ATLAS Experiment Brochure - Italian

CERN Multimedia

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - German

CERN Multimedia

AUTHOR|(CDS)2081027

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Japanese

CERN Multimedia

Anthony, Katarina

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Portuguese

CERN Multimedia

AUTHOR|(CDS)2081027

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Czech

CERN Multimedia

AUTHOR|(CDS)2081027

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Dutch

CERN Multimedia

AUTHOR|(CDS)2081027

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Romanian

CERN Multimedia

AUTHOR|(CDS)2081027

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Serbian

CERN Multimedia

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS IBL operational experience

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00237659; The ATLAS collaboration

2017-01-01

The Insertable B-Layer (IBL) is the inner most pixel layer in the ATLAS experiment, which was installed at 3.3 cm radius from the beam axis in 2014 to improve the tracking performance. To cope with the high radiation and hit occupancy due to proximity to the interaction point, a new read-out chip and two different silicon sensor technologies (planar and 3D) have been developed for the IBL. After the long shut-down period over 2013 and 2014, the ATLAS experiment started data-taking in May 2015 for Run-2 of the Large Hadron Collider (LHC). The IBL has been operated successfully since the beginning of Run-2 and shows excellent performance with the low dead module fraction, high data-taking efficiency and improved tracking capability. The experience and challenges in the operation of the IBL is described as well as its performance.

Cartea de Colorat a Experimentului ATLAS - ATLAS Experiment Colouring Book in Romanian

CERN Multimedia

Anthony, Katarina

2018-01-01

Language: Romanian - The ATLAS Experiment Colouring Book is a free-to-download educational book, ideal for kids aged 5-9. It aims to introduce children to the field of High-Energy Physics, as well as the work being carried out by the ATLAS Collaboration. Limba: Română - Cartea de Colorat a Experimentului ATLAS este o carte educativă gratuită, ideală pentru copiii cu vârsta cuprinsă între 5-9 ani. Scopul său este de a introduce copii în domeniul fizicii de înaltă energie, precum și activitatea desfășurată de colaborarea ATLAS.

Status of the ATLAS experiment at CERN

International Nuclear Information System (INIS)

Taylor, G.

2000-01-01

Full text: The ATLAS experiment, to operate at CERN's Large Hadron Collider (LHC), from 2005 is currently under construction. The Australian HEP Consortium is participating in the development and construction of the semi-conductor tracker (SCT) sub-system of ATLAS. Australian scientists play significant roles in many aspects of the SCT detector module development, including design, prototyping, measurement, beam tests and simulation. Production facilities for construction of two hundred high precision detector modules for the SCT Forward region are well advanced in Melbourne and Sydney laboratories. This talk will give an overview of ATLAS experiment goals and status. It will concentrate on the Australian contribution. The talk will conclude with an outline of the future schedule and plans

ATLAS Experiment Brochure - Chinese (Traditional)

CERN Multimedia

AUTHOR|(CDS)2081027

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

ATLAS Experiment Brochure - Chinese (Simplified)

CERN Multimedia

Anthony, Katarina

2018-01-01

ATLAS is one of the four major experiments at the Large Hadron Collider at CERN. It is a general-purpose particle physics experiment run by an international collaboration, and is designed to exploit the full discovery potential and the huge range of physics opportunities that the LHC provides.

The Detector Safety System of the ATLAS experiment

International Nuclear Information System (INIS)

Beltramello, O; Burckhart, H J; Franz, S; Jaekel, M; Jeckel, M; Lueders, S; Morpurgo, G; Santos Pedrosa, F dos; Pommes, K; Sandaker, H

2009-01-01

The ATLAS detector at the Large Hadron Collider at CERN is one of the most advanced detectors for High Energy Physics experiments ever built. It consists of the order of ten functionally independent sub-detectors, which all have dedicated services like power, cooling, gas supply. A Detector Safety System has been built to detect possible operational problems and abnormal and potentially dangerous situations at an early stage and, if needed, to bring the relevant part of ATLAS automatically into a safe state. The procedures and the configuration specific to ATLAS are described in detail and first operational experience is given.

Learning with the ATLAS Experiment at CERN

Science.gov (United States)

Barnett, R. M.; Johansson, K. E.; Kourkoumelis, C.; Long, L.; Pequenao, J.; Reimers, C.; Watkins, P.

2012-01-01

With the start of the LHC, the new particle collider at CERN, the ATLAS experiment is also providing high-energy particle collisions for educational purposes. Several education projects--education scenarios--have been developed and tested on students and teachers in several European countries within the Learning with ATLAS@CERN project. These…

Studien zur Messung von Rekonstruktionseffizienz und Untergrund der $\\tau$-Lepton-Identifikation im Zerfall $Z\\to \\tau \\tau$ beim ATLAS-Experiment aus Daten

CERN Document Server

Johnert, Sebastian

2008-01-01

In dieser Diplomarbeit werden zwei Methoden vorgestellt, mit denen τ -Leptonen in den zuk ̈nf- u tigen Daten des ATLAS-Experiments untersucht werden sollen. Den ersten Teil bildet die Be- stimmung von Missidentifikationsraten von Jets aus QCD-2-Jet-Ereignissen als τ -Leptonen. Der zweite Teil ist die Entwicklung einer Methode zur Bestimmung der τ -Rekonstruktions- und -Identifikationseffizienz relativ zur μ-Effizienz. In diesem Zusammenhang werden invariante Massen aus Z → ll-Ereignissen bestimmt, die Massen aus Z → τ τ -Ereignissen mit denen aus Z → ee und Z → μμ verglichen, τ -Effizienzen gemittelt uber alle Bereiche und in verschiedenen ̈ o η-Bereichen berechnet sowie eine M ̈glichkeit zur Bestimmung von τ -Effizienzen in unterschied- lichen Transversalimpulsbereichen vorgestellt. Des Weiteren wird eine verbesserte Absch ̈tzung a des QCD-Untergrunds vorgenommen und das Verhalten der τ -Effizienz unter Ber ̈cksichtigung u des Triggers untersucht.

Trigger Menu-aware Monitoring for the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00441925; The ATLAS collaboration

2017-01-01

Changes in the trigger menu, the online algorithmic event-selection of the ATLAS experiment at the LHC, are followed by adjustments to the ATLAS trigger monitoring systems. During Run 1, and so far in Run 2, ATLAS has deployed monitoring updates with the installation of new software releases at Tier-0, the first level of the ATLAS computing grid. Having to wait for a new software release to be installed at Tier-0, in order to update ATLAS offline trigger monitoring configurations, results in a lag with respect to the modification of the trigger menu. We present the design and implementation of a `trigger menu-aware' monitoring system that aims to simplify the ATLAS operational workflows by allowing monitoring configuration changes to be made at the Tier-0 site by utilising an Oracle SQL database.

Physics with Photons at the ATLAS experiment

International Nuclear Information System (INIS)

Perez-Reale, V.

2008-01-01

The identification of photons in the ATLAS experiment is crucial for the study of a number of physics channels, including the search for a Higgs boson decaying to photon pairs, and measurements of direct production of single photons and photon pairs. The photon-photon and photon-jet channels are interesting in their own right, allowing the study of QCD at the new energy range of the LHC. The photon-identification strategy in ATLAS will be presented along with photon-jet cross section measurements and the potential ATLAS constrains on the gluon structure function

Analysis of ATLAS FLB-EC6 Experiment using SPACE Code

International Nuclear Information System (INIS)

Lee, Donghyuk; Kim, Yohan; Kim, Seyun

2013-01-01

The new code is named SPACE(Safety and Performance Analysis Code for Nuclear Power Plant). As a part of code validation effort, simulation of ATLAS FLB(Feedwater Line Break) experiment using SPACE code has been performed. The FLB-EC6 experiment is economizer break of a main feedwater line. The calculated results using the SPACE code are compared with those from the experiment. The ATLAS FLB-EC6 experiment, which is economizer feedwater line break, was simulated using the SPACE code. The calculated results were compared with those from the experiment. The comparisons of break flow rate and steam generator water level show good agreement with the experiment. The SPACE code is capable of predicting physical phenomena occurring during ATLAS FLB-EC6 experiment

Resonance Project; Music from the ATLAS Experiment

CERN Multimedia

Claudia Marcelloni

2010-01-01

The ATLAS Collaboration comprises physicists, engineers, technicians and support staff from 38 countries who have come together at CERN to build and run one of the largest, most complex scientific experiments known to mankind. Drawn together by our common love of science, many of us are also passionate about music. In October 2008, we marked the completion of the ATLAS detector construction with a series of live performances, and thus was born the idea for Resonance. The recording experience was exciting and enjoyable for all of us, many of whom had never entered a studio before. Resonance is a double CD featuring a variety of musical styles from classical to heavy metal. It also includes a DVD with footage of the recording sessions and interviews with some of the musicians. For more information go to www.atlas-resonance.ch

ATLAS: Applications experiences and further developments

International Nuclear Information System (INIS)

Beraha, D.; Pointner, W.; Voggenberger, T.

1999-01-01

An overview of the plant analyzer ATLAS is given, describing its configuration, the process models and the supplementary modules which enhance the functionality of ATLAS for a range of applications in reactor safety analysis. These modules include the Reliability Advisory System, which supports the user by information from probabilistic safety analysis, the Procedure Analysis for development and test of emergency operating procedures, and a diagnostic system for steam-generator tube rupture. The development of plant specific analysers for various power plants is described, and the user experience related. Finally, the intended further development directions are discussed, centering on a tracking simulator, the migration of the visualisation system to Windows NT, and the construction of the Analysis Center as a multimedia environment for the operation of ATLAS. (author)

Trigger Menu-aware Monitoring for the ATLAS experiment

CERN Document Server

Hoad, Xanthe; The ATLAS collaboration

2016-01-01

Changes in the trigger menu, the online algorithmic event-selection of the ATLAS experiment at the LHC in response to luminosity and detector changes are followed by adjustments in their monitoring system. This is done to ensure that the collected data is useful, and can be properly reconstructed at Tier-0, the first level of the computing grid. During Run 1, ATLAS deployed monitoring updates with the installation of new software releases at Tier-0. This created unnecessary overhead for developers and operators, and unavoidably led to different releases for the data-taking and the monitoring setup. We present a "trigger menu-aware" monitoring system designed for the ATLAS Run 2 data-taking. The new monitoring system aims to simplify the ATLAS operational workflows, and allows for easy and flexible monitoring configuration changes at the Tier-0 site via an Oracle DB interface. We present the design and the implementation of the menu-aware monitoring, along with lessons from the operational experience of the ne...

ATLAS Pixel Detector Operational Experience

CERN Document Server

Di Girolamo, B; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.9% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Next generation PanDA pilot for ATLAS and other experiments

International Nuclear Information System (INIS)

Nilsson, P; De, K; Megino, F Barreiro; Llamas, R Medrano; Bejar, J Caballero; Hover, J; Maeno, T; Wenaus, T; Love, P; Walker, R

2014-01-01

The Production and Distributed Analysis system (PanDA) has been in use in the ATLAS Experiment since 2005. It uses a sophisticated pilot system to execute submitted jobs on the worker nodes. While originally designed for ATLAS, the PanDA Pilot has recently been refactored to facilitate use outside of ATLAS. Experiments are now handled as plug-ins such that a new PanDA Pilot user only has to implement a set of prototyped methods in the plug-in classes, and provide a script that configures and runs the experiment-specific payload. We will give an overview of the Next Generation PanDA Pilot system and will present major features and recent improvements including live user payload debugging, data access via the Federated XRootD system, stage-out to alternative storage elements, support for the new ATLAS DDM system (Rucio), and an improved integration with glExec, as well as a description of the experiment-specific plug-in classes. The performance of the pilot system in processing LHC data on the OSG, LCG and Nordugrid infrastructures used by ATLAS will also be presented. We will describe plans for future development on the time scale of the next few years.

Data handling and processing for the ATLAS experiment

CERN Document Server

Barberis, D; The ATLAS collaboration

2011-01-01

The ATLAS experiment has taken data steadily since Autumn 2009, collecting close to 1 fm-1 of data (several petabytes of raw and reconstructed data per year of data-taking). Data are calibrated, reconstructed, distributed and analysed at over 100 different sites using the World-wide LHC Computing Grid and the tools produced by the ATLAS Distributed Computing project. This paper reports on the experience of using this distributed computing infrastructure with real data and in real time, on the evolution of the computing model driven by this experience, and on the system performance during the first two years of operation.

First-year experience with the ATLAS online monitoring framework

International Nuclear Information System (INIS)

Corso-Radu, A

2010-01-01

ATLAS is one of the four experiments in the Large Hadron Collider (LHC) at CERN, which has been put in operation this year. The challenging experimental environment and the extreme detector complexity required development of a highly scalable distributed monitoring framework, which is currently being used to monitor the quality of the data being taken as well as operational conditions of the hardware and software elements of the detector, trigger and data acquisition systems. At the moment the ATLAS Trigger/DAQ system is distributed over more than 1000 computers, which is about one third of the final ATLAS size. At every minute of an ATLAS data taking session the monitoring framework serves several thousands physics events to monitoring data analysis applications, handles more than 4 million histograms updates coming from more than 4 thousands applications, executes 10 thousands advanced data quality checks for a subset of those histograms, displays histograms and results of these checks on several dozens of monitors installed in main and satellite ATLAS control rooms. This note presents the overview of the online monitoring software framework, and describes the experience, which was gained during an extensive commissioning period as well as at the first phase of LHC beam in September 2008. Performance results, obtained on the current ATLAS DAQ system will also be presented, showing that the performance of the framework is adequate for the final ATLAS system.

Material science experiments at the ATLAS facility

CERN Document Server

Keinigs, R K; Atchison, W L; Bartsch, R R; Faehl, R J; Flower-Maudlin, E C; Hammerberg, J E; Holtkamp, D B; Kyrala, G A; Oro, D M; Parker, J V; Preston, D L; Removsky, R E; Scudder, D W; Sheehey, P T; Shlachter, J S; Taylor, A J; Tonks, D L; Turchi, P J; Chandler, E A

2001-01-01

Summary form only given, as follows. Three experimental campaigns designed for fielding on the Atlas Pulsed Power Facility are discussed. The foci of these experiments are directed toward a better understanding of three material science issues; (1) strength at high strain and high strain rate, (2) friction at material interfaces moving at high relative velocities, and (3) material failure in convergent geometry. Atlas provides an environment for investigating these problems in parameter regimes and geometries that are inaccessible with standard techniques. For example, flow stress measurements of material strength using conventional Hopkinson bar experiments are limited to strain rates ~10/sup 4/ sec/sup -1/. Atlas will be capable of imploding metal shells to combined strains of 200% and strain rates >10/sup 6/ sec/sup -1/. Data obtained regimes is used to test different constitutive strength models used in several Los Alamos hydrocodes. Dynamic friction has been investigated for nearly 300 years, but a first...

Online remote monitoring facilities for the ATLAS experiment

CERN Document Server

Kolos, S; The ATLAS collaboration; Feng, E; Hauser, R; Yakovlev, A; Zaytsev, A

2011-01-01

ATLAS is one of the 4 LHC experiments which started to be operated in the collisions mode in 2010. The ATLAS apparatus itself as well as the Trigger and the DAQ system are extremely complex facilities which have been built up by the collaboration including 144 institutes from 33 countries. The effective running of the experiment is supported by a large number of experts distributed all over the world. This paper describes the online remote monitoring system which has been developed in the ATLAS Trigger and DAQ(TDAQ) community in order to support efficient participation of the experts from remote institutes in the exploitation of the experiment. The facilities provided by the remote monitoring system are ranging from the WEB based access to the general status and data quality for the ongoing data taking session to the scalable service providing real-time mirroring of the detailed monitoring data from the experimental area to the dedicated computers in the CERN public network, where this data is made available ...

Experience on 3D silicon sensors for ATLAS IBL

International Nuclear Information System (INIS)

Darbo, G.

2015-01-01

3D silicon sensors, where plasma micro-machining is used to etch deep narrow apertures in the silicon substrate to form electrodes of PIN junctions, represent possible solutions for inner pixel layers of the tracking detectors in high energy physics experiments. This type of sensors has been developed for the Insertable B-Layer (IBL), an additional pixel layer that has been installed in ATLAS during the present shutdown of the LHC collider at CERN. It is presented here the experience in designing, testing and qualifying sensors and detector modules that have been used to equip part of the IBL. Based on the gained experience with 3D silicon sensors for the ATLAS IBL, we discuss possible new developments for the upgrade of ATLAS and CMS at the high-luminosity LHC (HL-LHC)

The ATLAS experiment

CERN Document Server

Dunford, Monica Lynn

2014-01-01

In particle physics experiments, the discovery of increasingly more massive particles has brought deep understanding of the basic constituents of matter and of the fundamental forces among them. In order to explore Nature in its deepest elementary secrets, the Large Hadron Collider (LHC) was built at CERN, Geneva. The LHC provides the highest energy collisions in a laboratory, at very high rates to allow one to study very rare reactions. Two independent sophisticated huge instruments, called ATLAS and CMS detectors, are operated to explore in a most broad way the physics of these collisions. In addition to these two general-purpose detectors, smaller specialized experiments (LHCb, ALICE and some others) are collecting collision data as well.

High-Performance Scalable Information Service for the ATLAS Experiment

International Nuclear Information System (INIS)

Kolos, S; Boutsioukis, G; Hauser, R

2012-01-01

The ATLAS[1] experiment is operated by a highly distributed computing system which is constantly producing a lot of status information which is used to monitor the experiment operational conditions as well as to assess the quality of the physics data being taken. For example the ATLAS High Level Trigger(HLT) algorithms are executed on the online computing farm consisting from about 1500 nodes. Each HLT algorithm is producing few thousands histograms, which have to be integrated over the whole farm and carefully analyzed in order to properly tune the event rejection. In order to handle such non-physics data the Information Service (IS) facility has been developed in the scope of the ATLAS Trigger and Data Acquisition (TDAQ)[2] project. The IS provides a high-performance scalable solution for information exchange in distributed environment. In the course of an ATLAS data taking session the IS handles about a hundred gigabytes of information which is being constantly updated with the update interval varying from a second to a few tens of seconds. IS provides access to any information item on request as well as distributing notification to all the information subscribers. In the latter case IS subscribers receive information within a few milliseconds after it was updated. IS can handle arbitrary types of information, including histograms produced by the HLT applications, and provides C++, Java and Python API. The Information Service is a unique source of information for the majority of the online monitoring analysis and GUI applications used to control and monitor the ATLAS experiment. Information Service provides streaming functionality allowing efficient replication of all or part of the managed information. This functionality is used to duplicate the subset of the ATLAS monitoring data to the CERN public network with a latency of a few milliseconds, allowing efficient real-time monitoring of the data taking from outside the protected ATLAS network. Each information

Long-term operating experience for the ATLAS superconducting resonators

International Nuclear Information System (INIS)

Pardo, R.; Zinkann, G.

1999-01-01

Portions of the ATLAS accelerator have been operating now for over 21 years. The facility has accumulated several million resonator-hours of operation at this point and has demonstrated the long-term reliability of RF superconductivity. The overall operating performance of the ATLAS facility has established a level of beam quality, flexibility, and reliability not previously achieved with heavy-ion accelerator facilities. The actual operating experience and maintenance history of ATLAS are presented for ATLAS resonators and associated electronics systems. Solutions to problems that appeared in early operation as well as current problems needing further development are discussed

Next Generation PanDA Pilot for ATLAS and Other Experiments

CERN Document Server

Nilsson, P; The ATLAS collaboration; Caballero Bejar, J; De, K; Hover, J; Love, P; Maeno, T; Medrano Llamas, R; Walker, R; Wenaus, T

2013-01-01

The Production and Distributed Analysis system (PanDA) has been in use in the ATLAS Experiment since 2005. It uses a sophisticated pilot system to execute submitted jobs on the worker nodes. While originally designed for ATLAS, the PanDA Pilot has recently been refactored to facilitate use outside of ATLAS. Experiments are now handled as plug-ins such that a new PanDA Pilot user only has to implement a set of prototyped methods in the plug-in classes, and provide a script that configures and runs the experiment specific payload. We will give an overview of the Next Generation PanDA Pilot system and will present major features and recent improvements including live user payload debugging, data access via the Federated XRootD system, stage-out to alternative storage elements, support for the new ATLAS DDM system (Rucio), and an improved integration with glExec, as well as a description of the experiment specific plug-in classes. The performance of the pilot system in processing LHC data on the OSG, LCG and Nord...

Next Generation PanDA Pilot for ATLAS and Other Experiments

CERN Document Server

Nilsson, P; The ATLAS collaboration; Caballero Bejar, J; De, K; Hover, J; Love, P; Maeno, T; Medrano Llamas, R; Walker, R; Wenaus, T

2014-01-01

The Production and Distributed Analysis system (PanDA) has been in use in the ATLAS Experiment since 2005. It uses a sophisticated pilot system to execute submitted jobs on the worker nodes. While originally designed for ATLAS, the PanDA Pilot has recently been refactored to facilitate use outside of ATLAS. Experiments are now handled as plug-ins such that a new PanDA Pilot user only has to implement a set of prototyped methods in the plug-in classes, and provide a script that configures and runs the experiment specific payload. We will give an overview of the Next Generation PanDA Pilot system and will present major features and recent improvements including live user payload debugging, data access via the Federated XRootD system, stage-out to alternative storage elements, support for the new ATLAS DDM system (Rucio), and an improved integration with glExec, as well as a description of the experiment specific plug-in classes. The performance of the pilot system in processing LHC data on the OSG, LCG and Nord...

