confine it has such as possible in the vicinity of the excitation sources (the low-β triplets). An optical compensation scheme based on the use of skew quadrupoles is described in detail, as well as entailed residual dispersion. (author)

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...

Higgs physics at LHC

OpenAIRE

Unal, G

2006-01-01

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

Mueller-Navelet jets at 13 TeV LHC: dependence on dynamic constraints in the central rapidity region

Energy Technology Data Exchange (ETDEWEB)

Celiberto, F.G.; Papa, A. [Universita della Calabria, Dipartimento di Fisica, Cosenza (Italy); Gruppo collegato di Cosenza, Istituto Nazionale di Fisica Nucleare, Cosenza (Italy); Ivanov, D.Yu. [Sobolev Institute of Mathematics, Novosibirsk (Russian Federation); Novosibirsk State University, Novosibirsk (Russian Federation); Murdaca, B. [Gruppo collegato di Cosenza, Istituto Nazionale di Fisica Nucleare, Cosenza (Italy)

2016-04-15

We study the production of Mueller-Navelet jets at 13 TeV LHC, within collinear factorization and including the BFKL resummation of energy logarithms in the next-to-leading approximation. We calculate several azimuthal correlations for different values of the rapidity separation Y between the two jets and evaluate the effect of excluding those events where, for a given Y, one of the two jets is produced in the central region. (orig.)

The ATLAS Insertable B-Layer Detector (IBL)

CERN Document Server

Huegging, F; The ATLAS collaboration

2010-01-01

The upgrade for the ATLAS detector will undergo different phases towards SLHC. The first upgrade for the Pixel Detector will consist in the construction of a new pixel layer which will be installed during a longer shutdown of the LHC machine, the so-called Phase I Upgrade. The new detector, called Insertable B-Layer (IBL), will be inserted between the existing pixel detector and a new (smaller radius) beam-pipe at a radius of about 3.2 cm. The IBL requires the development of several new technologies to cope with the increase of radiation and pixel occupancy as well as to improve the physics performance of the existing pixel detector. In order to achieve these goals the pixel size is reduced and the material budget is minimized by using new lightweight mechanical support materials and a CO2 based cooling system. Main component of the module development for the IBL is the new ATLAS pixel readout chip, FE-I4, designed in 130 nm technology which features an array of 80 by 336 pixels with a pixel size of 50x250 µ...

Double-quarkonium production at a fixed-target experiment at the LHC (AFTER@LHC)

CERN Document Server

Lansberg, Jean-Philippe

2015-01-01

We present predictions for double-quarkonium production in the kinematical region relevant for the proposed fixed-target experiment using the LHC beams (dubbed as AFTER@LHC). These include all spin-triplet S -wave charmonium and bottomonium pairs, i.e. Psi(n_1S) + Psi(n_2S), Psi(n_1S) + Upsilon(m_1S) and Upsilon(m_1S) + Upsilon(m_2S ) with n_1,n_2 = 1,2 and m_1,m_2 = 1,2,3. We calculate the contributions from double-parton scatterings and single-parton scatterings. With an integrated luminosity of 20 fb-1 to be collected at AFTER@LHC, we find that the yields for double-charmonium production are large enough for differential distribution measurements. We discuss some differential distributions for J/Psi + J/Psi production, which can help to study the physics of double-parton and single-parton scatterings in a new energy range and which might also be sensitive to double intrinsic c-bar(c) coalescence at large negative Feynman x.

Saturation behaviour of the LHC NEG coated beam pipes

CERN Document Server

Porcelli, T; Lanza, G; Baglin, V; Jimenez, J M

2012-01-01

In the CERN Large Hadron Collider (LHC), about 6 km of the UHV beam pipe are at room temperature and serve as experimental or utility insertions. TiZrV non-evaporable getter (NEG) coating is used to maintain the design pressure during beam operation. Molecular desorption due to dynamic effects is stimulated during protons operation at high intensity. This phenomenon produces an important gas load from the vacuum chamber walls, which could lead to a partial or total saturation of the NEG coating. To keep the design vacuum performances and to schedule technical interventions for NEG reactivation, it is necessary to take into account all these aspects and to regularly evaluate the saturation level of the NEG coating. Experimental studies of a typical LHC vacuum sector were conducted in the laboratory in order to identify the best method to assess the saturation level of the beam pipe. Partial saturation of the NEG was performed and the effective pumping speed, transmission and capture probability are analysed.

Charged-particle multiplicity at LHC energies

CERN Multimedia

CERN. Geneva

2010-01-01

The talk presents the measurement of the pseudorapidity density and the multiplicity distribution with ALICE at the achieved LHC energies of 0.9 and 2.36 TeV.An overview about multiplicity measurements prior to LHC is given and the related theoretical concepts are briefly discussed.The analysis procedure is presented and the systematic uncertainties are detailed. The applied acceptance corrections and the treatment of diffraction are discussed.The results are compared with model predictions. The validity of KNO scaling in restricted phase space regions is revisited. 

Bulkhead insert for an internal combustion engine

Science.gov (United States)

Maki, Clifford E.; Chottiner, Jeffrey Eliot; Williams, Rick L.; Thibault, Mark W.; Ervin, James Douglas; Boileau, James Maurice; McKeough, Bryan

2017-08-01

An engine includes a cylinder block defining at least one main bearing bulkhead adjacent to a cylinder, and a crankshaft rotatably housed within the block by a main bearing. A bulkhead insert has a cap portion, and an insert portion provided within the bulkhead. The insert portion has having first and second end regions connected by first and second straps. Each strap having a flanged beam cross section. The first and second ends of the insert portion are configured to connect a main bearing cap column to a cylinder head column. Each of the first and second end regions define at least one protrusion having a surface substantially normal to engine combustion and reactive loads. The cap portion is configured to mate with the first end region at the main bearing cap column and support the main bearing.

CMS RPC muon detector performance with 2010-2012 LHC data

CERN Document Server

INSPIRE-00316302; Ban, Y.; Cai, J.; Li, Q.; Liu, S.; Qian, S.; Wang, D.; Xu, Z.; Zhang, F.; Choi, Y.; Kim, D.; Goh, J.; Choi, S.; Hong, B.; Kang, J.W.; Kang, M.; Kwon, J.H.; Lee, K.S.; Lee, S.K.; Park, S.K.; Pant, L.M.; Mohanty, A.K.; Chudasama, R.; Singh, J.B.; Bhatnagar, V.; Mehta, A.; Kumar, R.; Cauwenbergh, S.; Costantini, S.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Ocampo, A.; Poyraz, D.; Salva, S.; Thyssen, F.; Tytgat, M.; Zaganidis, N.; Doninck, W.V.; Cabrera, A.; Chaparro, L.; Gomez, J.P.; Gomez, B.; Sanabria, J.C.; Avila, C.; Ahmad, A.; Muhammad, S.; Shoaib, M.; Hoorani, H.; Awan, I.; Ali, I.; Ahmed, W.; Asghar, M.I.; Shahzad, H.; Sayed, A.; Ibrahim, A.; Aly, S.; Assran, Y.; Radi, A.; Elkafrawy, T.; Sharma, A.; Colafranceschi, S.; Abbrescia, M.; Calabria, C.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Nuzzo, S.; Radogna, R.; Venditti, R.; Verwilligen, P.; Benussi, L.; Bianco, S.; Piccolo, D.; Paolucci, P.; Buontempo, S.; Cavallo, N.; Merola, M.; Fabozzi, F.; Iorio, O.M.; Braghieri, A.; Montagna, P.; Riccardi, C.; Salvini, P.; Vitulo, P.; Vai, I.; Magnani, A.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Rodozov, M.; Sultanov, G.; Vutova, M.; Stoykova, S.; Hadjiiska, R.; Ibargüen, H.S.; Morales, M.I.P.; Bernardino, S.C.; Bagaturia, I.; Tsamalaidze, Z.; Crotty, I.; Kim, M.S.

2014-12-05

The muon spectrometer of the CMS (Compact Muon Solenoid) experiment at the Large Hadron Collider (LHC) is equipped with a redundant system made of Resistive Plate Chambers and Drift Tube in barrel and RPC and Cathode Strip Chamber in endcap region. In this paper, the operations and performance of the RPC system during the first three years of LHC activity will be reported. The integrated charge was about 2 mC/cm$^{2}$, for the most exposed detectors. The stability of RPC performance, with particular attention on the stability of detector performance such as efficiency, cluster size and noise, will be reported. Finally, the radiation background levels on the RPC system have been measured as a function of the LHC luminosity. Extrapolations to the LHC design conditions and HL-LHC are also discussed.

Templated sequence insertion polymorphisms in the human genome

Science.gov (United States)

Onozawa, Masahiro; Aplan, Peter

2016-11-01

Templated Sequence Insertion Polymorphism (TSIP) is a recently described form of polymorphism recognized in the human genome, in which a sequence that is templated from a distant genomic region is inserted into the genome, seemingly at random. TSIPs can be grouped into two classes based on nucleotide sequence features at the insertion junctions; Class 1 TSIPs show features of insertions that are mediated via the LINE-1 ORF2 protein, including 1) target-site duplication (TSD), 2) polyadenylation 10-30 nucleotides downstream of a “cryptic” polyadenylation signal, and 3) preference for insertion at a 5’-TTTT/A-3’ sequence. In contrast, class 2 TSIPs show features consistent with repair of a DNA double-strand break via insertion of a DNA “patch” that is derived from a distant genomic region. Survey of a large number of normal human volunteers demonstrates that most individuals have 25-30 TSIPs, and that these TSIPs track with specific geographic regions. Similar to other forms of human polymorphism, we suspect that these TSIPs may be important for the generation of human diversity and genetic diseases.

Spin and diffractive physics with a fixed-target experiment at the LHC (AFTER-LHC)

Energy Technology Data Exchange (ETDEWEB)

Lorce, C.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Rosier, P. [IPNO, Universite Paris-Sud, CNRS/IN2P3, F-91406, Orsay (France); Anselmino, M.; Arnaldi, R.; Scomparin, E. [INFN Sez. Torino, Via P. Giuria 1,1-10125, Torino (Italy); Brodsky, S. J. [SLAC National Accelerator Laboratory, Stanford U, Stanford, CA 94309, (United States); Ferreiro, E. G. [Departamento de Fisica de Particulas, Univ. de Santiago de C, 15782 Santiago de C (Spain); Fleuret, F. [Laboratoire Leprince Ringuet, Ecole Polytechnique, CNRS/IN2P3, 91128 Palaiseau (France); Rakotozafindrabe, A. [IRFU/SPhN, CFA Society, 91191 Gifsur-Yvette Cedex (France); Schienbein, I. [LPSC, Universite Joseph Fourier, CNRS/IN2P3/INPG, F-38026 Grenoble (France); Uggerhoj, U. I. [Department of Physics and Astronomy, University of Aarhus (Denmark)

2013-04-15

We report on the spin and diffractive physics at a future multi-purpose f xed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic f xed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The f xed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

Spin and diffractive physics with a fixed-target experiment at the LHC (AFTER-LHC)

International Nuclear Information System (INIS)

Lorcé, C.; Chambert, V.; Didelez, J. P.; Genolini, B.; Hadjidakis, C.; Lansberg, J. P.; Rosier, P.; Anselmino, M.; Arnaldi, R.; Scomparin, E.; Brodsky, S. J.; Ferreiro, E. G.; Fleuret, F.; Rakotozafindrabe, A.; Schienbein, I.; Uggerhøj, U. I.

2013-01-01

We report on the spin and diffractive physics at a future multi-purpose f xed-target experiment with proton and lead LHC beams extracted by a bent crystal. The LHC multi-TeV beams allow for the most energetic f xed-target experiments ever performed, opening new domains of particle and nuclear physics and complementing that of collider physics, in particular that of RHIC and the EIC projects. The luminosity achievable with AFTER using typical targets would surpass that of RHIC by more than 3 orders of magnitude. The f xed-target mode has the advantage to allow for measurements of single-spin asymmetries with polarized target as well as of single-diffractive processes in the target region.

Bringing the LHC and ATLAS to a regional planetarium

CERN Document Server

Schwienhorst, Reinhard

2011-01-01

An outreach effort has started at Michigan State University to bring particle physics, the Large Hadron Collider, and the ATLAS experiment to a general audience at the Abrams planetarium on the MSU campus. A team of undergraduate students majoring in physics, communications arts & sciences, and journalism are putting together short clips about ATLAS and the LHC to be shown at the planetarium.

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.

5th report from the LHC performance workshop

CERN Multimedia

Bulletin's correspondent from Chamonix

2012-01-01

The morning session on Friday 10 February - the final day of the workshop - saw further examination of the challenges of the High Luminosity LHC and included a look at the state of R&D for the new magnets required for the high luminosity interaction regions. There was then an entertaining look at even more distant future. Possible future projects under consideration include the Large Hadron electron Collider (LHeC) which foresees colliding 60 GeV electrons with 7 TeV protons, and the High Energy LHC (HE-LHC) in which the beam energy of the LHC is increased from 7 to 16.5 TeV. Serious technological challenges exist for both these options. In the afternoon Steve Myers, CERN's Director for Accelerators and Technology, presented a summary of the workshop recommendations. In brief, the LHC should operate at 4 TeV in 2012 with the key priorities being: delivering enough luminosity to ATLAS and CMS to allow them to independently discover or exclude the Higgs; the proton-Lead ion run; and machine deve...

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.

Overview of the ATLAS Insertable B-Layer (IBL) Project

CERN Document Server

Pohl, D-L; The ATLAS collaboration

2013-01-01

The upgrades for the ATLAS Pixel Detector will be staged in preparation for high luminosity LHC. The first upgrade for the Pixel Detector will be the construction of a new pixel layer which is currently under construction and will be installed during the first shutdown of the LHC machine, in 2013-14. The new detector, called the Insertable B-layer (IBL), will be installed between the existing Pixel Detector and a new, smaller radius beam-pipe at a radius of 3.3 cm. The IBL required the development of several new technologies to cope with increased radiation and pixel occupancy and also to improve the physics performance through reduction of the pixel size and a more stringent material budget. Two different silicon sensor technologies, planar n-in-n and 3D, will be used, connected with the new generation 130nm IBM CMOS FE-I4 readout chip via solder bump-bonds. 32 FEs with sensors are glued to a light weight carbon-carbon structure which incorporates a titanium cooling tube for a CO2 cooling system. In total th...

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...

ISABELLE insertion quadrupoles

International Nuclear Information System (INIS)

Kaugerts, J.; Polk, I.; Sampson, W.; Dahl, P.F.

1979-01-01

Beam focussing and control at the beam intersection regions of ISABELLE is accomplished by a number of superconducting insertion quadrupoles. These magnets differ from the standard ISABELLE quadrupoles in various ways. In particular, the requirements of limited space near the intersections and aperture for beam extraction impose constraints on their configuration. To achieve optimum beam focussing and provide tuning flexibility calls for stronger quadrupole trim windings than those in the standard quadrupoles. The magnetic and mechanical design of the insertion quadrupoles and their associated correction and steering windings to accomplish the above tasks is presented

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 ...

Beam Based Measurements of Field Multipoles in the RHIC Low Beta Insertions and Extrapolation of the Method to the LHC

CERN Document Server

Koutchouk, Jean-Pierre; Ptitsyn, V I

2001-01-01

The multipolar content of the dipoles and quadrupoles is known to limit the stability of the beam dynamics in super-conducting machines like RHIC and even more in LHC. The low-beta quadrupoles are thus equipped with correcting coils up to the dodecapole order. The correction is planned to rely on magnetic measurements. We show that a relatively simple method allows an accurate measurement of the multipolar field aberrations using the beam. The principle is to displace the beam in the non-linear fields by local closed orbit bumps and to measure the variation of sensitive beam observable. The resolution and robustness of the method are found appropriate. Experimentation at RHIC showed clearly the presence of normal and skew sextupolar field components in addition to a skew quadrupolar component in the interaction regions. Higher-order components up to decapole order appear as well.

Post LHC7 SUSY benchmark points for ILC physics

Energy Technology Data Exchange (ETDEWEB)

Baer, Howard [Oklahoma Univ., Norman, OK (United States); List, Jenny [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2012-05-15

We re-evaluate prospects for supersymmetry at the proposed International Linear e{sup +}e{sup -} Collider (ILC) in light of the first year of serious data taking at LHC with {radical}(s)=7 TeV and {proportional_to}5 fb{sup -1} of pp collisions (LHC7). Strong new limits from LHC SUSY searches, along with a hint of a Higgs boson signal around m{sub h}{proportional_to}125 GeV, suggest a paradigm shift from previously popular models to ones with new and compelling signatures. We present a variety of new ILC benchmark models, including: natural SUSY, hidden SUSY, NUHM2 with low m{sub A}, non-universal gaugino mass (NUGM) model, pMSSM, Kallosh-Linde model, Bruemmer-Buchmueller model, normal scalar mass hierarchy (NMH) plus one surviving case from mSUGRA/CMSSM in the far focus point region. While all these models at present elude the latest LHC limits, they do offer intriguing case study possibilities for ILC operating at {radical}(s){proportional_to}0.25-1 TeV, and present a view of some of the diverse SUSY phenomena which might be expected at both LHC and ILC in the post LHC7 era.

Post LHC7 SUSY benchmark points for ILC physics

International Nuclear Information System (INIS)

Baer, Howard; List, Jenny

2012-05-01

We re-evaluate prospects for supersymmetry at the proposed International Linear e + e - Collider (ILC) in light of the first year of serious data taking at LHC with √(s)=7 TeV and ∝5 fb -1 of pp collisions (LHC7). Strong new limits from LHC SUSY searches, along with a hint of a Higgs boson signal around m h ∝125 GeV, suggest a paradigm shift from previously popular models to ones with new and compelling signatures. We present a variety of new ILC benchmark models, including: natural SUSY, hidden SUSY, NUHM2 with low m A , non-universal gaugino mass (NUGM) model, pMSSM, Kallosh-Linde model, Bruemmer-Buchmueller model, normal scalar mass hierarchy (NMH) plus one surviving case from mSUGRA/CMSSM in the far focus point region. While all these models at present elude the latest LHC limits, they do offer intriguing case study possibilities for ILC operating at √(s)∝0.25-1 TeV, and present a view of some of the diverse SUSY phenomena which might be expected at both LHC and ILC in the post LHC7 era.

A full acceptance detector at the LHC

International Nuclear Information System (INIS)

Avati, V.; Eggert, K.; Taylor, C.

1999-01-01

The FELIX collaboration has proposed the construction of a full acceptance detector for the LHC, to be located at Intersection Region 4, and to be commissioned concurrently with the LHC. The primary mission of FELIX is QCD: to provide comprehensive and definitive observations of a very broad range of strong-interaction processes. This paper reviews the detector concept and performance characteristics, the physics menu, and plans for integration of FELIX into the collider lattice and physical environment. The current status of the FELIX Letter of Intent is discussed

Cold Leak Tests of LHC Beam Screens

CERN Document Server

Collomb-Patton, C; Jenninger, B; Kos, N

2009-01-01

In order to guide the high energy proton beams inside its two 27 km long vacuum rings, the Large Hadron Collider (LHC) at CERN, Geneva, makes use of superconducting technology to create the required magnetic fields. More than 4000 beam screens, cooled at 7 20 K, are inserted inside the 1.9 K beam vacuum tubes to intercept beam induced heat loads and to provide dynamic vacuum stability. As extremely high helium leak tightness is required, all beam screens have been leak tested under cold conditions in a dedicated test stand prior to their installation. After describing the beam screen design and its functions, this report focuses on the cold leak test sequence and discusses the results.

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.

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...

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...

Supersymmetric dark matter after LHC run 1

International Nuclear Information System (INIS)

Bagnaschi, E.A.; Buchmueller, O.; Cavanaugh, R.; Illinois Univ., Chicago, IL

2015-08-01

Different mechanisms operate in various regions of the MSSM parameter space to bring the relic density of the lightest neutralino, χ 0 1 , assumed here to be the LSP and thus the Dark Matter (DM) particle, into the range allowed by astrophysics and cosmology. These mechanisms include coannihilation with some nearly-degenerate next-to-lightest supersymmetric particle (NLSP) such as the lighter stau τ 1 , stop t 1 or chargino χ ± 1 , resonant annihilation via direct-channel heavy Higgs bosons H/A, the light Higgs boson h or the Z boson, and enhanced annihilation via a larger Higgsino component of the LSP in the focus-point region. These mechanisms typically select lower-dimensional subspaces in MSSM scenarios such as the CMSSM, NUHM1, NUHM2 and pMSSM10. We analyze how future LHC and direct DM searches can complement each other in the exploration of the different DM mechanisms within these scenarios. We find that the τ 1 coannihilation regions of the CMSSM, NUHM1, NUHM2 can largely be explored at the LHC via searches for missing E T events and long-lived charged particles, whereas their H/A funnel, focus-point and χ ± 1 coannihilation regions can largely be explored by the LZ and Darwin DM direct detection experiments. We find that the dominant DM mechanism in our pMSSM10 analysis is χ ± 1 coannihilation: parts of its parameter space can be explored by the LHC, and a larger portion by future direct DM searches.

Design, Fabrication and Initial Testing of a Large Bore Single Aperture 1 m Long Superconducting Dipole Made with Phenolic Inserts

CERN Document Server

Boschmann, H; Kirby, G A; Lucas, J; Ostojic, R; Russenschuck, Stephan; Siemko, A; Vanenkov, I; Weterings, W

1997-01-01

In the framework of the LHC magnet development programme, a large bore single aperture 1-meter long superconducting dipole has been built in collaboration with HOLEC. The magnet features a single layer coil wound using the LHC main dipole outer layer cable, phenolic inserts, and a keyed two part structural iron yoke. This paper presents the magnetic and mechanical design and optimisation of the magnet. We describe the coil winding and curing, and present the construction and assembly procedures. Finally we report on the mechanical behaviour during assembly and cooling, and present the magnet training behaviour.

The ATLAS Insertable B-Layer: from construction to operation

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00218666; The ATLAS collaboration

2016-01-01

The ATLAS Insertable B-Layer (IBL) is the innermost layer of pixel detectors, and was installed in May 2014 at a radius of 3.3 cm from the beam axis, between the existing Pixel detector and a new smaller radius beam-pipe. The new detector, built to cope with high radiation and occupancy, is the first large scale application of 3D sensors and CMOS 130 nm technology. The IBL detector construction was completed within about two years (2012-2014), and the key features and challenges met during the IBL project are presented, as well as its commissioning and operational experience at the LHC

The Cryogenic Design of the Phase I Upgrade Inner Triplet Magnets for LHC

CERN Document Server

van Weelderen, R; Peterson, T

2011-01-01

The LHC is operating with beam since end 2009. However, with the present interaction region magnets it cannot reach its nominal performance and a phased approach to upgrading them to reach that nominal performance is taken. The first phase of the LHC interaction region upgrade was approved by Council in December 2007. This phase relies on the mature Nb-Ti superconducting magnet technology with the target of increasing the LHC luminosity to 2 to 3×1034 cm-2s-1, while relying on the existing infrastructure which limits the total heat removal capacity at 1.9 K to 500 W. The Phase I Upgrade LHC interaction region final focus magnets will include four superconducting quadrupoles (low-β triplets) and one superconducting dipole (D1) cooled with pressurized, static superfluid helium (HeII) at 1.9 K. The heat absorbed in pressurized HeII, which may be more than 30 W/m due to dynamic heating from the particle beam halo, will be conducted to saturated He II at about 1.9 K and removed by the low pressure vapour. This p...