Data handling and processing for the ATLAS experiment

CERN Document Server

Barberis, D; The ATLAS collaboration

2011-01-01

The ATLAS experiment is taking data steadily since Autumn 2009, collecting so far over 2.5 fm-1 of data (several petabytes of raw and reconstructed data per year of data-taking). Data are calibrated, reconstructed, distributed and analysed at over 100 different sites using the World-wide LHC Computing Grid and the tools produced by the ATLAS Distributed Computing project. This paper reports on the experience of setting up and operating this distributed computing infrastructure with real data and in real time, on the evolution of the computing model driven by this experience, and on the system performance during the first two years of operation.

Dedication of the massive ATLAS art mural painted by Josef Kristofoletti directly above the cavern of the ATLAS Experiment at CERN

CERN Multimedia

Claudia Marcelloni, Michael Barnett

2010-01-01

Ceremony to celebrate the massive mural of the ATLAS detector at CERN painted by artist Josef Kristofoletti. The mural is located at the ATLAS Experiment site, and it shows on two perpendicular walls the detector with a collision event superimposed. The event on the large wall shows a simulation of an event that would be recorded in ATLAS if a Higgs boson was produced. The cavern of the ATLAS Experiment with the detector is 100 meters directly below the mural. The height of the mural is about 12 meters (40 feet). The actual ATLAS detector is more than twice as big.

Operational Experience with the ATLAS Pixel Detector

CERN Document Server

Djama, Fares; The ATLAS collaboration

2017-01-01

Run 2 of the LHC collider sets new challenges to track and vertex reconstruction because of its higher energy, pileup and luminosity. The ATLAS tracking performance relies critically on the Pixel Detector. Therefore, in view of Run 2, the ATLAS collaboration has constructed the first 4-layer pixel detector in Particle Physics by installing a new pixel layer, called Insertable B-Layer (IBL). Operational experience and performance of the 4-layer Pixel Detector during Run 2 are presented.

Multilevel Workflow System in the ATLAS Experiment

CERN Document Server

Borodin, M; The ATLAS collaboration; Golubkov, D; Klimentov, A; Maeno, T; Vaniachine, A

2015-01-01

The ATLAS experiment is scaling up Big Data processing for the next LHC run using a multilevel workflow system comprised of many layers. In Big Data processing ATLAS deals with datasets, not individual files. Similarly a task (comprised of many jobs) has become a unit of the ATLAS workflow in distributed computing, with about 0.8M tasks processed per year. In order to manage the diversity of LHC physics (exceeding 35K physics samples per year), the individual data processing tasks are organized into workflows. For example, the Monte Carlo workflow is composed of many steps: generate or configure hard-processes, hadronize signal and minimum-bias (pileup) events, simulate energy deposition in the ATLAS detector, digitize electronics response, simulate triggers, reconstruct data, convert the reconstructed data into ROOT ntuples for physics analysis, etc. Outputs are merged and/or filtered as necessary to optimize the chain. The bi-level workflow manager - ProdSys2 - generates actual workflow tasks and their jobs...

High-performance scalable Information Service for the ATLAS experiment

CERN Document Server

Kolos, S; The ATLAS collaboration; Hauser, R

2012-01-01

The ATLAS experiment is being operated by highly distributed computing system which is constantly producing a lot of status information which is used to monitor the experiment operational conditions as well as to access the quality of the physics data being taken. For example the ATLAS High Level Trigger(HLT) algorithms are executed on the online computing farm consisting from about 1500 nodes. Each HLT algorithm is producing few thousands histograms, which have to be integrated over the whole farm and carefully analyzed in order to properly tune the event rejection. In order to handle such non-physics data the Information Service (IS) facility has been developed in the scope of the ATLAS TDAQ project. The IS provides high-performance scalable solution for information exchange in distributed environment. In the course of an ATLAS data taking session the IS handles about hundred gigabytes of information which is being constantly updated with the update interval varying from a second to few tens of seconds. IS ...

Online remote monitoring facilities for the ATLAS experiment

CERN Document Server

Kolos, S; The ATLAS collaboration; Feng, E; Hauser, R; Yakovlev, A; Zaytsev, A

2010-01-01

ATLAS is one of the 4 LHC experiments which started to be operated in the collisions mode in 2010. The ATLAS apparatus itself as well as the Trigger and the DAQ system are extremely complex facilities which have been built up by the collaboration including 144 institutes from 33 countries. The effective running of the experiment is supported by a large number of experts distributed all over the world. This paper describes the online remote monitoring system which has been developed in the ATLAS TDAQ community in order to support efficient participation of the experts from remote institutes in the exploitation of the experiment. The facilities provided by the remote monitoring system are ranging from the WEB based access to the general status and data quality for the ongoing data taking session to the scalable service providing real-time mirroring of the detailed monitoring data from the experimental area to the dedicated computers in the CERN public network, where this data is made available to remote users t...

Continuous software quality analysis for the ATLAS experiment

CERN Document Server

Washbrook, Andrew; The ATLAS collaboration

2017-01-01

The software for the ATLAS experiment on the Large Hadron Collider at CERN has evolved over many years to meet the demands of Monte Carlo simulation, particle detector reconstruction and data analysis. At present over 3.8 million lines of C++ code (and close to 6 million total lines of code) are maintained by an active worldwide developer community. In order to run the experiment software efficiently at hundreds of computing centres it is essential to maintain a high level of software quality standards. The methods proposed to improve software quality practices by incorporating checks into the new ATLAS software build infrastructure.

Test Management Framework for the ATLAS Experiment

CERN Document Server

Kazarov, Andrei; The ATLAS collaboration; Avolio, Giuseppe

2018-01-01

Test Management Framework for the Data Acquisition of the ATLAS Experiment Data Acquisition (DAQ) of the ATLAS experiment is a large distributed and inhomogeneous system: it consists of thousands of interconnected computers and electronics devices that operate coherently to read out and select relevant physics data. Advanced diagnostics capabilities of the TDAQ control system are a crucial feature which contributes significantly to smooth operation and fast recovery in case of the problems and, finally, to the high efficiency of the whole experiment. The base layer of the verification and diagnostic functionality is a test management framework. We have developed a flexible test management system that allows the experts to define and configure tests for different components, indicate follow-up actions to test failures and describe inter-dependencies between DAQ or detector elements. This development is based on the experience gained with the previous test system that was used during the first three years of th...

Integration of Detectors Into a Large Experiment: Examples From ATLAS and CMS

CERN Document Server

Froidevaux, D

2011-01-01

Integration of Detectors Into a Large Experiment: Examples From ATLAS andCMS, part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B2: Detectors for Particles and Radiation. Part 2: Systems and Applications'. This document is part of Part 2 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Chapter '5 Integration of Detectors Into a Large Experiment: Examples From ATLAS and CMS' with the content: 5 Integration of Detectors Into a Large Experiment: Examples From ATLAS and CMS 5.1 Introduction 5.1.1 The context 5.1.2 The main initial physics goals of ATLAS and CMS at the LHC 5.1.3 A snapshot of the current status of the ATLAS and CMS experiments 5.2 Overall detector concept and magnet systems 5.2.1 Overall detector concept 5.2.2 Magnet systems 5.2.2.1 Rad...

Highlights from the ATLAS experiment

CERN Document Server

Grabowska-Bold, Iwona; The ATLAS collaboration

2018-01-01

An overview of the heavy-ion results from the ATLAS experiment is given. It includes a discussion of measurements with non-UPC dimuons in Pb+Pb collisions, dijet asymmetry, charged-hadron Raa and flow harmonics in the Xe+Xe collisions, vn-pt correlations in Pb+Pb collisions, symmetric and asymmetric cumulants in small systems and many more.

Review of the ATLAS experiment at the LHC (CERN)

International Nuclear Information System (INIS)

Taylor, G.

1998-01-01

Full text: This talk gives in overview of the physics program for the next generation high energy physics experiments at CERN's Large Hadron Collider (LHC). Emphasis will be on the ATLAS experiment and in particular on the Australian participation in that experiment. Australian physicists from Melbourne, Sydney and Wollongong are playing a significant role in the development, production, installation and operation of the ambitious Semiconductor Tracker (SCT) in the ATLAS' Inner Detector. The SCT, particularly important for the detection and measurement of high energy electrons, will be essential in the search for the Higgs Boson through electron decay channels (amongst other reactions). The design calls for a total detector surface area an order of magnitude larger than in current silicon detectors, in a harsh radiation environment. Prodigious data rates and high speed electronics add to the complications of this detector. The talk will review progress and describe the schedule for the completion of the SCT and ATLAS

Jet calibration in the ATLAS experiment at LHC

CERN Document Server

Francavilla, P

2009-01-01

Jets produced in the hadronisation of quarks and gluons play a central role in the rich physics program that will be covered by the ATLAS experiment at the LHC, and are central elements of the signature for many physics channels. A well understood energy scale, which for some processes demands an uncertainty in the energy scale of order 1%, is a prerequisite. Moreover, in early data we face the challenge of dealing with the unexpected issues of a brand new detector in an unexplored energy domain. The ATLAS collaboration is carrying out a program to revisit the jet calibration strategies used in earlier hadron-collider experiments and develop a strategy which takes into account the new experimental problems introduced from higher measurement precision and from the LHC environment. The ATLAS calorimeter is intrinsically non-compensating and we will discuss the use of different offline approaches based on cell energy density and jet topology to correct the linearity response while improving the resolution. In ad...

Targets for the APEX experiment at ATLAS

International Nuclear Information System (INIS)

Greene, J.P.; Thomas, G.E.; Leonard, R.H.

1994-01-01

Targets of lead, tantalum, thorium and uranium have been produced for experiments with the APEX (Argonne Positron Experiment) apparatus at ATLAS (Argonne Tandem Linac Accelerator System). APEX is a device built at Argonne National Laboratory to investigate the anomalous positrons observed in collisions of very heavy ion beams on heavy targets. Both fixed and rotating targets have been used. The rotating target system involves a 4-quadrant wheel rotating at speeds up to 700 rpm with the position encoded into the data stream. In addition to the hundreds of targets produced for the heavy-ion reactions studied, a wide variety of targets were employed for beam diagnostics, detector calibration and target wheel development. The experiment used very heavy ion beams ( 238 U, 206 Pb and 208 Pb) from ATLAS and targets of 206 Pb, 208 Pb, 232 Th and 238 U produced in the laboratory

The detector control system of the ATLAS experiment

International Nuclear Information System (INIS)

Poy, A Barriuso; Burckhart, H J; Cook, J; Franz, S; Gutzwiller, O; Hallgren, B; Schlenker, S; Varela, F; Boterenbrood, H; Filimonov, V; Khomutnikov, V

2008-01-01

The ATLAS experiment is one of the experiments at the Large Hadron Collider, constructed to study elementary particle interactions in collisions of high-energy proton beams. The individual detector components as well as the common experimental infrastructure are supervised by the Detector Control System (DCS). The DCS enables equipment supervision using operator commands, reads, processes and archives the operational parameters of the detector, allows for error recognition and handling, manages the communication with external control systems, and provides a synchronization mechanism with the physics data acquisition system. Given the enormous size and complexity of ATLAS, special emphasis was put on the use of standardized hardware and software components enabling efficient development and long-term maintainability of the DCS over the lifetime of the experiment. Currently, the DCS is being used successfully during the experiment commissioning phase

Trigger Menu-aware Monitoring for the ATLAS experiment

Science.gov (United States)

Hoad, Xanthe; ATLAS Collaboration

2017-10-01

We present a“trigger menu-aware” monitoring system designed for the Run-2 data-taking of the ATLAS experiment at the LHC. Unlike Run-1, where a change in the trigger menu had to be matched by the installation of a new software release at Tier-0, the new monitoring system aims to simplify the ATLAS operational workflows. This is achieved by integrating monitoring updates in a quick and flexible manner via an Oracle DB interface. We present the design and the implementation of the menu-aware monitoring, along with lessons from the operational experience of the new system with the 2016 collision data.

The simulation for the ATLAS experiment Present status and outlook

CERN Document Server

Rimoldi, A; Gallas, M; Nairz, A; Boudreau, J; Tsulaia, V; Costanzo, D

2004-01-01

The simulation program for the ATLAS experiment is presently operational in a full OO environment. This important physics application has been successfully integrated into ATLAS's common analysis framework, ATHENA. In the last year, following a well stated strategy of transition from a GEANT3 to a GEANT4-based simulation, a careful validation programme confirmed the reliability, performance and robustness of this new tool, as well as its consistency with the results of previous simulation. Generation, simulation and digitization steps on different sets of full physics events we retested for performance. The same software used to simulate the full the ATLAS detector is also used with testbeam configurations. Comparisons to real data in the testbeam validate both the detector description and the physics processes within each subcomponent. In this paper we present the current status of ATLAS GEANT4 simulation, describe the functionality tests performed during its validation phase, and the experience with distrib...

Multilevel Workflow System in the ATLAS Experiment

International Nuclear Information System (INIS)

Borodin, M; De, K; Navarro, J Garcia; Golubkov, D; Klimentov, A; Maeno, T; Vaniachine, A

2015-01-01

The ATLAS experiment is scaling up Big Data processing for the next LHC run using a multilevel workflow system comprised of many layers. In Big Data processing ATLAS deals with datasets, not individual files. Similarly a task (comprised of many jobs) has become a unit of the ATLAS workflow in distributed computing, with about 0.8M tasks processed per year. In order to manage the diversity of LHC physics (exceeding 35K physics samples per year), the individual data processing tasks are organized into workflows. For example, the Monte Carlo workflow is composed of many steps: generate or configure hard-processes, hadronize signal and minimum-bias (pileup) events, simulate energy deposition in the ATLAS detector, digitize electronics response, simulate triggers, reconstruct data, convert the reconstructed data into ROOT ntuples for physics analysis, etc. Outputs are merged and/or filtered as necessary to optimize the chain. The bi-level workflow manager - ProdSys2 - generates actual workflow tasks and their jobs are executed across more than a hundred distributed computing sites by PanDA - the ATLAS job-level workload management system. On the outer level, the Database Engine for Tasks (DEfT) empowers production managers with templated workflow definitions. On the next level, the Job Execution and Definition Interface (JEDI) is integrated with PanDA to provide dynamic job definition tailored to the sites capabilities. We report on scaling up the production system to accommodate a growing number of requirements from main ATLAS areas: Trigger, Physics and Data Preparation. (paper)

The ATLAS online High Level Trigger framework: Experience reusing offline software components in the ATLAS trigger

International Nuclear Information System (INIS)

Wiedenmann, Werner

2010-01-01

Event selection in the ATLAS High Level Trigger is accomplished to a large extent by reusing software components and event selection algorithms developed and tested in an offline environment. Many of these offline software modules are not specifically designed to run in a heavily multi-threaded online data flow environment. The ATLAS High Level Trigger (HLT) framework based on the GAUDI and ATLAS ATHENA frameworks, forms the interface layer, which allows the execution of the HLT selection and monitoring code within the online run control and data flow software. While such an approach provides a unified environment for trigger event selection across all of ATLAS, it also poses strict requirements on the reused software components in terms of performance, memory usage and stability. Experience of running the HLT selection software in the different environments and especially on large multi-node trigger farms has been gained in several commissioning periods using preloaded Monte Carlo events, in data taking periods with cosmic events and in a short period with proton beams from LHC. The contribution discusses the architectural aspects of the HLT framework, its performance and its software environment within the ATLAS computing, trigger and data flow projects. Emphasis is also put on the architectural implications for the software by the use of multi-core processors in the computing farms and the experiences gained with multi-threading and multi-process technologies.

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

Material science experiments on the Atlas Facility

International Nuclear Information System (INIS)

Keinigs, Rhonald K.; Atchison, Walter L.; Faehl, Rickey J.; Lindemuth, Irvin R.; Anderson, Wallace E.; Bartsch, Robert Richard; Flower-Maudlin, Elane C.; Hammerberg, James E.; Holtkamp, David B.; Jones, Michael E.; Kyrala, George A.; Oro, David M.; Parker, Jerald V.; Preston, Dean L.; Reinovsky, Robert E.; Scudder, David W.; Sheehey, Peter T.; Shlacter, Jack S.; Stokes, John L.; Taylor, Antoinette J.; Tonks, Davis L.; Turchi, Peter J.

2001-01-01

Three material properties experiments that are to be performed on the Atlas pulsed power facility are described; friction at sliding metal interfaces, spallation and damage in convergent geomety, and plastic flow at high strain and high strain rate. Construction of this facility has been completed and experiments in high energy density hydrodynamics and material dynamics will begin in 2001.

Jet calibration in the ATLAS experiment at LHC

CERN Document Server

The ATLAS collaboration

2009-01-01

Jets produced in the hadronisation of quarks and gluons play a central role in the rich physics program that will be covered by the ATLAS experiment at the LHC, and are central elements of the signature for many physics channels. A well understood energy scale, which for some process demands an uncertainty in the energy scale of order 1%, is a prerequisite. Moreover, in early data we face the challenge of dealing with the unexpected issues of a brand new detector in an unexplored energy domain. The ATLAS collaboration is carrying out a program to revisit the jet calibration strategies used in earlier hadron-collider experiments and develop a strategy which takes account of the new experimental problems and demand for greater measurement precision which will be faced at the LHC. The ATLAS calorimeter is intrinsically non-compensating and we will present the use of different offline approaches based on cell energy density and jet topology to correct for this effect on jet energy resolution and scale. In additio...

ATLAS Experiment: Collaboration at the frontiers of science and technology

CERN Document Server

2018-01-01

ATLAS is run by a collaboration of physicists, engineers, technicians and support staff from around the world. It is one of the largest collaborative efforts ever attempted in science, with over 5000 members and almost 3000 scientific authors. The ATLAS Collaboration welcomes new collaborators for long-term engagement in the experiment.

Operational Experience and Performance with the ATLAS Pixel detector

CERN Document Server

Martin, Christopher Blake; The ATLAS collaboration

2018-01-01

The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider, with record breaking instantaneous luminosities of $1.3\\times10^{34}\\text{cm}^{{-2}}\\text{s}^{{-1}}$ recently surpassed. The key status and performance metrics of the ATLAS Pixel Detector are summarized, and the operational experience and requirements to ensure optimum data quality and data taking efficiency are described, with special emphasis to radiation damage experience.

Operational Experience and Performance with the ATLAS Pixel detector

CERN Document Server

Martin, Christopher Blake; The ATLAS collaboration

2018-01-01

The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider, with record breaking instantaneous luminosities of 1.3 x 10^34 cm-2 s-1 recently surpassed. The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency are described, with special emphasis to radiation damage experience.

Discovery of SM Higgs Boson in ATLAS Experiment

Indian Academy of Sciences (India)

IAS Admin

ics, Higgs boson, particle detec- tors, trigger, grid computing. Discovery of SM Higgs Boson in ATLAS Experiment. Prafulla Kumar Behera. Prafulla Kumar Behera is an experimental high energy physicist at the. IITM, Chennai. He has participated in many large-scale collider experiments namely. BELLE at Japan, BABAR.

Operational experience with the ATLAS Pixel Detector

CERN Document Server

Ince, T; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost element of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience of the ATLAS Pixel detector

CERN Document Server

Hirschbuehl, D; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience of the ATLAS Pixel Detector

CERN Document Server

Marcisovsky, M; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

The Virtual Point 1 event display for the ATLAS experiment

International Nuclear Information System (INIS)

Kittelmann, Thomas; Tsulaia, Vakhtang; Boudreau, Joseph; Moyse, Edward

2010-01-01

We present an event display for the ATLAS Experiment, called Virtual Point 1 (VP1), designed initially for deployment at point 1 of the LHC, the location of the ATLAS detector. The Qt/OpenGL based application provides truthful and interactive 3D representations of both event and non-event data, and now serves a general-purpose role within the experiment. Thus, VP1 is used both online (in the control room itself or remotely via a special 'live' mode) and offline environments to provide fast debugging and understanding of events, detector status and software. In addition to a flexible plugin infrastructure and a high level of configurability, this multi-purpose role is mainly facilitated by embedding the application directly into the ATLAS offline software framework, enabling it to use the native Event Data Model directly, and thus run on any source of ATLAS data, or even directly from within processes such as reconstruction jobs. Finally, VP1 provides high-quality pictures and movies, useful for outreach purposes.

Complex terrain experiments in the New European Wind Atlas

Science.gov (United States)

Angelou, N.; Callies, D.; Cantero, E.; Arroyo, R. Chávez; Courtney, M.; Cuxart, J.; Dellwik, E.; Gottschall, J.; Ivanell, S.; Kühn, P.; Lea, G.; Matos, J. C.; Palma, J. M. L. M.; Peña, A.; Rodrigo, J. Sanz; Söderberg, S.; Vasiljevic, N.; Rodrigues, C. Veiga

2017-01-01

The New European Wind Atlas project will create a freely accessible wind atlas covering Europe and Turkey, develop the model chain to create the atlas and perform a series of experiments on flow in many different kinds of complex terrain to validate the models. This paper describes the experiments of which some are nearly completed while others are in the planning stage. All experiments focus on the flow properties that are relevant for wind turbines, so the main focus is the mean flow and the turbulence at heights between 40 and 300 m. Also extreme winds, wind shear and veer, and diurnal and seasonal variations of the wind are of interest. Common to all the experiments is the use of Doppler lidar systems to supplement and in some cases replace completely meteorological towers. Many of the lidars will be equipped with scan heads that will allow for arbitrary scan patterns by several synchronized systems. Two pilot experiments, one in Portugal and one in Germany, show the value of using multiple synchronized, scanning lidar, both in terms of the accuracy of the measurements and the atmospheric physical processes that can be studied. The experimental data will be used for validation of atmospheric flow models and will by the end of the project be freely available. This article is part of the themed issue ‘Wind energy in complex terrains’. PMID:28265025

Operational Experience with the ATLAS Pixel Detector

CERN Document Server

Djama, Fares; The ATLAS collaboration

2017-01-01

Run-2 of the LHC is providing new challenges to track and vertex reconstruction imposed by the higher collision energy, pileup and luminosity that are being delivered. The ATLAS tracking performance relies critically on the Pixel Detector, therefore, in view of Run-2 of LHC, the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). Pixel detector was refurbished with a new service quarter panel to recover about 3% of defective modules lost during run-1 and an additional optical link per module was added to overcome in some layers the readout bandwidth limitation when LHC will exceed the nominal peak luminosity by almost a factor of 3. The key features and challenges met during the IBL project will be presented, as well as its operational experience and Pixel Detector performance in LHC.

World-wide online monitoring interface of the ATLAS experiment

CERN Document Server

Kolos, S; The ATLAS collaboration; Mineev, M; Hauser, R; Salnikov, A

2014-01-01

The ATLAS collaboration accounts for more than 3000 members located all over the world. The efficiency of the experiment can be improved allowing system experts not present on site to follow the ATLAS operations in real-time, spotting potential problems which otherwise may remain unattended for a non-negligible time. Taking into account the wide geographical spread of the ATLAS collaboration, the solution of this problem is to have all monitoring information with minimal access latency available world-wide. We have implemented a framework which defines a standard approach for retrieving arbitrary monitoring information from the ATLAS private network via HTTP. An information request is made by specifying one of the predefined URLs with some optional parameters refining data which has to be shipped back in XML format. The framework takes care of receiving, parsing and forwarding such requests to the appropriate plugins. The plugins retrieve the requested data and convert it to XML (or optionally to JSON) format...

The ATLAS online High Level Trigger framework experience reusing offline software components in the ATLAS trigger

CERN Document Server

Wiedenmann, W

2009-01-01

Event selection in the Atlas High Level Trigger is accomplished to a large extent by reusing software components and event selection algorithms developed and tested in an offline environment. Many of these offline software modules are not specifically designed to run in a heavily multi-threaded online data flow environment. The Atlas High Level Trigger (HLT) framework based on the Gaudi and Atlas Athena frameworks, forms the interface layer, which allows the execution of the HLT selection and monitoring code within the online run control and data flow software. While such an approach provides a unified environment for trigger event selection across all of Atlas, it also poses strict requirements on the reused software components in terms of performance, memory usage and stability. Experience of running the HLT selection software in the different environments and especially on large multi-node trigger farms has been gained in several commissioning periods using preloaded Monte Carlo events, in data taking peri...

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

Energy Technology Data Exchange (ETDEWEB)

Aad, G.; Abat, E.; Abbott, B.; Abdallah, J.; Abdelalim, A.A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Acharya, Bobby Samir; Adams, D.L.; Addy, T.N.; Adorisio, C.; Adragna, P.; Adye, T.; Aguilar-Saavedra, J.A.; Aharrouche, M.; Ahlen, S.P.; Ahles, F.; Ahmad, A.; /SUNY, Albany /Alberta U. /Ankara U. /Annecy, LAPP /Argonne /Arizona U. /Texas U., Arlington /Athens U. /Natl. Tech. U., Athens /Baku, Inst. Phys. /Barcelona, IFAE /Belgrade U. /VINCA Inst. Nucl. Sci., Belgrade /Bergen U. /LBL, Berkeley /Humboldt U., Berlin /Bern U., LHEP /Birmingham U. /Bogazici U. /INFN, Bologna /Bologna U.

2011-11-28

The Large Hadron Collider (LHC) at CERN promises a major step forward in the understanding of the fundamental nature of matter. The ATLAS experiment is a general-purpose detector for the LHC, whose design was guided by the need to accommodate the wide spectrum of possible physics signatures. The major remit of the ATLAS experiment is the exploration of the TeV mass scale where groundbreaking discoveries are expected. In the focus are the investigation of the electroweak symmetry breaking and linked to this the search for the Higgs boson as well as the search for Physics beyond the Standard Model. In this report a detailed examination of the expected performance of the ATLAS detector is provided, with a major aim being to investigate the experimental sensitivity to a wide range of measurements and potential observations of new physical processes. An earlier summary of the expected capabilities of ATLAS was compiled in 1999 [1]. A survey of physics capabilities of the CMS detector was published in [2]. The design of the ATLAS detector has now been finalised, and its construction and installation have been completed [3]. An extensive test-beam programme was undertaken. Furthermore, the simulation and reconstruction software code and frameworks have been completely rewritten. Revisions incorporated reflect improved detector modelling as well as major technical changes to the software technology. Greatly improved understanding of calibration and alignment techniques, and their practical impact on performance, is now in place. The studies reported here are based on full simulations of the ATLAS detector response. A variety of event generators were employed. The simulation and reconstruction of these large event samples thus provided an important operational test of the new ATLAS software system. In addition, the processing was distributed world-wide over the ATLAS Grid facilities and hence provided an important test of the ATLAS computing system - this is the origin of

FTK: the hardware Fast TracKer of the ATLAS experiment at CERN

CERN Document Server

Maznas, Ioannis; The ATLAS collaboration

2016-01-01

FTK: the hardware Fast TracKer of the ATLAS experiment at CERN In the ever increasing pile-up of the Large Hadron Collider environment, the trigger systems of the experiments have to be exceedingly sophisticated and fast at the same time, in order to select the relevant physics processes against the background processes. The Fast TracKer (FTK) is a track finding implementation at hardware level that is designed to deliver full-scan tracks with $p_{T}$ above 1 GeV to the ATLAS trigger system for every L1 accept (at a maximum rate of 100kHz). To accomplish this, FTK is a highly parallel system which is currently under installation in ATLAS. It will first provide the trigger system with tracks in the central region of the ATLAS detector, and next year it is expected to cover the whole detector. The system is based on pattern matching between hits coming from the silicon trackers of the ATLAS detector and 1 billion simulated patterns stored in specially designed ASIC chips (Associative memory – AM06). In a firs...

Prompt data reconstruction at the ATLAS experiment

International Nuclear Information System (INIS)

Andrew Stewart, Graeme; Boyd, Jamie; Unal, Guillaume; Firmino da Costa, João; Tuggle, Joseph

2012-01-01

The ATLAS experiment at the LHC collider recorded more than 5 fb −1 data of pp collisions at a centre-of-mass energy of 7 TeV during 2011. The recorded data are promptly reconstructed in two steps at a large computing farm at CERN to provide fast access to high quality data for physics analysis. In the first step, a subset of the data, corresponding to the express stream and having 10Hz of events, is processed in parallel with data taking. Data quality, detector calibration constants, and the beam spot position are determined using the reconstructed data within 48 hours. In the second step all recorded data are processed with the updated parameters. The LHC significantly increased the instantaneous luminosity and the number of interactions per bunch crossing in 2011; the data recording rate by ATLAS exceeds 400 Hz. To cope with these challenges the performance and reliability of the ATLAS reconstruction software have been improved. In this paper we describe how the prompt data reconstruction system quickly and stably provides high quality data to analysers.

Towards a Level-1 Tracking Trigger for the ATLAS Experiment

CERN Document Server

De Santo, A; The ATLAS collaboration

2016-01-01

In preparation for the high-luminosity phase of the Large Hadron Collider, ATLAS is planning a trigger upgrade that will enable the experiment to use tracking information already at the first trigger level. This will provide enhanced background rejection power at trigger level while preserving much needed flexibility for the trigger system. The status and current plans for the new ATLAS Level-1 tracking trigger are presented.

New results on Higgs boson physics from the ATLAS experiment

CERN Multimedia

CERN. Geneva

2018-01-01

The ATLAS Collaboration has recently released several results that shed more light on the nature of the Higgs boson particle and the BEH mechanism. A selection of these Higgs boson results, including some results based on up to 80 fb-1of integrated luminosity collected at a centre-of-mass energy of 13 TeV with the ATLAS experiment at the LHC, will be presented.

Operational experience of ATLAS SCT and Pixel Detector

CERN Document Server

Kocian, Martin; The ATLAS collaboration

2017-01-01

The ATLAS Inner Detector based on silicon sensors is consisting of a strip detector (SCT) and a pixel detector. It is the crucial component for vertexing and tracking in the ATLAS experiment. With the excellent performance of the LHC well beyond the original specification the silicon tracking detectors are facing substantial challenges in terms of data acquisition, radiation damage to the sensors, and SEUs in the readout ASICs. The approaches on how the detector systems cope with the demands of high luminosity operation while maintaining excellent performance through hardware upgrades, software and firmware algorithms, and operational settings, are presented.

Distributed Analysis Experience using Ganga on an ATLAS Tier2 infrastructure

International Nuclear Information System (INIS)

Fassi, F.; Cabrera, S.; Vives, R.; Fernandez, A.; Gonzalez de la Hoz, S.; Sanchez, J.; March, L.; Salt, J.; Kaci, M.; Lamas, A.; Amoros, G.

2007-01-01

The ATLAS detector will explore the high-energy frontier of Particle Physics collecting the proton-proton collisions delivered by the LHC (Large Hadron Collider). Starting in spring 2008, the LHC will produce more than 10 Peta bytes of data per year. The adapted tiered hierarchy for computing model at the LHC is: Tier-0 (CERN), Tiers-1 and Tiers-2 centres distributed around the word. The ATLAS Distributed Analysis (DA) system has the goal of enabling physicists to perform Grid-based analysis on distributed data using distributed computing resources. IFIC Tier-2 facility is participating in several aspects of DA. In support of the ATLAS DA activities a prototype is being tested, deployed and integrated. The analysis data processing applications are based on the Athena framework. GANGA, developed by LHCb and ATLAS experiments, allows simple switching between testing on a local batch system and large-scale processing on the Grid, hiding Grid complexities. GANGA deals with providing physicists an integrated environment for job preparation, bookkeeping and archiving, job splitting and merging. The experience with the deployment, configuration and operation of the DA prototype will be presented. Experiences gained of using DA system and GANGA in the Top physics analysis will be described. (Author)

Studies for reconstruction efficiency and background measurements of {tau} lepton identification in Z {yields} {tau}{tau} decays in data of the ATLAS experiment; Studien zur Messung von Rekonstruktionseffizienz und Untergrund der {tau}-Lepton-Identifikation im Zerfall Z {yields} {tau}{tau} beim ATLAS-Experiment aus Daten

Energy Technology Data Exchange (ETDEWEB)

Johnert, Sebastian

2008-11-15

In this diploma thesis two methods are presented, by which {tau} leptons shall be studied in the future data of the ATLAS experiment. The first part is formed by the determination of misidentification rates of jets from QCD 2-jet events as {tau} particles. The second part is the development of a method for the determination of the {tau} reconstruction and identification efficiency relatively to the {mu} efficiency. In this connection invariant masses from Z{yields}ll events are determined, the masses from Z{yields}{tau}{tau} events compared with those from Z{yields}ee and Z{yields}{mu}{mu}, {tau} efficiencies averaged over all ranges and in different {eta} ranges calculated as well as a mehtod for the determination of {tau} efficiencies in different transverse-momentum ranges presented. Furthermore an improved estimation of the QCD background is performed and the behaviour of the {tau} efficiency under regardment of the trigger studied. [German] In dieser Diplomarbeit werden zwei Methoden vorgestellt, mit denen {tau}-Leptonen in den zukuenftigen Daten des ATLAS-Experiments untersucht werden sollen. Den ersten Teil bildet die Bestimmung von Missidentifikationsraten von Jets aus QCD-2-Jet-Ereignissen als {tau}-Leptonen. Der zweite Teil ist die Entwicklung einer Methode zur Bestimmung der {tau}-Rekonstruktions und -Identifikationseffizienz relativ zur {mu}-Effizienz. In diesem Zusammenhang werden invariante Massen aus Z {yields} ll-Ereignissen bestimmt, die Massen aus Z {yields} {tau}{tau}-Ereignissen mit denen aus Z {yields} ee und Z {yields} {mu}{mu} verglichen, {tau}-Effizienzen gemittelt ueber alle Bereiche und in verschiedenen {eta}-Bereichen berechnet sowie eine Moeglichkeit zur Bestimmung von {tau}-Effizienzen in unterschiedlichen Transversalimpulsbereichen vorgestellt. Des Weiteren wird eine verbesserte Abschaetzung des QCD-Untergrunds vorgenommen und das Verhalten der {tau}-Effizienz unter Beruecksichtigung des Triggers untersucht. (orig.)

The ATLAS Trigger: Recent Experience and Future Plans

CERN Document Server

The ATLAS collaboration

2009-01-01

This paper will give an overview of the ATLAS trigger design and its innovative features. It will describe the valuable experience gained in running the trigger reconstruction and event selection in the fastchanging environment of the detector commissioning during 2008. It will also include a description of the trigger selection menu and its 2009 deployment plan from first collisions to the nominal luminosity. ATLAS is one of the two general-purpose detectors at the Large Hadron Collider (LHC). The trigger system needs to efficiently reject a large rate of background events and still select potentially interesting ones with high efficiency. After a first level trigger implemented in custom electronics, the trigger event selection is made by the High Level Trigger (HLT) system, implemented in software. To reduce the processing time to manageable levels, the HLT uses seeded, step-wise and fast selection algorithms, aiming at the earliest possible rejection of background events. The ATLAS trigger event selection...

Concepts and Plans towards fast large scale Monte Carlo production for the ATLAS Experiment

Science.gov (United States)

Ritsch, E.; Atlas Collaboration

2014-06-01

The huge success of the physics program of the ATLAS experiment at the Large Hadron Collider (LHC) during Run 1 relies upon a great number of simulated Monte Carlo events. This Monte Carlo production takes the biggest part of the computing resources being in use by ATLAS as of now. In this document we describe the plans to overcome the computing resource limitations for large scale Monte Carlo production in the ATLAS Experiment for Run 2, and beyond. A number of fast detector simulation, digitization and reconstruction techniques are being discussed, based upon a new flexible detector simulation framework. To optimally benefit from these developments, a redesigned ATLAS MC production chain is presented at the end of this document.

Experience with highly-parallel software for the storage system of the ATLAS Experiment at CERN

CERN Document Server

Colombo, T; The ATLAS collaboration

2012-01-01

The ATLAS experiment is observing proton-proton collisions delivered by the LHC accelerator. The ATLAS Trigger and Data Acquisition (TDAQ) system selects interesting events on-line in a three-level trigger system in order to store them at a budgeted rate of several hundred Hz. This paper focuses on the TDAQ data-logging system and in particular on the implementation and performance of a novel parallel software design. In this respect, the main challenge presented by the data-logging workload is the conflict between the largely parallel nature of the event processing, especially the recently introduced event compression, and the constraint of sequential file writing and checksum evaluation. This is further complicated by the necessity of operating in a fully data-driven mode, to cope with continuously evolving trigger and detector configurations. In this paper we report on the design of the new ATLAS on-line storage software. In particular we will discuss our development experience using recent concurrency-ori...

Discovery of SM Higgs Boson in ATLAS Experiment

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 3. Discovery of SM Higgs Boson in ATLAS Experiment. Prafulla Kumar Behera. General Article Volume 18 Issue 3 March 2013 pp 248-263. Fulltext. Click here to view fulltext PDF. Permanent link:

b-tagging performance at 13 TeV for the ATLAS experiment

International Nuclear Information System (INIS)

Lapertosa, A.

2017-01-01

The correct identification of jets containing b hadrons (hence b-tagging) is of capital importance for the hadron collider experiments, such as ATLAS and CMS at the Large Hadron Collider. In particular, b-tagging is an important tool for many physics analyses: for top quark studies and Higgs boson searches, as well as the search for new physics fenomena beyond Standard Model. ATLAS developed its own algorithms for b-jet identification, exploiting the typical properties of the b quarks and the B hadrons emerging from the jet: the long lifetime, the high decay multiplicity and the high invariant mass above all. The status of the most recent b-tagging algorithms developed by the ATLAS experiment is presented, along with the methods used to measure the b-tagging efficiency on a charm jets sample at 13TeV with 2015 data.

Top Quark Properties Measurements with the ATLAS Experiment

International Nuclear Information System (INIS)

Quijada, J A Murillo

2016-01-01

Results on recent measurements of top quark properties with the ATLAS experiment at the European Laboratory, CERN, are shown. The measurements are performed using the full data set recorded during the LHC Run-I. The full data set consists of a collected integrated luminosities ∫Tdt of 4.6 fb -1 recorded at a proton-proton collision energy of √ s = 7 TeV and 20.3 fb -1 collected at 8 TeV. The mentioned top quark properties include: spin correlation, charge asymmetry, W-boson polarization, color flow, top mass and top width in events with a top and anti-top quark pair ( tt ). An introduction to the LHC and the ATLAS detector is included and latest main results from this experiment. The contents include the current world benchmark results for the different properties and plans for future measurements during the ongoing LHC Run-II. (paper)

Experience running a distributed Tier-2 in Spain for the ATLAS experiment

International Nuclear Information System (INIS)

March, L; Hoz, S Gonzales de la; Kaci, M; Fassi, F; Fernandez, A; Lamas, A; Salt, J; Sanchez, J; Peso, J del; Fernandez, P; Munoz, L; Pardo, J; Espinal, X; Garitaonandia, H; Mir, M L; Nadal, J; Pacheco, A; Shuskov, S

2008-01-01

The main role of the Tier-2s is to provide computing resources for production of physics simulated events and distributed data analysis. The Spanish ATLAS Tier-2 is geographically distributed among three HEP institutes: IFAE (Barcelona), IFIC (Valencia) and UAM (Madrid). Currently it has a computing power of 430 kSI2K CPU, a disk storage capacity of 87 TB and a network bandwidth, connecting the three sites and the nearest Tier-1 (PIC), of 1 Gb/s. These resources will be increased according to the ATLAS Computing Model with time in parallel to those of all ATLAS Tier-2s. Since 2002, it has been participating into the different Data Challenge exercises. Currently, it is achieving around 1.5% of the whole ATLAS collaboration production in the framework of the Computing System Commissioning exercise. A distributed data management is also arising as an important issue in the daily activities of the Tier-2. The distribution in three sites has shown to be useful due to an increasing service redundancy, a faster solution of problems, the share of computing expertise and know-how. Experience gained running the distributed Tier-2 in order to be ready at the LHC start-up will be presented

Entwicklung und Anwendung bildgebender Verfahren für die Messung der elektrischen Feldstärke mit Hilfe der Lochbrennspektroskopie

OpenAIRE

Balzer, Herbert

2002-01-01

In der Arbeit wird ein neues bildgebendes Verfahren zur optischen Sensorik der elektrischen Feldstärke vorgestellt, das auf der laserspektroskopischen Methode des stabilen spektralen Lochbrennens beruht. Hierbei erfolgt die Bestimmung der Feldstärkeverteilung durch Messung der E-Feldinduzierten Änderung der Absorption im Zentrum eines stabilen spektralen Loches, das mit einem schmalbandigen Laser in das Absorptionsspektrum einer Sensorschicht, bestehend aus dem Polymer Polyvinylbutyral dotier...

ATLAS experience with HEP software at the Argonne leadership computing facility

International Nuclear Information System (INIS)

Uram, Thomas D; LeCompte, Thomas J; Benjamin, D

2014-01-01

A number of HEP software packages used by the ATLAS experiment, including GEANT4, ROOT and ALPGEN, have been adapted to run on the IBM Blue Gene supercomputers at the Argonne Leadership Computing Facility. These computers use a non-x86 architecture and have a considerably less rich operating environment than in common use in HEP, but also represent a computing capacity an order of magnitude beyond what ATLAS is presently using via the LCG. The status and potential for making use of leadership-class computing, including the status of integration with the ATLAS production system, is discussed.

ATLAS Experience with HEP Software at the Argonne Leadership Computing Facility

CERN Document Server

LeCompte, T; The ATLAS collaboration; Benjamin, D

2014-01-01

A number of HEP software packages used by the ATLAS experiment, including GEANT4, ROOT and ALPGEN, have been adapted to run on the IBM Blue Gene supercomputers at the Argonne Leadership Computing Facility. These computers use a non-x86 architecture and have a considerably less rich operating environment than in common use in HEP, but also represent a computing capacity an order of magnitude beyond what ATLAS is presently using via the LCG. The status and potential for making use of leadership-class computing, including the status of integration with the ATLAS production system, is discussed.