Quench propagation in the superconducting 6 kA flexible busbars of the LHC

International Nuclear Information System (INIS)

Herzog, R.; Calvi, M.; Sonnemann, F.; Pelegrin-Carcelen, J.M.

2002-01-01

Flexible superconducting cables with currents up to 6 kA will be used to power magnets individually in the insertion regions of the LHC. In case of a quench, the currents in these circuits will decay very fast (with time constants of about 200 ms) such that relatively small copper cross sections are sufficient for these busbars. Quench propagation experiments on a prototype cable and corresponding simulations led to a detailed understanding of the quench behavior of these busbars and to recommendations for the design and application of the cable. Simulations of the quench process in a multi-strand conductor led to a detailed understanding of the way current crosses from superconducting to pure copper strands and how this affects the quench propagation velocity. At nominal current (6 kA), the quench propagation velocities are high (10 m/s) and the hot spot temperature increases rapidly. In this situation, timely quench detection and energy extraction (current reduction) are vital to prevent damage of circuit components

Quench Propagation in the Superconducting 6 kA Flexible Busbars of the LHC

CERN Document Server

Calvi, M; Pelegrin-Carcelen, J M; Sonnemann, F

2002-01-01

Flexible superconducting cables with currents up to 6 kA will be used to power magnets individually in the insertion regions of the LHC. In case of a quench, the currents in these circuits will decay very fast (with time constants of about 200 ms) such that relatively small copper cross sections are sufficient for these busbars. Quench propagation experiments on a prototype cable and corresponding simulations led to a detailed understanding of the quench behavior of these busbars and to recommendations for the design and application of the cable. Simulations of the quench process in a multi-strand conductor led to a detailed understanding of the way current crosses from superconducting to pure copper strands and how this affects the quench propagation velocity. At nominal current (6 kA), the quench propagation velocities are high (10 m/s) and the hot spot temperature increases rapidly. In this situation, timely quench detection and energy extraction (current reduction) are vital to prevent damage of circuit c...

Quench propagation in the superconducting 6 kA flexible busbars of the LHC

Science.gov (United States)

Herzog, R.; Calvi, M.; Sonnemann, F.; Pelegrin-Carcelen, J. M.

2002-05-01

Flexible superconducting cables with currents up to 6 kA will be used to power magnets individually in the insertion regions of the LHC. In case of a quench, the currents in these circuits will decay very fast (with time constants of about 200 ms) such that relatively small copper cross sections are sufficient for these busbars. Quench propagation experiments on a prototype cable and corresponding simulations led to a detailed understanding of the quench behavior of these busbars and to recommendations for the design and application of the cable. Simulations of the quench process in a multi-strand conductor led to a detailed understanding of the way current crosses from superconducting to pure copper strands and how this affects the quench propagation velocity. At nominal current (6 kA), the quench propagation velocities are high (10 m/s) and the hot spot temperature increases rapidly. In this situation, timely quench detection and energy extraction (current reduction) are vital to prevent damage of circuit components.

Upgrade of the CMS Tracker for the High Luminosity LHC

CERN Document Server

Auzinger, Georg

2016-01-01

The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about $ 5 \\times 10^{34}$cm$^{-2}$s$^{-1}$ in 2028, possibly reaching an integrated luminosity of 3000 fb$^{-1}$ by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 Upgrade. The current CMS Tracker, including both inner pixel and outer strip systems, is already running beyond design specifications and will not be able to survive HL-LHC radiation conditions. CMS will need a completely new device in order to fully exploit the demanding operating conditions and the delivered luminosity. The upgrade plan includes extending the Pixel Detector in the forward region from the current coverage of $ \\lvert \\eta \\rvert < 2.4 $ to $ \\lvert \\eta \\rvert < 4$, where up to seven forward- and four extension disks will compose the new detector. Additionally, the new outer system should also have trigger capabilities. To achieve such goals, R\\&...

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...

The ATLAS liquid argon calorimeter: upgrade plans for the HL-LHC

CERN Document Server

Novgorodova, O; The ATLAS collaboration

2014-01-01

The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 1034cm-2s-1. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudorapidity region |η|<3.2, and for hadronic calorimetry in the region from |η|=1.5 to |η|=4.9. Although the nominal LHC experimental programme is still in progress, plans for a High Luminosity LHC (HL-LHC) are already being developed for operation of the collider and associated detectors at luminosities of up to (5-7)×1034 cm-2s-1, with the goal of accumulating an integrated luminosity of 3000 fb-1. The proposed instantaneous and integrated luminosities are both well beyond the values for which the detectors were designed. The electromagnetic and hadronic calorimeters will be able to tolerate the increased particle flux, but the performance of the forward calorimeter (FCal) will be affected. Two solutions for this are un...

Alignment of the ATLAS inner detector for the LHC Run II

CERN Document Server

Butti, Pierfrancesco; The ATLAS collaboration

2015-01-01

ATLAS a multipurpose experiment at the LHC proton-proton collider. Its physics goals require high resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system, notably quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). Offline track alignment of the ATLAS tracking system has to deal with about 700,000 degrees of freedom (DoF) defining its geometrical parameters. The task requires using very large data sets and represents a considerable numerical challenge in terms of both CPU time and precision. The adopted strategy uses a hierarchical approach to alignment, combining local and global least squares techniques. An outl...

Alignment of the ATLAS Inner Detector in the LHC Run II

CERN Document Server

Barranco Navarro, Laura; The ATLAS collaboration

2015-01-01

ATLAS physics goals require excellent resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system and on the quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the Run II of the LHC, the system was upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). An outline of the track based alignment approach and its implementation within the ATLAS software will be presented. Special attention will be paid to integration of the IBL into the alignment framework, techniques allowing to identify and eliminate tracking systematics as well as strategies to deal with time-dependent alignment. Performance from the commissioning of Cosmic data and potentially early LHC Run II proton-proton collisions will be discussed.

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...

Beam Cleaning in Experimental IRs in HL-LHC for the Incoming Beam

CERN Document Server

Garcia-Morales, H; Bruce, Roderik; Redaelli, Stefano

2015-01-01

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) optics layout, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches or machine damage. This paper studies the effectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that additional tertiary collimators would be beneficial in order to protect not only the final focusing triplets but also the two quadrupoles further upstream.

Beam cleaning of the incoming beam in experimental IRs in HL-LHC

CERN Document Server

Garcia Morales, Hector; Redaelli, Stefano; De Maria, Riccardo; CERN. Geneva. ATS Department

2017-01-01

The HL-LHC will store 675 MJ of energy per beam, about 300 MJ more than the nominal LHC. Due to the increase in stored energy and a different interaction region (IR) layout and optics design, the collimation system for the incoming beam must be revisited in order to avoid dangerous losses that could cause quenches and machine damage. This paper studies the effectiveness of the current LHC collimation system in intercepting cleaning losses close to the experiments in the HL-LHC. The study reveals that in addition to the triplet also the Q4 needs local protection, which could be provided by an additional pair of TCTs.

Double diffractive cross-section measurement in the forward region at LHC

Czech Academy of Sciences Publication Activity Database

Antchev, G.; Aspell, P.; Atanassov, I.; Kašpar, Jan; Kopal, Josef; Kundrát, Jan; Lokajíček, Miloš V.; Procházka, Jiří

2013-01-01

Roč. 111, č. 26 (2013), "262001-1"-"262001-6" ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LG13031 Institutional support: RVO:68378271 Keywords : LHC * TOTEM * diffractive production Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 7.728, year: 2013

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

Confronting SUSY models with LHC data via electroweakino production

Energy Technology Data Exchange (ETDEWEB)

Arina, Chiara [Centre for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,B-1348 Louvain-la-Neuve (Belgium); Chala, Mikael [Deutsches Elektronen Synchrotron,Notkestrasse 85, D-22603, Hamburg (Germany); Martín-Lozano, Víctor [Departamento de Física Teórica & Instituto de Física Teórica UAM/CSIC,Universidad Autónoma de Madrid,E-28049, Madrid (Spain); Bethe Center for Theoretical Physics & Physikalisches Institut der Universität Bonn,Nußallee 12, 53115, Bonn (Germany); Nardini, Germano [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics,University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland)

2016-12-29

We investigate multi-lepton signals produced by ElectroWeakino (EWino) decays in the MSSM and the TMSSM scenarios with sfermions, gluinos and non Standard Model Higgses at the TeV scale, with dark matter due to electroweak-scale Binos. We recast the present LHC constraints on EWinos for these models and we find that wide MSSM and TMSSM parameter regions prove to be allowed. We forecast the number of events expected in the signal regions of the experimental multi-lepton analyses in the next LHC runs. The correlations among these numbers will help to determine whether future deviations in multi-lepton data are ascribable to the EWinos, as well as the supersymmetric model they originate from.

Confronting SUSY models with LHC data via electroweakino production

International Nuclear Information System (INIS)

Arina, Chiara; Chala, Mikael; Martin-Lozano, Victor; Bonn Univ.; Nardini, Germano

2016-12-01

We investigate multi-lepton signals produced by ElectroWeakino (EWino) decays in the MSSM and the TMSSM scenarios with sfermions, gluinos and non Standard Model Higgses at the TeV scale, being the Bino electroweak-scale dark matter. We recast the present LHC constraints on EWinos for these models and we find that wide MSSM and TMSSM parameter regions prove to be allowed. We forecast the number of events expected in the signal regions of the experimental multi-lepton analyses in the next LHC runs. The correlations among these numbers will help to determine whether future deviations in multi-lepton data are ascribable to the EWinos, as well as the supersymmetric model they originate from.

FELIX. A full acceptance detector at the LHC

International Nuclear Information System (INIS)

Avati, V.; Eggert, K.; Taylor, C.

1999-01-01

The FELIX collaboration has proposed the construction of a full acceptance detector for the LHC, to be located at Intersection Region 4, and to be commissioned concurrently with the LHC. The primary mission of FELIX is QCD: to provide comprehensive and definitive observations of a very broad range of strong-interaction processes. This paper reviews the detector concept and performance characteristics, the physics menu, and plans for integration of FELIX into the collider lattice and physical environment. The current status of the FELIX letter of intent is discussed. (orig.)

FELIX a full-acceptance detector at the LHC

CERN Document Server

Avati, V.; Taylor, C.

1999-01-01

The FELIX collaboration has proposed the construction of a full acceptance detector for the LHC, to be located at Intersection Region 4, and to be commissioned concurrently with the LHC. The primary mission of FELIX is QCD: to provide comprehensive and definitive observations of a very broad range of strong-interaction processes. This paper reviews the detector concept and performance characteristics, the physics menu, and plans for integration of FELIX into the collider lattice and physical environment. The current status of the FELIX Letter of Intent is discussed.

Upgrade of the ATLAS hadronic Tile calorimeter for the High luminosity LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00236332; The ATLAS collaboration

2016-01-01

The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It is a sampling calorimeter consisting of alternating thin steel plates and scintillating tiles. Wavelength shifting fibers coupled to the tiles collect the produced light and are read out by photomultiplier tubes. An analog sum of the processed signal of several photomultipliers serves as input to the first level of trigger. Photomultiplier signals are then digitized and stored on detector and are only transferred off detector once the first trigger acceptance has been confirmed. The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the detector and data acquisition system for the HL-LHC. In particular, TileCal will undergo a major replacement of its on- and off-detector electronics. All signals will be digitized and then...

Upgrade of the ATLAS hadronic Tile calorimeter for the High luminosity LHC

CERN Document Server

Mlynarikova, Michaela; The ATLAS collaboration

2017-01-01

The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It is a sampling calorimeter consisting of alternating thin steel plates and scintillating tiles. Wavelength shifting fibers coupled to the tiles collect the produced light and are read out by photomultiplier tubes. Currently, an analog sum of the processed signal of several photomultipliers serves as input to the first level of trigger. Photomultiplier signals are then digitized and stored on detector and are only transferred off detector once the first trigger acceptance has been confirmed. The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the detector and data acquisition system for the HL-LHC. In particular, TileCal will undergo a major replacement of its on- and off-detector electronics. All signals will be digitiz...

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...

The CMS Tracker Upgrade for HL-LHC\\\\ Sensor R$\\&$D

CERN Document Server

Naseri, Mohsen

2014-01-01

At an instantaneous luminosity of 5~$\\times10^{34}~cm^{-2}~s^{-1}$, the high-luminosity phase of the Large Hadron Collider (HL-LHC) is expected to deliver a total of 3000~fb$^{-1}$ of collisions, hereby increasing the discovery potential of the LHC experiments significantly. However, the radiation environment of the tracking system will be severe, requiring new radiation hard sensors for the CMS tracker. Focusing on the upgrade of the outer tracker region, the CMS tracker collaboration has almost completed a large material investigation and irradiation campaign to identify the silicon material and design that fulfils all requirements of a new tracking detector at HL-LHC. Focusing on the upgrade of the outer tracker region, pad diodes as well as fully functional strip sensors have been implemented on silicon wafers with different material properties and thicknesses. The samples were irradiated with a mixture of neutrons and protons corresponding to fluences as expected for various positions in the future track...

Irradiation of a very forward calorimeter in the LHC environment: some consequences

International Nuclear Information System (INIS)

Ferrando, A.; Josa, M.I.; Malinin, A.; Martinez-Laso, L.; Pojidaev; V.; Salicio, J.M.

1994-01-01

We have computed the level of irradiation in the very forward region (2.5< <4.7) of an LHC experimental, using the proposed CMS (Compact Solenoidal Detector for LHC) setup. Information about the induced radioactivity in the absorber of a proposed iron/gas Very Forward Calorimeter has been extracted. (Author) 11 refs

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.)

Z Production as a Test of Nuclear Effects at the LHC

CERN Document Server

Zhang, X; Zhang, Xiaofei; Fai, George

2002-01-01

We predict the Z transverse momentum distribution from proton-proton and nuclear collisions at the LHC. After demonstrating that higher-twist nuclear effects are very small, we propose $Z^0$ production as a precision test for leading-twist pQCD in the TeV energy region. We also point out that shadowing may result in unexpected phenomenology at the LHC.

Inter-comparison of MARS and FLUKA: Predictions on Energy Deposition in LHC IR Quadrupoles

CERN Document Server

Hoa, C; Cerutti, F; Ferrai, A

2008-01-01

Detailed modellings of the LHC insertion regions (IR) have earlier been performed to evaluate energy deposition in the IR superconducting magnets [1-4]. Proton-proton collisions at 14 TeV in the centre of mass lead to debris, depositing energy in the IR components. To evaluate uncertainties in those simulations and gain further confidence in the tools and approaches used, inter-comparison calculations have been performed with the latest versions of the FLUKA (2006.3b) [5, 6] and MARS15 [7, 8] Monte Carlo codes. These two codes, used worldwide for multi particle interaction and transport in accelerator, detector and shielding components, have been thoroughly benchmarked by the code authors and the user community (see, for example, recent [9, 10]). In the study described below, a better than 5% agreement was obtained for energy deposition calculated with these two codes - based on different independent physics models - for the identical geometry and initial conditions of a simple model representing the IR5 and ...

Inter-comparison of MARS and FLUKA: Predictions on energy deposition in LHC IR quadrupoles

International Nuclear Information System (INIS)

Hoa, Christine; Cerutti, F.; Ferrari, A.; Mokhov, N.V.

2008-01-01

Detailed modelings of the LHC insertion regions (IR) have earlier been performed to evaluate energy deposition in the IR superconducting magnets [1-4]. Proton-proton collisions at 14 TeV in the centre of mass lead to debris, depositing energy in the IR components. To evaluate uncertainties in those simulations and gain further confidence in the tools and approaches used, inter-comparison calculations have been performed with the latest versions of the FLUKA (2006.3b) [5, 6] and MARS15 [7, 8] Monte Carlo codes. These two codes, used worldwide for multi particle interaction and transport in accelerator, detector and shielding components, have been thoroughly benchmarked by the code authors and the user community (see, for example, recent [9, 10]). In the study described below, a better than 5% agreement was obtained for energy deposition calculated with these two codes--based on different independent physics models--for the identical geometry and initial conditions of a simple model representing the IR5 and its first quadrupole

Studying Radiation Tolerant ICs for LHC

CERN Multimedia

Faccio, F; Snoeys, W; Campbell, M; Casas-cubillos, J; Gomes, P

2002-01-01

%title\\\\ \\\\In the recent years, intensive work has been carried out on the development of custom ICs for the readout electronics for LHC experiments. As far as radiation hardness is concerned, attention has been focussed on high total dose applications, mainly for the tracker systems. The dose foreseen in this inner region is estimated to be higher than 1~Mrad/year. In the framework of R&D projects (RD-9 and RD-20) and in the ATLAS and CMS experiments, the study of different radiation hard processes has been pursued and good contacts with the manufacturers have been established. The results of these studies have been discussed during the Microelectronics User Group (MUG) rad-hard meetings, and now some HEP groups are working to develop radiation hard ICs for the LHC experiments on some of the available rad-hard processes.\\\\ \\\\In addition, a lot of the standard commercial electronic components and ASICs which are planned to be installed near the LHC machine and in the detectors will receive total doses in ...

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/

Irradiation of a very forward calorimeter in the LHC environment: Some consequences

International Nuclear Information System (INIS)

Ferrando, A.; Josa, M. I.; Malinin, A.; Martinez-Laso, L.; Pojidaev, V.; Salicio, J. M.

1994-01-01

We have computed the level of irradiation in the very forward region (2.5 < | η | < 4.7) 4.7) of an LHC experiment, using the proposed CMS (Compact Solenoidal Detector for LHC) setup. Information about the induced radioactivity in the absorber of a proposed iron/gas Very Forward Calorimeter has been extracted. (Author) 11 refs

Irradiation of a very forward calorimeter in the LHC environment: Some consequences

Energy Technology Data Exchange (ETDEWEB)

Ferrando, A.; Josa, M. I.; Malinin, A.; Martinez-Laso, L.; Pojidaev, V.; Salicio, J. M.

1994-07-01

We have computed the level of irradiation in the very forward region (2.5 < | {eta} | < 4.7) 4.7) of an LHC experiment, using the proposed CMS (Compact Solenoidal Detector for LHC) setup. Information about the induced radioactivity in the absorber of a proposed iron/gas Very Forward Calorimeter has been extracted. (Author) 11 refs.

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 Physics Programme Of The MoEDAL Experiment At The LHC

CERN Document Server

Acharya, B.; Bernabeu, J.; Campbell, M.; Cecchini, S.; Chwastowski, J.; De Montigny, M.; Derendarz, D.; De Roeck, A.; Ellis, J.R.; Fairbairn, M.; Felea, D.; Frank, M.; Frekers, D.; Garcia, C.; Giacomelli, G.; Giorgini, M.; Hasegan, D.; Hott, T.; J.Jak\\r u; Katre, A.; Kim, D-W.; King, M.G.L.; Kinoshita, K.; Lacarrere, D.; Lee, S.C.; Leroy, C.; Margiotta, A.; Mauri, N.; Mavromatos, N.E.; Mermod, P.; Mitsou, V.A.; Orava, R.; Pasqualini, L.; Patrizii, L.; Pavalas, G.E.; Pinfold, J.L.; Platkevic, M.; Popa, V.; Pozzato, M.; Pospisil, S.; Rajantie, A.; Sahnoun, Z.; Sakellariadou, M.; Sarkar, S.; Semenoff, G.; Sirri, G.; Sliwa, K.; Soluk, R.; Spurio, M.; Srivastava, Y.N.; Staszewski, R.; Swain, J.; Tenti, M.; Togo, V.; Trzebinski, M.; Tuszynski, J.A.; Vento, V.; Vives, O.; Vykydal, Z.; Widom, A.; Yoon, J.H.

2014-01-01

The MoEDAL experiment at Point 8 of the LHC ring is the seventh and newest LHC experiment. It is dedicated to the search for highly ionizing particle avatars of physics beyond the Standard Model, extending significantly the discovery horizon of the LHC. A MoEDAL discovery would have revolutionary implications for our fundamental understanding of the Microcosm. MoEDAL is an unconventional and largely passive LHC detector comprised of the largest array of Nuclear Track Detector stacks ever deployed at an accelerator, surrounding the intersection region at Point 8 on the LHC ring. Another novel feature is the use of paramagnetic trapping volumes to capture both electrically and magnetically charged highly-ionizing particles predicted in new physics scenarios. It includes an array of TimePix pixel devices for monitoring highly-ionizing particle backgrounds. The main passive elements of the MoEDAL detector do not require a trigger system, electronic readout, or online computerized data acquisition. The aim of this...

Novel time-dependent alignment of the ATLAS Inner Detector in the LHC Run 2

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00386283; The ATLAS collaboration

2016-01-01

ATLAS is a multipurpose experiment at the LHC proton-proton collider. Its physics goals require an unbiased and high resolution measurement of the charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system and the quality of the alignment of its components. For the LHC Run 2, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). ATLAS Inner Detector alignment framework has been adapted and upgraded to correct very short time scale movements of the sub-detectors. In particular, a mechanical distortion of the IBL staves up to 20 μm and a vertical displacement of the Pixel detector of ~6 μm have been observed during data-taking. The techniques used to correct for these effects and to match the required Inner Detector performance will be presented.

Alignment of the ATLAS Inner Detector upgraded for the LHC Run II

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00386283; The ATLAS collaboration

2015-01-01

ATLAS is a multipurpose experiment at the LHC proton-proton collider. Its physics goals require high resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system, notably quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). Offline track alignment of the ATLAS tracking system has to deal with about 700,000 degrees of freedom (DoF) defining its geometrical parameters. The task requires using very large data sets and represents a considerable numerical challenge in terms of both CPU time and precision. The adopted strategy uses a hierarchical approach to alignment, combining local and global least squares techniques. An o...

Alignment of the ATLAS Inner Detector Upgraded for the LHC Run II

CERN Document Server

Butti, Pierfrancesco; The ATLAS collaboration

2015-01-01

ATLAS is a multipurpose experiment at the LHC proton-proton collider. Its physics goals require high resolution, unbiased measurement of all charged particle kinematic parameters. These critically depend on the layout and performance of the tracking system, notably quality of its offline alignment. ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift- tubes, all embedded in a 2T solenoidal magnetic field. For the LHC Run II, the system has been upgraded with the installation of a new pixel layer, the Insertable B-layer (IBL). Offline track alignment of the ATLAS tracking system has to deal with about 700,000 degrees of freedom (DoF) defining its geometrical parameters. The task requires using very large data sets and represents a considerable numerical challenge in terms of both CPU time and precision. The adopted strategy uses a hierarchical approach to alignment, combining local and global least squares techniques. An o...

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)

Upgrade of the beam extraction system of the GTS-LHC electron cyclotron resonance ion source at CERN.

Science.gov (United States)

Toivanen, V; Bellodi, G; Dimov, V; Küchler, D; Lombardi, A M; Maintrot, M

2016-02-01

Linac3 is the first accelerator in the heavy ion injector chain of the Large Hadron Collider (LHC), providing multiply charged heavy ion beams for the CERN experimental program. The ion beams are produced with GTS-LHC, a 14.5 GHz electron cyclotron resonance ion source, operated in afterglow mode. Improvement of the GTS-LHC beam formation and beam transport along Linac3 is part of the upgrade program of the injector chain in preparation for the future high luminosity LHC. A mismatch between the ion beam properties in the ion source extraction region and the acceptance of the following Low Energy Beam Transport (LEBT) section has been identified as one of the factors limiting the Linac3 performance. The installation of a new focusing element, an einzel lens, into the GTS-LHC extraction region is foreseen as a part of the Linac3 upgrade, as well as a redesign of the first section of the LEBT. Details of the upgrade and results of a beam dynamics study of the extraction region and LEBT modifications will be presented.

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.

CERN receives its first US-built component for the LHC

CERN Multimedia

Maximilien Brice

2003-01-01

In a milestone for global science collaboration, CERN has taken delivery of the first US-built contribution to the LHC. The 25-tonne interaction-region dipole magnet, which will guide the LHC's two counter-rotating beams of protons into collision, was built at the US Brookhaven National Laboratory. It is the first of 20 that the laboratory will ultimately provide and took nine months for more than 100 scientists, engineers and technicians to construct. Brookhaven's Superconducting Magnet Division is now building the remaining 19 magnets, which will be shipped to CERN later this year. They are provided for the LHC under the terms of a 1998 agreement between CERN and the US Department of Energy and National Science Foundation.

Progress with Long-Range Beam-Beam Compensation Studies for High Luminosity LHC

Energy Technology Data Exchange (ETDEWEB)

Rossi, Adriana; et al.

2017-05-01

Long-range beam-beam (LRBB) interactions can be a source of emittance growth and beam losses in the LHC during physics and will become even more relevant with the smaller '* and higher bunch intensities foreseen for the High Luminosity LHC upgrade (HL-LHC), in particular if operated without crab cavities. Both beam losses and emittance growth could be mitigated by compensat-ing the non-linear LRBB kick with a correctly placed current carrying wire. Such a compensation scheme is currently being studied in the LHC through a demonstration test using current-bearing wires embedded into col-limator jaws, installed either side of the high luminosity interaction regions. For HL-LHC two options are considered, a current-bearing wire as for the demonstrator, or electron lenses, as the ideal distance between the particle beam and compensating current may be too small to allow the use of solid materials. This paper reports on the ongoing activities for both options, covering the progress of the wire-in-jaw collimators, the foreseen LRBB experiments at the LHC, and first considerations for the design of the electron lenses to ultimately replace material wires for HL-LHC.

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.

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

Upgrade of the ATLAS hadronic Tile calorimeter for the High luminosity LHC

CERN Document Server

Asensi Tortajada, Ignacio; The ATLAS collaboration

2017-01-01

The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the central region of the ATLAS detector at the LHC. It is a sampling calorimeter consisting of alternating thin steel plates and scintillating tiles. Wavelength shifting fibers coupled to the tiles collect the produced light and are read out by photomultiplier tubes. An analog sum of the processed signal of several photomultipliers serves as input to the first level of trigger. Photomultiplier signals are then digitized at 40 MHz and stored on detector and are only transferred off detector once the first level trigger acceptance has been confirmed (at a rate of maximum 100 kHz). The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade, in 2024, will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. In particular, TileCal will undergo a major replacement of its on- and of...

Field measurement of a Fermilab-built full scale prototype quadrupole magnet for the LHC interaction regions

CERN Document Server

Bossert, R; Di Marco, J; Fehér, S; Glass, H; Kerby, J S; Lamm, M J; Nobrega, A; Nicol, T H; Ogitsu, T; Orris, D; Page, T; Rabehl, Roger Jon; Sabbi, G L; Schlabach, P; Strait, J B; Sylvester, C D; Tartaglia, M; Tompkins, J C; Velev, G V; Zlobin, A V

2002-01-01

Superconducting low-beta quadrupole magnets for the interaction regions of the Large Hadron Collider have been developed by the US- LHC Accelerator Project. These 70 mm bore 5.5 m long quadrupoles are intended to operate in superfluid helium at 1.9 K with a nominal field gradient of 215 T/m. Following a series of 2 m long models, a full scale cryostated cold mass has been fabricated and cold tested at Fermilab. Magnetic field measurements of the prototype, including determination of the field axis using a single stretched wire, have been performed. These measurements and comparisons with results from the model magnets as well as field quality and alignment requirements are reported in this paper. (8 refs).

Cryogenic Beam Loss Monitoring for the LHC

CERN Document Server

Kurfuerst, C; Sapinski, M

A Beam Loss Monitoring (BLM) system was installed on the outside surface of the LHC magnet cryostats to protect the accelerator equipment from beam losses. The protection is achieved by extracting the beam from the ring in case thresholds imposed on measured radiation levels are exceeded. Close to the interaction regions of the LHC, the present BLM system is sensitive to particle showers generated in the interaction region of the two beams. In the future, with beams of higher energy and brightness resulting in higher luminosity, distinguishing between these interaction products and possible quench-provoking beam losses from the primary proton beams will be challenging. The particle showers measured by the present BLM configuration are partly shielded by the cryostat and the iron yoke of the magnets. The system can hence be optimised by locating beam loss monitors as close as possible to the protected element, i. e. the superconducting coils, inside the cold mass of the magnets in superfluid helium at 1.9 K. T...

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...

Upgrade of the ATLAS Silicon Tracker for the sLHC

CERN Document Server

Minano, M; The ATLAS collaboration

2009-01-01

While the CERN Large Hadron Collider (LHC) will start taking data this year, scenarios for a machine upgrade to achieve a much higher luminosity are being developed. In the current planning, it is foreseen to increase the luminosity of the LHC at CERN around 2016 by about an order of magnitude, with the upgraded muchine dubbed Super-LHC or SLHC. As radiation damage scales with integrated luminosity, the particle physics experiments at the SLHC will need to be equipped with a new generation of radiation-hard detectors. This is of particular importance for the semiconductor tracking detectors located close to the LHC interaction region, where the higest radiation doses occur. The ATLAS experiment will require a new particle tracking system for SLHC operation. In order to cope with the increase in background events by about one order of magnitude at the higher luminosity, an all silicon detector with enhanced radiation hardness is being designed. The new silicon strip detector will use significantly shorter stri...

CERN-LHC accelerator superconducting magnet. Development and international cooperation

International Nuclear Information System (INIS)

Yamamoto, Akira; Nakamoto, Tatsushi; Sasaki, Ken-ichi

2009-01-01

CERN-LHC accelerator superconducting magnets and a cooperative work for interaction region quadrupole magnets are introduced. The accelerator commissioning and the incident happened during the commissioning in 2008 is also briefly discussed. (author)

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...

Nb$_{3}$Sn quadrupole magnets for the LHC IR

CERN Document Server

Sabbi, G L; Chiesa, L; Coccoli, M; Dietderich, D R; Ferracin, P; Gourlay, S A; Hafalia, R R; Lietzke, A F; McInturff, A D; Scanlan, R M

2003-01-01

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 * 10/sup 34/ cm/sup -2/s/sup -1/ at the Large Hadron Collider (LHC). At present, Nb/sub 3/Sn is the only practical conductor which can meet these requirements. Since Nb/sub 3/Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented. (25 refs).

Nb3Sn Quadrupole Magnets for the LHC IR

International Nuclear Information System (INIS)

Sabbi, G.; Caspi, S.; Chiesa, L.; Coccoli, M.; Dietderich, D.R.; Ferracin, P.; Gourlay, S.A.; Hafalia, R.R.; Lietzke, A.F.; McInturff, A.D.; Scanlan, R.M.

2001-01-01

The development of insertion quadrupoles with 205 T/m gradient and 90 mm bore represents a promising strategy to achieve the ultimate luminosity goal of 2.5 x 10 34 cm -2 s -1 at the Large Hadron Collider (LHC). At present, Nb 3 Sn is the only practical conductor which can meet these requirements. Since Nb 3 Sn is brittle, and considerably more strain sensitive than NbTi, the design concepts and fabrication techniques developed for NbTi magnets need to be modified appropriately. In addition, IR magnets must provide high field quality and operate reliably under severe radiation loads. The results of conceptual design studies addressing these issues are presented.

Overview of the ATLAS Insertable B-Layer (IBL) Project

International Nuclear Information System (INIS)

Røhne, O.

2013-01-01

The upgrades for the ATLAS Pixel Detector will be staged in preparation for high luminosity LHC. The first upgrade for the Pixel Detector is the construction of a new pixel layer which will be installed during the first shutdown of the LHC machine, in 2013–2014. The new detector, called the Insertable B-Layer (IBL), will be installed between the existing Pixel Detector and a new, smaller radius beam-pipe at a radius of 3.3 cm. The IBL has required the development of several new technologies to cope with increased radiation and pixel occupancy and also to improve the physics performance through reduction of the pixel size and a more stringent material budget. The IBL presents several changes to the design of the present ATLAS Pixel Detector: two different and promising silicon sensor technologies, planar n-in-n and 3D, will be used for the IBL. A new read-out chip FE-I4 has been designed in 130 nm technology, the material budget is minimized by using new lightweight mechanical support materials and a CO 2 based cooling system has been developed. An overview of the IBL project, of the module design and the qualification for these sensor technologies with particular emphasis on irradiation and beam tests will be presented

Upgrade of the ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC

CERN Document Server

Hildebrand, Kevin; The ATLAS collaboration

2017-01-01

The Tile Calorimeter is the hadronic calorimeter covering the central region of the ATLAS detector at the Large Hadron Collider. It is a scintillator-steel sampling calorimeter read out via wavelength shifting fibers coupled to photomultiplier tubes (PMT). The PMT signals are digitized and stored on detector until a trigger is received. The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade (2024-2025) will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. In particular, TileCal will undergo a major replacement of its on- and off-detector electronics. In the new architecture, all signals will be digitized and then transferred directly to the off-detector electronics, where the signals will be reconstructed, stored, and sent to the first level of trigger at the rate of 40 MHz. This will provide better precision of the calorimeter signals...

Upgrade of the ATLAS Hadronic Tile Calorimeter for the High Luminosity LHC

CERN Document Server

Hildebrand, Kevin; The ATLAS collaboration

2017-01-01

The Tile Calorimeter is the hadronic calorimeter covering the central region of the ATLAS detector at the Large Hadron Collider. It is a scintillator-steel sampling calorimeter read out via wavelength shifting fibers coupled to photomultiplier tubes (PMT). . The Large Hadron Collider (LHC) has envisaged a series of upgrades towards a High Luminosity LHC (HL-LHC) delivering five times the LHC nominal instantaneous luminosity. The ATLAS Phase II upgrade (2024-2025) will accommodate the upgrade of the detector and data acquisition system for the HL-LHC. In particular, TileCal will undergo a major replacement of its on- and off-detector electronics. In the new architecture, all signals will be digitized and sent to the first level of trigger at the rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the reliability and redundancy of the system. ...

A general method, a la Transport, for evaluation of the perturbing effects of solenoidal inserts in storage ring interaction regions

International Nuclear Information System (INIS)

Murray, J.J.

1976-07-01

It may be expected that solenoid magnets will be used in many storage ring experiments. Typically an insert would consist of a main solenoid at the interaction point with a symmetrical pair of compensating solenoids located somewhere between the main solenoid and the ends of the interaction region. The magnetic fields of such an insert may significantly affect storage ring performance. We suggest here a simple, systematic method for evaluation of the effects, which together with adequate design supervision and field measurements will help to prevent any serious operational problems that might result if significant perturbations went unnoticed. 5 refs

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)

Supersymmetry, Dark Matter and the LHC

International Nuclear Information System (INIS)

Tata, Xerxes

2010-01-01

The conceptually simplest scenario for dark matter (DM) is that it is a stable thermal relic from standard Big Bang cosmology, in many SUSY models the lightest neutralino. The relic density determination selects special regions in SUSY model parameter space with concomitant implications for collider physics, dark matter searches and low energy measurements. By studying various one-parameter extensions of the much-studied mSUGRA model (where we relax the untested universality assumptions) constructed to be in accord with the measured relic density, we show that these implications are in general model-dependent, so that LHC and DM measurements will provide clues to how sparticles acquire their masses. We point out some relatively robust implications for LHC and DM searches and conclude with an outlook for the future.

Parametric Study of Heat Deposition from Collision Debris into the Insertion Superconducting Magnets for the LHC Luminosity Upgrade

CERN Document Server

Hoa, C; Cerutti, F; Koutchouk, Jean-Pierre; Sterbini, G; Wildner, E

2007-01-01

With a new geometry in a higher luminosity environment, the power deposition in the superconducting magnets becomes a critical aspect to analyze and to integrate in the insertion design. In this paper, we quantify the power deposited in magnets insertion at variable positions from the interaction point (IP). A fine characterization of the debris due to the proton-proton collisions at 7 TeV, shows that the energetic particles in the very forward direction give rise to non intuitive dependences of the impacting energy on the magnet front face and inner surface. The power deposition does not vary significantly with the distance to the interaction point, because of counterbalancing effects of different contributions to power deposition. We have found out that peak power density in the magnet insertion does not vary significantly with or without the Target Absorber Secondaries (TAS) protection.

$Z^{0}$ production as a test of nuclear effects at the LHC

CERN Document Server

Xiao Fei Zhang

2002-01-01

We predict the Z/sup 0/ transverse momentum distribution from proton- proton and nuclear collisions at the LHC. After demonstrating that higher-twist nuclear effects are very small, we propose Z/sup 0/ production as a precision test for leading-twist pQCD in the TeV energy region. We also point out that shadowing may result in unexpected phenomenology at the LHC. (21 refs).

Quench protection of the LHC inner triplet quadrupoles built at Fermilab

CERN Document Server

Bauer, P; Chiesa, L; Di Marco, J; Fehér, S; Lamm, M J; McInturff, A D; Nobrega, A; Orris, D; Tartaglia, M; Tompkins, J C; Zlobin, A V

2001-01-01

High gradient quadrupoles are being developed by the US-LHC Accelerator project for the LHC interaction region inner triplets. These 5.5 m long magnets have a single 70 mm aperture and operate in superfluid helium at a peak gradient of 215 T/m. Through the construction and test of eight 2 meter long model quadrupoles, strip heaters of various geometries and insulation thicknesses have proven to be effective in protecting the magnets from excessively high coil temperatures and coil voltages to ground. This paper reports on the results of the model program to optimize the heater performance within the context of the LHC inner triplet electrical power and quench detection scheme. (6 refs).

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.

Precision Drell-Yan Measurements at the LHC and Implications for the Diphoton Excess

CERN Document Server

Goertz, Florian; Son, Minho; Urbano, Alfredo

2016-01-01

Precision measurements of the Drell-Yan (DY) cross section at the LHC constrain new physics scenarios that involve new states with electroweak (EW) charges. We analyze these constraints and apply them to models that can address the LHC diphoton excess at 750 GeV. We confront these findings with LEP EW precision tests and show that DY provides stronger constraints than the LEP data. While 8 TeV data can already probe some parts of the interesting region of parameter space, LHC14 results are expected to cover a substantial part of the relevant terrain. We derive the bounds from the existing data, estimate LHC14 reach and compare them to the bounds one gets from LEP and future FCC-ee precision measurements.

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.

Observation of channeling for 6500 GeV/c protons in the crystal assisted collimation setup for LHC

International Nuclear Information System (INIS)

Scandale, W.; Arduini, G.; Butcher, M.; Cerutti, F.; Garattini, M.; Gilardoni, S.; Lechner, A.; Losito, R.; Masi, A.; Mirarchi, D.; Montesano, S.; Redaelli, S.; Rossi, R.; Schoofs, P.; Smirnov, G.; Valentino, G.; Breton, D.; Burmistrov, L.; Chaumat, V.; Dubos, S.

2016-01-01

Two high-accuracy goniometers equipped with two bent silicon crystals were installed in the betatron cleaning insertion of the CERN Large Hadron Collider (LHC) during its long shutdown. First beam tests were recently performed at the LHC with 450 GeV/c and 6500 GeV/c stored proton beams to investigate the feasibility of beam halo collimation assisted by bent crystals. For the first time channeling of 6500 GeV/c protons was observed in a particle accelerator. A strong reduction of beam losses due to nuclear inelastic interactions in the aligned crystal in comparison with its amorphous orientation was detected. The loss reduction value was about 24. Thus, the results show that deflection of particles by a bent crystal due to channeling is effective for this record particle energy.

Observation of channeling for 6500 GeV/c protons in the crystal assisted collimation setup for LHC

Energy Technology Data Exchange (ETDEWEB)

Scandale, W. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Laboratoire de l' Accelerateur Lineaire (LAL), Universite Paris Sud Orsay, Orsay (France); INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Arduini, G.; Butcher, M.; Cerutti, F.; Garattini, M.; Gilardoni, S.; Lechner, A.; Losito, R.; Masi, A.; Mirarchi, D.; Montesano, S.; Redaelli, S. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Rossi, R. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Schoofs, P. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Smirnov, G. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); INFN Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Valentino, G. [CERN, European Organization for Nuclear Research, CH-1211 Geneva 23 (Switzerland); Breton, D.; Burmistrov, L.; Chaumat, V.; Dubos, S. [Laboratoire de l' Accelerateur Lineaire (LAL), Universite Paris Sud Orsay, Orsay (France); and others

2016-07-10

Two high-accuracy goniometers equipped with two bent silicon crystals were installed in the betatron cleaning insertion of the CERN Large Hadron Collider (LHC) during its long shutdown. First beam tests were recently performed at the LHC with 450 GeV/c and 6500 GeV/c stored proton beams to investigate the feasibility of beam halo collimation assisted by bent crystals. For the first time channeling of 6500 GeV/c protons was observed in a particle accelerator. A strong reduction of beam losses due to nuclear inelastic interactions in the aligned crystal in comparison with its amorphous orientation was detected. The loss reduction value was about 24. Thus, the results show that deflection of particles by a bent crystal due to channeling is effective for this record particle energy.

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)

The Performance of the New TCDQ System in the LHC Beam Dumping Region

CERN Document Server

Presland, Andrew; Weterings, Wim

2005-01-01

The superconducting quadrupole magnet Q4 and other downstream LHC machine elements risk destruction in the event of a beam dump that is not synchronised with the abort gap. In order to protect these elements, a single sided mobile graphite diluter block TCDQ, in combination with a two-sided secondary collimator TCS and iron shield TCDQM, will be installed in front of Q4. This protection system should also intercept spurious particles in the beam abort gap to prevent quenches from occurring during regular beam aborts, and must also intercept the particles from the secondary halo during low beam lifetime without provoking quenches. The conceptual design of the TCDQ system is briefly presented, with the load conditions and performance criteria. The FLUKA simulations are described results discussed in the context of the expected performance levels for LHC operation.

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...

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

Overview of LHC Beam Loss Measurements

CERN Document Server

Dehning, B; Effinger, E; Emery, J; Fadakis, E; Holzer, E B; Jackson, S; Kruk, G; Kurfuerst, C; Marsili, A; Misiowiec, M; Nebot Del Busto, E; Nordt, A; Priebe, A; Roderick, C; Sapinski, M; Zamantzas, C; Grishin, V; Griesmayer, E

2011-01-01

The LHC beam loss monitoring system provides measurements with an update rate of 1 Hz and high time resolution data by event triggering. These informations are used for the initiation of beam aborts, fixed displays and the off line analysis. The analysis of fast and localized loss events resulted in the determination of its rate, duration, peak amplitudes, its scaling with intensity, number of bunches and beam energy. The calibration of the secondary shower beam loss signal in respect to the needed beam energy deposition to quench the magnet coil is addressed at 450GeV and 3.5T eV . The adjustment of collimators is checked my measuring the loss pattern and its variation in the collimation regions of the LHC. Loss pattern changes during a fill allow the observation of non typical fill parameters.

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.

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

The LHCf experiment modelling cosmic rays at LHC

CERN Document Server

Tricomi, A; Bonechi, L; Bongi, M; Castellini, G; D'Alessandro, R; Faus, A; Fukui, K; Haguenauer, M; Itow, Y; Kasahara, K; Macina, D; Mase, T; Masuda, K; Matsubara, Y; Mizuishi, M; Menjo, H; Muraki, Y; Papini, P; Perrot, A L; Ricciarini, S B; Sako, T; Shimizu, Y; Tamura, T; Taki, K; Torii, S; Tricomi, A; Turner, W C; Velasco, J; Watanabe, H; Yoshida, K

2008-01-01

The LHCf experiment at LHC has been designed to provide a calibration of nuclear interaction models used in cosmic ray physics up to energies relevant to test the region between the knee and the GZK cut-off. Details of the detector and its performances are discussed.

Upgrade Plans for ATLAS Forward Calorimetry for the HL-LHC

CERN Document Server

Krieger, P; The ATLAS collaboration

2013-01-01

The ATLAS detector was designed and built to study proton-proton (pp) collisions produced by the Large Hadron Collider (LHC) at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to $10^{34}{\\rm cm}^{-2}{\\rm s}^{-1}$. At the higher instantaneous luminosity ($5\\times 10^{34}{\\rm cm}^{-2}{\\rm s}^{-1}$) proposed for the High-Luminosity LHC (HL-LHC), some components of ATLAS will not operate properly, while others may not survive the dose that will be accumulated while collecting the proposed 3000 fb$^{-1}$ of pp collision data. For the ATLAS liquid argon (LAr) calorimeter, problems are anticipated in the forward region where the particle flux is particularly high. The existing Forward Calorimeter (FCal) was designed with very narrow LAr gaps (250-500 $\\mu$m) in order to avoid problems due to ion build-up that would distort the electric field. At HL-LHC luminosities, these gaps are no longer sufficiently narrow. The resulting distortions of the electric field in the gaps would be exacerbated b...

Minimal Z' models: present bounds and early LHC reach

International Nuclear Information System (INIS)

Salvioni, Ennio; Zwirner, Fabio; Villadoro, Giovanni

2009-01-01

We consider 'minimal' Z' models, whose phenomenology is controlled by only three parameters beyond the Standard Model ones: the Z' mass and two effective coupling constants. They encompass many popular models motivated by grand unification, as well as many arising in other theoretical contexts. This parameterization takes also into account both mass and kinetic mixing effects, which we show to be sizable in some cases. After discussing the interplay between the bounds from electroweak precision tests and recent direct searches at the Tevatron, we extend our analysis to estimate the early LHC discovery potential. We consider a center-of-mass energy from 7 towards 10 TeV and an integrated luminosity from 50 to several hundred pb -1 , taking all existing bounds into account. We find that the LHC will start exploring virgin land in parameter space for M Z' around 700 GeV, with lower masses still excluded by the Tevatron and higher masses still excluded by electroweak precision tests. Increasing the energy up to 10 TeV, the LHC will start probing a wider range of Z' masses and couplings, although several hundred pb -1 will be needed to explore the regions of couplings favored by grand unification and to overcome the Tevatron bounds in the mass region around 250 GeV.

Cleaning Insertions and Collimation Challenges

Science.gov (United States)

Redaelli, S.; Appleby, R. B.; Bertarelli, A.; Bruce, R.; Jowett, J. M.; Lechner, A.; Losito, R.

High-performance collimation systems are essential for operating efficiently modern hadron machine with large beam intensities. In particular, at the LHC the collimation system ensures a clean disposal of beam halos in the superconducting environment. The challenges of the HL-LHC study pose various demanding requests for beam collimation. In this paper we review the present collimation system and its performance during the LHC Run 1 in 2010-2013. Various collimation solutions under study to address the HL-LHC requirements are then reviewed, identifying the main upgrade baseline and pointing out advanced collimation concept for further enhancement of the performance.

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...