The C-RORC PCIe Card and its Application in the ALICE and ATLAS Experiments

CERN Document Server

Engel, H; Costa, F; Crone, G J; Eschweiler, D; Francis, D; Green, B; Joos, M; Kebschull, U; Kiss, T; Kugel, A; Panduro Vasquez, J G; Soos, C; Teixeira-Dias, P; Tremblet, L; Vande Vyvre, P; Vandelli, W; Vermeulen, J C; Werner, P; Wickens, F J

2015-01-01

The ALICE and ATLAS DAQ systems read out detector data via point-to-point serial links into custom hardware modules, the ALICE RORC and ATLAS ROBIN. To meet the increase in operational requirements both experiments are replacing their respective modules with a new common module, the C-RORC. This card, developed by ALICE, implements a PCIe Gen 2 x8 interface and interfaces to twelve optical links via three QSFP transceivers. This paper presents the design of the C-RORC, its performance and its application in the ALICE and ATLAS experiments.

Commissioning of the ATLAS Experiment

CERN Document Server

AUTHOR|(CDS)2069446

2008-01-01

The status of the commissioning of the ATLAS experiment as of May 2008 is presented. The subdetector integration in recent milestone weeks is described, especially the cosmic commissioning in milestone week M6, focusing on simultaneous running and combined track analysis of the muon detector and inner detector. The liquid argon and tile calorimeters have achieved near-full operation, and are integrated with the calorimeter trigger. The High-Level-Trigger infrastructure is installed and algorithms tested in technical runs. Problems with the inner detector cooling compressors are being fixed.

Concepts and Plans towards fast large scale Monte Carlo production for the ATLAS Experiment

CERN Document Server

Chapman, J; Duehrssen, M; Elsing, M; Froidevaux, D; Harrington, R; Jansky, R; Langenberg, R; Mandrysch, R; Marshall, Z; Ritsch, E; Salzburger, A

2014-01-01

The huge success of the physics program of the ATLAS experiment at the Large Hadron Collider (LHC) during run I relies upon a great number of simulated Monte Carlo events. This Monte Carlo production takes the biggest part of the computing resources being in use by ATLAS as of now. In this document we describe the plans to overcome the computing resource limitations for large scale Monte Carlo production in the ATLAS Experiment for run II, and beyond. A number of fast detector simulation, digitization and reconstruction techniques and are being discussed, based upon a new flexible detector simulation framework. To optimally benefit from these developments, a redesigned ATLAS MC production chain is presented at the end of this document.

The Social Content Strategy of the ATLAS Experiment

CERN Document Server

Sidoti, Antonio; The ATLAS collaboration

2018-01-01

Social media is an essential tool for communicating particle physics results to a wide audience. This presentation will explore how the nature of social media platforms has impacted the content being shared across them, and the subsequent effect this has had on the user experience. The ATLAS Experiment has adapted its communication strategy to match this social media evolution, producing content specifically targeting this emerging audience. The success of this approach is examined and the effect on user experience is evaluated.

Overview of recent results from the ATLAS experiment

CERN Document Server

Grabowska-Bold, Iwona; The ATLAS collaboration

2017-01-01

The heavy-ion program in the ATLAS experiment at the LHC originated as an extensive program to probe and characterize the hot, dense matter created in relativistic lead-lead collisions. In recent years, the program has also broadened to a detailed study of collective behavior in smaller systems. In particular, the techniques used to study larger systems are also applied to proton-proton and proton-lead collisions over a wide range of particle multiplicities, to try and understand the early-time dynamics which lead to similar flow-like features in all of the systems. Another recent development is a program studying ultra-peripheral collisions, which provide gamma-gamma and photonuclear processes over a wide range of CM energy, to probe the nuclear wavefunction. This talk presents the most recent results from the ATLAS experiment based on Run 1 and Run 2 data, including measurements of collectivity over a wide range of collision systems, potential nPDF modifications — using electroweak bosons, inclusive jets,...

The next generation PanDA Pilot for and beyond the ATLAS experiment

CERN Document Server

Nilsson, Paul; The ATLAS collaboration

2018-01-01

The Production and Distributed Analysis system (PanDA) is a pilot-based workload management system that was originally designed for the ATLAS Experiment at the LHC to operate on grid sites. Since the coming LHC data taking runs will require more resources than grid computing alone can provide, the various LHC experiments are engaged in an ambitious program to extend the computing model to include opportunistically used resources such as High Performance Computers (HPCs), clouds and volunteer computers. To this end, PanDA is being extended beyond grids and ATLAS to be used on the new types of resources as well as by other experiments. A new key component is being developed, the next generation PanDA Pilot (Pilot 2). Pilot 2 is a complete rewrite of the original PanDA Pilot which has been used in the ATLAS Experiment for over a decade. The new Pilot architecture follows a component-based approach which improves system flexibility, enables a clear workflow control, evolves the system according to modern function...

Calibrating the CERN ATLAS Experiment with $E/p$

CERN Document Server

Froeschl, R; Aleksa, M

2009-01-01

Inside the ATLAS experiment two proton beams will collide with a center of mass energy of 14 TeV. These proton beams will be delivered with unprecedented high collision rates by the Large Hadron Collider (LHC) at the European Center of Particle Physics, CERN. For important parts of the physics program of ATLAS, e.g. the search for the Higgs boson, the performance of the electromagnetic calorimeter, whose primary task is to measure the energy of electrons and photons, is crucial. The main topic of this thesis is the intercalibration of the energy scale of the electromagnetic calorimeter and the momentum scale of the inner detector. This is an important consistency test for these two detectors. The intercalibration is performed by investigating the ratio E/p for electrons, i.e. the ratio of the energy E measured by the electromagnetic calorimeter and the momentum p measured by the inner detector. The starting point is the Combined Test Beam (CTB) 2004, where a segment of the ATLAS detector was exposed to differ...

First Results from the Online Radiation Dose Monitoring System in ATLAS experiment

CERN Document Server

Mandić, I; The ATLAS collaboration; Deliyergiyev, M; Gorišek, A; Kramberger, G; Mikuž, M; Franz, S; Hartert, J; Dawson, I; Miyagawa, P S; Nicolas, L

2011-01-01

High radiation doses which will accumulate in components of ATLAS experiment during data taking will cause damage to detectors and readout electronics. It is therefore important to continuously monitor the doses to estimate the level of degradation caused by radiation. Online radiation monitoring system measures ionizing dose in SiO2 and fluences of 1-MeV(Si) equivalent neutrons and thermal neutrons at several locations in ATLAS detector. In this paper measurements collected during two years of ATLAS data taking are presented and compared to predictions from radiation background simulations.

Experiences with the new ATLAS Distributed Data Management System

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00214543; The ATLAS collaboration

2016-01-01

The ATLAS Distributed Data Management (DDM) system has evolved drastically in the last two years with the Rucio software fully replacing the previous system before the start of LHC Run-2. The ATLAS DDM system manages now more than 200 petabytes spread on 130 storage sites and can handle file transfer rates of up to 30Hz. In this talk, we discuss our experience acquired in developing, commissioning, running and maintaining such a large system. First, we describe the general architecture of the system, our integration with external services like the WLCG File Transfer Service and the evolution of the system over its first year of production. Then, we show the performance of the system, describe the integration of new technologies such as object stores, and outline future developments which mainly focus on performance and automation. Finally we discuss the long term evolution of ATLAS data management.

The zero degree calorimeter for the ATLAS experiment

International Nuclear Information System (INIS)

Leite, Marco

2009-01-01

Full text. The Zero Degree Calorimeter (ZDC) of the ATLAS experiment at the LHC will measure neutral particles (photons and neutrons) produced at very forward directions in heavy ions and low luminosity p + p collisions. While its main application will be the determination of the centrality of the heavy ions collisions and trigger integration in ATLAS, the design of the ZDC also provides many other interesting heavy ion physics possibilities, like the measurements of the direct flow (by directly measuring the reaction plane formed by the spectator neutrons transverse momentum), ultra-peripheral quarkonia photo-production etc. During low luminosity p+p runs, the ZDC will give valuable information about forward neutron and neutral mesons cross-section production at the LHC energies. The ZDC will also be used in independent luminosity measurements during the early stages of the LHC operation, helping to achieve a better understanding of the standard ATLAS luminosity monitor system (LUCID). The ZDC comprises two sampling calorimeter modules, symmetrically located along the beam line and each one separated 140m from the ATLAS interaction point. This is the region where the accelerator neutral beam absorbers are installed, and the ZDC is strategically inserted inside a slot in these absorbers, extending the ATLAS pseudo-rapidity calorimeter coverage to |η| > 8. Each ZDC module is divided in 4 sections: one electromagnetic followed by three hadronic sections. Built using Tungsten absorber blocs interspersed by quartz fibers for the sampling of the shower, each one of these modules provides energy measurements of the incident particles. The electromagnetic and the first hadronic section can also perform position measurements perpendicular to the projected beam direction due to their segmentation. Instrumenting this realm presents several challenges due to the extremely high radiation levels. To account for the large energy dynamic range (14 bits equivalent), a combination

Abdominal fat-evaluation by use of single scan computed tomography; Computertomographische Bestimmung des intraabdominellen Fettvolumens mittels Einschicht-Messung

Energy Technology Data Exchange (ETDEWEB)

Jacobi, V. [Klinikum der Johann-Wolfgang-Goethe-Univ., Frankfurt am Main (Germany). Inst. fuer Allgemeine Roentgendiagnostik; Steinkamp, M. [Klinikum der Johann-Wolfgang-Goethe-Univ., Frankfurt am Main (Germany). Inst. fuer Allgemeine Roentgendiagnostik; Kirchner, J. [Klinikum der Johann-Wolfgang-Goethe-Univ., Frankfurt am Main (Germany). Inst. fuer Allgemeine Roentgendiagnostik; Fischer, H. [Klinikum der Johann-Wolfgang-Goethe-Univ., Frankfurt am Main (Germany). 2. Medizinische Klinik; Diedrich, C.F. [Klinikum der Johann-Wolfgang-Goethe-Univ., Frankfurt am Main (Germany). 2. Medizinische Klinik; Kollath, J. [Klinikum der Johann-Wolfgang-Goethe-Univ., Frankfurt am Main (Germany). 2. Medizinische Klinik

1997-02-01

Purpose: Several studies emphasised the importance of the relationship between intraabdominal and total body adipose tissue as a risk factor for the development of metabolic or cardiovascular diseases. Therefore, the aim of the present study was to examine whether a single scan computed tomography is able to determine the whole intraabdominal fat volume with high accuracy and reproducibility. Materials and methods: Regions of interests (ROIs) were drawn manually for measuring intraabdominal fat in 51 unsuspicious abdominal CT. Results: The sexual differentiation of adipose tissue already described in a lot of studies could be confirmed in this study. Fat still predominates in females in lower half of the body (gynoid obesity). In men it predominates in the upper half (android obesity). Significant correlation concerning measuring the whole intraabdominal fat volume could be found in L1-level in women (r=0.992) and in L2-level in men (r=0.992). Measurement of a single scan enables us to assess whole intraabdominal fat volume due to a special formula. Conclusion: The determination of intraabdominal fat measured by a single scan computed tomography is a procedure associated with high accuracy and reproducibility. (orig.) [Deutsch] Ziel: Da in zahlreichen Studien hervorgehobene Bedeutung des intraabdominellen Fettgewebes gegenueber dem Gesamtkoerperfett als Risikofaktor fuer die Entwicklung metabolischer und kardiovaskulaerer Erkrankungen fordert ein Verfahren zur annaehernd exakten Bestimmung des intraabdominellen Fettgewebes. Ziel der vorliegenden Studie war zu pruefen, ob mit genuegender Genauigkeit die Verwendung einer Einschicht-Methode einen gezielten Einsatz der Computertomographie ermoeglicht und welche Lokalisation der zu waehlenden Schicht die aussagekraeftigste Messung ermoeglicht. Material und Methode: Anhand von 51 Computertomographien des Abdomens anderer Indikation (Normalbefunde) wurde das gesamte intraabdominelle Fettvolumen semiautomatisch mittels ROI-Messung

De-squeeze the beams: the TOTEM and ATLAS/ALFA experiments

CERN Multimedia

Stefania Pandolfi

2016-01-01

A special week-long proton–proton run with larger beam sizes at the interaction point is intended to probe the p-p elastic scattering regime at small angles.   Nicola Turini, deputy spokesperson for TOTEM, in front of one of the experiment’s ‘Roman Pot’ detectors in the LHC tunnel. (Photo: Maximilien Brice/CERN) Usually, the motto of the LHC is “maximum luminosity”. But for a few days per year, the LHC ignores its motto to run at very low luminosity for the forward experiments. This week, the LHC will provide the TOTEM and ATLAS/ALFA experiments with data for a broad physics programme. The TOTEM experiment at Point 5 and the ATLAS/ALFA experiment at Point 1 study the elastic scattering of protons, which are not observable in normal operation runs. In the elastic scattering process, the two protons survive their encounter intact and only change directions by exchanging momentum. To allow this special run, the operators play with the so-c...

MHD modeling of ATLAS experiments to study transverse shear interface interactions

CERN Document Server

Faehl, R J; Keinigs, R K; Lindemuth, I R

2001-01-01

Summary form only given. The transverse shear established at the interface of two solids moving at differential velocities on the order of the sound speed is being studied in experiments on the ATLAS capacitor bank at Los Alamos, beginning in August 2001. The ATLAS bank has finished certification tests and has demonstrated peak currents of 27.5 MA with a 5 microsecond risetime into an inductive load. One- and two-dimensional MHD calculations have been performed in support of these "friction-like" ATLAS experiments. Current flowing along the outer surface of a thick aluminum liner, roughly 8 mm thick, accelerates the solid liner to velocities ~1 km/s. This cylindrically imploding liner then impacts a target assembly, composed of alternating regions of high and low density materials. The different shock speeds in the two materials leads to a differential velocity along the interface. Shock heating, elastic- plastic flow, and stress transport are included in the calculations. Material strength properties are tre...

Production experience with the ATLAS Event Service

Science.gov (United States)

Benjamin, D.; Calafiura, P.; Childers, T.; De, K.; Guan, W.; Maeno, T.; Nilsson, P.; Tsulaia, V.; Van Gemmeren, P.; Wenaus, T.; ATLAS Collaboration

2017-10-01

The ATLAS Event Service (AES) has been designed and implemented for efficient running of ATLAS production workflows on a variety of computing platforms, ranging from conventional Grid sites to opportunistic, often short-lived resources, such as spot market commercial clouds, supercomputers and volunteer computing. The Event Service architecture allows real time delivery of fine grained workloads to running payload applications which process dispatched events or event ranges and immediately stream the outputs to highly scalable Object Stores. Thanks to its agile and flexible architecture the AES is currently being used by grid sites for assigning low priority workloads to otherwise idle computing resources; similarly harvesting HPC resources in an efficient back-fill mode; and massively scaling out to the 50-100k concurrent core level on the Amazon spot market to efficiently utilize those transient resources for peak production needs. Platform ports in development include ATLAS@Home (BOINC) and the Google Compute Engine, and a growing number of HPC platforms. After briefly reviewing the concept and the architecture of the Event Service, we will report the status and experience gained in AES commissioning and production operations on supercomputers, and our plans for extending ES application beyond Geant4 simulation to other workflows, such as reconstruction and data analysis.

Higgs boson results from the ATLAS experiment at LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00216944; The ATLAS collaboration

2017-01-01

This report highlights some of the latest results on the Higgs boson studies with the ATLAS experiment at the LHC, using proton-proton collision data at centre-of-mass energy of $\\sqrt {s} =$ 13~TeV collected during 2015 and 2016.

First operational experience with the positive-ion injector of ATLAS

Energy Technology Data Exchange (ETDEWEB)

Bollinger, L M; Pardo, R C; Shepard, K W; Bogaty, J M; Clifft, B E; Munson, F H; Zinkann, G [Argonne National Lab., IL (United States)

1993-04-15

The recently completed positive-ion injector for the heavy-ion accelerator ATLAS was designed as a replacement for the tandem injector of the present tandem-linac system and, unlike the tandem, the positive-ion injector is required to provide ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and initial experience in the acceleration of heavy-ion beams through the entire ATLAS system is discussed. The unusually good longitudinal beam quality of ATLAS with its new injector is emphasized. (orig.).

First operational experience with the positive-ion injector of ATLAS

International Nuclear Information System (INIS)

Bollinger, L.M.; Pardo, R.C.; Shepard, K.W.; Bogaty, J.M.; Clifft, B.E.; Munson, F.H.; Zinkann, G.

1992-01-01

The recently completed positive-ion injector for the heavy-ion accelerator ATLAS was designed as a replacement for the tandem injector of the present tandem-linac system and, unlike the tandem, the positive-ion injector is required to provide ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and initial experience in the acceleration of heavy-ion beams through the entire ATLAS system is discussed. The unusually good longitudinal beam quality of ATLAS with its new injector is emphasized

First operational experience with the positive-ion injector of ATLAS

Energy Technology Data Exchange (ETDEWEB)

Bollinger, L.M.; Pardo, R.C.; Shepard, K.W.; Bogaty, J.M.; Clifft, B.E.; Munson, F.H.; Zinkann, G.

1992-08-01

The recently completed positive-ion injector for the heavy-ion accelerator ATLAS was designed as a replacement for the tandem injector of the present tandem-linac system and, unlike the tandem, the positive-ion injector is required to provide ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and initial experience in the acceleration of heavy-ion beams through the entire ATLAS system is discussed. The unusually good longitudinal beam quality of ATLAS with its new injector is emphasized.

First operational experience with the positive-ion injector of ATLAS

Energy Technology Data Exchange (ETDEWEB)

Bollinger, L.M.; Pardo, R.C.; Shepard, K.W.; Bogaty, J.M.; Clifft, B.E.; Munson, F.H.; Zinkann, G.

1992-01-01

The recently completed positive-ion injector for the heavy-ion accelerator ATLAS was designed as a replacement for the tandem injector of the present tandem-linac system and, unlike the tandem, the positive-ion injector is required to provide ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and initial experience in the acceleration of heavy-ion beams through the entire ATLAS system is discussed. The unusually good longitudinal beam quality of ATLAS with its new injector is emphasized.

Modern SQL and NoSQL database technologies for the ATLAS experiment

CERN Document Server

Barberis, Dario; The ATLAS collaboration

2017-01-01

Structured data storage technologies evolve very rapidly in the IT world. LHC experiments, and ATLAS in particular, try to select and use these technologies balancing the performance for a given set of use cases with the availability, ease of use and of getting support, and stability of the product. We definitely and definitively moved from the “one fits all” (or “all has to fit into one”) paradigm to choosing the best solution for each group of data and for the applications that use these data. This paper describes the solutions in use, or under study, for the ATLAS experiment and their selection process and performance measurements.

Modern SQL and NoSQL database technologies for the ATLAS experiment

CERN Document Server

Barberis, Dario; The ATLAS collaboration

2017-01-01

Structured data storage technologies evolve very rapidly in the IT world. LHC experiments, and ATLAS in particular, try to select and use these technologies balancing the performance for a given set of use cases with the availability, ease of use and of getting support, and stability of the product. We definitely and definitively moved from the “one fits all” (or “all has to fit into one”) paradigm to choosing the best solution for each group of data and for the applications that use these data. This talk describes the solutions in use, or under study, for the ATLAS experiment and their selection process and performance.

Operational Experience with the ATLAS Pixel Detector at LHC

CERN Document Server

Keil, M

2013-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus crucial for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via front-end chips bump-bonded to 1744 n-on-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including calibration procedures, detector performance and measurements of radiation damage. The detector performance is excellent: more than 95% of the pixels are operational, noise occupancy and hit efficiency exceed the des...

DI-HIGGS RESULTS FROM THE ATLAS AND CMS EXPERIMENTS

CERN Document Server

Kagan, Michael; The ATLAS collaboration

2018-01-01

Measurements of di-Higgs production are of fundamental importance to understanding the process of electroweak symmetry breaking and the structure of the Higgs potential. While the Standard Model (SM) predicted production cross section for this process is too small to be observed by current LHC datasets, searches for this process at the ATLAS and CMS experiments can limit the SM production rate, anomalous Higgs self-couplings and Beyond the SM di-Higgs interaction vertices, and contributions to this process from new heavy resonances. Results from current experimental searches by ATLAS and CMS using data from Run 1 (2009- 2013) and Run 2 (2015-2018) of the LHC are presented.

ATLAS experiment : mapping the secrets of the universe

CERN Multimedia

ATLAS Outreach

2010-01-01

This 4 page color brochure describes ATLAS and the LHC, the ATLAS inner detector, calorimeters, muon spectrometer, magnet system, a short definition of the terms "particles," "dark matter," "mass," "antimatter." It also explains the ATLAS collaboration and provides the ATLAS website address with some images of the detector and the ATLAS collaboration at work.

Travel in the heart of matter: the Atlas experiment at CERN, pop-up book; Voyage au coeur de la matiere: l'experience Atlas au CERN, Livre anime

Energy Technology Data Exchange (ETDEWEB)

Sanders, Emma; Radevsky, Anton; Blanche, Eugenie

2011-12-01

This 'pop-up' book, fully illustrated, proposes a travel towards the birth of the universe through Atlas, one of the four particle physics experiments at the Large Hadron Collider at CERN (LHC). The ATLAS detector is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy. ATLAS will learn about the basic forces that have shaped our Universe since the beginning of time and that will determine its fate. Among the possible unknowns are the search for the Higgs boson, the origin of mass, the extra dimensions of space, the unification of fundamental forces, and evidence for dark matter candidates in the Universe

The ATLAS SCT: Commissioning experience and SLHC upgrade

Energy Technology Data Exchange (ETDEWEB)

Mitrevski, J. [Santa Cruz Institute for Particle Physics, University of California, Santa Cruz, CA 95064 (United States)], E-mail: Jovan.Mitrevski@cern.ch

2009-06-01

The ATLAS Semiconductor Tracker (SCT) has been installed, and fully connected to electrical, optical and cooling services. Commissioning has been performed both with calibration data and cosmic ray events. The cosmics were used to align the detector, measure the hit efficiency and set the timing. The SCT is now ready to take data when the LHC turns on this autumn. At the same time, it is clear that the present ATLAS tracker will need to be renewed for projected luminosity upgrade of the LHC, the SLHC. This is mainly driven by occupancy and radiation hardness issues. The new tracker will likely be entirely made of silicon, with the space of the present SCT largely taken up by detectors with much shorter strips. Several large-scale R and D projects on the sensors and module concepts for this upgrade are running, including sensor and module prototyping. We will report upon the commissioning experience from the SCT, use it to extract valuable lessons for future silicon tracker projects, and give an up-to-date overview of the status and results of the R and D efforts for the ATLAS tracker upgrade.

The ATLAS SCT: Commissioning experience and SLHC upgrade

International Nuclear Information System (INIS)

Mitrevski, J.

2009-01-01

The ATLAS Semiconductor Tracker (SCT) has been installed, and fully connected to electrical, optical and cooling services. Commissioning has been performed both with calibration data and cosmic ray events. The cosmics were used to align the detector, measure the hit efficiency and set the timing. The SCT is now ready to take data when the LHC turns on this autumn. At the same time, it is clear that the present ATLAS tracker will need to be renewed for projected luminosity upgrade of the LHC, the SLHC. This is mainly driven by occupancy and radiation hardness issues. The new tracker will likely be entirely made of silicon, with the space of the present SCT largely taken up by detectors with much shorter strips. Several large-scale R and D projects on the sensors and module concepts for this upgrade are running, including sensor and module prototyping. We will report upon the commissioning experience from the SCT, use it to extract valuable lessons for future silicon tracker projects, and give an up-to-date overview of the status and results of the R and D efforts for the ATLAS tracker upgrade.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00444174; The ATLAS collaboration

2015-01-01

Some recent searches for the Higgs boson in the context of beyond the Standard Model, performed by the ATLAS experiment are presented: high mass Higgs boson searches, lepton flavour violating Higgs decay, NMSSM, con- straint from the search for three photons. The interpretation based on the measurements of Higgs couplings are shown, along with the constraint on the Higgs boson invisible decays. Except the latter has some part using both full √s = 7 TeV and √s = 8 TeV data, the rest are performed with the √s = 8 TeV data of proton-proton collisions collected by the ATLAS experiment. No sig- nificant excess of data over the predicted background is observed in all those searches. Limits are placed in certain quantities depending on the searches.

Highlights from the ATLAS experiment at CERN LHC

CERN Document Server

Tsukerman, Ilya; The ATLAS collaboration

2018-01-01

Highlights from the ATLAS Experiment at the LHC are presented. Results shown are mostly based on the analysis of 2015-2016 year dataset which corresponds to the luminosity 36 inverse fb. Mainly recent measurements of Higgs boson production and decay are discussed while only summary of summaries is given for the SM processes, top production, SUSY and Exotics.

Experience commissioning the ATLAS distributed data management system on top of the WLCG service

International Nuclear Information System (INIS)

Campana, S

2010-01-01

The ATLAS experiment at CERN developed an automated system for distribution of simulated and detector data. Such system, which partially consists of various ATLAS specific services, strongly relies on the WLCG infrastructure, both at the level of middleware components, service deployment and operations. Because of the complexity of the system and its highly distributed nature, a dedicated effort was put in place to deliver a reliable service for ATLAS data distribution, offering the necessary performance, high availability and accommodating the main use cases. This contribution will describe the various challenges and activities carried on in 2008 for the commissioning of the system, together with the experience distributing simulated data and detector data. The main commissioning activity was concentrated in two Combined Computing Resource Challenges, in February and May 2008, where it was demonstrated that the WLCG service and the ATLAS system could sustain the peak load of data transfer according to the computing model, for several days in a row, concurrently with other LHC experiment activities. This dedicated effort led to the consequential improvements of ATLAS and WLCG services and to daily operation activities throughout the last year. The system has been delivering to WLCG tiers many hundreds of terabytes of simulated data and, since the summer of 2008, more than two petabytes of cosmic and beam data.

Charged Higgs boson searches and SemiConductor Tracker commissioning for the ATLAS experiment

CERN Document Server

Mohn, Bjarte Alsaker

The ATLAS (A Toroidal Lhc ApparatuS) experiment is one of four major experiments presently being installed at the upcoming Large Hadron Collider (LHC) at the European Centre for Nuclear Research (CERN) outside Geneva. In this thesis we present work done on both the simulation of the ATLAS physics potential for a charged Higgs boson and the construction of the Semiconductor Tracker (SCT) - a subdetector within the ATLAS Inner Detector. The discovery of a charged Higgs boson would be an unambiguous sign of physics beyond the Standard Model (SM) and it is thus of great interest to study the ATLAS potential for a charged Higgs discovery. Two such studies have been conducted for this thesis. In the first study a large-mass-splitting Minimal Supersymmetric Standard Model (MSSM) is assumed in which the charged Higgs boson decays into a W boson and a neutral Higgs may receive a large branching ratio.We conclude, however, that charged Higgs searches in this decay channel are made difficult by a large irreducible SM ba...

Primary Vertex Reconstruction at the ATLAS Experiment

CERN Document Server

Grimm, Kathryn; The ATLAS collaboration

2016-01-01

Efficient and precise reconstruction of the primary vertex in an LHC collision is essential in both the reconstruction of the full kinematic properties of a hard-scatter event and of soft interactions as a measure of the amount of pile-up. The reconstruction of primary vertices in the busy, high pile-up environment of Run-2 of the LHC is a challenging task. New methods have been developed by the ATLAS experiment to reconstruct vertices in such environments. Advances in vertex seeding include methods taken from medical imaging, which allow for reconstruction of multiple vertices with small spatial separation. The adoption of this new seeding algorithm within the ATLAS adaptive vertex finding and fitting procedure will be discussed, and the first results of the new techniques from Run-2 data will be presented. Additionally, data-driven methods to evaluate vertex resolution will be presented with special focus on correct methods to evaluate the effect of the beam spot constraint; results from these methods in Ru...

Experience from a pilot based system for ATLAS

International Nuclear Information System (INIS)

Nilsson, P

2008-01-01

The PanDA software provides a highly performing distributed production and distributed analysis system. It is the first system in the ATLAS experiment to use a pilot based late job delivery technique. This paper describes the architecture of the pilot system used in PanDA. Unique features have been implemented for high reliability automation in a distributed environment. Performance of PanDA is analyzed from one and a half years of experience of performing distributed computing on the Open Science Grid (OSG) infrastructure. Experience with pilot delivery mechanism using Condor-G, and a glide-in factory developed under OSG will be described

Role Based Access Control system in the ATLAS experiment

CERN Document Server

Valsan, M L; The ATLAS collaboration; Lehmann Miotto, G; Scannicchio, D A; Schlenker, S; Filimonov, V; Khomoutnikov, V; Dumitru, I; Zaytsev, A S; Korol, A A; Bogdantchikov, A; Caramarcu, C; Ballestrero, S; Darlea, G L; Twomey, M; Bujor, F; Avolio, G

2011-01-01

The complexity of the ATLAS experiment motivated the deployment of an integrated Access Control System in order to guarantee safe and optimal access for a large number of users to the various software and hardware resources. Such an integrated system was foreseen since the design of the infrastructure and is now central to the operations model. In order to cope with the ever growing needs of restricting access to all resources used within the experiment, the Roles Based Access Control (RBAC) previously developed has been extended and improved. The paper starts with a short presentation of the RBAC design, implementation and the changes made to the system to allow the management and usage of roles to control access to the vast and diverse set of resources. The paper continues with a detailed description of the integration across all areas of the system: local Linux and Windows nodes in the ATLAS Control Network (ATCN), the Linux application gateways offering remote access inside ATCN, the Windows Terminal Serv...

Role Based Access Control System in the ATLAS Experiment

CERN Document Server

Valsan, M L; The ATLAS collaboration; Lehmann Miotto, G; Scannicchio, D A; Schlenker, S; Filimonov, V; Khomoutnikov, V; Dumitru, I; Zaytsev, A S; Korol, A A; Bogdantchikov, A; Avolio, G; Caramarcu, C; Ballestrero, S; Darlea, G L; Twomey, M; Bujor, F

2010-01-01

The complexity of the ATLAS experiment motivated the deployment of an integrated Access Control System in order to guarantee safe and optimal access for a large number of users to the various software and hardware resources. Such an integrated system was foreseen since the design of the infrastructure and is now central to the operations model. In order to cope with the ever growing needs of restricting access to all resources used within the experiment, the Roles Based Access Control (RBAC) previously developed has been extended and improved. The paper starts with a short presentation of the RBAC design, implementation and the changes made to the system to allow the management and usage of roles to control access to the vast and diverse set of resources. The paper continues with a detailed description of the integration across all areas of the system: local Linux and Windows nodes in the ATLAS Control Network (ATCN), the Linux application gateways offering remote access inside ATCN, the Windows Terminal Serv...

Comparison calculation/experiment on the load case ``shutdown of TH high pressure pumps under consideration of fluid structure interaction``; Vergleich Rechnung/Messung zum Lastfall ``Abschaltung der TH-Hochdruckpumpen unter Beruecksichtigung der Fluid-Struktur-Wechselwirkung``

Energy Technology Data Exchange (ETDEWEB)

Erath, W.; Nowotny, B.; Maetz, J. [KED, Rodenbach (Germany)

1998-11-01

Measurements of an experiment in a pipe system with pump shutdown and valve closing have been performed in the nuclear power plant KRB II. Comparative calculations of fluid and structure including interaction show an excellent agreement with the measured results. Theory and implementation of the fluid/structure interaction and the results of the comparison are described. It turns out that the consideration of the fluid/structure interaction is mostly a significant increase of the effective structural damping. (orig.) [Deutsch] Es wurden Messungen am nuklearen Nachkuehlsystem des Kernkraftwerks Gundremmingen (KRB II) bei einem Versuche mit Pumpenabschalten und Ventilschliessen durchgefuehrt. Vergleichsrechnungen der Fluid-Strukturdynamik unter echter Beruecksichtigung der Wechselwirkung ergaben eine ausgezeichnete Uebereinstimmung der Rechnung mit den Messungen. Es werden Theorie und Implementierung der Koppelung der Fluid- und Struktur-Berechnungen sowie die Vergleiche von Messung und Rechnung beschrieben. Es ergibt sich, dass die Beruecksichtigung der Wechselwirkung notwendig ist zur genaueren Berechnung von `weichen` Rohrleitungsystemen. Eine wichtige Folge der Wechselwirkung ist meist eine deutliche Erhoehung der effektiven Strukturdaempfung. (orig.)

The forward Detectors of the ATLAS experiment

CERN Document Server

Vittori, Camilla; The ATLAS collaboration

2017-01-01

In this poster, a review of the ATLAS forward detectors operating in the 2015-2016 data taking is given. This includes a description of LUCID, the preferred ATLAS luminosity provider; of the ALFA detector, aimed to measure elastically scattered protons at small angle for the total proton-proton cross section measurement; of the ATLAS Forward Proton project AFP, which was partially installed and took the first data in 2015, and of the Zero Degree Calorimeter ZDC built for the ATLAS Heavy Ions physics program. The near future plans for these detectors will also be addressed.

Enabling the ATLAS Experiment at the LHC for High Performance Computing

CERN Document Server

AUTHOR|(CDS)2091107; Ereditato, Antonio

In this thesis, I studied the feasibility of running computer data analysis programs from the Worldwide LHC Computing Grid, in particular large-scale simulations of the ATLAS experiment at the CERN LHC, on current general purpose High Performance Computing (HPC) systems. An approach for integrating HPC systems into the Grid is proposed, which has been implemented and tested on the „Todi” HPC machine at the Swiss National Supercomputing Centre (CSCS). Over the course of the test, more than 500000 CPU-hours of processing time have been provided to ATLAS, which is roughly equivalent to the combined computing power of the two ATLAS clusters at the University of Bern. This showed that current HPC systems can be used to efficiently run large-scale simulations of the ATLAS detector and of the detected physics processes. As a first conclusion of my work, one can argue that, in perspective, running large-scale tasks on a few large machines might be more cost-effective than running on relatively small dedicated com...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Keil, M; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC and its status after three years of operation will be presented, including calibration procedures, timing optimization and detector performance. The detector performance is excellent: ~96 % of the pixels are operational, noise occupancy and hit efficiency e...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Keil, M; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Hirschbuehl, D; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.7% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Lapoire, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Lapoire, C; The ATLAS collaboration

2012-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as B-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures and detector performance. The detector performance is excellent: 96.2% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification.

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Keil, M

2012-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper results from the successful operation of the Pixel Detector at the LHC will be presented, including calibration procedures, timing optimization and detector performance. The detector performance is excellent: approximately 97% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Ince, T; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 96.8% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational experience with the ATLAS Pixel detector at the LHC

CERN Document Server

Deluca, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this paper, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5\\% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, ...

Operational Experience with the ATLAS Pixel Detector at the LHC

CERN Document Server

Lange, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump- bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, a...

Operational experience with the ATLAS Pixel detector at the LHC

CERN Document Server

Deluca, C; The ATLAS collaboration

2011-01-01

The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN, providing high-resolution measurements of charged particle tracks in the high radiation environment close to the collision region. This capability is vital for the identification and measurement of proper decay times of long-lived particles such as b-hadrons, and thus vital for the ATLAS physics program. The detector provides hermetic coverage with three cylindrical layers and three layers of forward and backward pixel detectors. It consists of approximately 80 million pixels that are individually read out via chips bump-bonded to 1744 n-in-n silicon substrates. In this talk, results from the successful operation of the Pixel Detector at the LHC will be presented, including monitoring, calibration procedures, timing optimization and detector performance. The detector performance is excellent: 97,5% of the pixels are operational, noise occupancy and hit efficiency exceed the design specification, an...

Operational Experience of the ATLAS SemiConductor Tracker and Pixel Detector

CERN Document Server

Robinson, Dave; The ATLAS collaboration

2016-01-01

The tracking performance of the ATLAS detector relies critically on the silicon and gaseous tracking subsystems that form the ATLAS Inner Detector. Those subsystems have undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the LHC during Run2. The key status and performance metrics of the Pixel Detector and the Semi Conductor Tracker are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency are described.

The positive-ion injector of ATLAS: design and operating experience

Energy Technology Data Exchange (ETDEWEB)

Bollinger, L M [Physics Div., Argonne National Lab., IL (United States); Pardo, R C [Physics Div., Argonne National Lab., IL (United States); Shepard, K W [Physics Div., Argonne National Lab., IL (United States); Billquist, P J [Physics Div., Argonne National Lab., IL (United States); Bogaty, J M [Physics Div., Argonne National Lab., IL (United States); Clifft, B E [Physics Div., Argonne National Lab., IL (United States); Harkewicz, R [Physics Div., Argonne National Lab., IL (United States); Munson, F H [Physics Div., Argonne National Lab., IL (United States); Nolen, J A [Physics Div., Argonne National Lab., IL (United States); Zinkann, G P [Physics Div., Argonne National Lab., IL (United States)

1993-06-01

The recently completed positive-ion injector for the heavy-ion accelerator ATLAS is a replacement for the tandem injector of the present tandem-linac system. Unlike the tandem, the new injector provides ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and experience in the operation of ATLAS with its new injector is discussed. (orig.)

The positive-ion injector of ATLAS: Design and operating experience

International Nuclear Information System (INIS)

Bollinger, L.M.; Pardo, R.C.; Shepard, K.W.; Billquist, P.J.; Bogaty, J.M.; Clifft, B.E.; Harkewicz, R.; Munson, F.H.; Nolen, J.A.; Zinkann, G.P.

1992-01-01

The recently completed Positive-Ion Injector for the heavy-ion accelerator ATLAS is a replacement for the tandem injector of the present tandem-linac system. Unlike the tandem, the new injector provides ions from the full range of the periodic table. The concept for the new injector, which consists of an ECR ion source on a voltage platform coupled to a very-low-velocity superconducting linac, introduces technical problems and uncertainties that are well beyond those encountered previously for superconducting linacs. The solution to these problems and their relationship to performance are outlined, and experience in the operation of ATLAS with its new injector is discussed

Operational experience of the ATLAS accelerator

Energy Technology Data Exchange (ETDEWEB)

Den Hartog, P K; Bogaty, J M; Bollinger, L M; Clifft, B E; Craig, S L; Harden, R E; Markovich, P; Munson, F H; Nixon, J M; Pardo, R C; Phillips, D R; Shepard, K W; Tilbrook, I R; Zinkmann, G P [Argonne National Lab., IL (USA). Physics Div.

1990-02-01

The ATLAS accelerator consists of a HVEC model FN tandem accelerator injecting into a linac of independently-phased niobium superconducting resonators. The accelerator provides beams with masses 6 {le} A {le} 127 and with energies ranging up to 20 MeV/A for the lightest ions and 4 MeV/A for the heaviest ions. Portions of the linac have been in operation since 1978 and, over the last decade, more than 35000 h of operating experience have been accumulated. The long-term stability of niobium resonators, and their feasibility for use in heavy-ion accelerators is now well established. (orig.).

ATLAS Virtual Visits bringing the world into the ATLAS control room

CERN Document Server

AUTHOR|(CDS)2051192; The ATLAS collaboration; Yacoob, Sahal

2016-01-01

ATLAS Virtual Visits is a project initiated in 2011 for the Education & Outreach program of the ATLAS Experiment at CERN. Its goal is to promote public appreciation of the LHC physics program and particle physics, in general, through direct dialogue between ATLAS physicists and remote audiences. A Virtual Visit is an IP-based videoconference, coupled with a public webcast and video recording, between ATLAS physicists and remote locations around the world, that typically include high school or university classrooms, Masterclasses, science fairs, or other special events, usually hosted by collaboration members. Over the past two years, more than 10,000 people, from all of the world’s continents, have actively participated in ATLAS Virtual Visits, with many more enjoying the experience from the publicly available webcasts and recordings. We present an overview of our experience and discuss potential development for the future.

PanDA: Exascale Federation of Resources for the ATLAS Experiment at the LHC

Directory of Open Access Journals (Sweden)

Megino Fernando Barreiro

2016-01-01

The PanDA (Production and Distributed Analysis system was developed in 2005 for the ATLAS experiment on top of this heterogeneous infrastructure to seamlessly integrate the computational resources and give the users the feeling of a unique system. Since its origins, PanDA has evolved together with upcoming computing paradigms in and outside HEP, such as changes in the networking model, Cloud Computing and HPC. It is currently running steadily up to 200 thousand simultaneous cores (limited by the available resources for ATLAS, up to two million aggregated jobs per day and processes over an exabyte of data per year. The success of PanDA in ATLAS is triggering the widespread adoption and testing by other experiments. In this contribution we will give an overview of the PanDA components and focus on the new features and upcoming challenges that are relevant to the next decade of distributed computing workload management using PanDA.

Atlas Pulsed Power Facility for High Energy Density Physics Experiments

International Nuclear Information System (INIS)

Miller, R.B.; Ballard, E.O.; Barr, G.W.; Bowman, D.W.; Chochrane, J.C.; Davis, H.A.; Elizondo, J.M.; Gribble, R.F.; Griego, J.R.; Hicks, R.D.; Hinckley, W.B.; Hosack, K.W.; Nielsen, K.E.; Parker, J.V.; Parsons, M.O.; Rickets, R.L.; Salazar, H.R.; Sanchez, P.G.; Scudder, D.W.; Shapiro, C.; Thompson, M.C.; Trainor, R.J.; Valdez, G.A.; Vigil, B.N.; Watt, R.G.; Wysock, F.J.