Evaluation of Beam Loss and Energy Depositions for a Possible Phase II Design for LHC Collimation

International Nuclear Information System (INIS)

Lari, L.; Assmann, R.; Bracco, C.; Brugger, M.; Cerutti, F.; Doyle, E.; Ferrari, A.; Keller, L.; Lundgren, S.; Markiewicz, Thomas W.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Smith, J.; Vlachoudis, V.; Weiler, T.

2011-01-01

The LHC beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

Small-x physics at LEP/LHC

International Nuclear Information System (INIS)

Bartels, J.; Schuler, G.A.

1990-12-01

The small-x behavior of deep inelastic structure functions in QCD is discussed. After a brief review of theoretical ideas we describe numerical estimates which show that LEP/LHC will be extremely useful for distinguishing between 'standard QCD' and 'new' physics in the low-x region. We also discuss which measurements will be useful for unravelling the new features of small-x physics. (orig.)

LHC benchmark scenarios for the real Higgs singlet extension of the standard model

International Nuclear Information System (INIS)

Robens, Tania; Stefaniak, Tim

2016-01-01

We present benchmark scenarios for searches for an additional Higgs state in the real Higgs singlet extension of the Standard Model in Run 2 of the LHC. The scenarios are selected such that they fulfill all relevant current theoretical and experimental constraints, but can potentially be discovered at the current LHC run. We take into account the results presented in earlier work and update the experimental constraints from relevant LHC Higgs searches and signal rate measurements. The benchmark scenarios are given separately for the low-mass and high-mass region, i.e. the mass range where the additional Higgs state is lighter or heavier than the discovered Higgs state at around 125 GeV. They have also been presented in the framework of the LHC Higgs Cross Section Working Group. (orig.)

Magnetic field measurements of LHC inner triplet quadrupoles fabricated at Fermilab

International Nuclear Information System (INIS)

Velev, G.V.; Bossert, R.; Carcagno, R.; DiMarco, J.; Feher, S.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Orris, D.; Schlabach, P.; Strait, J.

2006-01-01

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly comprise the Q2 optical elements of the final focus triplets in the LHC interaction regions. The field quality of the quadrupoles is measured at room temperature during construction of the cold masses as well as during cold testing of the cryogenic assembly. We summarize data from the series measurements of the magnets and discuss various topics of interest

Magnetic field measurements of LHC inner triplet quadrupoles fabricated at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Velev, G.V.; Bossert, R.; Carcagno, R.; DiMarco, J.; Feher, S.; Kashikhin, V.V.; Kerby, J.; Lamm, M.; Orris, D.; Schlabach, P.; Strait, J.; /Fermilab

2006-08-01

Fermilab, as part of the US-LHC Accelerator Project, is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 5.5 m long magnets are designed to operate in superfluid helium at 1.9 K with a nominal gradient of 205 T/m in the 70 mm bore. Two quadrupoles separated by a dipole orbit corrector in a single cryogenic assembly comprise the Q2 optical elements of the final focus triplets in the LHC interaction regions. The field quality of the quadrupoles is measured at room temperature during construction of the cold masses as well as during cold testing of the cryogenic assembly. We summarize data from the series measurements of the magnets and discuss various topics of interest.

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...

Evaluation of a high resolution silicon PET insert module

Energy Technology Data Exchange (ETDEWEB)

Grkovski, Milan, E-mail: milan.grkovski@ijs.si [Jožef Stefan Institute, Ljubljana (Slovenia); Memorial Sloan Kettering Cancer Center, New York, NY (United States); Brzezinski, Karol [IFIC/CSIC, Valencia (Spain); Cindro, Vladimir [Jožef Stefan Institute, Ljubljana (Slovenia); Clinthorne, Neal H. [University of Michigan, Ann Arbor, MI (United States); Kagan, Harris [Ohio State University, Columbus, OH (United States); Lacasta, Carlos [IFIC/CSIC, Valencia (Spain); Mikuž, Marko [Jožef Stefan Institute, Ljubljana (Slovenia); Solaz, Carles [IFIC/CSIC, Valencia (Spain); Studen, Andrej [Jožef Stefan Institute, Ljubljana (Slovenia); Weilhammer, Peter [Ohio State University, Columbus, OH (United States); Žontar, Dejan [Jožef Stefan Institute, Ljubljana (Slovenia)

2015-07-11

Conventional PET systems can be augmented with additional detectors placed in close proximity of the region of interest. We developed a high resolution PET insert module to evaluate the added benefit of such a combination. The insert module consists of two back-to-back 1 mm thick silicon sensors, each segmented into 1040 1 mm{sup 2} pads arranged in a 40 by 26 array. A set of 16 VATAGP7.1 ASICs and a custom assembled data acquisition board were used to read out the signal from the insert module. Data were acquired in slice (2D) geometry with a Jaszczak phantom (rod diameters of 1.2–4.8 mm) filled with {sup 18}F-FDG and the images were reconstructed with ML-EM method. Both data with full and limited angular coverage from the insert module were considered and three types of coincidence events were combined. The ratio of high-resolution data that substantially improves quality of the reconstructed image for the region near the surface of the insert module was estimated to be about 4%. Results from our previous studies suggest that such ratio could be achieved at a moderate technological expense by using an equivalent of two insert modules (an effective sensor thickness of 4 mm)

The ATLAS Insertable B-Layer: from construction to operation

CERN Document Server

La Rosa, Alessandro; The ATLAS collaboration

2016-01-01

The ATLAS Insertable B-Layer (IBL) is a fourth layer of pixel detectors, and has been installed in May 2014 at a radius of 3.3 cm between the existing Pixel Detector and a new smaller radius beam-pipe. The new detector, built to cope with high radiation and occupancy, is the first large scale application of 3D detectors and CMOS 130nm technology. The IBL detector construction was achieved within about two years starting from mid-2012 to the May 2014 installation in ATLAS, a very tight schedule to meet the ATLAS installation and detector closure before starting the Run2 in Spring 2015. The key features and challenges met during the IBL project will be presented, as well as its commissioning and operational experience in LHC.

FE-I4 Chip Development for Upgraded ATLAS Pixel Detector at LHC

CERN Document Server

Barbero, M; The ATLAS collaboration

2010-01-01

A new ATLAS pixel chip FE-I4 has been developed for use in upgraded LHC luminosity environments, including the near-term Insertable B-Layer upgrade. FE-I4 is designed in a 130 nm CMOS technology, presenting advantages in terms of radiation tolerance and digital logic density compared to the 0.25 μm CMOS technology used for the current ATLAS pixel IC, FE-I3. FE-I4 architecture is based on an array of 80×336 pixels, each 50×250 μm2, consisting of analog and digital sections. The analog pixel section is designed for low power consumption and compatibility to several sensor candidates. It is based on a two-stage architecture with a pre-amp AC-coupled to a second stage of amplification. It features leakage current compensation circuitry, local 4-bit pre-amp feedback tuning and a discriminator locally adjusted through 5 configuration bits. The digital architecture is based on a 4-pixel unit called Pixel Digital Region (PDR) allowing for local storage of hits in 5-deep data buffers at pixel level for the duratio...

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 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...

Swirl flow analysis in a helical wire inserted tube using CFD code

International Nuclear Information System (INIS)

Park, Yusun; Chang, Soon Heung

2010-01-01

An analysis on the two-phase flow in a helical wire inserted tube using commercial CFD code, CFX11.0, was performed in bubbly flow and annular flow regions. The analysis method was validated with the experimental results of Takeshima. Bubbly and annular flows in a 10 mm inner diameter tube with varying pitch lengths and inserted wire diameters were simulated using the same analysis methods after validation. The geometry range of p/D was 1-4 and e/D was 0.08-0.12. The results show that the inserted wire with a larger diameter increased swirl flow generation. An increasing swirl flow was seen as the pitch length increased. Regarding pressure loss, smaller pitch lengths and inserted wires with larger diameters resulted in larger pressure loss. The average liquid film thickness increased as the pitch length and the diameter of the inserted wire increased in the annular flow region. Both in the bubbly flow and annular flow regions, the effect of pitch length on swirl flow generation and pressure loss was more significant than that of the inserted wire diameters. Pitch length is a more dominant factor than inserted wire diameter for the design of the swirl flow generator in small diameter tubes.

Lithium Insertion In Silicon Nanowires: An ab Initio Study

KAUST Repository

Zhang, Qianfan

2010-09-08

The ultrahigh specific lithium ion storage capacity of Si nanowires (SiNWs) has been demonstrated recently and has opened up exciting opportunities for energy storage. However, a systematic theoretical study on lithium insertion in SiNWs remains a challenge, and as a result, understanding of the fundamental interaction and microscopic dynamics during lithium insertion is still lacking. This paper focuses on the study of single Li atom insertion into SiNWs with different sizes and axis orientations by using full ab initio calculations. We show that the binding energy of interstitial Li increases as the SiNW diameter grows. The binding energies at different insertion sites, which can be classified as surface, intermediate, and core sites, are quite different. We find that surface sites are energetically the most favorable insertion positions and that intermediate sites are the most unfavorable insertion positions. Compared with the other growth directions, the [110] SiNWs with different diameters always present the highest binding energies on various insertion locations, which indicates that [110] SiNWs are more favorable by Li doping. Furthermore, we study Li diffusion inside SiNWs. The results show that the Li surface diffusion has a much higher chance to occur than the surface to core diffusion, which is consistent with the experimental observation that the Li insertion in SiNWs is layer by layer from surface to inner region. After overcoming a large barrier crossing surface-to-intermediate region, the diffusion toward center has a higher possibility to occur than the inverse process. © 2010 American Chemical Society.

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.

Ultrasonic Guided Insertion of Central Venous Catheter in Infants ...

African Journals Online (AJOL)

Background/Purpose: ultrasound is licensed for application of regional blocks and insertion of vascular access. We aimed to compare ultrasonic guided (USG) and anatomical landmark technique (ALT) for insertion of central venous catheter (CVC) as regard success rate and rate of complications in infants and children.

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.

Identification of a single-nucleotide insertion in the promoter region affecting the sodC promoter activity in Brucella neotomae.

Directory of Open Access Journals (Sweden)

Dina A Moustafa

Full Text Available Brucella neotomae is not known to be associated with clinical disease in any host species. Previous research suggested that B. neotomae might not express detectable levels of Cu/Zn superoxide dismutase (SOD, a periplasmic enzyme known to be involved in protecting Brucella from oxidative bactericidal effects of host phagocytes. This study was undertaken to investigate the genetic basis for the disparity in SOD expression in B. neotomae. Our Western blot and SOD enzyme assay analyses indicated that B. neotomae does express SOD, but at a substantially reduced level. Nucleotide sequence analysis of region upstream to the sodC gene identified a single-nucleotide insertion in the potential promoter region. The same single-nucleotide insertion was also detected in the sodC promoter of B. suis strain Thomsen, belonging to biovar 2 in which SOD expression was undetectable previously. Examination of the sodC promoter activities using translational fusion constructs with E. coli β-galactosidase demonstrated that the B. neotomae and B. suis biovar 2 promoters were very weak in driving gene expression. Site-directed mutation studies indicated that the insertion of A in the B. neotomae sodC promoter reduced the promoter activity. Increasing the level of SOD expression in B. neotomae through complementation with B. abortus sodC gene did not alter the bacterial survival in J774A.1 macrophage-like cells and in tissues of BALB/c and C57BL/6 mice. These results for the first time demonstrate the occurrence of a single-nucleotide polymorphism affecting promoter function and gene expression in Brucella.

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

Magnetic Measurements on the First CERN-Built Models of the Insertion Quadrupole MQXF for HL-LHC

CERN Document Server

Fiscarelli, L; Dunkel, O; Ferracin, P; Izquierdo Bermudez, S; Russenschuck, S; Todesco, E; Ambrosio, G

2018-01-01

The high-luminosity upgrade of the large hadron collider (HL-LHC) requires new high-field and large-aperture quadrupole magnets for the low-beta inner triplets (MQXF). CERN and LARP are currently collaborating to develop a 150-mm-aperture quadrupole based on Nb$_3$Sn superconducting cables for the coils, and an aluminum shell with the bladder-key technology for the support structure. This paper presents the test setup for magnetic measurements, both at ambient and cryogenic temperatures, and the instrumentation being used for the first two short-models of MQXF built and tested at CERN. Finally, the measurement results, in terms of field quality, effects of persistent currents, and iron saturation are reported and discussed.

Other Exotic Scenarios at the LHC

CERN Document Server

Benslama, K

2006-01-01

The considerable center-of-mass energy and luminosity at the LHC will ensure a discovery reach for new particles which extends well into the mlti-TeV region. ATLAS and CMS carried out many studies of the implications of this capability for Beyond the Standard Model Physics. In this talk, I will focus on studies involving extra-dimensions, little higgs, strong symmetry breaking, compositeness and new gauge bosons.

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

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

Comparison of CMS Resistive Plate Chambers performance during LHC RUN-1 and RUN-2

CERN Document Server

INSPIRE-00207984

2016-01-01

The Resistive Plate Chambers detector system at the CMS experiment at the LHC provides robustness and redundancy to the muon trigger. A total of 1056 double-gap chambers cover the pseudo-rapidity region < 1.6. The main detector parameters and environmental conditions are constantly and closely monitored to achieve operational stability and high quality data in the harsh conditions of the second run period of the LHC with center-of-mass energy of 13 TeV. First results of overall detector stability with 2015 data and comparisons with data from the LHC RUN-1 period at 8 TeV are presented.

Comparison of CMS Resistive Plate Chambers performance during LHC RUN-1 and RUN-2

CERN Document Server

Shah, Mehar Ali

2016-01-01

The Resistive Plate Chambers detector system at the CMS experiment at the LHC provides robustness and redundancy to the muon trigger. A total of 1056 double-gap chambers cover the pseudo-rapidity region lt 1.6. The main detector parameters and environmental conditions are constantly and closely monitored to achieve operational stability and high quality data in the harsh conditions of the second run period of the LHC with center-of-mass energy of 13 TeV. First results of overall detector stability with 2015 data and comparisons with data from the LHC RUN-1 period at 8 TeV are presented.

Experience with LHC Magnets from Prototyping to Large Scale Industrial Production and Integration

CERN Multimedia

Rossi, L

2004-01-01

The construction of the LHC superconducting magnets is approaching its half way to completion. At the end of 2003, main dipoles cold masses for more than one octant were delivered; meanwhile the winding for the second octant was almost completed. The other large magnets, like the main quadrupoles and the insertion quadrupoles, have entered into series production as well. Providing more than 20 km of superconducting magnets, with the quality required for an accelerator like LHC, is an unprecedented challenge in term of complexity that has required many steps from the construction of 1 meterlong magnets in the laboratory to today’s production of more than one 15 meter-long magnet per day in Industry. The work and its organization is made even more complex by the fact that CERN supplies most of the critical components and part of the main tooling to the magnet manufacturers, both for cost reduction and for quality issues. In this paper the critical aspects of the construction will be reviewed and the actual ...

Latin American collaboration to the CERN-LHC accelerator assembly and its projects

Energy Technology Data Exchange (ETDEWEB)

Sajo B, L. [Universidad Simon Bolivar, Nuclear Physics Laboratory, Caracas 1080-A (Venezuela, Bolivarian Republic of)

2016-10-15

Summary of Latin American (LA) scientists main contributions to the construction of a heavy ion detector assembly currently operating at the Large Hadron Collider (LHC) at CERN, Geneva,Switzerland is given with description of the provided support for posterior data analysis. This joint effort highlights the much needed recognition of LA as a technologically emerging region. It has also shown a net benefit in development of science for our region. Details are given on the LHC-Alice experiment where several LA countries have contributed with innovative technological solutions. These include the ability to build part of the numerous detectors, including the central barrel as well as acquired knowledge on aspects concerning high energy dosimetry and radiation damage. (Author)

Latin American collaboration to the CERN-LHC accelerator assembly and its projects

International Nuclear Information System (INIS)

Sajo B, L.

2016-10-01

Summary of Latin American (LA) scientists main contributions to the construction of a heavy ion detector assembly currently operating at the Large Hadron Collider (LHC) at CERN, Geneva,Switzerland is given with description of the provided support for posterior data analysis. This joint effort highlights the much needed recognition of LA as a technologically emerging region. It has also shown a net benefit in development of science for our region. Details are given on the LHC-Alice experiment where several LA countries have contributed with innovative technological solutions. These include the ability to build part of the numerous detectors, including the central barrel as well as acquired knowledge on aspects concerning high energy dosimetry and radiation damage. (Author)

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 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...

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...

Wrong vertex displacements due to Lee-Wick resonances at LHC

International Nuclear Information System (INIS)

Alvarez, E.; Schat, C.; Rold, L. da; Szynkman, A.

2009-01-01

We show how a resonance from the recently proposed Lee-Wick Standard Model could lead to wrong vertex displacements at LHCb. We study which could be the possible 'longest lived' Lee-Wick particle that could be created at LHC, and we study its possible decays and detections. We conclude that there is a region in the parameter space which would give wrong vertex displacements as a unique signature of the Lee-Wick Standard Model at LHCb. Further numerical simulation shows that LHC era could explore these wrong vertex displacements through Lee-Wick leptons below 500 GeV. (author)

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

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

Application of diamond based beam loss monitors at LHC

International Nuclear Information System (INIS)

Hempel, Maria

2013-04-01

collimators. Ionization chambers have a time resolution of 40 s that is a half LHC turn and in case of a large beam loss, they request a beam dump. Another type of beam loss monitors are diamond sensors because of a time resolution of about one nanosecond and high radiation hardness. One diamond detector system is located in the cleaning region of the LHC and is able to detect various types of beam losses. Another diamond detector system (BCM1F) is installed inside the CMS detector to protect the CMS from adverse beam conditions. BCM1F monitors also the luminosity during collisions and delivers important beam parameters. Additional condition monitors, based on the BCM1F system, are located next to CMS, near to LHCb and ALICE to measure large beam losses in the LHC ring. The process of a beam loss due to dust particles is explained, and additional simulations were done to understand these process in more detail. The result of the simulation are also given. Beam loss data recorded by the diamond sensors in the cleaning region and the BCM1F diamonds are presented.

From hybrid to CMOS pixels ... a possibility for LHC's pixel future?

International Nuclear Information System (INIS)

Wermes, N.

2015-01-01

Hybrid pixel detectors have been invented for the LHC to make tracking and vertexing possible at all in LHC's radiation intense environment. The LHC pixel detectors have meanwhile very successfully fulfilled their promises and R and D for the planned HL-LHC upgrade is in full swing, targeting even higher ionising doses and non-ionising fluences. In terms of rate and radiation tolerance hybrid pixels are unrivaled. But they have disadvantages as well, most notably material thickness, production complexity, and cost. Meanwhile also active pixel sensors (DEPFET, MAPS) have become real pixel detectors but they would by far not stand the rates and radiation faced from HL-LHC. New MAPS developments, so-called DMAPS (depleted MAPS) which are full CMOS-pixel structures with charge collection in a depleted region have come in the R and D focus for pixels at high rate/radiation levels. This goal can perhaps be realised exploiting HV technologies, high ohmic substrates and/or SOI based technologies. The paper covers the main ideas and some encouraging results from prototyping R and D, not hiding the difficulties

LHC signals of radiatively-induced neutrino masses and implications for the Zee-Babu model

Science.gov (United States)

Alcaide, Julien; Chala, Mikael; Santamaria, Arcadi

2018-04-01

Contrary to the see-saw models, extended Higgs sectors leading to radiatively-induced neutrino masses do require the extra particles to be at the TeV scale. However, these new states have often exotic decays, to which experimental LHC searches performed so far, focused on scalars decaying into pairs of same-sign leptons, are not sensitive. In this paper we show that their experimental signatures can start to be tested with current LHC data if dedicated multi-region analyses correlating different observables are used. We also provide high-accuracy estimations of the complicated Standard Model backgrounds involved. For the case of the Zee-Babu model, we show that regions not yet constrained by neutrino data and low-energy experiments can be already probed, while most of the parameter space could be excluded at the 95% C.L. in a high-luminosity phase of the LHC.

ATLAS Tile Calorimeter Readout Electronics Upgrade Program for the High Luminosity LHC

CERN Document Server

Cerqueira, A S; The ATLAS collaboration

2013-01-01

The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. The ATLAS upgrade program is divided in three phases: The Phase 0 occurs during 2013-2014 and prepares the LHC to reach peak luminosities of 1034 cm2s-1; Phase 1, foreseen for 2018-1019, prepares the LHC for peak luminosity up to 2-3 x 1034 cm2s-1, corresponding to 55 to 80 interactions per bunch-crossing with 25 ns bunch interval; and Phase 2 is foreseen for 2022-2023, whereafter the peak luminosity will reach 5-7 x 1034 cm2s-1 (HL-LHC). With luminosity leveling, the average luminosity will increase with a factor 10. The main TileCal upgrade is focused on the HL-LHC period. The upgrade aims at replacing the majority of the on- and off-detector electronics so that all calorimeter signals are directly digitized and sent to the off-detector electronics in the counting room. All new electronics must be able to cope with the increased rad...

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 ...

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 ...

FELIX: A Full Acceptance Detector at the LHC. Letter of Intent

Energy Technology Data Exchange (ETDEWEB)

Bjorken, James

2003-08-20

The FELIX Collaboration proposes the construction of a full acceptance detector for the LHC, to be located at Intersection Region 4, and to be commissioned concurrently with the LHC. The primary mission of FELIX is the study of QCD: to provide comprehensive and definitive observations of a very broad range of strong-interaction processes. This document contains a description of the detector concept including details of the individual detector elements and their performance characteristics, an extensive discussion of the physics menu, and the plans for integration of FELIX into the collider lattice and physical environment.

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

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...

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)

Pulling the trigger on LHC electronics

CERN Document Server

CERN. Geneva

2001-01-01

The conditions at CERN's Large Hadron Collider pose severe challenges for the designers and builders of front-end, trigger and data acquisition electronics. A recent workshop reviewed the encouraging progress so far and discussed what remains to be done. The LHC experiments have addressed level one trigger systems with a variety of high-speed hardware. The CMS Calorimeter Level One Regional Trigger uses 160 MHz logic boards plugged into the front and back of a custom backplane, which provides point-to-point links between the cards. Much of the processing in this system is performed by five types of 160 MHz digital applications-specific integrated circuits designed using Vitesse submicron high-integration gallium arsenide gate array technology. The LHC experiments make extensive use of field programmable gate arrays (FPGAs). These offer programmable reconfigurable logic, which has the flexibility that trigger designers need to be able to alter algorithms so that they can follow the physics and detector perform...

Identification of multiple sites suitable for insertion of foreign genes in herpes simplex virus genomes.

Science.gov (United States)

Morimoto, Tomomi; Arii, Jun; Akashi, Hiroomi; Kawaguchi, Yasushi

2009-03-01

Information on sites in HSV genomes at which foreign gene(s) can be inserted without disrupting viral genes or affecting properties of the parental virus are important for basic research on HSV and development of HSV-based vectors for human therapy. The intergenic region between HSV-1 UL3 and UL4 genes has been reported to satisfy the requirements for such an insertion site. The UL3 and UL4 genes are oriented toward the intergenic region and, therefore, insertion of a foreign gene(s) into the region between the UL3 and UL4 polyadenylation signals should not disrupt any viral genes or transcriptional units. HSV-1 and HSV-2 each have more than 10 additional regions structurally similar to the intergenic region between UL3 and UL4. In the studies reported here, it has been demonstrated that insertion of a reporter gene expression cassette into several of the HSV-1 and HSV-2 intergenic regions has no effect on viral growth in cell culture or virulence in mice, suggesting that these multiple intergenic regions may be suitable HSV sites for insertion of foreign genes.