1999-01-01

The Atlas facility, now under construction at Los Alamos National Laboratory (LANL), will provide a unique capability for performing high-energy-density experiments in support of weapon-physics and basic-research programs. It is intended to be an international user facility, providing opportunities for researchers from national laboratories and academic institutions around the world. Emphasizing institutions around the world. Emphasizing hydrodynamic experiments, Atlas will provide the capability for achieving steady shock pressures exceeding 10-Mbar in a volume of several cubic centimeters. In addition, the kinetic energy associated with solid liner implosion velocities exceeding 12 km/s is sufficient to drive dense, hydrodynamic targets into the ionized regime, permitting the study of complex issues associated with strongly-coupled plasmas. The primary element of Atlas is a 23-MJ capacitor bank, comprised of 96 separate Marx generators housed in 12 separate oil-filled tanks, surrounding a central target chamber. Each tank will house two, independently-removable maintenance units, with each maintenance unit consisting of four Marx modules. Each Marx module has four capacitors that can each be charged to a maximum of 60 kilovolts. When railgap switches are triggered, the marx modules erect to a maximum of 240 kV. The parallel discharge of these 96 Marx modules will deliver a 30-MA current pulse with a 4-5-micros risetime to a cylindrical, imploding liner via 24 vertical, tri-plate, oil-insulated transmission lines. An experimental program for testing and certifying all Marx and transmission line components has been completed. A complete maintenance module and its associated transmission line (the First Article) are now under construction and testing. The current Atlas schedule calls for construction of the machine to be complete by August, 2000. Acceptance testing is scheduled to begin in November, 2000, leading to initial operations in January, 2001

Primary vertex reconstruction at the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00301388; The ATLAS collaboration; Casper, D.; Hooberman, B.; Gui, B.; Lee, G.; Maurer, J.; Morley, A.; Pagan Griso, S.; Petersen, B.; Prokofiev, K.; Shan, L.; Shope, D.; Wharton, A.; Whitmore, B.; Zhang, M.

2017-01-01

These proceedings present the method and performance of primary vertex reconstruction at the ATLAS experiment during Runs 1 and 2 at the LHC. The studies presented focus on data taken during 2012 at a centre-of-mass energy of $\\sqrt{s} = 8$ TeV, and during 2015-2016 at $\\sqrt{s} = 13$ TeV. Some predictions toward future runs are also presented. The measurement of the position and size of the luminous region and its use as a constraint to improve the primary vertex resolution are discussed.

Online radiation dose measurement system for ATLAS experiment

International Nuclear Information System (INIS)

Mandic, I.; Cindro, V.; Dolenc, I.; Gorisek, A.; Kramberger, G.; Mikuz, M.; Bronner, J.; Hartet, J.; Franz, S.

2009-01-01

In experiments at Large Hadron Collider, detectors and electronics will be exposed to high fluxes of photons, charged particles and neutrons. Damage caused by the radiation will influence performance of detectors. It will therefore be important to continuously monitor the radiation dose in order to follow the level of degradation of detectors and electronics and to correctly predict future radiation damage. A system for online radiation monitoring using semiconductor radiation sensors at large number of locations has been installed in the ATLAS experiment. Ionizing dose in SiO 2 will be measured with RadFETs, displacement damage in silicon in units of 1-MeV(Si) equivalent neutron fluence with p-i-n diodes. At 14 monitoring locations where highest radiation levels are expected the fluence of thermal neutrons will be measured from current gain degradation in dedicated bipolar transistors. The design of the system and tests of its performance in mixed radiation field is described in this paper. First results from this test campaign confirm that doses can be measured with sufficient sensitivity (mGy for total ionizing dose measurements, 10 9 n/cm 2 for NIEL (non-ionizing energy loss) measurements, 10 12 n/cm 2 for thermal neutrons) and accuracy (about 20%) for usage in the ATLAS detector

Conditions and configuration metadata for the ATLAS experiment

International Nuclear Information System (INIS)

Gallas, E J; Pachal, K E; Tseng, J C L; Albrand, S; Fulachier, J; Lambert, F; Zhang, Q

2012-01-01

In the ATLAS experiment, a system called COMA (Conditions/Configuration Metadata for ATLAS), has been developed to make globally important run-level metadata more readily accessible. It is based on a relational database storing directly extracted, refined, reduced, and derived information from system-specific database sources as well as information from non-database sources. This information facilitates a variety of unique dynamic interfaces and provides information to enhance the functionality of other systems. This presentation will give an overview of the components of the COMA system, enumerate its diverse data sources, and give examples of some of the interfaces it facilitates. We list important principles behind COMA schema and interface design, and how features of these principles create coherence and eliminate redundancy among the components of the overall system. In addition, we elucidate how interface logging data has been used to refine COMA content and improve the value and performance of end-user reports and browsers.

Conditions and configuration metadata for the ATLAS experiment

CERN Document Server

Gallas, E J; Albrand, S; Fulachier, J; Lambert, F; Pachal, K E; Tseng, J C L; Zhang, Q

2012-01-01

In the ATLAS experiment, a system called COMA (Conditions/Configuration Metadata for ATLAS), has been developed to make globally important run-level metadata more readily accessible. It is based on a relational database storing directly extracted, refined, reduced, and derived information from system-specific database sources as well as information from non-database sources. This information facilitates a variety of unique dynamic interfaces and provides information to enhance the functionality of other systems. This presentation will give an overview of the components of the COMA system, enumerate its diverse data sources, and give examples of some of the interfaces it facilitates. We list important principles behind COMA schema and interface design, and how features of these principles create coherence and eliminate redundancy among the components of the overall system. In addition, we elucidate how interface logging data has been used to refine COMA content and improve the value and performance of end-user...

Requirements for a Next Generation Framework: ATLAS Experience

CERN Document Server

Kama, Sami; The ATLAS collaboration

2015-01-01

The challenge faced by HEP experiments from the current and expected architectural evolution of CPUs and co-processors is how to successfully exploit concurrency and keep memory consumption within reasonable limits. This is a major change from frameworks which were designed for serial event processing on single core processors in the 2000s. ATLAS has recently considered this problem in some detail through its Future Frameworks Requirements group. Here we report on the major considerations of the group, which was charged with considering the best strategies to exploit current and anticipated CPU technologies. The group has re-examined the basic architecture of event processing and considered how the building blocks of a framework (algorithms, services, tools and incidents) should evolve. The group has also had to take special care to ensure that the use cases of the ATLAS high level trigger are encompassed, which differ in important ways from offline event processing (for example, 99% of events are rejected, w...

Online Radiation Dose Measurement System for ATLAS experiment

CERN Document Server

Mandić, I; The ATLAS collaboration

2012-01-01

Particle detectors and readout electronics in the high energy physics experiment ATLAS at the Large Hadron Collider at CERN operate in radiation field containing photons, charged particles and neutrons. The particles in the radiation field originate from proton-proton interactions as well as from interactions of these particles with material in the experimental apparatus. In the innermost parts of ATLAS detector components will be exposed to ionizing doses exceeding 100 kGy. Energetic hadrons will also cause displacement damage in silicon equivalent to fluences of several times 10e14 1 MeV-neutrons per cm2. Such radiation doses can have severe influence on the performance of detectors. It is therefore very important to continuously monitor the accumulated doses to understand the detector performance and to correctly predict the lifetime of radiation sensitive components. Measurements of doses are important also to verify the simulations and represent a crucial input into the models used for predicting future ...

New data access with HTTP/WebDAV in the ATLAS experiment

CERN Document Server

Elmsheuser, Johannes; The ATLAS collaboration; Serfon, Cedric; Garonne, Vincent; Blunier, Sylvain; Lavorini, Vincenzo; Nilsson, Paul

2015-01-01

With the exponential growth of LHC (Large Hadron Collider) data in the years 2010-2012, distributed computing has become the established way to analyze collider data. The ATLAS experiment Grid infrastructure includes more than 130 sites worldwide, ranging from large national computing centres to smaller university clusters. So far the storage technologies and access protocols to the clusters that host this tremendous amount of data vary from site to site. HTTP/WebDAV offers the possibility to use a unified industry standard to access the storage. We present the deployment and testing of HTTP/WebDAV for local and remote data access in the ATLAS experiment for the new data management system Rucio and the PanDA workload management system. Deployment and large scale tests have been performed using the Grid testing system HammerCloud and the ROOT HTTP plugin Davix.

New data access with HTTP/WebDAV in the ATLAS experiment

CERN Document Server

Elmsheuser, Johannes; The ATLAS collaboration; Serfon, Cedric; Garonne, Vincent; Blunier, Sylvain; Lavorini, Vincenzo; Nilsson, Paul

2015-01-01

With the exponential growth of LHC (Large Hadron Collider) data in the years 2010-2012, distributed computing has become the established way to analyse collider data. The ATLAS experiment Grid infrastructure includes more than 130 sites worldwide, ranging from large national computing centres to smaller university clusters. So far the storage technologies and access protocols to the clusters that host this tremendous amount of data vary from site to site. HTTP/WebDAV offers the possibility to use a unified industry standard to access the storage. We present the deployment and testing of HTTP/WebDAV for local and remote data access in the ATLAS experiment for the new data management system Rucio and the PanDA workload management system. Deployment and large scale tests have been performed using the Grid testing system HammerCloud and the ROOT HTTP plugin Davix.

The Evolution of the Trigger and Data Acquisition System in the ATLAS Experiment

CERN Document Server

Garelli, N; The ATLAS collaboration

2014-01-01

The ATLAS experiment, aimed at recording the results of LHC proton-proton collisions, is upgrading its Trigger and Data Acquisition (TDAQ) system during the current LHC first long shutdown. The purpose of such upgrade is to add robustness and flexibility to the selection and the conveyance of the physics data, simplify the maintenance of the infrastructure, exploit new technologies and, overall, make ATLAS data-taking capable of dealing with increasing event rates. \

Expected performance of the upgrade ATLAS experiment for HL-LHC

CERN Document Server

Liu, Peilian; The ATLAS collaboration

2018-01-01

The Large Hadron Collider (LHC) has been successfully delivering proton-proton collision data at the unprecedented center of mass energy of 13 TeV. An upgrade is planned to increase the instantaneous luminosity delivered by the LHC in what is called the HL-LHC, aiming to deliver a total of up 3000/fb to 4000/fb of data per experiment. To cope with the expected data-taking conditions ATLAS is planning major upgrades of the detector. It is now a critical time for these upgrade projects and during the last year and a half, six Technical Design Reports (TDR) were produced by the ATLAS Collaboration. In these TDRs the physics motivation and benefits of such upgrades are discussed together with details on the upgrade project itself. In this contribution we review the expected performance of the upgraded ATLAS detector and the expected reach for physics measurements as well as the discovery potential for new physics that is expected by the end of the HL-LHC data-taking. The performance of object reconstruction under...

Muon Event Filter Software for the ATLAS Experiment at LHC

CERN Document Server

Biglietti, M; Assamagan, Ketevi A; Baines, J T M; Bee, C P; Bellomo, M; Bogaerts, J A C; Boisvert, V; Bosman, M; Caron, B; Casado, M P; Cataldi, G; Cavalli, D; Cervetto, M; Comune, G; Conde, P; Conde-Muíño, P; De Santo, A; De Seixas, J M; Di Mattia, A; Dos Anjos, A; Dosil, M; Díaz-Gómez, M; Ellis, Nick; Emeliyanov, D; Epp, B; Falciano, S; Farilla, A; George, S; Ghete, V M; González, S; Grothe, M; Kabana, S; Khomich, A; Kilvington, G; Konstantinidis, N P; Kootz, A; Lowe, A; Luminari, L; Maeno, T; Masik, J; Meessen, C; Mello, A G; Merino, G; Moore, R; Morettini, P; Negri, A; Nikitin, N V; Nisati, A; Padilla, C; Panikashvili, N; Parodi, F; Pinfold, J L; Pinto, P; Primavera, M; Pérez-Réale, V; Qian, Z; Resconi, S; Rosati, S; Santamarina-Rios, C; Scannicchio, D A; Schiavi, C; Segura, E; Sivoklokov, S Yu; Soluk, R A; Stefanidis, E; Sushkov, S; Sutton, M; Sánchez, C; Tapprogge, Stefan; Thomas, E; Touchard, F; Venda-Pinto, B; Ventura, A; Vercesi, V; Werner, P; Wheeler, S; Wickens, F J; Wiedenmann, W; Wielers, M; Zobernig, G; Computing In High Energy Physics

2005-01-01

At LHC the 40 MHz bunch crossing rate dictates a high selectivity of the ATLAS Trigger system, which has to keep the full physics potential of the experiment in spite of a limited storage capability. The level-1 trigger, implemented in a custom hardware, will reduce the initial rate to 75 kHz and is followed by the software based level-2 and Event Filter, usually referred as High Level Triggers (HLT), which further reduce the rate to about 100 Hz. In this paper an overview of the implementation of the offline muon recostruction algortihms MOORE (Muon Object Oriented REconstruction) and MuId (Muon Identification) as Event Filter in the ATLAS online framework is given. The MOORE algorithm performs the reconstruction inside the Muon Spectrometer providing a precise measurement of the muon track parameters outside the calorimeters; MuId combines the measurements of all ATLAS sub-detectors in order to identify muons and provides the best estimate of their momentum at the production vertex. In the HLT implementatio...

Operational experience of the ATLAS accelerator

International Nuclear Information System (INIS)

Den Hartog, P.K.; Bogaty, J.M.; Bollinger, L.M.

1989-01-01

The ATLAS accelerator consists of a HVEC model FN tandem accelerator injecting into a linac of independently-phased niobium superconducting resonators. The accelerator provides beams with masses from 6≤A≤127 and with energies ranging up to 20 MeV/A for the lightest ions and 4 MeV/A for the heaviest ions. Portions of the linac have been in operation since 1978 and, over the last decade, more than 35,000 hours of operating experience have been accumulated. The long-term stability of niobium resonators, and their feasibility for use in heavy-ion accelerators is now well established. 11 refs., 3 figs., 1 tab

Early 13 TeV Results from the ATLAS Experiment

CERN Multimedia

CERN. Geneva

2015-01-01

The ATLAS experiment has recorded almost 200 pb-1 of collision data at 13 TeV centre-of-mass energy. The seminar presents the status of the data taking, the commissioning of the event reconstruction, focusing on the key techniques that have allowed to quickly reach a good understanding of the basic physics objects, and early physics results.

C++ Software Quality in the ATLAS Experiment: Tools and Experience

CERN Document Server

Kluth, Stefan; The ATLAS collaboration; Obreshkov, Emil; Roe, Shaun; Seuster, Rolf; Snyder, Scott; Stewart, Graeme

2016-01-01

The ATLAS experiment at CERN uses about six million lines of code and currently has about 420 developers whose background is largely from physics. In this paper we explain how the C++ code quality is managed using a range of tools from compile-time through to run time testing and reflect on the great progress made in the last year largely through the use of static analysis tools such as Coverity®, an industry-standard tool which enables quality comparison with general open source C++ code. Other tools including cppcheck, Include-What-You-Use and run-time 'sanitizers' are also discussed.

Experience with using unfolding procedures in ATLAS

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00407321; The ATLAS collaboration

2016-01-01

In the ATLAS experiment, several unfolding methods are used to correct experimental measurements for detector effects, like acceptance and resolution. These methods use as input the raw experimental distributions, as well as Monte Carlo simulation for the description of the detector effects. The systematic uncertainties associated to the various unfolding methods are evaluated. The statistical and systematic uncertainties affecting the raw measurements and/or the simulation are propagated through the unfolding procedure. The resulting corrected measurements with their uncertainties can be directly compared with the corresponding theoretical predictions.

FTK: The hardware Fast TracKer of the ATLAS experiment at CERN

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00525014; The ATLAS collaboration

2017-01-01

In the ever increasing pile-up of the Large Hadron Collider environment the trigger systems of the experiments have to be exceedingly sophisticated and fast at the same time in order to increase the rate of relevant physics processes with respect to background processes. The Fast TracKer (FTK) is a track finding implementation at hardware level that is designed to deliver full-scan tracks with $p_{T}$ above 1GeV to the ATLAS trigger system for every L1 accept (at a maximum rate of 100kHz). To accomplish this, FTK is a highly parallel system which is currently under installation in ATLAS. It will first provide the trigger system with tracks in the central region of the ATLAS detector, and next year it is expected that it will cover the whole detector. The system is based on pattern matching between hits coming from the silicon trackers of the ATLAS detector and 1 billion simulated patterns stored in specially designed ASIC chips (Associative Memory – AM06). In a first stage, coarse resolution hits are matche...

Experiences with the new ATLAS Distributed Data Management System

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00214543; The ATLAS collaboration; Serfon, Cedric; Barisits, Martin-Stefan; Lassnig, Mario; Beermann, Thomas; Guan, Wen

2017-01-01

The ATLAS Distributed Data Management (DDM) system has evolved drastically in the last two years with the Rucio software fully replacing the previous system before the start of LHC Run-2. The ATLAS DDM system manages now more than 250 petabytes spread on 130 storage sites and can handle file transfer rates of up to 30Hz. In this paper, we discuss our experience acquired in developing, commissioning, running and maintaining such a large system. First, we describe the general architecture of the system, our integration with external services like the WLCG File Transfer Service and the evolution of the system over its first years of production. Then, we show the performance of the system, describe the integration of new technologies such as object stores, and outline some new developments, which mainly focus on performance and automation.

The physics analysis tools project for the ATLAS experiment

International Nuclear Information System (INIS)

Lenzi, Bruno

2012-01-01

The Large Hadron Collider is expected to start colliding proton beams in 2009. The enormous amount of data produced by the ATLAS experiment (≅1 PB per year) will be used in searches for the Higgs boson and Physics beyond the standard model. In order to meet this challenge, a suite of common Physics Analysis Tools has been developed as part of the Physics Analysis software project. These tools run within the ATLAS software framework, ATHENA, covering a wide range of applications. There are tools responsible for event selection based on analysed data and detector quality information, tools responsible for specific physics analysis operations including data quality monitoring and physics validation, and complete analysis tool-kits (frameworks) with the goal to aid the physicist to perform his analysis hiding the details of the ATHENA framework. (authors)

ATLAS Forward Proton (AFP) time-of-flight (ToF) detector: construction & existing experiences

CERN Document Server

Sykora, Tomas; The ATLAS collaboration

2018-01-01

In 2017 the ATLAS collaboration successfully completed the installation of the ATLAS Forward Proton (AFP) detector to measure diffractive protons leaving under very small angles (hundreds of micro radians) the ATLAS proton-proton interaction point. The AFP tags and measures forward protons scattered in single diffraction or hard central diffraction, where two protons are emitted and a central system is created. In addition, the AFP has a potential to measure two-photon exchange processes, and to be sensitive to eventual anomalous quartic couplings of Vector Bosons: γγW+W−, γγZZ, and γγγγ. Such measurements at high luminosities will be possible only due the combination of high resolution tracking (semi-edgeless 3D Silicon pixel) detectors and ultra-high precision ToF (Quartz-Cherenkov) detectors at both sides of the ATLAS detector. The ToF detector construction and experiences with its operation represent the subject of the talk.

Deployment of job priority mechanisms in the Italian Cloud of the ATLAS experiment

International Nuclear Information System (INIS)

Doria, Alessandra; Carlino, Gianpaolo; Salvo, Alessandro De; Musto, Elisa; Barchiesi, Alex; Campana, Simone; Ciocca, Claudia; Italiano, Alessandro; Rinaldi, Lorenzo; Salomoni, Davide; Perini, Laura; Pistolese, Massimo; Vaccarossa, Luca; Vilucchi, Elisabetta

2010-01-01

An optimized use of the Grid computing resources in the ATLAS experiment requires the enforcement of a mechanism of job priorities and of resource sharing among the different activities inside the ATLAS VO. This mechanism has been implemented through the VOViews publication in the information system and the fair share implementation per UNIX group in the batch system. The VOView concept consists of publishing resource information, such as running and waiting jobs, as a function of VO groups and roles. The ATLAS Italian Cloud is composed of the CNAF Tier1 and Roma Tier2, with farms based on the LSF batch system, and the Tier2s of Frascati, Milano and Napoli based on PBS/Torque. In this paper we describe how test and deployment of the job priorities has been performed in the cloud, where the VOMS-based regional group /atlas/it has been created. We show that the VOViews are published and correctly managed by the WMS and that the resources allocated to generic VO users, users with production role and users of the /atlas/it group correspond to the defined share.