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. &...

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)

The TOTEM Detector at LHC

OpenAIRE

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

2010-01-01

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

Final Technical Report for ``Paths to Discovery at the LHC : Dark Matter and Track Triggering"

Energy Technology Data Exchange (ETDEWEB)

Hahn, Kristian [Northwestern Univ., Evanston, IL (United States)

2016-10-24

Particle Dark Matter (DM) is perhaps the most compelling and experimentally well-motivated new physics scenario anticipated at the Large Hadron Collider (LHC). The DE-SC0014073 award allowed the PI to define and pursue a path to the discovery of Dark Matter in Run-2 of the LHC with the Compact Muon Solenoid (CMS) experiment. CMS can probe regions of Dark Matter phase-space that direct and indirect detection experiments are unable to constrain. The PI’s team initiated the exploration of these regions, searching specifically for the associated production of Dark Matter with top quarks. The effort focuses on the high-yield, hadronic decays of W bosons produced in top decay, which provides the highest sensitivity to DM produced via through low-mass spin-0 mediators. The group developed identification algorithms that achieve high efficiency and purity in the selection of hadronic top decays, and analysis techniques that provide powerful signal discrimination in Run-2. The ultimate reach of new physics searches with CMS will be established at the high-luminosity LHC (HL-LHC). To fully realize the sensitivity the HL-LHC promises, CMS must minimize the impact of soft, inelastic (“pileup”) interactions on the real-time “trigger” system the experiment uses for data refinement. Charged particle trajectory information (“tracking”) will be essential for pileup mitigation at the HL-LHC. The award allowed the PI’s team to develop firmware-based data delivery and track fitting algorithms for an unprecedented, real-time tracking trigger to sustain the experiment’s sensitivity to new physics in the next decade.

He II Heat Exchanger Test Unit for the LHC Inner Triplet

CERN Document Server

Blanco-Viñuela, E; Huang, Y; Nicol, T H; Peterson, T; Van Weelderen, R

2002-01-01

The Inner Triplet Heat Exchanger Test Unit (IT-HXTU) is a 30-m long thermal model designed at Fermilab, built in US industry, fully automated and tested at CERN as part of the US LHC program to develop the LHC Interaction Region quadrupole system. The cooling scheme of the IT-HXTU is based on heat exchange between stagnant pressurized He II in the magnet cold mass and saturated He II (two-phase) flowing in a heat exchanger located outside of and parallel to the cold mass. The purposes of this test are, among others, to validate the proposed cooling scheme and to define an optimal control strategy to be implemented in the future LHC accelerator. This paper discusses the results for the heat exchanger test runs and emphasizes the thermal and hydraulic behavior of He II for the inner triplet cooling scheme.

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.

Evaluation of Beam Losses And Energy Deposition for a Possible Phase II Design for LHC Collimation

International Nuclear Information System (INIS)

Lari, L.; Bracco, C.; Assmann, R.W.; Brugger, M.; Cerutti, F.; Ferrari, A.; Mauri, M.; Redaelli, S.; Sarchiapone, L.; Vlachoudis, V.; Weiler, T.; Doyle, J.E.; Keller, L.; Lundgren, S.A.; Markiewicz, T.W.; Smith, J.C.

2011-01-01

The Large Hadron Collider (LHC) beams are designed to have high stability and to be stored for many hours. The nominal beam intensity lifetime is expected to be of the order of 20h. The Phase II collimation system has to be able to handle particle losses in stable physics conditions at 7 TeV in order to avoid beam aborts and to allow correction of parameters and restoration to nominal conditions. Monte Carlo simulations are needed in order to evaluate the behavior of metallic high-Z collimators during operation scenarios using a realistic distribution of losses, which is a mix of the three limiting halo cases. Moreover, the consequences in the IR7 insertion of the worst (case) abnormal beam loss are evaluated. The case refers to a spontaneous trigger of the horizontal extraction kicker at top energy, when Phase II collimators are used. These studies are an important input for engineering design of the collimation Phase II system and for the evaluation of their effect on adjacent components. The goal is to build collimators that can survive the expected conditions during LHC stable physics runs, in order to avoid quenches of the SC magnets and to protect other LHC equipments.

Proceedings of Chamonix 2012 workshop on LHC Performance

International Nuclear Information System (INIS)

Carli, C.

2012-01-01

During this workshop on LHC performance, operation of the machine in 2012, activities during the first long shutdown LS1 aiming at preparing for operation at 7 TeV per beam and substantial long term upgrades of both the injector chain and the LHC have been discussed. After a session dedicated to observations and lessons from the run 2011, strategies for the run 2012 have been discussed in order to optimize the machine performance and, in particular, the maximum and integrated luminosity provided to the main experiments. Two session were dedicated to the preparation of the first long shutdown (LS1) followed by a session aiming at optimizing the performance to be expected after this first shutdown. The last two session of the workshop were dedicated to substantial upgrades of the injector complex and the LHC aiming at increasing the integrated luminosity to 250 inverse femto-barn per year after implementation in a second long shutdown. Improvements of the injector complex comprise increased injection energies in the PS Booster and the PS, an upgrade of the SPS vacuum chamber to alleviate limitations due to electron cloud build up and many more upgrades required for the generation of beams with higher brightness and smaller emittances than possible with the present machines. Plans for the LHC comprise an upgrade of the interaction regions to allow for a smaller beta*, crab cavities for luminosity levelling and, upgrades of the collimation and other systems

Achievement and Evaluation of the Beam Vacuum Performance of the LHC Long Straight Sections

CERN Document Server

Bregliozzi, G; Blanchard, S; Hansen, J; Jiménez, J M; Weiss, K

2008-01-01

The bake-out and activation of the TiZrV NEG coatings of the 6 km Long Straight Sections (LSS) of the Large Hadron Collider (LHC) is in its final step. After the bakeout and the NEG activation, the average ultimate pressure, over more than one hundred vacuum sectors, is below 10^-10 Pa. Therefore, the nominal requirement for the four experimental insertions is fulfilled. The nominal performances are also ensured for all the insertions housing the collimator systems, the RF cavities and the beam dumping systems. The main difficulties encountered during the bake-out and the activation of the NEG coated chambers is presented and discussed. In particular, the acceptance test and the limiting factors of the reached ultimate pressures are addressed. Furthermore, the influence on the ultimate pressures of the beam components (collimators, beam instrumentation, etc.) is discussed. Finally, preliminary results obtained from a NEG vacuum pilot sector installed in the laboratory and dedicated to the evaluation of the NE...

LHC IR Upgrade Nb-Ti, 120mm Aperture Model Quadrupole Test Results at 1.8K

CERN Document Server

Kirby, G A; Bajko, M; Datskov, V I; Durante, M; Fessia, P; Feuvrier, J; Guinchard, M; Giloux, C; Granieri, P P; Manil, P; Perez, J C; Ravaioli, E; Rifflet, J M; Russenschuck, S; Sahner, T; Segreti, M; Todesco, E; Willering, G

2014-01-01

Over the last five years, the model MQXC quadruple, a 120 mm aperture, 120 T/m, 1.8 m long, Nb-Ti version of the LHC insertion upgrade (due in 2021), has been developed at CERN. The magnet incorporates several novel concepts to extract high levels of heat flux and provide high quality field harmonics throughout the full operating current range. Existing LHC-dipole cable with new, open cable and ground insulation was used. Two, nominally identical 1.8 m long magnets were built and tested at 1.8 K at the CERN SM18 test facility. This paper compares in detail the two magnet tests and presents: quench performance, internal stresses, heat extraction simulating radiation loading in the superconducting coils, and quench protection measurements. The first set of tests highlighted the conflict between high magnet cooling capability and quench protection. The second magnet had additional instrumentation to investigate further this phenomenon. Finally we present test results from a new type of superconducting magnet pro...

The ALICE time projection chamber - a technological challenge in LHC heavy ion physics

CERN Document Server

Bächler, J

2004-01-01

The Time Projection Chamber is the main tracking detector in the central region of the ALICE experiment. This paper addresses the specific technological challenges for the detector and the solutions adopted to cope with the extreme particle densities in LHC heavy ion collisions. We will present the major components of the detector with an outlook of its expected performance in the LHC heavy ion program, as well as recent results from the comprehensive ALICE TPC test facility. (3 refs).

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.

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.

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.

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....

Application of diamond based beam loss monitors at LHC

Energy Technology Data Exchange (ETDEWEB)

Hempel, Maria

2013-04-15

the LHC, especially near each quadrupole and next to collimators. Ionization chambers have a time resolution of 40 s that is a half LHC turn and in case of a large beam loss, they request a beam dump. Another type of beam loss monitors are diamond sensors because of a time resolution of about one nanosecond and high radiation hardness. One diamond detector system is located in the cleaning region of the LHC and is able to detect various types of beam losses. Another diamond detector system (BCM1F) is installed inside the CMS detector to protect the CMS from adverse beam conditions. BCM1F monitors also the luminosity during collisions and delivers important beam parameters. Additional condition monitors, based on the BCM1F system, are located next to CMS, near to LHCb and ALICE to measure large beam losses in the LHC ring. The process of a beam loss due to dust particles is explained, and additional simulations were done to understand these process in more detail. The result of the simulation are also given. Beam loss data recorded by the diamond sensors in the cleaning region and the BCM1F diamonds are presented.

Influence of Micro-Damage on Reliability of Cryogenic Bellows in the LHC Interconnections

CERN Document Server

Garion, C

2008-01-01

To achieve maximum beam energy in the LHC the accumulated length of the interconnections between LHC main magnets has been limited to around 3% of the total magnetic length in the Arcs and Dispersion Suppressors. Such a low ratio leads to a very compact design of components located in the LHC interconnections. This implies development and evolution of high intensity plastic strain fields in the stainless steel expansion bellows subjected to thermo-mechanical loads at low temperatures. These components have been optimised to ensure high reliability standards required for the LHC. Nevertheless, initial damage can occur and lead to a premature fatigue failure. For structures in which plasticity is not confined to the crack tip region, standard failure mechanics, based classically on the stress intensity factor or the strain energy density release rate, can not be used. In the present paper, a constitutive model taking into account plastic strain induced g->a' phase transformation and orthotropic ductile damage i...

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...

Hard QCD Measurements at LHC

CERN Document Server

Pasztor, Gabriella

2018-01-01

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

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.

The BRAN luminosity detectors for the LHC

Energy Technology Data Exchange (ETDEWEB)

Matis, H.S.; Placidi, M.; Ratti, A.; Turner, W.C. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Bravin, E. [CERN, 1211 Geneva 23 (Switzerland); Miyamoto, R. [European Spallation Source, ESS AB, P.O. Box 176, SE-221 00 Lund (Sweden)

2017-03-11

This paper describes the several phases which led, from the conceptual design, prototyping, construction and tests with beam, to the installation and operation of the BRAN (Beam RAte of Neutrals) relative luminosity monitors for the LHC. The detectors have been operating since 2009 to contribute, optimize and maintain the accelerator performance in the two high luminosity interaction regions (IR), the IR1 (ATLAS) and the IR5 (CMS). The devices are gas ionization chambers installed inside a neutral particle absorber 140 m away from the Interaction Points in IR1 and IR5 and monitor the energy deposited by electromagnetic showers produced by high-energy neutral particles from the collisions. The detectors have the capability to resolve the bunch-by-bunch luminosity at the 40 MHz bunch rate, as well as to survive the extreme level of radiation during the nominal LHC operation. The devices have operated since the early commissioning phase of the accelerator over a broad range of luminosities reaching 1.4×10{sup 34} cm{sup −2} s{sup −1} with a peak pileup of 45 events per bunch crossing. Even though the nominal design luminosity of the LHC has been exceeded, the BRAN is operating well. After describing how the BRAN can be used to monitor the luminosity of the collider, we discuss the technical choices that led to its construction and the different tests performed prior to the installation in two IRs of the LHC. Performance simulations are presented together with operational results obtained during p-p operations, including runs at 40 MHz bunch rate, Pb-Pb operations and p-Pb operations.

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...

Non-linear advanced control of the LHC inner triplet heat exchanger test unit

International Nuclear Information System (INIS)

Vinuela, E. Blanco; Cubillos, J. Casas; Prada Moraga, C. de; Cristea, S.

2002-01-01

The future Large Hadron Collider (LHC) at CERN will include eight interaction region final focus magnet systems, the so-called 'Inner Triplet', one on each side of the four beam collision points. The Inner Triplets will be cooled in a static bath of pressurized He II nominally at 1.9 K. This temperature is a control parameter and has very severe constraints in order to avoid the transition from the superconducting to normal resistive state. The main difference in these special zones with respect to a regular LHC cell is higher dynamic heat load unevenly distributed which modifies largely the process characteristics and hence the controller performance. Several control strategies have already been tested at CERN in a pilot plant (LHC String Test) which reproduced a LHC half-cell. In order to validate a common control structure along the whole LHC ring, a Nonlinear Model Predictive Control (NMPC) has been developed and implemented in the Inner Triplet Heat Exchanger Unit (IT-HXTU) at CERN. Automation of the Inner Triplet setup and the advanced control techniques deployed based on the Model Based Predictive Control (MBPC) principle are presented

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/

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

CERN Document Server

Sauerwein, Christoph; Tiseanu, Ion; Williams, Lloyd R; Caspers, Fritz

2010-01-01

At the European Organisation for Nuclear Research ( CERN) the worlds largest particle accelerator ring, the Large Hadron collider (LHC), is being put into operation. It has been found useful to have a tool for diagnosis of the st ate of components in the interconnection regions of the LHC. This tool, for non-destructive testing (NDT) must w ork without opening the interconnection elements, without breaking the inte grity of the vacuum, and without the need to warm up the sector which would be costly an d time consuming. In addition the NDT tool has to be transportable in order to positi on it anywhere around the 27 km long LHC ring. The approach is an X-Ray inspection with the aim of an unambiguous representation of all structural elements in the interconnection regi ons of the LHC ring. The minimum criterion is to achieve an inspection result which allows verification of the correct position and integrity of all important components. 3D X-Ray computed tomography (3D CT) would be the i deal solution for such ...

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

Low missing mass, single- and double diffraction dissociation at the LHC

CERN Document Server

Jenkovszky, Laszlo; Orava, Risto; Salii, Andrii

2014-01-01

Low missing mass, single- and double diffraction dissociation is calculated for the LHC energies from a dual-Regge model, dominated by a Pomeron Regge pole exchange. The model reproduces the rich resonance structure in the low missing mass Mx region. The diffractionly excited states lie on the nucleon trajectory, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single- and double diffraction dissociation in the kinematical range of present and future LHC measurements are given. The model predicts a possible turn-down of the cross section towards, t -> 0 in a region probably accessible in future experiments in the nearly forward direction. The present work is a continuation and extension (e.g. with double diffraction) of a previous work using the dual Regge approach.

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.

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...

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...

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...

The TOTEM Detector at LHC

CERN Document Server

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

2010-01-01

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

Bottom production asymmetries at the LHC

Energy Technology Data Exchange (ETDEWEB)

Norrbin, E.; Vogt, R.

1999-01-01

We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward rapidities. At very large rapidities intrinsic production could dominate but this region is probably out of reach of any experiment.

Bottom production asymmetries at the LHC

International Nuclear Information System (INIS)

Norrbin, E.; Vogt, R.

1999-01-01

We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward rapidities. At very large rapidities intrinsic production could dominate but this region is probably out of reach of any experiment

Searches for Prompt R-Parity-Violating Supersymmetry at the LHC

International Nuclear Information System (INIS)

Redelbach, Andreas

2015-01-01

Searches for supersymmetry (SUSY) at the LHC frequently assume the conservation of R-parity in their design, optimization, and interpretation. In the case that R-parity is not conserved, constraints on SUSY particle masses tend to be weakened with respect to R-parity-conserving models. We review the current status of searches for R-parity-violating (RPV) supersymmetry models at the ATLAS and CMS experiments, limited to 8 TeV search results published or submitted for publication as of the end of March 2015. All forms of renormalisable RPV terms leading to prompt signatures have been considered in the set of analyses under review. Discussing results for searches for prompt R-parity-violating SUSY signatures summarizes the main constraints for various RPV models from LHC Run I and also defines the basis for promising signal regions to be optimized for Run II. In addition to identifying highly constrained regions from existing searches, also gaps in the coverage of the parameter space of RPV SUSY are outlined

WZ di-boson measurements with the ATLAS experiment at the LHC and performance of resistive Micromegas in view of HL-LHC applications

International Nuclear Information System (INIS)

Manjarres-Ramos, Joany

2013-01-01

During the past two years, the CERN Large Hadron Collider (LHC) has performed exceptionally. The data collected by ATLAS made possible the first Standard Model physics measurements and produced a number of important experimental results. In the first part of this document the measurement of the WZ production with the ATLAS detector is presented and the second part is devoted to the study of resistive Micromegas properties, in view of the installation in the ATLAS spectrometer forward regions for the first phase of High Luminosity LHC (HL-LHC). The measurement of the WZ production probes the electroweak sector of the Standard Model at high energies and allows for generic tests for New Physics beyond the Standard Model. Two datasets of LHC proton-proton collisions were analyzed, 4.8 fb -1 of integrated luminosity at center-of-mass energy of 7 TeV, and 13 fb -1 at 8 TeV, collected in 2011 and the first half of 2012 respectively. Fully leptonic decay events are selected with electrons, muons and missing transverse momentum in the final state. Different date-driven estimates of the background were developed in the context of this analysis. The fiducial and total cross section of WZ production are measured and limits on anomalous triple gauge boson couplings are set. The second part of the document is devoted to the upgrade of the ATLAS detector. The conditions at the High Luminosity LHC calls for detectors capable of operating in a flux of collisions and background particles approximately ten times larger compared to today's conditions. The efficiency, resolution and robustness of resistive Micromegas were studied, as part of the R and D project aimed at the construction of large-area spark-resistant muon chambers using the Micromegas technology. (author) [fr

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.

Silicon microstrip detectors in 3D technology for the sLHC

Energy Technology Data Exchange (ETDEWEB)

Parzefall, Ulrich [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany)], E-mail: ulrich.parzefall@physik.uni-freiburg.de; Dalla Betta, Gian-Franco [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Eckert, Simon [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Eklund, Lars; Fleta, Celeste [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Jakobs, Karl; Kuehn, Susanne; Pahn, Gregor [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Parkes, Chris; Pennicard, David [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Ronchin, Sabina [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Zoboli, Andrea [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Zorzi, Nicola [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy)

2009-08-01

The projected luminosity upgrade of the large hadron collider (LHC), the sLHC, will constitute a challenging radiation environment for tracking detectors. Massive improvements in radiation hardness are required with respect to the LHC. In the layout for the new ATLAS tracker, silicon strip detectors (SSDs) with short strips cover the region from 28 to 60 cm distance to the beam. These SSDs will be exposed to fluences up to 10{sup 15}N{sub eq}/cm{sup 2}, hence radiation resistance is the major concern. It is advantageous to fuse the superior radiation hardness of the 3D design originally conceived for pixel-style applications with the benefits of the well-known planar technology for strip detectors. This is achieved by ganging rows of 3D columns together to form strips. Several prototype sLHC detector modules using 3D SSD with short strips, processed on p-type silicon, and LHC-speed front-end electronics from the present ATLAS semi-conductor tracker (SCT) were built. The modules were tested before and after irradiation to fluences of 10{sup 15}N{sub eq}/cm{sup 2}. The tests were performed with three systems: a highly focused IR-laser with 5{mu}m spot size to make position-resolved scans of the charge collection efficiency (CCE), a Sr{sup 90}{beta}-source set-up to measure the signal levels for a minimum ionizing particles (MIPs), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of the performance of these 3D modules, and draws conclusions about options for using 3D strip sensors as tracking detectors at the sLHC.

Silicon microstrip detectors in 3D technology for the sLHC

International Nuclear Information System (INIS)

Parzefall, Ulrich; Dalla Betta, Gian-Franco; Eckert, Simon; Eklund, Lars; Fleta, Celeste; Jakobs, Karl; Kuehn, Susanne; Pahn, Gregor; Parkes, Chris; Pennicard, David; Ronchin, Sabina; Zoboli, Andrea; Zorzi, Nicola

2009-01-01

The projected luminosity upgrade of the large hadron collider (LHC), the sLHC, will constitute a challenging radiation environment for tracking detectors. Massive improvements in radiation hardness are required with respect to the LHC. In the layout for the new ATLAS tracker, silicon strip detectors (SSDs) with short strips cover the region from 28 to 60 cm distance to the beam. These SSDs will be exposed to fluences up to 10 15 N eq /cm 2 , hence radiation resistance is the major concern. It is advantageous to fuse the superior radiation hardness of the 3D design originally conceived for pixel-style applications with the benefits of the well-known planar technology for strip detectors. This is achieved by ganging rows of 3D columns together to form strips. Several prototype sLHC detector modules using 3D SSD with short strips, processed on p-type silicon, and LHC-speed front-end electronics from the present ATLAS semi-conductor tracker (SCT) were built. The modules were tested before and after irradiation to fluences of 10 15 N eq /cm 2 . The tests were performed with three systems: a highly focused IR-laser with 5μm spot size to make position-resolved scans of the charge collection efficiency (CCE), a Sr 90 β-source set-up to measure the signal levels for a minimum ionizing particles (MIPs), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of the performance of these 3D modules, and draws conclusions about options for using 3D strip sensors as tracking detectors at the sLHC.

ATLAS LAr Calorimeter Performance in LHC Run-2

CERN Document Server

Yatsenko, Elena; The ATLAS collaboration

2017-01-01

The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities up to 1034 cm−2 s−1. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic calorimetry in the region from |η| = 1.5 to |η| = 4.9. In the first LHC run a total luminosity of 27 fb−1 has been collected at center-of-mass energies of 7-8 TeV between year of 2010 to 2012. Following a period of detector consolidation during a long shutdown, Run-2 started with approximately 3.9 fb-1 and 35.6 fb-1 of data at a center-of-mass energy of 13 TeV recorded in 2015 and 2016, respectively. In order to realize the level-1 acceptance rate of 100 kHz in Run-2 data taking, number of read-out samples for the energy and the time measurement has been modified from five to four with keeping the expected performance. The well calibrated and highly granular Liquid Ar...

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.

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.

Quantitative mapping of matrix content and distribution across the ligament-to-bone insertion.

Directory of Open Access Journals (Sweden)

Jeffrey P Spalazzi

Full Text Available The interface between bone and connective tissues such as the Anterior Cruciate Ligament (ACL constitutes a complex transition traversing multiple tissue regions, including non-calcified and calcified fibrocartilage, which integrates and enables load transfer between otherwise structurally and functionally distinct tissue types. The objective of this study was to investigate region-dependent changes in collagen, proteoglycan and mineral distribution, as well as collagen orientation, across the ligament-to-bone insertion site using Fourier transform infrared spectroscopic imaging (FTIR-I. Insertion site-related differences in matrix content were also evaluated by comparing tibial and femoral entheses. Both region- and site-related changes were observed. Collagen content was higher in the ligament and bone regions, while decreasing across the fibrocartilage interface. Moreover, interfacial collagen fibrils were aligned parallel to the ligament-bone interface near the ligament region, assuming a more random orientation through the bulk of the interface. Proteoglycan content was uniform on average across the insertion, while its distribution was relatively less variable at the tibial compared to the femoral insertion. Mineral was only detected in the calcified interface region, and its content increased exponentially across the mineralized fibrocartilage region toward bone. In addition to new insights into matrix composition and organization across the complex multi-tissue junction, findings from this study provide critical benchmarks for the regeneration of soft tissue-to-bone interfaces and integrative soft tissue repair.

Quantitative Mapping of Matrix Content and Distribution across the Ligament-to-Bone Insertion

Science.gov (United States)

Spalazzi, Jeffrey P.; Boskey, Adele L.; Pleshko, Nancy; Lu, Helen H.

2013-01-01

The interface between bone and connective tissues such as the Anterior Cruciate Ligament (ACL) constitutes a complex transition traversing multiple tissue regions, including non-calcified and calcified fibrocartilage, which integrates and enables load transfer between otherwise structurally and functionally distinct tissue types. The objective of this study was to investigate region-dependent changes in collagen, proteoglycan and mineral distribution, as well as collagen orientation, across the ligament-to-bone insertion site using Fourier transform infrared spectroscopic imaging (FTIR-I). Insertion site-related differences in matrix content were also evaluated by comparing tibial and femoral entheses. Both region- and site-related changes were observed. Collagen content was higher in the ligament and bone regions, while decreasing across the fibrocartilage interface. Moreover, interfacial collagen fibrils were aligned parallel to the ligament-bone interface near the ligament region, assuming a more random orientation through the bulk of the interface. Proteoglycan content was uniform on average across the insertion, while its distribution was relatively less variable at the tibial compared to the femoral insertion. Mineral was only detected in the calcified interface region, and its content increased exponentially across the mineralized fibrocartilage region toward bone. In addition to new insights into matrix composition and organization across the complex multi-tissue junction, findings from this study provide critical benchmarks for the regeneration of soft tissue-to-bone interfaces and integrative soft tissue repair. PMID:24019964

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...

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...

Performance reach in the LHC for 2012

International Nuclear Information System (INIS)

Arduini, G.

2012-01-01

Based on the 2011 experience and Machine Development study results, the performance reach of the LHC with 25 and 50 ns beams will be addressed for operation at 3.5 and 4 TeV. The possible scrubbing scenarios and potential intensity limitations resulting from vacuum, heating will be taken into account wherever possible. The paper mainly covers the performance of the two high luminosity regions in IR1 and IR5. (author)

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.

Identification of Dark Matter particles with LHC and direct detection data

CERN Document Server

Bertone, Gianfranco; Fornasa, Mattia; de Austri, Roberto Ruiz; Trotta, Roberto

2010-01-01

Dark matter (DM) is currently searched for with a variety of detection strategies. Accelerator searches are particularly promising, but even if Weakly Interacting Massive Particles (WIMPs) are found at the Large Hadron Collider (LHC), it will be difficult to prove that they constitute the bulk of the DM in the Universe. We show that a significantly better reconstruction of the DM properties can be obtained with a combined analysis of LHC and direct detection (DD) data, by making a simple Ansatz on the WIMP local density, i.e. by assuming that the local density scales with the cosmological relic abundance. We demonstrate this method in an explicit example in the context of a 24-parameter supersymmetric model, with a neutralino LSP in the stau co-annihilation region. Our results show that future ton-scale DD experiments will allow to break degeneracies in the SUSY parameter space and achieve a significantly better reconstruction of the neutralino composition and its relic density than with LHC data alone.

Fast polycrystalline CdTe detectors for bunch-by-bunch luminosity monitoring in the LHC

CERN Document Server

Brambilla, A; Jolliot, M; Bravin, E

2008-01-01

The luminosity at the four interaction points of the Large Hadron Collider (LHC) must be continuously monitored in order to provide an adequate tool for the control and optimisation of beam parameters. Polycrystalline cadmium telluride (CdTe) detectors have previously been tested, showing their high potential to fulfil the requirements of luminosity measurement in the severe environment of the LHC interaction regions. Further, the large signal yield and the fast response time should allow bunch-by-bunch measurement of the luminosity at 40 MHz with high accuracy. Four luminosity monitors with two rows of five polycrystalline CdTe detectors each have been fabricated and will be installed at both sides of the low-luminosity interaction points ALICE and LHC-b. A detector housing was specially designed to meet the mechanical constraints in the LHC. A series of elementary CdTe detectors were fabricated and tested, of which 40 were selected for the luminosity monitors. A sensitivity of 104 electrons per minimum ioni...

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.

Identification and insertion polymorphisms of short interspersed nuclear elements (SINEs) in Brassica genomes

International Nuclear Information System (INIS)

Nouroz, F.; Naveed, M.

2018-01-01

The non-LTR retrotransposons (retroposons) are abundant in plant genomes including members of Brassicaceae. Of the retroposons, long interspersed nuclear elements (LINEs) are more copious followed by short interspersed nuclear elements (SINEs) in sequenced eukaryotic genomes. The SINEs are short elements and ranged from 100-500 bps flanked by variable sized target site duplications, 5' tRNA region with polymerase III promoter, internal tRNA unrelated region, 3' LINEs derived region and a poly adenosine tail. Different computational approaches were used for the identification and characterization of SINEs, while PCR was used to detect the SINEs insertion polymorphisms in various Brassica genotypes. Ten previously unidentified families of SINEs were identified and characterized from Brassica genomes. The structural features of these SINEs were studied in detail, which showed typical SINE features displaying small sizes, target site duplications, head regions, internal regions (body) of variable sizes and a poly (A) tail at the 3' terminus. The elements from various families ranged from 206-558 bp, where BoSINE2 family displayed smallest SINE element (206 bp), while larger members belonged to BoSINE9 family (524-558 bp). The distribution and abundance of SINEs in various Brassica species and genotypes (40) at a particular site/locus were investigated by SINEs based PCR markers. Various SINE insertion polymorphisms were detected from different genotypes, where higher PCR bands amplified the SINE insertions, while lower bands amplified the pre-insertion sites (flanking regions). The analysis of Brassica SINEs copy numbers from 10 identified families revealed that around 860 and 1712 copies of SINEs were calculated from B. rapa and B. oleracea Whole-genome shotgun contigs (WGS) respectively. Analysis of insertion sites of Brassica SINEs revealed that the members from all 10 SINE families had shown an insertion preference in AT rich regions. The present

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.)

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...

Optics Designs of Final-Focus Systems for Future LHC Upgrades

CERN Document Server

Abelleira, J L; Zimmermann, Frank; Rivkin, Leonid

2014-01-01

The main topic of the thesis is the study of a novel option for the high-luminosity upgrade of the Large Hadron Collider (LHC) comprising a large Piwinski angle, flat beams, and crab waists. Flat beams and crab waists are not only pre-requisites for a crab-waist scheme, but, even by themselves; each of these two elements alone could boost the luminosity of the existing collider as built. The new optics involves an upgrade of the interaction region of the two high-luminosity experiments, ATLAS and CMS, in order to provide them with a substantially higher luminosity. To this end, a flat-beam optics scenario has been explored for the High Luminosity LHC (HL-LHC), with a much reduced vertical beta function at the interaction point (IP), $\\beta_y^*$. In addition, a large Piwinski angle is considered. Advantages of a large Piwinski angle include a reduction in the hourglass effect over the length of the collision area, which allows for the significant $\\beta_y^*$ decrease. In addition there is a reduction of the be...

Magnetic Frequency Response of HL-LHC Beam Screens

CERN Document Server

Morrone, M; De Maria, R; Fitterer, M; Garion, C

2017-01-01

Magnetic fields used to control particle beams in accelerators are usually controlled by regulating the electrical current of the power converters. In order to minimize lifetime degradation and ultimately luminosity loss in circular colliders, current-noise is a highly critical figure of merit of power converters, in particular for magnets located in areas with high beta-function, like the High Luminosity Large Hadron Collider (HL-LHC) insertions. However, what is directly acting upon the beam is the magnetic field and not the current of the power converter, which undergoes several frequency-dependent transformations until the desired magnetic field, seen by the beam, is obtained. Beam screens are very rarely considered when assessing or specifying the noise figure of merit, but their magnetic frequency response is such that they realize relatively effective low pass filtering of the magnetic field produced by the system magnet-power converter. This work aims at filling this gap by quantifying the expected im...

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

Supersymmetry and Dark Matter in Light of LHC 2010 and Xenon100 Data

CERN Document Server

Buchmueller, O.; Colling, D.; De Roeck, A.; Dolan, M.J.; Ellis, J.R.; Flacher, H.; Heinemeyer, S.; Isidori, G.; Santos, D.Martinez; Olive, K.A.; Rogerson, S.; Ronga, F.J.; Weiglein, G.

2011-01-01

We make frequentist analyses of the CMSSM, NUHM1, VCMSSM and mSUGRA parameter spaces taking into account all the public results of searches for supersymmetry using data from the 2010 LHC run and the Xenon100 direct search for dark matter scattering. The LHC data set includes ATLAS and CMS searches for jets + ETslash events (with or without leptons) and for the heavier MSSM Higgs bosons, and the upper limit on bs to mu mu including data from LHCb as well as CDF and D0. The absences of signals in the LHC data favour somewhat heavier mass spectra than in our previous analyses of the CMSSM, NUHM1 and VCMSSM, and somewhat smaller dark matter scattering cross sections, all close to or within the pre-LHC 68% CL ranges, but do not impact significantly the favoured regions of the mSUGRA parameter space. We also discuss the impact of the Xenon100 constraint on spin-independent dark matter scattering, stressing the importance of taking into account the uncertainty in the pi-nucleon sigma term, that affects the spin-inde...

High Luminosity LHC (HL-LHC) general infographics

CERN Multimedia

Landua, Fabienne

2016-01-01

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

Probing Higgs-radion mixing in warped models through complementary searches at the LHC and the ILC

Science.gov (United States)

Frank, Mariana; Huitu, Katri; Maitra, Ushoshi; Patra, Monalisa

2016-09-01

We consider the Higgs-radion mixing in the context of warped space extradimensional models with custodial symmetry and investigate the prospects of detecting the mixed radion. Custodial symmetries allow the Kaluza-Klein excitations to be lighter and protect Z b b ¯ to be in agreement with experimental constraints. We perform a complementary study of discovery reaches of the Higgs-radion mixed state at the 13 and 14 TeV LHC and at the 500 and 1000 GeV International Linear Collider (ILC). We carry out a comprehensive analysis of the most significant production and decay modes of the mixed radion in the 80 GeV-1 TeV mass range and indicate the parameter space that can be probed at the LHC and the ILC. There exists a region of the parameter space which can be probed, at the LHC, through the diphoton channel even for a relatively low luminosity of 50 fb-1 . The reach of the four-lepton final state in probing the parameter space is also studied in the context of 14 TeV LHC, for a luminosity of 1000 fb-1 . At the ILC, with an integrated luminosity of 500 fb-1 , we analyze the Z -radion associated production and the W W fusion production, followed by the radion decay into b b ¯ and W+W-. The W W fusion production is favored over the Z -radion associated channel in probing regions of the parameter space beyond the LHC reach. The complementary study at the LHC and the ILC is useful both for the discovery of the radion and the understanding of its mixing sector.

Electronics at LHC

CERN Document Server

Hall, Geoffrey

1998-01-01

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

Silicon strip detectors for the ATLAS HL-LHC upgrade

CERN Document Server

Gonzalez Sevilla, S; The ATLAS collaboration

2011-01-01

The LHC upgrade is foreseen to increase the ATLAS design luminosity by a factor ten, implying the need to build a new tracker suited to the harsh HL-LHC conditions in terms of particle rates and radiation doses. In order to cope with the increase in pile-up backgrounds at the higher luminosity, an all silicon detector is being designed. To successfully face the increased radiation dose, a new generation of extremely radiation hard silicon detectors is being designed. We give an overview of the ATLAS tracker upgrade project, in particular focusing on the crucial innermost silicon strip layers. Results from a wide range of irradiated silicon detectors for the strip region of the future ATLAS tracker are presented. Layout concepts for lightweight yet mechanically very rigid detector modules with high service integration are shown.

LHC beam dumping system Extraction channel layout and acceptance

CERN Document Server

Goddard, B; Uythoven, J; Veness, R; Weterings, W

2003-01-01

The LHC beam dumping system must safely abort the LHC beams under all conditions, including those resulting from abnormal behaviour of machine elements or subsystems of the beam dumping system itself. The extraction channels must provide sufficient aperture both for the circulating and extracted beams, over the whole energy range and under various beam parameters. These requirements impose tight constraints on the tolerances of various extraction channel components, and also on the allowed range of beam positions in the region of these components. Operation of the beam dumping system under various fault states has been considered, and the resulting apertures calculated. After describing briefly the beam dumping system and the extraction channel geometry, the various assumptions made in the analysis are presented, before deriving tolerance limits for the relevant equipment and beam parameters.

Status of the LHC machine

International Nuclear Information System (INIS)

Faugeras, P.

1997-01-01

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

Prompt double J/ψ production in proton-proton collisions at the LHC

International Nuclear Information System (INIS)

Baranov, S.P.; Rezaeian, Amir H.

2015-11-01

We provide a detailed study of prompt double J/ψ production within the non-relativistic QCD (NRQCD) framework in proton-proton collisions at the LHC.We confront the recent LHC data with the results obtained at leading-order (LO) in the NRQCD framework within two approaches of the collinear factorization and the k T -factorization. We show that the LHCb data can be fairly described within the k T -factorized LO NRQCD, while the collinearly factorized LO NRQCD significantly overshoots the LHCb data at low J/ψ-pair invariant mass. We show that the LO NRQCD formalism cannot describe the recent CMS data, with about one order of magnitude discrepancy. If the CMS data are confirmed, this indicates rather large higher-order corrections for prompt double J/ψ production. We provide various predictions which can further test the NRQCD-based approach at the LHC in a kinematic region that LO contributions dominate. We also investigate long-range in rapidity double J/ψ correlations. We found no evidence of a ridge-like structure for double J/ψ production in proton-proton collisions at the LHC up to subleading α 6 s accuracy.

Commissioning of the LHC

CERN Multimedia

CERN. Geneva

2007-01-01

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

Production LHC HTS power lead test results

CERN Document Server

Tartaglia, M; Fehér, S; Huang, Y; Orris, D F; Pischalnikov, Y; Rabehl, Roger Jon; Sylvester, C D; Zbasnik, J

2005-01-01

The Fermilab Magnet test facility has built and operated a test stand to characterize the performance of HTS power leads. We report here the results of production tests of 20 pairs of 7.5 kA HTS power leads manufactured by industry for installation in feed boxes for the LHC Interaction Region quadrupole strings. Included are discussions of the thermal, electrical, and quench characteristics under "standard" and "extreme" operating conditions, and the stability of performance across thermal cycles.

Production LHC HTS power lead test results

International Nuclear Information System (INIS)

Tartaglia, M.A.; Carcagno, R.H.; Feher, S.; Huang, Y.; Orris, D.F.; Pischalnikov, Y.; Rabehl, R.J.; Sylvester, C.; Zbasnik, J.

2004-01-01

The Fermilab Magnet test facility has built and operated a test stand to characterize the performance of HTS power leads. We report here the results of production tests of 20 pairs of 7.5 kA HTS power leads manufactured by industry for installation in feed boxes for the LHC Interaction Region quadrupole strings. Included are discussions of the thermal, electrical, and quench characteristics under ''standard'' and ''extreme'' operating conditions, and the stability of performance across thermal cycles

LHC Highlights, from dream to reality

CERN Multimedia

CERN Bulletin

2010-01-01

The idea of the Large Hadron Collider (LHC) was born in the early 1980s. Although LEP (CERN’s previous large accelerator) was still under construction at that time, scientists were already starting to think about re-using the 27-kilometre ring for an even more powerful machine. Turning this ambitious scientific plan into reality proved to be an immensely complex task. Civil engineering work, state-of-the-art technologies, a new approach to data storage and analysis: many people worked hard for many years to accomplish all this.   Here are some of the highlights: 1984. A symposium organized in Lausanne, Switzerland, is the official starting point for the LHC. LHC prototype of the two beam pipes (1992). 1989. The first embryonic collaborations begin. 1992. A meeting in Evian, France, marks the beginning of the LHC experiments. 1994. The CERN Council approves the construction of the LHC accelerator. 1995. Japan becomes an Observer of CERN and announces a financial contribution to ...

Performance of the LHC Pre-Injectors

CERN Document Server

Benedikt, Michael; Chanel, M; Garoby, R; Giovannozzi, Massimo; Hancock, S; Martini, M; Métral, Elias; Métral, G; Schindl, Karlheinz; Vallet, J L

2001-01-01

The LHC pre-injector complex, comprising Linac 2, the PS Booster (PSB) and the PS, has undergone a major upgrade in order to meet the very stringent requirements of the LHC. Whereas bunches with the nominal spacing and transverse beam brightness were already available from the PS in 1999 [1], their length proved to be outside tolerance due to a debunching procedure plagued by microwave instabilities. An alternative scenario was then proposed, based on a series of bunch-splitting steps in the PS. The entire process has recently been implemented successfully, and beams whose longitudinal characteristics are safely inside LHC specifications are now routinely available. Variants of the method also enable bunch trains with gaps of different lengths to be generated. These are of interest for the study and possible cure of electron cloud effects in both the SPS and LHC. The paper summarizes the beam dynamics issues that had to be addressed to produce beams with all the requisite qualities for the LHC.

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...

Overview of the ATLAS Insertable B-Layer (IBL) Project

CERN Document Server

Kagan, M; The ATLAS collaboration

2014-01-01

The first upgrade for the Pixel Detector will be a new pixel layer which is currently under construction and will be installed during the first shutdown of the LHC machine, in 2013-14. The new detector, called the Insertable B-layer (IBL), will be installed between the existing Pixel Detector and a new, smaller radius beam-pipe. Two different silicon sensor technologies, planar n-in-n and 3D, will be used, connected with the new generation 130nm IBM CMOS FE-I4 readout chip via solder bump-bonds. A production quality control test bench was setup in the ATLAS inner detector assembly clean room to verify and rate the performance of the detector elements before integration around the beam pipe. An overview of the IBL project, of the module design, the qualification for these sensor technologies, the integration quality control setups and recent results in the construction of this full scale new concept detector is discussed.

Overview of the ATLAS Insertable B-Layer (IBL) Project

Science.gov (United States)

Kagan, M. A.

2014-06-01

The first upgrade for the Pixel Detector will be a new pixel layer which is currently under construction and will be installed during the first shutdown of the LHC machine, in 2013-14. The new detector, called the Insertable B-layer (IBL), will be installed between the existing Pixel Detector and a new, smaller radius beam-pipe. Two different silicon sensor technologies, planar n-in-n and 3D, will be used, connected with the new generation 130nm IBM CMOS FE-I4 readout chip via solder bump-bonds. A production quality control test bench was set up in the ATLAS inner detector assembly clean room to verify and rate the performance of the detector elements before integration around the beam-pipe. An overview of the IBL project, of the module design, the qualification for these sensor technologies, the integration quality control setups and recent results in the construction of this full scale new concept detector is discussed.

To the LHC and beyond

CERN Document Server

Rodgers, Peter

2004-01-01

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

Review of LHC dark matter searches

International Nuclear Information System (INIS)

Kahlhoefer, Felix

2017-02-01

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

Review of LHC dark matter searches

Energy Technology Data Exchange (ETDEWEB)

Kahlhoefer, Felix

2017-02-15

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

First Results of the LHC Collision Rate Monitors

CERN Document Server

Burger, S; Bart Pedersen, S; Boccardi, A; Dutriat, C; Miyamoto, R; Doolittle, L; Matis, H S; Placidi, M; Ratti, A; Stezelberger, T; Yaver, H

2011-01-01

The aim of CERN large hadron collider (LHC) is to collide protons and heavy ions with centre of mass energies up to 14 zTeV. In order to monitor and optimize the collision rates special detectors have been developed and installed around the four luminous interaction regions. Due to the different conditions at the high luminosity experiments (ATLAS and CMS) and the low luminosity experiments (ALICE and LHC-b) two very different types of monitors are used: a fast ionisation chamber (BRAN-A) and a Cd-Te solid state detector (BRAN-B respectively. Moreover, in order to cope with the low collision rates foreseen for the initial run, a third type of monitor, based on a simple scintillating pad, was installed in parallel with the BRAN-A (BRAN-P). This contribution illustrates the results obtained during the 2010 run with an outlook for 2011 and beyond.

Baseline review of the U.S. LHC Accelerator project

International Nuclear Information System (INIS)

1998-02-01

The Department of Energy (DOE) Review of the U.S. Large Hadron Collider (LHC) Accelerator project was conducted February 23--26, 1998, at the request of Dr. John R. O'Fallon, Director, Division of High Energy Physics, Office of Energy Research, U.S. DOE. This is the first review of the U.S. LHC Accelerator project. Overall, the Committee found that the U.S. LHC Accelerator project effort is off to a good start and that the proposed scope is very conservative for the funding available. The Committee recommends that the project be initially baselined at a total cost of $110 million, with a scheduled completion data of 2005. The U.S. LHC Accelerator project will supply high technology superconducting magnets for the interaction regions (IRs) and the radio frequency (rf) straight section of the LHC intersecting storage rings. In addition, the project provides the cryogenic support interface boxes to service the magnets and radiation absorbers to protect the IR dipoles and the inner triplet quadrupoles. US scientists will provide support in analyzing some of the detailed aspects of accelerator physics in the two rings. The three laboratories participating in this project are Brookhaven National Laboratory, Fermi National Accelerator Laboratory (Fermilab), and Lawrence Berkeley National Laboratory. The Committee was very impressed by the technical capabilities of the US LHC Accelerator project team. Cost estimates for each subsystem of the US LHC Accelerator project were presented to the Review Committee, with a total cost including contingency of $110 million (then year dollars). The cost estimates were deemed to be conservative. A re-examination of the funding profile, costs, and schedules on a centralized project basis should lead to an increased list of deliverables. The Committee concluded that the proposed scope of US deliverables to CERN can be readily accomplished with the $110 million total cost baseline for the project. The current deliverables should serve as

Delivering LHC software to HPC compute elements

CERN Document Server

Blomer, Jakob; Hardi, Nikola; Popescu, Radu

2017-01-01

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

New U.S. LHC Web site launched

CERN Multimedia

Katie Yurkewicz

2007-01-01

On September 12, the U.S. Department of Energy's Office of Science launched a new Web site, www.uslhc.us, to tell the story of the U.S. role in the LHC. The site provides general information for the public about the LHC and its six experiments, as well as detailed information about the participation of physicists, engineers and students from the United States. The U.S. site joins the UK's LHC site in providing information for a national audience, with sites from several more countries expected to launch within the next year. The US LHC site features news and information about the LHC, along with high-resolution images and resources for students and educators. The site also features blogs by four particle physicists, including ATLAS collaborators Monica Dunford from the University of Chicago and Peter Steinberg from Brookhaven National Laboratory. More than 1,300 scientists from over 90 U.S. institutions participate in the LHC and its experiments, representing universities and national laboratories from...

Protecting LHC components against radiation resulting from an unsynchronized beam abort

International Nuclear Information System (INIS)

Mokhov, Nikolai V.