The ATLAS muon trigger: Experience and performance in the first 3 years of LHC pp runs

International Nuclear Information System (INIS)

Ventura, Andrea

2013-01-01

The ATLAS experiment at CERN's Large Hadron Collider (LHC) deploys a three-level processing scheme for the trigger system. The Level-1 muon trigger system gets its input from fast muon trigger detectors. Sector logic boards select muon candidates, which are passed via an interface board to the central trigger processor and then to the High Level Trigger (HLT). The muon HLT is purely software based and encompasses a Level-2 trigger followed by an event filter for a staged trigger approach. It has access to the data of the precision muon detectors and other detector elements to refine the muon hypothesis. The ATLAS experiment has taken data with high efficiency continuously over entire running periods from 2010 to 2012, for which sophisticated triggers to guard the highest physics output while reducing effectively the event rate were mandatory. The ATLAS muon trigger has successfully adapted to this challenging environment. The selection strategy has been optimized for the various physics analyses involving muons in the final state. This work briefly summarizes these three years of experience in the ATLAS muon trigger and reports about efficiency, resolution, and general performance of the muon trigger

Measurement of fake rates for hadronically decaying τ leptons in the ATLAS experiment

Energy Technology Data Exchange (ETDEWEB)

Dreyer, Timo; Janus, Michel; Lai, Stan [II. Physikalisches Institut, Georg-August-Universitaet Goettingen (Germany)

2016-07-01

The τ lepton is the heaviest lepton in the standard model and an important probe of physics at high energy scales. The joint observation of the H → ττ signal in 2015 by the CMS and ATLAS experiments, for example, was the first direct observation of the Higgs boson coupling to fermions. For signatures involving hadronically decaying τ leptons, it is important to have a good understanding of the τ reconstruction and identification algorithms that are used for data analysis in the ATLAS experiment. In particular, the probability for jets originating from quarks and gluons to be misidentified as hadronically decaying τ leptons (the so-called fake rate), is important for background estimation from a variety of sources. This fake rate depends on many kinematic variables, as well as the quark-gluon composition of the process in question. This talk presents an approach using 13 TeV ATLAS data, to measure the fake rate using the tag-and-probe technique. The dependence of the fake rate on the above mentioned factors is also discussed.

Analysis facility infrastructure (Tier-3) for ATLAS experiment

International Nuclear Information System (INIS)

Gonzalez de la Hoz, S.; March, L.; Ros, E.; Sanchez, J.; Amoros, G.; Fassi, F.; Fernandez, A.; Kaci, M.; Lamas, A.; Salt, J.

2008-01-01

In the ATLAS computing model the tiered hierarchy ranged from the Tier-0 (CERN) down to desktops or workstations (Tier-3). The focus on defining the roles of each tiered component has evolved with the initial emphasis on the Tier-0 and Tier-1 definition and roles. The various LHC (Large Hadron Collider) projects, including ATLAS, then evolved the tiered hierarchy to include Tier-2's (Regional centers) as part of their projects. Tier-3 centres, on the other hand, have been defined as whatever an institution could construct to support their Physics goals using institutional and otherwise leveraged resources and therefore have not been considered to be part of the official ATLAS computing resources. However, Tier-3 centres are going to exist and will have implications on how the computing model should support ATLAS physicists. Tier-3 users will want to access LHC data and simulations and will want to enable their resources to support their analysis and simulation work. This document will define how IFIC (Instituto de Fisica Corpuscular de Valencia), after discussing with the ATLAS Tier-3 task force, should interact with the ATLAS computing model, detail the conditions under which Tier-3 centres can expect some level of support and set reasonable expectations for the scope and support of ATLAS Tier-3 sites. (orig.)

ATLAS strip detector: Operational Experience and Run1 → Run2 transition

CERN Document Server

NAGAI, K; The ATLAS collaboration

2014-01-01

The ATLAS SCT operational experience and the detector performance during the RUN1 period of LHC will be reported. Additionally the preparation outward to RUN2 during the long shut down 1 will be mentioned.

Online radiation dose measurement system for ATLAS experiment

Energy Technology Data Exchange (ETDEWEB)

Mandic, I.; Cindro, V.; Dolenc, I.; Gorisek, A.; Kramberger, G. [Jozef Stefan Institute, Jamova 39, Ljubljana (Slovenia); Mikuz, M. [Jozef Stefan Institute, Jamova 39, Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana (Slovenia); Bronner, J.; Hartet, J. [Physikalisches Institut, Universitat Freiburg, Hermann-Herder-Str. 3, Freiburg (Germany); Franz, S. [CERN, Geneva (Switzerland)

2009-07-01

In experiments at Large Hadron Collider, detectors and electronics will be exposed to high fluxes of photons, charged particles and neutrons. Damage caused by the radiation will influence performance of detectors. It will therefore be important to continuously monitor the radiation dose in order to follow the level of degradation of detectors and electronics and to correctly predict future radiation damage. A system for online radiation monitoring using semiconductor radiation sensors at large number of locations has been installed in the ATLAS experiment. Ionizing dose in SiO{sub 2} will be measured with RadFETs, displacement damage in silicon in units of 1-MeV(Si) equivalent neutron fluence with p-i-n diodes. At 14 monitoring locations where highest radiation levels are expected the fluence of thermal neutrons will be measured from current gain degradation in dedicated bipolar transistors. The design of the system and tests of its performance in mixed radiation field is described in this paper. First results from this test campaign confirm that doses can be measured with sufficient sensitivity (mGy for total ionizing dose measurements, 10{sup 9} n/cm{sup 2} for NIEL (non-ionizing energy loss) measurements, 10{sup 12} n/cm{sup 2} for thermal neutrons) and accuracy (about 20%) for usage in the ATLAS detector

Konstruktion und Validierung einer Skala zur relativen Messung von physischer Attraktivität mit einem Item : das Attraktivitätsrating 1 (AR1)

OpenAIRE

Lutz, Johannes; Kemper, Christoph J.; Beierlein, Constanze; Margraf-Stiksrud, Jutta; Rammstedt, Beatrice

2013-01-01

"Physische Attraktivität ist ein wichtiger Faktor sozialer Interaktion und Kognition, z.B. bei der Partnerwahl oder dem Eindruck, den sich Menschen von sich selbst und von anderen bilden. Auch im Rahmen von Umfragen könnte die physische Attraktivität sozial- und gesundheitswissenschaftliche Erklärungsmodelle sinnvoll ergänzen. So finden sich unter anderem Zusammenhänge mit Kriterien des Berufserfolgs, diversen Gesundheitsvariablen und der allgemeinen Lebenszufriedenheit. Die Messung physische...

Distributed Data Analysis in the ATLAS Experiment: Challenges and Solutions

International Nuclear Information System (INIS)

Elmsheuser, Johannes; Van der Ster, Daniel

2012-01-01

The ATLAS experiment at the LHC at CERN is recording and simulating several 10's of PetaBytes of data per year. To analyse these data the ATLAS experiment has developed and operates a mature and stable distributed analysis (DA) service on the Worldwide LHC Computing Grid. The service is actively used: more than 1400 users have submitted jobs in the year 2011 and a total of more 1 million jobs run every week. Users are provided with a suite of tools to submit Athena, ROOT or generic jobs to the Grid, and the PanDA workload management system is responsible for their execution. The reliability of the DA service is high but steadily improving; Grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters provides user support and communicates user problems to the sites. This paper will review the state of the DA tools and services, summarize the past year of distributed analysis activity, and present the directions for future improvements to the system.

AGIS: The ATLAS Grid Information System

CERN Document Server

Anisenkov, Alexey; Di Girolamo, Alessandro; Gayazov, Stavro; Klimentov, Alexei; Oleynik, Danila; Senchenko, Alexander

2012-01-01

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The experiment produces petabytes of data annually through simulation production and tens petabytes of data per year from the detector itself. The ATLAS Computing model embraces the Grid paradigm and a high degree of decentralization and computing resources able to meet ATLAS requirements of petabytes scale data operations. In this paper we present ATLAS Grid Information System (AGIS) designed to integrate configuration and status information about resources, services and topology of whole ATLAS Grid needed by ATLAS Distributed Computing applications and services.

FTK: The hardware Fast TracKer of the ATLAS experiment at CERN

Directory of Open Access Journals (Sweden)

Maznas Ioannis

2017-01-01

Full Text Available In the ever increasing pile-up environment of the Large Hadron Collider, trigger systems of the experiments must use more sophisticated techniques in order to increase purity of signal physics processes with respect to background processes. The Fast TracKer (FTK is a track finding system implemented in custom hardware that is designed to deliver full-scan tracks with pT above 1 GeV to the ATLAS trigger system for every Level-1 (L1 accept (at a maximum rate of 100 kHz. To accomplish this, FTK is a highly parallel system which is currently being installed in ATLAS. It will first provide the trigger system with tracks in the central region of the ATLAS detector, and next year it is expected that it will cover the whole detector. The system is based on pattern matching between hits coming from the silicon trackers of the ATLAS detector and one billion simulated patterns stored in specially designed ASIC Associative Memory chips. This document will provide an overview of the FTK system architecture, its design and information about its expected performance.

First Results from the Online Radiation Dose Monitoring System in ATLAS experiment

CERN Document Server

Mandić, I; The ATLAS collaboration; Deliyergiyev, M; Gorišek, A; Kramberger, G; Mikuž, M; Franz, S; Hartert, J; Dawson, I; Miyagawa, P; Nicolas, L

2011-01-01

High radiation doses which will accumulate in components of ATLAS experiment during data taking will causes damage to detectors and readout electronics. It is therefore important to continuously monitor the doses to estimate the level of degradation caused by radiation. Online radiation monitoring system measures ionizing dose in SiO2 , displacement damage in silicon in terms of 1-MeV(Si) equivalent neutron fluence and fluence of thermal neutrons at several locations in ATLAS detector. In this paper design of the system, results of measurements and comparison of measured integrated doses and fluences with predictions from FLUKA simulation will be shown.

Using boosted decision trees for tau identification in the ATLAS experiment

CERN Document Server

Godfrey, Jennifer

The ATLAS detector will begin taking data from p - p collisions in 2009. This experiment will allo w for man y dif ferent physics measurements and searches. The production of tau leptons at the LHC is a key signature of the decay of both the standard model Higgs (via H ! t t ) and SUSY particles. Taus have a short lifetime ( c t = 87 m m) and decay hadroni- cally 65% of the time. Man y QCD interactions produce similar hadronic sho wers and have cross-sections about 1 billion times lar ger than tau production. Multi variate techniques are therefore often used to distinguish taus from this background. Boosted Decision Trees (BDTs) are a machine-learning technique for developing cut-based discriminants which can signicantly aid in extracting small signal samples from overwhelming backgrounds. In this study , BDTs are used for tau identication for the ATLAS experiment. The y are a fast, exible alternati ve to existing discriminants with comparable or better performance.

Test and performances of the RPC trigger chambers of the ATLAS experiment at LHC

CERN Document Server

Aielli, G; Ammosov, A; Biglietti, M; Brambilla, Elena; Camarri, P; Canale, V; Caprio, M A; Cardarelli, R; Carlino, G; Cataldi, G; Chiodini, G; Di Simone, A; Di Ciaccio, A; Della Volpe, D; De Asmundis, R; Della Pietra, M; Grancagnolo, F; Gorini, E; Iengo, P; Liberti, B; Patricelli, S; Perrino, R; Primavera, M; Santonico, R; Sehkniadze, G; Spagnolo, S; Sviridov, Yu; Zaetz, V G

2004-01-01

RPCs will be used as trigger detectors in the barrel region of the Muon Spectrometer of the ATLAS experiment at LHC. The total number of RPC units to be installed is 1088, covering a total surface of about 3500m**2. ATLAS RPCs work in avalanche mode with C//2H//2F //4/C//4H //1//0/SF//6 (94.7%/5%/0.3%) gas mixture. A cosmic ray test stand has been designed and built in Naples laboratories in order to carry out a complete test of the ATLAS RPC units. Since August 2002 about 300 units have been tested. A description of the test stand, test procedure and results are presented.

First experience and adaptation of existing tools to ATLAS distributed analysis

International Nuclear Information System (INIS)

De La Hoz, S.G.; Ruiz, L.M.; Liko, D.

2008-01-01

The ATLAS production system has been successfully used to run production of simulation data at an unprecedented scale in ATLAS. Up to 10000 jobs were processed on about 100 sites in one day. The experiences obtained operating the system on several grid flavours was essential to perform a user analysis using grid resources. First tests of the distributed analysis system were then performed. In the preparation phase data was registered in the LHC file catalog (LFC) and replicated in external sites. For the main test, few resources were used. All these tests are only a first step towards the validation of the computing model. The ATLAS management computing board decided to integrate the collaboration efforts in distributed analysis in only one project, GANGA. The goal is to test the reconstruction and analysis software in a large scale Data production using grid flavors in several sites. GANGA allows trivial switching between running test jobs on a local batch system and running large-scale analyses on the grid; it provides job splitting and merging, and includes automated job monitoring and output retrieval. (orig.)

ATLAS: Exceeding all expectations

CERN Multimedia

CERN Bulletin

2010-01-01

“One year ago it would have been impossible for us to guess that the machine and the experiments could achieve so much so quickly”, says Fabiola Gianotti, ATLAS spokesperson. The whole chain – from collision to data analysis – has worked remarkably well in ATLAS.   The first LHC proton run undoubtedly exceeded expectations for the ATLAS experiment. “ATLAS has worked very well since the beginning. Its overall data-taking efficiency is greater than 90%”, says Fabiola Gianotti. “The quality and maturity of the reconstruction and simulation software turned out to be better than we expected for this initial stage of the experiment. The Grid is a great success, and right from the beginning it has allowed members of the collaboration all over the world to participate in the data analysis in an effective and timely manner, and to deliver physics results very quickly”. In just a few months of data taking, ATLAS has observed t...

SUSY Searches with the ATLAS Experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00236698; The ATLAS collaboration

2016-01-01

The Standard Model describes the elementary particles and their interactions. Supersymmetry, a symmetry beyond those included in SM, could resolve some shortcomings of Standard Model. It can provide a solution to the hierarchy problem and a candidate for Dark Matter. The Large Hadron Collider has the potential to produce some of the particles predicted by supersymmetry. This document presents searches for supersymmetric particles in proton-proton collision data recorded by the ATLAS experiment. The analyses are done using $\\mathscr{L}=3.2$~fb$^{-1}$ proton-proton collisions at $\\sqrt{s}=13$~TeV collected in 2015. Also, searches performed using up to $\\mathscr{L}=20.3$~fb$^{-1}$ dataset at $\\sqrt{s}=7$ and 8~TeV collected in 2011 and 2012 are presented.

Development of a picosecond time-of-flight system in the ATLAS experiment

International Nuclear Information System (INIS)

Grabas, Herve

2013-01-01

In this thesis, we present a study of the sensitivity to Beyond Standard Model physics brought by the design and installation of picosecond time-of-flight detectors in the forward region of the ATLAS experiment at the LHC. The first part of the thesis present a study of the sensitivity to the quartic gauge anomalous coupling between the photon and the W boson, using exclusive WW pair production in ATLAS. The event selection is built considering the semi-leptonic decay of WW pair and the presence of the AFP detector in ATLAS. The second part gives a description of large area picosecond photo-detectors design and time reconstruction algorithms with a special care given to signal sampling and processing for precision timing. The third part presents the design of SamPic: a custom picosecond readout integrated circuit. At the end, its first results are reported, and in particular a world-class 5 ps timing precision in measuring the delay between two fast pulses. (author) [fr

Detector Control System for the AFP detector in ATLAS experiment at CERN

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00211068; The ATLAS collaboration; Caforio, Davide; Czekierda, Sabina; Hajduk, Zbigniew; Olszowska, Jolanta; Oleiro Seabra, Luis Filipe; Sicho, Petr

2017-01-01

The ATLAS Forward Proton (AFP) detector consists of two forward detectors located at 205 m and 217 m on either side of the ATLAS experiment. The aim is to measure the momenta and angles of diffractively scattered protons. In 2016, two detector stations on one side of the ATLAS interaction point were installed and commissioned. The detector infrastructure and necessary services were installed and are supervised by the Detector Control System (DCS), which is responsible for the coherent and safe operation of the detector. A large variety of used equipment represents a considerable challenge for the AFP DCS design. Industrial Supervisory Control and Data Acquisition (SCADA) product Siemens WinCCOA, together with the CERN Joint Control Project (JCOP) framework and standard industrial and custom developed server applications and protocols are used for reading, processing, monitoring and archiving of the detector parameters. Graphical user interfaces allow for overall detector operation and visualization of the det...

Report to users of Atlas

International Nuclear Information System (INIS)

Ahmad, I.; Glagola, B.

1996-06-01

This report contains the following topics: Status of the ATLAS Accelerator; Highlights of Recent Research at ATLAS; Program Advisory Committee; ATLAS User Group Executive Committee; FMA Information Available On The World Wide Web; Conference on Nuclear Structure at the Limits; and Workshop on Experiments with Gammasphere at ATLAS

A new experiment-agnostic mechanism to persistify and serve the detector geometry of ATLAS

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00211497; The ATLAS collaboration; Boudreau, Joseph; Vukotic, Ilija

2017-01-01

The complex geometry of the whole detector of the ATLAS experiment at LHC is currently stored only in custom online databases, from which it is built on-the-fly on request. Accessing the online geometry guarantees accessing the latest version of the detector description, but requires the setup of the full ATLAS software framework "Athena", which provides the online services and the tools to retrieve the data from the database. This operation is cumbersome and slows down the applications that need to access the geometry. Moreover, all applications that need to access the detector geometry need to be built and run on the same platform as the ATLAS framework, preventing the usage of the actual detector geometry in stand-alone applications. Here we propose a new mechanism to persistify and serve the geometry of HEP experiments. The new mechanism is composed by a new file format and the modules to make use of it. The new file format allows to store the whole detector description locally in a flat file, and it is e...

Physics Capabilities of the ATLAS Experiment in Pb+Pb Collisions at the LHC

CERN Document Server

Derendarz, D; The ATLAS collaboration

2010-01-01

Relativistic heavy ion collisions at the LHC will uncover properties of hot and dense medium formed at collision energy thirty times larger than energy presently available at RHIC. ATLAS is one of three experiments participating in the heavy ion program at the LHC. A brief overview of variety of observables which will be measured by ATLAS to study soft and hard QCD phenomena in heavy ion environment is presented. In particular the detector will measure global observables like charged particle multiplicity, azimuthal anisotropy and energy flow. The detector provides also an excellent capability to probe the quark gluon plasma by measurement of high energy jets and photons as well as quarkonia states. Performance of a high granularity calorimeter, silicon tracking detector and muon spectrometer in heavy ion collisions is reported. A unique ATLAS potential to study Pb+Pb interactions is discussed.

Operational Experience with the ATLAS Pixel Detector

CERN Document Server

Lantzsch, Kerstin; The ATLAS collaboration

2016-01-01

Run 2 of the LHC is providing new challenges to track and vertex reconstruction with higher energies, denser jets and higher rates. Therefore the ATLAS experiment has constructed the first 4-layer Pixel detector in HEP, installing a new Pixel layer, also called Insertable B-Layer (IBL). In addition the Pixel detector was refurbished with new service quarter panels to recover about 3% of defective modules lost during run 1 and a new optical readout system to readout the data at higher speed while reducing the occupancy when running with increased luminosity. The commissioning, operation and performance of the 4-layer Pixel Detector will be presented.

AGIS: The ATLAS Grid Information System

OpenAIRE

Anisenkov, Alexey; Belov, Sergey; Di Girolamo, Alessandro; Gayazov, Stavro; Klimentov, Alexei; Oleynik, Danila; Senchenko, Alexander

2012-01-01

ATLAS is a particle physics experiment at the Large Hadron Collider at CERN. The experiment produces petabytes of data annually through simulation production and tens petabytes of data per year from the detector itself. The ATLAS Computing model embraces the Grid paradigm and a high degree of decentralization and computing resources able to meet ATLAS requirements of petabytes scale data operations. In this paper we present ATLAS Grid Information System (AGIS) designed to integrate configurat...

Picturing diversity in the ATLAS experiment.

CERN Document Server

Biondi, Silvia; The ATLAS collaboration

2017-01-01

With over 3,000 members from 178 institutes, the ATLAS Collaboration is naturally diverse. However, capturing this diversity through pictures can be a challenge. Photography is a powerful tool, allowing us to reveal the faces behind a story and give the public the unique opportunity to understand and appreciate the human aspects of ATLAS’s scientific research. The role of photographs in portraying the diversity of the ATLAS Collaboration will be described. Their role on various communication platforms will be described and their impact examined, with focus on engagement of new audiences.

Experience with the gLite workload management system in ATLAS Monte Carlo production on LCG

International Nuclear Information System (INIS)

Campana, S; Sciaba, A; Rebatto, D

2008-01-01

The ATLAS experiment has been running continuous simulated events production since more than two years. A considerable fraction of the jobs is daily submitted and handled via the gLite Workload Management System, which overcomes several limitations of the previous LCG Resource Broker. The gLite WMS has been tested very intensively for the LHC experiments use cases for more than six months, both in terms of performance and reliability. The tests were carried out by the LCG Experiment Integration Support team (in close contact with the experiments) together with the EGEE integration and certification team and the gLite middleware developers. A pragmatic iterative and interactive approach allowed a very quick rollout of fixes and their rapid deployment, together with new functionalities, for the ATLAS production activities. The same approach is being adopted for other middleware components like the gLite and CREAM Computing Elements. In this contribution we will summarize the learning from the gLite WMS testing activity, pointing out the most important achievements and the open issues. In addition, we will present the current situation of the ATLAS simulated event production activity on the EGEE infrastructure based on the gLite WMS, showing the main improvements and benefits from the new middleware. Finally, the gLite WMS is being used by many other VOs, including the LHC experiments. In particular, some statistics will be shown on the CMS experience running WMS user analysis via the WMS

Advances in ATLAS@Home towards a major ATLAS computing resource

CERN Document Server

Cameron, David; The ATLAS collaboration

2018-01-01

The volunteer computing project ATLAS@Home has been providing a stable computing resource for the ATLAS experiment since 2013. It has recently undergone some significant developments and as a result has become one of the largest resources contributing to ATLAS computing, by expanding its scope beyond traditional volunteers and into exploitation of idle computing power in ATLAS data centres. Removing the need for virtualization on Linux and instead using container technology has made the entry barrier significantly lower data centre participation and in this paper, we describe the implementation and results of this change. We also present other recent changes and improvements in the project. In early 2017 the ATLAS@Home project was merged into a combined LHC@Home platform, providing a unified gateway to all CERN-related volunteer computing projects. The ATLAS Event Service shifts data processing from file-level to event-level and we describe how ATLAS@Home was incorporated into this new paradigm. The finishing...