2001-01-01

The effect of possible accidental beam loss in the LHC on the IP5 and IP6 insertion elements is studied via realistic Monte Carlo simulations. The scenario studied is beam loss due to unsynchronized abort at an accidental prefire of one of the abort kicker modules. Simulations show that this beam loss would result in severe heating of the IP5 and IP6 superconducting (SC) quadrupoles. Contrary to the previous considerations with a stationary set of collimators in IP5, collimators in IP6 close to the cause are proposed: a movable collimator upstream of the Q4 quadrupole and a stationary one upstream of the extraction septumMSD. The calculated temperature rise in the optimal set of collimators is quite acceptable. All SC magnets are protected by these collimators against damage

Protecting LHC Components Against Radiation Resulting From an Unsynchronized Beam Abort

CERN Document Server

Drozhdin, A I; Mokhov, N V; Rakhno, I L; Weisse, E

2001-01-01

The effect of possible accidental beam loss in the LHC on the IP5 and IP6 insertion elements is studied via realistic Monte Carlo simulations. The scenario studied is beam loss due to unsynchronized abort at an accidental prefire of one of the abort kicker modules. Simulations show that this beam loss would result in severe heating of the IP5 and IP6 superconducting (SC) quadrupoles. Contrary to the previous considerations with a stationary set of collimators in IP5, collimators in IP6 close to the cause are proposed: a movable collimator upstream of the Q4 quadrupole and a stationary one upstream of the extraction septum MSD. The calculated temperature rise in the optimal set of collimators is quite acceptable. All SC magnets are protected by these collimators against damage.

Beam-gas Background Observations at LHC

CERN Document Server

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

2017-01-01

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

A High-Granularity Timing Detector (HGTD) in ATLAS : Performance at the HL-LHC

CERN Document Server

Allaire, Corentin; The ATLAS collaboration

2018-01-01

The large increase of pileup is one of the main experimental challenges for the HL-LHC physics program. A powerful new way to address this challenge is to exploit the time spread of the interactions to distinguish between collisions occurring very close in space but well separated in time. A High-Granularity Timing Detector, based on low gain avalanche detector technology, is proposed for the ATLAS Phase-II upgrade. Covering the pseudorapidity region between 2.4 and 4.0, with a timing resolution of 30 ps for minimum-ionizing particles, this device will significantly improve the performance in the forward region. High-precision timing greatly improves the track-to-vertex associ- ation, leading to a performance similar to that in the central region for both jet and lepton reconstruction, as well as the tagging of heavy-flavour jets. These improvements in object reconstruction performance translate into impor- tant sensitivity gains and enhance the reach of the HL-LHC physics program. In addition, the HGTD offer...

Budker INP in the LHC Machine (2)

CERN Multimedia

2001-01-01

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

Le futur du project LHC

CERN Multimedia

Heyoka

2007-01-01

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

THREE-BEAM INSTABILITY IN THE LHC*

CERN Document Server

Burov, A

2013-01-01

In the LHC, a transverse instability is regularly observed at 4TeV right after the beta-squeeze, when the beams are separated by about their ten transverse rms sizes [1-3], and only one of the two beams is seen as oscillating. So far only a single hypothesis is consistent with all the observations and basic concepts, one about a third beam - an electron cloud, generated by the two proton beams in the high-beta areas of the interaction regions. The instability results from a combined action of the cloud nonlinear focusing and impedance.

CERN LHC dipole prototype success

International Nuclear Information System (INIS)

Anon.

1994-01-01

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

Le LHC, un tunnel cosmique

CERN Multimedia

CERN. Geneva

2009-01-01

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

$A^t_{FB}$ Meets LHC

Energy Technology Data Exchange (ETDEWEB)

Hewett, JoAnne L.; /SLAC; Shelton, Jessie; /Yale U.; Spannowsky, Michael; /Oregon U.; Tait, Tim M.P.; /UC, Irvine; Takeuchi, Michihisa; /Heidelberg U.

2012-02-14

The recent Tevatron measurement of the forward-backward asymmetry of the top quark shows an intriguing discrepancy with Standard Model expectations, particularly at large t{bar t} invariant masses. Measurements of this quantity are subtle at the LHC, due to its pp initial state, however, one can define a forward-central-charge asymmetry which captures the physics. We study the capability of the LHC to measure this asymmetry and find that within the SM a measurement at the 5{sigma} level is possible with roughly 60 fb{sup -1} at {radical}s = 14 TeV. If nature realizes a model which enhances the asymmetry (as is necessary to explain the Tevatron measurements), a significant difference from zero can be observed much earlier, perhaps even during early LHC running at {radical}s = 7 TeV. We further explore the capabilities of the 7 TeV LHC to discover resonances or contact interactions which modify the t{bar t} invariant mass distribution using recent boosted top tagging techniques. We find that TeV-scale color octet resonances can be discovered, even with small coupling strengths and that contact interactions can be probed at scales exceeding 6 TeV. Overall, the LHC has good potential to clarify the situation with regards to the Tevatron forward-backward measurement.

Transverse emittance measurement and preservation at the LHC

Energy Technology Data Exchange (ETDEWEB)

Kuhn, Maria

2016-06-20

The Large Hadron Collider (LHC) at CERN is a high energy storage ring that provides proton and heavy ion collisions to study fundamental particle physics. The luminosity production is closely linked to emittance preservation in the accelerator. The transverse emittance is the phase space density of the beam and should be conserved when the particle beam is transformed through the accelerator. Perturbing effects, however, can lead to emittance increase and hence luminosity degradation. Measuring the emittance growth is a complex task with high intensity beams and changing energies. The machine optics and the transverse beam size have to be measured as accurately as possible. Beta function measurements with k-modulation are discussed. With this method the quadrupole focussing strength is varied and the resulting tune change is traced to determine the beta function at the quadrupole. A new k-modulation measurement tool was developed for the LHC. The fully automatic and online measurement system takes constraints of various systems such as tune measurement precision and powering limitations of the LHC superconducting circuits into account. With sinusoidal k-modulation record low beta function measurement uncertainties in the LHC have been reached. 2015 LHC beta function and β*, which is the beta function at the collision point, measurements with k-modulation will be presented. Wire scanners and synchrotron light monitors are presently used in the LHC to measure the transverse beam size. Accuracy and limitations of the LHC transverse profile monitors are discussed. During the 2012 LHC proton run it was found that wire scanner photomultiplier saturation added significant uncertainty on all measurements. A large discrepancy between emittances from wire scanners and luminosity was discovered but not solved. During Long Shutdown 1 the wire scanner system was upgraded with new photomultipliers. A thorough study of LHC wire scanner measurement precision in 2015 is presented

Proposal to negotiate a collaboration agreement for the design, testing and prototyping of superconducting elements for the High Luminosity LHC (HL-LHC) project and for the production of spare quadrupole magnets for LHC

CERN Document Server

2016-01-01

Proposal to negotiate a collaboration agreement for the design, testing and prototyping of superconducting elements for the High Luminosity LHC (HL-LHC) project and for the production of spare quadrupole magnets for LHC

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.

Tissue-engineering strategies for the tendon/ligament-to-bone insertion.

Science.gov (United States)

Smith, Lester; Xia, Younan; Galatz, Leesa M; Genin, Guy M; Thomopoulos, Stavros

2012-01-01

Injuries to connective tissues are painful and disabling and result in costly medical expenses. These injuries often require reattachment of an unmineralized connective tissue to bone. The uninjured tendon/ligament-to-bone insertion (enthesis) is a functionally graded material that exhibits a gradual transition from soft tissue (i.e., tendon or ligament) to hard tissue (i.e., mineralized bone) through a fibrocartilaginous transition region. This transition is believed to facilitate force transmission between the two dissimilar tissues by ameliorating potentially damaging interfacial stress concentrations. The transition region is impaired or lost upon tendon/ligament injury and is not regenerated following surgical repair or natural healing, exposing the tissue to risk of reinjury. The need to regenerate a robust tendon-to-bone insertion has led a number of tissue engineering repair strategies. This review treats the tendon-to-bone insertion site as a tissue structure whose primary role is mechanical and discusses current and emerging strategies for engineering the tendon/ligament-to-bone insertion in this context. The focus lies on strategies for producing mechanical structures that can guide and subsequently sustain a graded tissue structure and the associated cell populations.

LHC bending magnet coil

CERN Multimedia

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

LHC Report: Back in operation

CERN Multimedia

2016-01-01

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

Keeping the LHC in power

CERN Multimedia

CERN Bulletin

2013-01-01

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

ATLAS LAr Calorimeter Performance and Commissioning for LHC Run-2

CERN Document Server

Spettel, Fabian; The ATLAS collaboration

2015-01-01

The ATLAS detector was designed and built to study proton-proton colli- sions produced at the LHC at centre-of-mass energies up to 14 TeV and in- stantaneous luminosities up to $10^{34} \\text{cm}^{-2} \\text{s}^{-1}$. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudorapidity region $|\\eta|<3.2$, and for hadronic calorimetry in the region from $|\\eta|=1.5$ to $|\\eta|=4.9$. In the first LHC run a total luminosity of 27 $\\text{fb}^{-1}$ as been collected at center-of-mass energies of 7-8 TeV with very high operational efficiency of the LAr Calorimeters and excellent performance. The well calibrated and highly granular detector achieved its design values both in energy measurement as well as in direction resolution, which was a main ingredient for the successul discovery of a Higgs boson in the di-photon decay channel. The talk will give an overview of the procedures applied to calibrate the 180.000 read-out channels electronically as well as from using refe...

Integration of a neutral absorber for the LHC point 8

CERN Document Server

Santamaria, A; Alemany, R; Burkhardt, H; Cerutti, F

2014-01-01

The LHCb detector will be upgraded during the second long shutdown (LS2) of the LHC machine, in order to increase its statistical precision significantly. The upgraded LHCb foresees a peak luminosity of LHL = 1-21033cm-2s-11, with a pileup of ~5. This represents ten times more luminosity and five times more pile up than in the present LHC. With these conditions, the pp-collisions and beam losses will produce a non-negligeable beam-induced energy deposition in the interaction region. More precisely, studies [1] have shown that the energy deposition will especially increase on the D2 recombination dipole, which could bring them close to their safety thresholds. To avoid this, the placement of a minimal neutral absorber has been proposed. This absorber will have the same role as the TAN in the high luminosity Interaction Regions (IR) 1 and 5. This study shows the possible dimensions and location of this absorber, and how it would reduce both the peak power density and total heat load.

LS1 general planning and strategy for the LHC, LHC injectors

CERN Document Server

Foraz, K

2012-01-01

The goal of Long Shutdown 1 (LS1) is to perform the full maintenance of equipment, and the necessary consolidation and upgrade activities in order to ensure reliable LHC operation at nominal performance from mid 2014. LS1 not only concerns LHC but also its injectors. To ensure resources will be available an analysis is in progress to detect conflict/overload and decide what is compulsary, what we can afford, and what can be postponed to LS2. The strategy, time key drivers, constraints, and draft schedule will be presented here.

ATLAS LAr Calorimeters Performance in LHC Run-2

CERN Document Server

Camincher, Clement; The ATLAS collaboration

2018-01-01

The ATLAS detector was designed and built to study proton-proton collisions produced at the LHC at centre-of-mass energies up to 14 TeV and instantaneous luminosities above 1034 cm−2 s−1. Liquid argon (LAr) sampling calorimeters are employed for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. In the first LHC run a total luminosity of 27 fb−1 has been collected at center-of-mass energies of 7-8 TeV between year of 2010 to 2012. After a period of detector consolidation during a long shutdown, Run-2 started in 2015 and 3.9 fb-1, 35.6 fb-1 and 46.9 fb-1 of data at a center-of-mass energy of 13 TeV have been recorded up to now per year. In order to realize the level-1 acceptance rate of 100 kHz in Run-2 data taking, the number of read-out samples recorded and used for the energy and the time measurement has been modified from five to four while keeping the expected performance. The well calibra...

First LHC beam in 2017

CERN Multimedia

ATLAS Collaboration

2017-01-01

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

First LHC beam in 2017

CERN Multimedia

ATLAS Collaboration

2017-01-01

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

Field quality of the LHC inner triplet quadrupoles being fabricated at Fermilab

Energy Technology Data Exchange (ETDEWEB)

Gueorgui V. Velev et al.

2003-06-02

Fermilab, as part of the US-LHC Accelerator Project, has designed and is producing superconducting low-beta quadrupole magnets for the Large Hadron Collider (LHC). These 70 mm bore, 5.5 m long magnets operate in superfluid helium at 1.9 K with a maximum operating gradient of 214 T/m. Two quadrupoles, combined with a dipole orbit corrector, form a single LQXB cryogenic assembly, the Q2 optical element of the final focus triplets in the LHC interaction regions. Field quality was measured at room temperature during fabrication of the cold masses as well as at superfluid helium temperature in two thermal cycles for the first LQXB cryogenic assembly. Integral cold measurements were made with a 7.1 m long rotating coil and with a 0.8 m long rotating coil at 8 axial positions and in a range of currents. In addition to the magnetic measurements, this paper reports on the quench performance of the cold masses and on the measurements of their internal alignment.

Sensor R&D for the CMS Tracker Upgrade for the HL-LHC

CERN Document Server

Behnamian, Hadi

2014-01-01

At an instantaneous luminosity of $5\\times 10^{34} cm^{-2} s^{-1}$, the high-luminosity phase of the Large Hadron Collider (HL-LHC) is expected to deliver a total of 3000 $fb^{-1}$ of collisions, hereby increasing the discovery potential of the LHC experiments significantly. However, the radiation environment of the tracking system will be severe, requiring new radiation hard sensors for the CMS tracker. The CMS tracker collaboration has almost completed a large material investigation and irradiation campaign to identify the silicon material and design that fulfills all requirements of a new tracking detector at HL-LHC. Focusing on the upgrade of the outer tracker region, pad diodes as well as fully functional strip sensors have been implemented on silicon wafers with different material properties and thicknesses. The samples were irradiated with a mixture of neutrons and protons corresponding to fluences as expected for various positions in the future tracker. The measurements performed on the structures inc...

Gravitino LSP scneario at the LHC

International Nuclear Information System (INIS)

Heisig, Jan

2010-05-01

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

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.

LHC Dipoles Accelerate

CERN Multimedia

2001-01-01

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

The Physics Landscape of the High Luminosity LHC

CERN Document Server

Mangano, M

2015-01-01

We review the status of HEP after the first run of the LHC and discuss the opportunities offered by the HL-LHC, in light of the needs for future progress that are emerging from the data. The HL-LHC will push to the systematic limit the precision of most measurements of the Higgs boson, and will be necessary to firmly establish some of the more rare decays foreseen by the Standard Model, such as the decays to dimuons and to a Z+ photon pair. The HL-LHC luminosity will provide additional statistics required by the quantitative study of any discovery the LHC may achieve during the first 300 inverse femtobarn, and will further extend the discovery potential of the LHC, particularly for rare, elusive or low-sensitivity processes.

The CMS Outer Tracker for HL-LHC

CERN Document Server

Dierlamm, Alexander Hermann

2018-01-01

The LHC is planning an upgrade program, which will bring the luminosity to about $5-7\\times10^{34}$~cm$^{-2}$s$^{-1}$ in 2026, with a goal of an integrated luminosity of 3000 fb$^{-1}$ by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 Upgrade. The current CMS Tracker is already running beyond design specifications and will not be able to cope with the HL-LHC radiation conditions. CMS will need a completely new Tracker in order to fully exploit the highly demanding operating conditions and the delivered luminosity. The new Outer Tracker system is designed to provide robust tracking as well as Level-1 trigger capabilities using closely spaced modules composed of silicon macro-pixel and/or strip sensors. Research and development activities are ongoing to explore options and develop module components and designs for the HL-LHC environment. The design choices for the CMS Outer Tracker Upgrade are discussed along with some highlig...

1754 Days to the LHC and counting!

CERN Multimedia

2001-01-01

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

Particles are back in the LHC

CERN Multimedia

CERN Bulletin

2016-01-01

The LHC has introduced beam for the first time since the year-end technical stop began in December 2015.   CERN Management and LHC operators applaud as the first beam circulates in the LHC, on Friday 25 March.   On Friday, the LHC opened its doors to allow particles to travel around the ring for the first time since the year-end technical stop (YETS) began in December 2015. At 10:30 a.m., a first bunch was circulating and by midday the beam was circulating in both directions. Progress over the weekend has been good and low intensity beam has already been taken to 6.5 TeV and through the squeeze. Last week, the LHC underwent the final phase of preparation before beam -known as the machine checkout. During this phase all the systems of the LHC are put through their paces without beam. A key part of the process is driving the magnetic circuits, radiofrequency accelerating cavities, collimators, transverse dampers etc. repeatedly through the nominal LHC cycle. A fu...

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...

LHC Power Converters: A Precision Game

CERN Multimedia

2001-01-01

The LHC test-bed, String 2, is close to commissioning and one important element to get a first chance to prove what it can do is the power converter system. In String 2 there are 16 converters, in the full LHC there will be almost 1800. This article takes a look at what is so special about the power converters for the LHC. The 13 000 Amps power converters with the watercooled cables going to the String 2 feedboxes. The LHC's superconducting magnets will be the pinnacle of high technology. But to work, they'll need the help of high-precision power converters to supply them with extremely stable DC current. Perfection will be the name of the game, with an accuracy of just 1-2 parts per million (ppm) required. LEP, for the sake of comparison, could live with 10-20 ppm. The LHC's power converters will be very different from those of LEP or the SPS since the new accelerator's magnets are mostly superconducting. That means that they require much higher currents at a lower voltage since superconductors have no re...

Prototype HL-LHC magnet undergoes testing

CERN Multimedia

Corinne Pralavorio

2016-01-01

A preliminary short prototype of the quadrupole magnets for the High-Luminosity LHC has passed its first tests.   The first short prototype of the quadrupole magnet for the High Luminosity LHC. (Photo: G. Ambrosio (US-LARP and Fermilab), P. Ferracin and E. Todesco (CERN TE-MSC)) Momentum is gathering behind the High-Luminosity LHC (HL-LHC) project. In laboratories on either side of the Atlantic, a host of tests are being carried out on the various magnet models. In mid-March, a short prototype of the quadrupole magnet underwent its first testing phase at the Fermilab laboratory in the United States. This magnet is a pre-prototype of the quadrupole magnets that will be installed near to the ATLAS and CMS detectors to squeeze the beams before collisions. Six quadrupole magnets will be installed on each side of each experiment, giving a total of 24 magnets, and will replace the LHC's triplet magnets. Made of superconducting niobium-tin, the magnets will be more powerful than their p...

High Luminosity LHC: challenges and plans

Science.gov (United States)

Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.; Brüning, O.; Buffat, X.; Cai, Y.; Carver, L. R.; Fartoukh, S.; Giovannozzi, M.; Iadarola, G.; Li, K.; Lechner, A.; Medina Medrano, L.; Métral, E.; Nosochkov, Y.; Papaphilippou, Y.; Pellegrini, D.; Pieloni, T.; Qiang, J.; Redaelli, S.; Romano, A.; Rossi, L.; Rumolo, G.; Salvant, B.; Schenk, M.; Tambasco, C.; Tomás, R.; Valishev, S.; Van der Veken, F. F.

2016-12-01

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11-12 T superconducting magnets, including Nb3Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. The dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.

High Luminosity LHC: Challenges and plans

International Nuclear Information System (INIS)

Arduini, G.; Barranco, J.; Bertarelli, A.; Biancacci, N.; Bruce, R.

2016-01-01

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will undergo a major upgrade in the 2020s. This will increase its rate of collisions by a factor of five beyond the original design value and the integrated luminosity by a factor ten. The new configuration, known as High Luminosity LHC (HL-LHC), will rely on a number of key innovations that push accelerator technology beyond its present limits. Among these are cutting-edge 11–12 T superconducting magnets, including Nb 3 Sn-based magnets never used in accelerators before, compact superconducting cavities for longitudinal beam rotation, new technology and physical processes for beam collimation. As a result, the dynamics of the HL-LHC beams will be also particularly challenging and this aspect is the main focus of this paper.

Press Conference: LHC Restart, Season 2

CERN Multimedia

CERN. Geneva

2015-01-01

PRESS BRIEFING ON THE LARGE HADRON COLLIDER (LHC) RE-START, SEASON 2 AT CERN, GLOBE OF SCIENCE AND INNOVATION Where :   http://cern.ch/directions   at the Globe of Science and Innovation When : Thursday, 12 March from 2.30 to 3.30pm - Open seating as from 2.15pm Speakers : CERN’s Director General, Rolf Heuer and Director of Accelerators, Frédérick Bordry, and representatives of the LHC experiments Webcast : https://webcast.web.cern.ch/webcast/ Dear Journalists, CERN is pleased to invite you to the above press briefing which will take place on Thursday 12 March, in the Globe of Science and Innovation, 1st floor, from 2.30 to 3.30pm. The Large Hadron Collider (LHC) is ready to start up for its second three-year run. The 27km LHC is the largest and most powerful particle accelerator in the world operating at a temperature of -217 degrees Centigrade and powered to a current of 11,000 amps. Run 2 of the LHC follows a two-year technical s...

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

A non-canonical transferred DNA insertion at the BRI1 locus in Arabidopsis thaliana.

Science.gov (United States)

Zhao, Zhong; Zhu, Yan; Erhardt, Mathieu; Ruan, Ying; Shen, Wen-Hui

2009-04-01

Agrobacterium-mediated transformation is widely used in transgenic plant engineering and has been proven to be a powerful tool for insertional mutagenesis of the plant genome. The transferred DNA (T-DNA) from Agrobacterium is integrated into the plant genome through illegitimate recombination between the T-DNA and the plant DNA. Contrasting to the canonical insertion, here we report on a locus showing a complex mutation associated with T-DNA insertion at the BRI1 gene in Arabidopsis thaliana. We obtained a mutant line, named salade for its phenotype of dwarf stature and proliferating rosette. Molecular characterization of this mutant revealed that in addition to T-DNA a non-T-DNA-localized transposon from bacteria was inserted in the Arabidopsis genome and that a region of more than 11.5 kb of the Arabidopsis genome was deleted at the insertion site. The deleted region contains the brassinosteroid receptor gene BRI1 and the transcription factor gene WRKY13. Our finding reveals non-canonical T-DNA insertion, implicating horizontal gene transfer and cautioning the use of T-DNA as mutagen in transgenic research.

LHC INAUGURATION, LHC Fest highlights: exhibition time!

CERN Multimedia

2008-01-01

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

From the LHC to Future Colliders

Energy Technology Data Exchange (ETDEWEB)

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

2010-06-11

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

Design of the LHC US ATLAS Barrel Cryostat

CERN Document Server

Rehak, M L; Farah, Y; Grandinetti, R; Müller, T; Norton, S; Sondericker, J

2002-01-01

One of the experiments of CERN's Large Hadron Collider (LHC) is the ATLAS Liquid Argon detector. The Liquid Argon Barrel Cryostat is part of the United States contribution to the LHC project and its design is presented here. The device is made up of four concentric cylinders: the smallest and largest of which form a vacuum vessel enclosing a cold vessel cryostat filled with liquid argon. The Cryostat serves as the housing for an electromagnetic barrel calorimeter, supports and provides space in vacuum for a solenoid magnet while the toroidal opening furnishes room for a tracker detector. Design requirements are determined by its use in a collider experiment: the construction has to be compact, the material between the interaction region and the calorimeter has to be minimal and made of aluminum to reduce the amount of absorbing material. The design complies with code regulations while being optimized for its use in a physics environment. (2 refs).

Method of inserting fuel rod

International Nuclear Information System (INIS)

Kamimoto, Shuji; Imoo, Makoto; Tsuchida, Kenji.

1991-01-01

The present invention concerns a method of inserting a fuel rod upon automatic assembling, automatic dismantling and reassembling of a fuel assembly in a light water moderated reactor, as well as a device and components used therefor. That is, a fuel rod is inserted reliably to an aimed point of insertion by surrounding the periphery of the fuel rod to be inserted with guide rods, and thereby suppressing the movement of the fuel rod during insertion. Alternatively, a fuel rod is inserted reliably to a point of insertion by inserting guide rods at the periphery of the point of insertion for the fuel rod to be inserted thereby surrounding the point of insertion with the guide rods or fuel rods. By utilizing fuel rods already present in the fuel assembly as the guide rods described above, the fuel rod can be inserted reliably to the point of insertion with no additional devices. Dummy fuel rods are previously inserted in a fuel assembly which are then utilized as the above-mentioned guide rods to accurately insert the fuel rod to the point of insertion. (I.S.)

Radiation-hard semiconductor detectors for SuperLHC

CERN Document Server

Bruzzi, Mara; Al-Ajili, A A; Alexandrov, P; Alfieri, G; Allport, Philip P; Andreazza, A; Artuso, M; Assouak, S; Avset, B S; Barabash, L; Baranova, E; Barcz, A; Basile, A; Bates, R; Belova, N; Betta, G F D; Biagi, S F; Bilei, G M; Bisello, D; Blue, A; Blumenau, A; Boisvert, V; Bölla, G; Bondarenko, G B; Borchi, E; Borrello, L; Bortoletto, D; Boscardin, M; Bosisio, L; Bowcock, T J V; Brodbeck, T J; Broz, J; Brukhanov, A; Brzozowski, A; Buda, M; Buhmann, P; Buttar, C; Campabadal, F; Campbell, D; Candelori, A; Casse, G; Cavallini, A; Chilingarov, A G; Chren, D; Cindro, V; Citterio, M; Collins, P; Coluccia, R; Contarato, D; Coutinho, J; Creanza, D; Cunningham, W; Cvetkov, V; Davies, G; Dawson, I; De Palma, M; Demina, R; Dervan, P; Dierlamm, A; Dittongo, S; Dobrzanski, L; Dolezal, Z; Dolgolenko, A; Eberlein, T; Eremin, V; Fall, C; Fasolo, F; Ferbel, T; Fizzotti, F; Fleta, C; Focardi, E; Forton, E; Franchenko, S; Fretwurst, E; Gamaz, F; García-Navarro, J E; García, C; Gaubas, E; Genest, M H; Gill, K A; Giolo, K; Glaser, M; Gössling, C; Golovine, V; Gorelov, I; Goss, J; Gouldwell, A; Grégoire, G; Gregori, P; Grigoriev, E; Grigson, C; Grillo, A; Groza, A; Guskov, J; Haddad, L; Harding, R; Härkönen, J; Hauler, F; Hayama, S; Hoeferkamp, M; Honniger, F; Horazdovsky, T; Horisberger, R P; Horn, M; Houdayer, A; Hourahine, B; Hruban, A; Hughes, G; Ilyashenko, Yu S; Irmscher, K; Ivanov, A; Jarasiunas, K; Jin, T; Jones, B K; Jones, R; Joram, C; Jungermann, L; Kalinina, E; Kaminski, P; Karpenko, A; Karpov, A; Kazlauskiene, V; Kazukauskas, V; Khivrich, V; Khomenkov, V P; Kierstead, J A; Klaiber Lodewigs, J M; Kleverman, M; Klingenberg, R; Kodys, P; Kohout, Z; Korjenevski, S; Kowalik, A; Kozlowski, R; Kozodaev, M; Kramberger, G; Krasel, O; Kuznetsov, A; Kwan, S; Lagomarsino, S; Lari, T; Lassila-Perini, K M; Lastovetsky, V F; Latino, G; Latushkin, S T; Lazanu, I; Lazanu, S; Lebel, C; Leinonen, K; Leroy, C; Li, Z; Lindström, G; Lindström, L; Linhart, V; Litovchenko, A P; Litovchenko, P G; Litvinov, V; Lo Giudice, A; Lozano, M; Luczynski, Z; Luukka, Panja; Macchiolo, A; Mainwood, A; Makarenko, L F; Mandic, I; Manfredotti, C; Martí i García, S; Marunko, S; Mathieson, K; Melone, J; Menichelli, D; Meroni, C; Messineo, A; Miglio, S; Mikuz, M; Miyamoto, J; Moll, M; Monakhov, E; Moscatelli, F; Mozzanti, A; Murin, L; Naoumov, D; Nava, F; Nossarzhevska, E; Nummela, S; Nysten, J; Olivero, P; O'Shea, V; Palviainen, T; Paolini, C; Parkes, C; Passeri, D; Pein, U; Pellegrini, G; Perera, L; Petasecca, M; Piatkowski, B; Piemonte, C; Pignatel, G U; Pinho, N; Pintilie, I; Pintilie, L; Polivtsev, L; Polozov, P; Popa, A I; Popule, J; Pospísil, S; Pucker, G; Radicci, V; Rafí, J M; Ragusa, F; Rahman, M; Rando, R; Röder, R; Rohe, T; Ronchin, S; Rott, C; Roy, A; Roy, P; Ruzin, A; Ryazanov, A; Sadrozinski, H F W; Sakalauskas, S; Scaringella, M; Schiavulli, L; Schnetzer, S; Schumm, B; Sciortino, S; Scorzoni, A; Segneri, G; Seidel, S; Seiden, A; Sellberg, G; Sellin, P J; Sentenac, D; Sevilla, S G; Shipsey, I; Sícho, P; Sloan, T; Solar, M; Son, S; Sopko, B; Spencer, N; Stahl, J; Stavitski, I; Stolze, D; Stone, R; Storasta, J; Strokan, N; Strupinski, W; Sudzius, M; Surma, B; Suuronen, J; Suvorov, A; Svensson, B G; Tipton, P; Tomasek, M; Troncon, C; Tsvetkov, A; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Uher, J; Ullán, M; Vaitkus, J V; Vanni, P; Velthuis, J; Verbitskaya, E; Verzellesi, G; Vrba, V; Wagner, G; Wilhelm, I; Worm, S; Wright, V; Wunstorf, R; Zabierowski, P; Zaluzhny, A; Zavrtanik, M; Zen, M; Zhukov, V; Zorzi, N; de Boer, Wim

2005-01-01

An option of increasing the luminosity of the Large Hadron Collider (LHC) at CERN to 10/sup 35/ cm-/sup 2/s-/sup 1/ has been envisaged to extend the physics reach of the machine. An efficient tracking down to a few centimetres from the interaction point will be required to exploit the physics potential of the upgraded LHC. As a consequence, the semiconductor detectors close to the interaction region will receive severe doses of fast hadron irradiation and the inner tracker detectors will need to survive fast hadron fluences of up to above 10 /sup 16/ cm-/sup 2/. The CERN-RD50 project "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" has been established in 2002 to explore detector materials and technologies that will allow to operate devices up to, or beyond, this limit. The strategies followed by RD50 to enhance the radiation tolerance include the development of new or defect engineered detector materials (SiC, GaN, Czochralski and epitaxial silicon, oxygen enriched Flo...

Gravitino LSP scneario at the LHC

Energy Technology Data Exchange (ETDEWEB)

Heisig, Jan

2010-06-15

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

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...

LHC Nobel Symposium Proceedings

Science.gov (United States)

Ekelöf, Tord

2013-12-01

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

Fast crab cavity failures in HL-LHC

CERN Document Server

Yee-Rendon, B; Calaga, R; Tomas, R; Zimmermann, F; Barranco, J

2014-01-01

Crab cavities (CCs) are a key ingredient of the High-Luminosity Large Hadron Collider (HL-LHC) to ensure head on collisions at the main experiments (ATLAS and CMS) and fully profit from the smaller provided by the ATS optics [1]. At KEKB, CCs have exhibited abrupt changes of phase and voltage during a time period of few LHC turns and considering the large energy stored in the HL-LHC beam, CC failures represent a serious risk to the LHC machine protection. In this paper, we discuss the effect of CC voltage or phase changes on a time interval similar to, or longer than, the one needed to dump the beam. The simulations assume a realistic steady-state distribution to assess the beam losses for the HL-LHC. Additionally, some strategies are studied in order to reduce the damage caused by the CC failures.

Resistive wall instability for the LHC: intermediate review

CERN Document Server

Brandt, D

2001-01-01

As the design of some basic components of the LHC becomes available, it is possible to refine the evaluation of the expected contribution of these elements to the total impedance budget of the machine. The LHC beam-screen being expected to be the main contributor for the resistive wall effect, it appeared justified to review the impedance budget, taking into account the latest available data. This note first recalls the original estimations presented in the LHC Conceptual Design [1], then presents an updated review of the instability rise times and finally discusses a possible reduction of this rather large contribution. ------------- !!Note!!: Please note that updated values for the LHC impedance budget are now available from the report CERN LHC Project Report 585 (Coupled Bunch Instabilities in the LHC, D. Angal-Kalinin and L. Vos, EPAC, July 2002 ).

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)

Plans for the upgrade of the LHC injectors

CERN Document Server

Garoby, R; Goddard, B; Hanke, K; Meddahi, M; Vretenar, M

2011-01-01

The LHC injectors upgrade (LIU) project has been launched at the end of 2010 to prepare the CERN accelerator complex for reliably providing beam with the challenging characteristics required by the high luminosity LHC until at least 2030. Based on the work already started on Linac4, PS Booster, PS and SPS, the LIU project coordinates studies and implementation, and interfaces with the high luminosity LHC (HL-LHC) project which looks after the upgrade of the LHC itself, expected by the end of the present decade. The anticipated beam characteristics are described, as well as the status of the studies and the solutions envisaged for improving the injector performances.

Multilepton signals of gauge mediated supersymmetry breaking at the LHC

Energy Technology Data Exchange (ETDEWEB)

D' Hondt, Jorgen [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Brussels (Belgium); De Causmaecker, Karen [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Brussels (Belgium); Theory Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Fuks, Benjamin [Theory Division, Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Institut Pluridisciplinaire Hubert Curien/Département Recherches Subatomiques, Université de Strasbourg/CNRS-IN2P3, 23 Rue du Loess, F-67037 Strasbourg (France); Mariotti, Alberto [Institute for Particle Physics Phenomenology, Durham University, Durham DH1 3LE (United Kingdom); Mawatari, Kentarou [Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels (Belgium); International Solvay Institutes, Brussels (Belgium); Petersson, Christoffer [International Solvay Institutes, Brussels (Belgium); Physique Théorique et Mathématique, Université Libre de Bruxelles, C.P. 231, B-1050 Brussels (Belgium); Department of Fundamental Physics, Chalmers University of Technology, 412 96 Göteborg (Sweden); Redigolo, Diego [International Solvay Institutes, Brussels (Belgium); Physique Théorique et Mathématique, Université Libre de Bruxelles, C.P. 231, B-1050 Brussels (Belgium)

2014-04-04

We investigate multilepton LHC signals arising from electroweak processes involving sleptons. We consider the framework of general gauge mediated supersymmetry breaking, focusing on models where the low mass region of the superpartner spectrum consists of the three generations of charged sleptons and the nearly massless gravitino. We demonstrate how such models can provide an explanation for the anomalous four lepton events recently observed by the CMS Collaboration, while satisfying other existing experimental constraints. The best fit to the CMS data is obtained for a selectron/smuon mass of around 145 GeV and a stau mass of around 90 GeV. These models also give rise to final states with more than four leptons, offering alternative channels in which they can be probed and we estimate the corresponding production rates at the LHC.

Upgrades to the SPS-to-LHC Transfer Line Beam Stoppers for the LHC High-Luminosity Era

CERN Document Server

Kain, Verena; Fraser, Matthew; Goddard, Brennan; Meddahi, Malika; Perillo Marcone, Antonio; Steele, Genevieve; Velotti, Francesco

2016-01-01

Each of the 3 km long transfer lines between the SPS and the LHC is equipped with two beam stoppers (TEDs), one at the beginning of the line and one close to the LHC injection point, which need to absorb the full transferred beam. The beam stoppers are used for setting up the SPS extractions and transfer lines with beam without having to inject into the LHC. Energy deposition and thermo-mechanical simulations have, however, shown that the TEDs will not be robust enough to safely absorb the high intensity beams foreseen for the high-luminosity LHC era. This paper will summarize the simulation results and limitations for upgrading the beam stoppers. An outline of the hardware upgrade strategy for the TEDs together with modifications to the SPS extraction interlock system to enforce intensity limitations for beam on the beam stoppers will be given.

Evolution of the CMS ECAL Performance and R&D Studies for Calorimetry Options at High Luminosity LHC

CERN Document Server

Lucchini, Marco Toliman; Auffray, Etiennette

During the past years the Large Hadron Collider (LHC) at CERN operated with a maximum center-of-mass energy of $\\sqrt{s} = 8$~TeV, a peak luminosity of around $7\\times 10^{33}$~cm$^{-2}$s$^{-1}$ and collected about $23$~fb$^{-1}$ of data which lead to the discovery of a Higgs Boson in July 2012. To further constrain the properties of the newly discovered Higgs boson, the decision to extend the LHC program has recently been made. In this framework, a major upgrade of the beam optics in the interaction region will take place around 2022 to achieve a leveled peak luminosity of $\\mathcal{L} = 5\\times10^{34}$~cm$^{-2}$s$^{-1}$. These will be the operating conditions during the High Luminosity LHC (HL-LHC) which is expected to deliver an integrated luminosity of 3000~fb$^{-1}$ by 2035. During HL-LHC phase the radiation levels will become much higher with respect to the nominal values for which the CMS detector was designed. Therefore it is of crucial importance to identify and quantify the effects ofradiation damag...

LHC: Past, Present, and Future

CERN Document Server

Landsberg, Greg

2013-01-01

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

Parton distributions with LHC data

CERN Document Server

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

2013-01-01

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

LS1 general planning and strategy for the LHC, LHC injectors

International Nuclear Information System (INIS)

Foraz, K.

2012-01-01

The goal of Long Shutdown 1 (LS1) is to perform the full maintenance of equipment and the necessary consolidation and upgrade activities in order to ensure reliable LHC operation at nominal performance from mid-2014. LS1 is scheduled to last 20 months. LS1 not only concerns the LHC but also its injectors. To ensure resources will be available an analysis is in progress to detect conflict/overload and decide what is compulsory, what we can afford, and what can be postponed until LS2. The strategy, time key drivers, constraints, and draft schedule are presented here. (author)

Lattice insertions for POPAE

International Nuclear Information System (INIS)

Cho, Y.; Crosbie, E.A.; Diebold, R.; Johnson, D.E.; Ohnuma, S.; Ruggiero, A.G.; Teng, L.C.

1977-01-01

Four types of insertions are described for the six 200-m straight sections of POPAE. All have dispersion matched to zero. (1) Injection-ejection insertion--This has proper high-β values and phase advances for horizontal injection and vertical ejection. (2) Phase-adjust insertion--The phase advance in this insertion is adjustable over a range of approximately 100 0 . (3) General-purpose insertion--The β* is adjustable from 2.5. to 200 m and the crossing angle is adjustable from 0 to 11 mrad. (4) High-luminosity insertion--This gives an even lower β + of meter

About the identification of signals at LHC

CERN Document Server

Mansoulié, Bruno

2015-01-01

This chapter describes the main ingredients and steps of the analysis used in the search for the Standard Model Higgs boson decaying into WW (l‎, l‎, νν‎) in the ATLAS experiment. It presents a short guide through a “modern” analysis, typical of the analyses performed on LHC data. The main ingredients are reviewed: irreducible and reducible backgrounds, background estimates from Monte Carlo or data-driven, signal and control regions, global fit, extraction of limits and signal, and the look-elsewhere effect.

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.

Academic Training: A walk through the LHC injector chain

CERN Multimedia

Françoise Benz

2005-01-01

2004-2005 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 21, 22, 23 March from 11.00 to 12.00 hrs - Main Auditorium, bldg. 500 A walk through the LHC injector chain M. BENEDIKT, P. COLLIER, K. SCHINDL /CERN-AB Proton linac, PS Booster, PS, SPS and the two transfer channels from SPS to LHC are used for LHC proton injection. The lectures will review the features of these faithful machines and underline the modifications required for the LHC era. Moreover, an overview of the LHC lead ion injector scheme from the ion source through ion linac, LEIR, PS and SPS right to the LHC entry will be given. The particular behaviour of heavy ions in the LHC will be sketched and the repercussions on the injectors will be discussed. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch

Considerations on Energy Frontier Colliders after LHC

Energy Technology Data Exchange (ETDEWEB)

Shiltsev, Vladimir [Fermilab

2016-11-15

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

Dashboard for the LHC experiments

International Nuclear Information System (INIS)

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

2008-01-01

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

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 Data and its Impact on nCTEQ15 PDFs

Energy Technology Data Exchange (ETDEWEB)

Clark, D. B. [Southern Methodist U.; Godat, E. [Southern Methodist U.; Ježo, T.; Keppel, C. [Jefferson Lab; Kovarík, K. [Munster U., ITP; Kusina, A. [Cracow, INP; Lyonnet, F. [Southern Methodist U.; Morfin, J. G. [Fermilab; Olness, F. I. [Southern Methodist U.; Owens, J. F. [Florida State U.; Schienbein, I. [LPSC, Grenoble; Yu, J. Y. [Southern Methodist U.

2018-01-10

The LHC heavy ion data for W/Z production can provide new incisive information on the PDFs. This data is sensitive to the heavier quark flavors (strange and charm) in a high energy kinematic region; this can facilitate the determination of PDFs in the small x region where previous data was limited. At present, the flavor separation of the proton PDFs is dependent on DIS data from nuclear targets. Therefore, improved nuclear corrections can also yield enhanced flavor determination of both the proton and nuclear PDFs.

High Intensity Beam Test of Low Z Materials for the Upgrade of SPS-to-LHC Transfer Line Collimators and LHC Injection Absorbers

CERN Document Server

Maciariello, Fausto; Butcher, Mark; Calviani, Marco; Folch, Ramon; Kain, Verena; Karagiannis, Konstantinos; Lamas Garcia, Inigo; Lechner, Anton; Nuiry, Francois-Xavier; Steele, Genevieve; Uythoven, Jan

2016-01-01

In the framework of the LHC Injector Upgrade (LIU) and High-Luminosity LHC (HL-LHC) project, the collimators in the SPS-to LHC transfer lines will undergo important modifications. The changes to these collimators will allow them to cope with beam brightness and intensity levels much increased with respect to their original design parameters: nominal and ultimate LHC. The necessity for replacement of the current materials will need to be confirmed by a test in the High Radiation to Materials (HRM) facility at CERN. This test will involve low Z materials (such as Graphite and 3-D Carbon/Carbon composite), and will recreate the worst case scenario those materials could see when directly impacted by High luminosity LHC (HL-LHC) or Batch Compression Merging and Splitting (BCMS) beams. Thermo-structural simulations used for the material studies and research, the experiment preparation phase, the experiment itself, pre irradiation analysis (including ultrasound and metrology tests on the target materials), the resul...

Multiparticle production at RHIC and LHC: a classical point of view

International Nuclear Information System (INIS)

Krasnitz, A.; Venugopalan, R.

2000-01-01

We report results of our ongoing nonperturbative numerical study of a classical effective theory describing low-x partons in the central region of a heavy-ion collision. In particular, we give estimates of the initial transverse energies and multiplicities for a wide range of collision regimes, including those at RHIC and at LHC

Abort Gap Cleaning for LHC Run 2

Energy Technology Data Exchange (ETDEWEB)

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

2014-07-01

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

Abort Gap Cleaning for LHC Run 2

CERN Document Server

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

2015-01-01

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

The B-Physics Programme of ATLAS in LHC Run-II and in HL-LHC

CERN Document Server

Reznicek, P; The ATLAS collaboration

2014-01-01

Slides for the talk to be given at Beauty 2014 conference in Edinburgh, 14-18 July 2014. The talk describes the ATLAS B-physics programme planned to future LHC runs: Run 2, 3 and HL-LHC. The relevant ATLAS detector upgrades are dicussed and a results of pilot sensitivity study of $B_{s} \\to J/\\psi \\phi$ measurement in the future runs are shown.

Requirements for the LHC collimation system

CERN Document Server

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

2002-01-01

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

The HL-LHC accelerator physics challenges

CERN Document Server

Fartoukh, S

2014-01-01

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

The HL-LHC Accelerator Physics Challenges

Science.gov (United States)

Fartoukh, S.; Zimmermann, F.

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

The HL-LHC accelerator physics challenges

CERN Document Server

Fartoukh, S

2015-01-01

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

Insertion Modeling and Its Applications

OpenAIRE

Alexander Letichevsky; Oleksandr Letychevskyi; Vladimir Peschanenko

2016-01-01

The paper relates to the theoretical and practical aspects of insertion modeling. Insertion modeling is a theory of agents and environments interaction where an environment is considered as agent with a special insertion function. The main notions of insertion modeling are presented. Insertion Modeling System is described as a tool for development of different kinds of insertion machines. The research and industrial applications of Insertion Modeling System are presented.

Standard Model at the LHC 2017

CERN Document Server

2017-01-01

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

The LHC detectors and the first CMS data

CERN Document Server

Green, Dan

2015-01-01

This chapter describes the subsystems of a generic LHC detector and explains how the values of the detector parameters were selected. The design of the LHC detectors follows from the requirement of confronting electroweak symmetry breaking in a decisive fashion. The LHC accelerator also meets those requirements.

LHC-ILC synergy

CERN Document Server

Godbole, Rohini M

2006-01-01

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

LHC beampipe interconnection

CERN Document Server

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

EU supports the LHC high-luminosity study

CERN Document Server

CERN Bulletin

2011-01-01

The design collision energy and luminosity of the LHC are already at record numbers, making the machine one of the most complex scientific instruments ever built. However, to extend its discovery potential even further, a major upgrade of the LHC will be required around 2020. This will increase its average luminosity by a factor of 5 to 10 beyond its design value. Fifteen worldwide institutions and the European Union are supporting the initial design phase of the project through the HiLumi LHC programme, whose kick-off meeting will take place on 16-18 November.   The CERN team that has successfully built and tested the Short Magnet Coil – a small 40 cm long magnet capable of producing a 12.5 T magnetic field. The upgrade of the LHC will require about 10 years of design, construction and implementation. The new machine configuration will be called “High Luminosity LHC” (HL-LHC). The similarly named “HiLumi LHC” is the EU programme that supports...

The CMS Tracker upgrade for HL-LHC

CERN Document Server

Ahuja, Sudha

2017-01-01

The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about 5 $\\times$ $10^{34} $cm$^{-2}$s$^{-1}$ in 2028, to possibly reach an integrated luminosity of 3000 fb$^{-1}$ by the end of 2037. This High Luminosity LHC scenario, HL-LHC, will require a preparation program of the LHC detectors known as Phase-2 upgrade. The current CMS Outer Tracker, already running beyond design specifications, and CMS Phase1 Pixel Detector will not be able to survive HL-LHC radiation conditions and CMS will need completely new devices, in order to fully exploit the high-demanding operating conditions and the delivered luminosity. The new Outer Tracker should have also trigger capabilities. To achieve such goals, R$\\&$D activities are ongoing to explore options both for the Outer Tracker, and for the pixel Inner Tracker. Solutions are being developed that would allow including tracking information at Level-1. The design choices for the Tracker upgrades are discussed along with some highlights...