PanDA: Exascale Federation of Resources for the ATLAS Experiment at the LHC

Science.gov (United States)

Barreiro Megino, Fernando; Caballero Bejar, Jose; De, Kaushik; Hover, John; Klimentov, Alexei; Maeno, Tadashi; Nilsson, Paul; Oleynik, Danila; Padolski, Siarhei; Panitkin, Sergey; Petrosyan, Artem; Wenaus, Torre

2016-02-01

After a scheduled maintenance and upgrade period, the world's largest and most powerful machine - the Large Hadron Collider(LHC) - is about to enter its second run at unprecedented energies. In order to exploit the scientific potential of the machine, the experiments at the LHC face computational challenges with enormous data volumes that need to be analysed by thousand of physics users and compared to simulated data. Given diverse funding constraints, the computational resources for the LHC have been deployed in a worldwide mesh of data centres, connected to each other through Grid technologies. The PanDA (Production and Distributed Analysis) system was developed in 2005 for the ATLAS experiment on top of this heterogeneous infrastructure to seamlessly integrate the computational resources and give the users the feeling of a unique system. Since its origins, PanDA has evolved together with upcoming computing paradigms in and outside HEP, such as changes in the networking model, Cloud Computing and HPC. It is currently running steadily up to 200 thousand simultaneous cores (limited by the available resources for ATLAS), up to two million aggregated jobs per day and processes over an exabyte of data per year. The success of PanDA in ATLAS is triggering the widespread adoption and testing by other experiments. In this contribution we will give an overview of the PanDA components and focus on the new features and upcoming challenges that are relevant to the next decade of distributed computing workload management using PanDA.

The Evolution of the Region of Interest Builder for the ATLAS Experiment at CERN

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00060668; Blair, Robert; Crone, Gordon Jeremy; Green, Barry; Love, Jeremy; Proudfoot, James; Rifki, Othmane; Panduro Vazquez, William; Vandelli, Wainer; Zhang, Jinlong

2016-01-01

ATLAS is a general purpose particle detector, at the Large Hadron Collider (LHC) at CERN, designed to measure the products of proton collisions. Given the high interaction rate (40 MHz), selective triggering in real time is required to reduce the rate to the experiment's data storage capacity (1 kHz). To meet this requirement, ATLAS employs a hardware trigger that reduces the rate to 100 kHz and software based triggers to select interesting interactions for physics analysis. The Region of Interest Builder (RoIB) is an essential part of the ATLAS detector Trigger and Data Acquisition (TDAQ) chain where the coordinates of the regions of interest (RoIs) identified by the first level trigger (L1) are collected and passed to the High Level Trigger (HLT) to make a decision. While the current custom VME based RoIB operated reliably during the first run of the LHC, it is desirable to have a more flexible RoIB and more operationally maintainable in the future, as the LHC reaches higher luminosity and ATLAS increases t...

Evaluierung eines FPGA und PCI Bus basierten Auslesespeichers für das Atlas Experiment

CERN Document Server

Müller, Matthias

2004-01-01

This dissertation evaluates a readout buffer system for the ATLAS detector trigger and data acquisition system. ATLAS is a high energy physics experiment at the large hadron collider (LHC) with the aim to reach new frontiers in the investigation of the structure of matter. The high precision ATLAS detector produces a huge amount of data, 40 TByte/s, which is reduced by a three-level trigger system for online event data selection. The readout buffer system acts as a data buffer while the second trigger level computes the trigger decision. ATLAS uses a sequential selection in the level 2 trigger which means that all event data required for the trigger decision is requested from the readout buffer component subsequently. This increases the complexity of the readout buffer device and its output event rate. Furthermore a region-of-interest (RoI) concept limits the amount of data necessary for the processing of one event inside the level 2 processor by defining the detector region with interesting data. Thus, appro...

Multi-threaded software framework development for the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00226135; Baines, John; Bold, Tomasz; Calafiura, Paolo; Dotti, Andrea; Farrell, Steven; Leggett, Charles; Malon, David; Ritsch, Elmar; Snyder, Scott; Tsulaia, Vakhtang; van Gemmeren, Peter; Wynne, Benjamin

2016-01-01

ATLAS's current software framework, Gaudi/Athena, has been very successful for the experiment in LHC Runs 1 and 2. However, its single threaded design has been recognised for some time to be increasingly problematic as CPUs have increased core counts and decreased available memory per core. Even the multi-process version of Athena, AthenaMP, will not scale to the range of architectures we expect to use beyond Run2. ATLAS examined the requirements on an updated multi-threaded framework and laid out plans for a new framework, including better support for high level trigger (HLT) use cases, in 2014. In this paper we report on our progress in developing the new multi-threaded task parallel extension of Athena, AthenaMT. Implementing AthenaMT has required many significant code changes. Progress has been made in updating key concepts of the framework, to allow the incorporation of different levels of thread safety in algorithmic code (from un-migrated thread-unsafe code, to thread safe copyable code to reentrant co...

Multi-threaded Software Framework Development for the ATLAS Experiment

CERN Document Server

Stewart, Graeme; The ATLAS collaboration; Baines, John; Calafiura, Paolo; Dotti, Andrea; Farrell, Steven; Leggett, Charles; Malon, David; Ritsch, Elmar; Snyder, Scott; Tsulaia, Vakhtang; van Gemmeren, Peter; Wynne, Benjamin

2016-01-01

ATLAS's current software framework, Gaudi/Athena, has been very successful for the experiment in LHC Runs 1 and 2. However, its single threaded design has been recognised for some time to be increasingly problematic as CPUs have increased core counts and decreased available memory per core. Even the multi-process version of Athena, AthenaMP, will not scale to the range of architectures we expect to use beyond Run2. ATLAS examined the requirements on an updated multi-threaded framework and layed out plans for a new framework, including better support for high level trigger (HLT) use cases, in 2014. In this paper we report on our progress in developing the new multi-threaded task parallel extension of Athena, AthenaMT. Implementing AthenaMT has required many significant code changes. Progress has been made in updating key concepts of the framework, to allow the incorporation of different levels of thread safety in algorithmic code (from un-migrated thread-unsafe code, to thread safe copyable code to reentrant c...

Reconstruction and identification of electrons in the Atlas experiment. Setup of a Tier 2 of the computing grid

International Nuclear Information System (INIS)

Derue, F.

2008-03-01

The origin of the mass of elementary particles is linked to the electroweak symmetry breaking mechanism. Its study will be one of the main efforts of the Atlas experiment at the Large Hadron Collider of CERN, starting in 2008. In most cases, studies will be limited by our knowledge of the detector performances, as the precision of the energy reconstruction or the efficiency to identify particles. This manuscript presents a work dedicated to the reconstruction of electrons in the Atlas experiment with simulated data and data taken during the combined test beam of 2004. The analysis of the Atlas data implies the use of a huge amount of computing and storage resources which brought to the development of a world computing grid. (author)

Detector Control System for the AFP detector in ATLAS experiment at CERN

Science.gov (United States)

Banaś, E.; Caforio, D.; Czekierda, S.; Hajduk, Z.; Olszowska, J.; Seabra, L.; Šícho, P.

2017-10-01

The ATLAS Forward Proton (AFP) detector consists of two forward detectors located at 205 m and 217 m on either side of the ATLAS experiment. The aim is to measure the momenta and angles of diffractively scattered protons. In 2016, two detector stations on one side of the ATLAS interaction point were installed and commissioned. The detector infrastructure and necessary services were installed and are supervised by the Detector Control System (DCS), which is responsible for the coherent and safe operation of the detector. A large variety of used equipment represents a considerable challenge for the AFP DCS design. Industrial Supervisory Control and Data Acquisition (SCADA) product Siemens WinCCOA, together with the CERN Joint Control Project (JCOP) framework and standard industrial and custom developed server applications and protocols are used for reading, processing, monitoring and archiving of the detector parameters. Graphical user interfaces allow for overall detector operation and visualization of the detector status. Parameters, important for the detector safety, are used for alert generation and interlock mechanisms.

Analysis of the ATLAS Cold Leg Top-Slot Break Experiment Using the MARS Code

Energy Technology Data Exchange (ETDEWEB)

Ha, T. W.; Jeong, J. J. [Pusan National University, Busan (Korea, Republic of)

2016-10-15

During a small-break loss of coolant accident (SBLOCA) or intermediate-break loss of coolant accident (IBLOCA) in a PWR, such as the APR1400, the steam volume in the reactor vessel upper plenum may continue to expand until the liquid phase in the horizontal intermediate legs is released, called loop seal clearing (LSC), due to the increase of the pressure in the upper plenum. A domestic standard problem (DSP) exercise using the ATLAS facility was promoted in order to transfer the database to domestic nuclear industries. For 4th DSP (DSP-04), the ATLAS cold leg top-slot break experiment was postulated. For the DSP-04, main concerns are to predict the LSC and LSR having a significantly effect on the behavior of the system under long term cooling. In this study, we simulated the ATLAS cold leg top-slot break experiment using the MARS code and the predicted LSC and LSR are compared to experimental results. The LTC-CL-04R was simulated using the MARS code. Most of the predicted results agree well with the experimental data. However, the timing of LSC and LSR is slightly different from each other and, thus, the behavior of the primary system is slightly different. The core heat up was not observed in the experiment and the calculation.

Study of a reconstruction algorithm for electrons in the ATLAS experiment in LHC

International Nuclear Information System (INIS)

Kerschen, N.

2006-09-01

The ATLAS experiment is a general purpose particle physics experiment mainly aimed at the discovery of the origin of mass through the research of the Higgs boson. In order to achieve this, the Large Hadron Collider at CERN will accelerate two proton beams and make them collide at the centre of the experiment. ATLAS will discover new particles through the measurement of their decay products. Electrons are such decay products: they produce an electromagnetic shower in the calorimeter by which they lose all their energy. The calorimeter is divided into cells and the deposited energy is reconstructed using an algorithm to assemble the cells into clusters. The purpose of this thesis is to study a new kind of algorithm adapting the cluster to the shower topology. In order to reconstruct the energy of the initially created electron, the cluster has to be calibrated by taking into account the energy lost in the dead material in front of the calorimeter. Therefore. a Monte-Carlo simulation of the ATLAS detector has been used to correct for effects of response modulation in position and in energy and to optimise the energy resolution as well as the linearity. An analysis of test beam data has been performed to study the behaviour of the algorithm in a more realistic environment. We show that the requirements of the experiment can be met for the linearity and resolution. The improvement of this new algorithm, compared to a fixed sized cluster. is the better recovery of Bremsstrahlung photons emitted by the electron in the material in front of the calorimeter. A Monte-Carlo analysis of the Higgs boson decay in four electrons confirms this result. (author)

New format for ATLAS e-news

CERN Multimedia

Pauline Gagnon

ATLAS e-news got a new look! As of November 30, 2007, we have a new format for ATLAS e-news. Please go to: http://atlas-service-enews.web.cern.ch/atlas-service-enews/index.html . ATLAS e-news will now be published on a weekly basis. If you are not an ATLAS colaboration member but still want to know how the ATLAS experiment is doing, we will soon have a version of ATLAS e-news intended for the general public. Information will be sent out in due time.

ATLAS Colouring Book

CERN Multimedia

Anthony, Katarina

2016-01-01

The ATLAS Experiment Colouring Book is a free-to-download educational book, ideal for kids aged 5-9. It aims to introduce children to the field of High-Energy Physics, as well as the work being carried out by the ATLAS Collaboration.

Data Quality Monitoring Display for ATLAS experiment

CERN Document Server

Ilchenko, Y; The ATLAS collaboration; Corso-Radu, A; Hadavand, H; Kolos, S; Slagle, K; Taffard, A

2009-01-01

The start of collisions at the LHC brings with it much excitement and many unknowns. It’s essential at this point in the experiment to be prepared with user-friendly tools to quickly and efficiently determine the quality of the data. Easy visualization of data for the shift crew and experts is one of the key factors in the data quality assessment process. The Data Quality Monitoring Display (DQMD) is a visualization tool for the automatic data quality assessment of the ATLAS experiment. It is the interface through which the shift crew and experts can validate the quality of the data being recorded or processed, be warned of problems related to data quality, and identify the origin of such problems. This tool allows great flexibility for visualization of results from automatic histogram checking through custom algorithms, the configuration used to run the algorithms, and histograms used for the check, with an overlay of reference histograms when applicable. The display also supports visualization of the resu...

ATLAS Maintenance and Operation management system

CERN Document Server

Copy, B

2007-01-01

The maintenance and operation of the ATLAS detector will involve thousands of contributors from 170 physics institutes. Planning and coordinating the action of ATLAS members, ensuring their expertise is properly leveraged and that no parts of the detector are understaffed or overstaffed will be a challenging task. The ATLAS Maintenance and Operation application (referred to as Operation Task Planner inside the ATLAS experiment) offers a fluent web based interface that combines the flexibility and comfort of a desktop application, intuitive data visualization and navigation techniques, with a lightweight service oriented architecture. We will review the application, its usage within the ATLAS experiment, its underlying design and implementation.

Measurement of transvers spin effects by means of two-hadron correlations in the COMPASS experiment; Messung transversaler Spineffekte mittels zwei Hadronen Korrelation am COMPASS-Experiment

Energy Technology Data Exchange (ETDEWEB)

Massmann, Frank Michael

2008-06-23

Helizitaets- Verteilungsfunktion {delta}q(x) und die transversale Quarkspin Verteilungsfunktion {delta}{sub T}q(x). Diese letztgenannte Funktion, genannt ''Transversity'' Funktion, ist chiral ungerade und kann deshalb nur in Kombination mit einer anderen chiral ungeraden Funktion gemessen werden. Eine Zugangsmoeglichkeit zur ''Transversity'' Funktion {delta}{sub T}q(x) ist die semi-inklusive zwei Hadronenproduktion in tief inelastischer Streuung an einem transversal polarisierten Target. Dabei misst man die Faltung der chiral ungeraden zwei Hadronen Interferenz Fragmentationsfunktion (IFF) H{sub 1} {sup angle} (z,M{sub h}{sup 2}) und der chiral ungeraden ''Transversity'' Funktion. Die IFF H{sub 1} {sup angle} (z,M{sub h}{sup 2}) ist der spinabhaengige Teil einer Fragmentationsfunktion, die die Fragmentation eines transversal polarisierten Quarks in zwei unpolarisierte Hadronen beschreibt. Die Produktion der zwei Hadronen erfolgt in einer Interferenz zwischen verschiedenen Wellenzustaenden der Hadronenpaare. Man misst azimuthale Asymmetrien in den erzeugten Hadronenpaaren. Die Messungen, die in dieser Arbeit beschrieben werden, wurden am COMPASS Experiment am CERN in den Jahren 2002-2004 durchgefuehrt, welches ein Feststoff Target Experiment am SPS Beschleuniger ist. Nach einer Einfuehrung werden in Kapitel 2 die zugrundeliegenden theoretischen Konzepte zur Messung der ''Transversity'' Funktion vorgestellt. In Kapitel 3 wird das COMPASS Experiment beschrieben. Schliesslich werden in Kapitel 4 die Auswertemethoden besprochen, die Ergebnisse der azimuthalen Asymmetrien gezeigt und mit theoretischen Vorhersagen verglichen. (orig.)

Inner Detector Track Reconstruction and Alignment at the ATLAS Experiment

CERN Document Server

Danninger, Matthias; The ATLAS collaboration

2017-01-01

The Inner Detector of the ATLAS experiment at the LHC is responsible for reconstructing the trajectories of charged particles (‘tracks’) with high efficiency and accuracy. It consists of three subdetectors, each using a different technology to provide measurements points. An overview of the use of each of these subdetectors in track 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 will be summarised. Of crucial importance for optimal tracking performance is precise knowledge of the relative positions of the detector elements. ATLAS uses a sophisticated, highly granular software alignment procedure to determine and correct for the positions of the sensors, including time-dependent effects appearing within single data runs. This alignment procedure will be discussed in detail, and its effect on Inner Detector tracking for LHC Run 2 proton-proton collision data highlighted.

CMOS pixel development for the ATLAS experiment at HL-LHC

CERN Document Server

Risti{c}, Branislav; The ATLAS collaboration

2017-01-01

To cope with the rate and radiation environment expected at the HL-LHC new approaches are being developed on CMOS pixel detectors, providing charge collection in a depleted layer. They are based on: HV enabling technologies that allow to use high depletion voltages (HV-MAPS), high resistivity wafers for large depletion depths (HR-MAPS); radiation hard processed with multiple nested wells to allow CMOS electronics embedded with sufficient shielding into the sensor substrate and backside processing and thinning for material minimization and backside voltage application. Since 2014, members of more than 20 groups in the ATLAS experiment are actively pursuing CMOS pixel R&D in an ATLAS Demonstrator program pursuing sensor design and characterizations. The goal of this program is to demonstrate that depleted CMOS pixels, with monolithic or hybrid designs, are suited for high rate, fast timing and high radiation operation at LHC. For this a number of technologies have been explored and characterized. In this pr...

Towards a Level-1 tracking trigger for the ATLAS experiment

CERN Document Server

Cerri, A; The ATLAS collaboration

2014-01-01

The future plans for the LHC accelerator allow, through a schedule of phased upgrades, an increase in the average instantaneous luminosity by a factor 5 with respect to the original design luminosity. The ATLAS experiment at the LHC will be able to maximise the physics potential from this higher luminosity only if the detector, trigger and DAQ infrastructure are adapted to handle the sustained increase in particle production rates. In this paper the changes expected to be required to the ATLAS detectors and trigger system to fulfill the requirement for working in such high luminosity scenario are described. The increased number of interactions per bunch crossing will result in higher occupancy in the detectors and increased rates at each level of the trigger system. The trigger selection will improve the selectivity partly from increased granularity for the sub detectors and the consequent higher resolution. One of the largest challenges will be the provision of tracking information at the first trigger level...

Towards a Level-1 Tracking Trigger for the ATLAS Experiment

CERN Document Server

De Santo, A; The ATLAS collaboration

2014-01-01

Plans for a physics-driven upgrade of the LHC foresee staged increases of the accelerator's average instantaneous luminosity, of up to a factor of five compared to the original design. In order to cope with the sustained luminosity increase, and the resulting higher detector occupancy and particle interaction rates, the ATLAS experiment is planning phased upgrades of the trigger system and of the DAQ infrastructure. In the new conditions, maintaining an adequate signal acceptance for electro-weak processes will pose unprecedented challenges, as the default solution to cope with the higher rates would be to increase thresholds on the transverse momenta of physics objects (leptons, jets, etc). Therefore the possibility to apply fast processing at the first trigger level in order to use tracking information as early as possible in the trigger selection represents a most appealing opportunity, which can preserve the ATLAS trigger's selectivity without reducing its flexibility. Studies to explore the feasibility o...

CMOS pixel development for the ATLAS experiment at HL-LHC

CERN Document Server

Rimoldi, Marco; The ATLAS collaboration

2017-01-01

To cope with the rate and radiation environment expected at the HL-LHC new approaches are being developed on CMOS pixel detectors, providing charge collection in a depleted layer. They are based on: HV enabling technologies that allow to use high depletion voltages, high resistivity wafers for large depletion depths; radiation hard processed with multiple nested wells to allow CMOS electronics embedded with sufficient shielding into the sensor substrate and backside processing and thinning for material minimization and backside voltage application. Since 2014, members of more than 20 groups in the ATLAS experiment are actively pursuing CMOS pixel R$\\&$D in an ATLAS Demonstrator program pursuing sensor design and characterizations. The goal of this program is to demonstrate that depleted CMOS pixels are suited for high rate, fast timing and high radiation operation at LHC. For this a number of technologies have been explored and characterized. In this presentation the challenges for the usage of CMOS pixel...

CMOS Pixel Development for the ATLAS Experiment at HL-LHC

CERN Document Server

Gaudiello, Andrea; The ATLAS collaboration

2017-01-01

To cope with the rate and radiation environment expected at the HL-LHC new approaches are being developed on CMOS pixel detectors, providing charge collection in a depleted layer. They are based on: HV enabling technologies that allow to use high depletion voltages (HV-MAPS), high resistivity wafers for large depletion depths (HR-MAPS); radiation hard processed with multiple nested wells to allow CMOS electronics embedded with sufficient shielding into the sensor substrate and backside processing and thinning for material minimization and backside voltage application. Since 2014, members of more than 20 groups in the ATLAS experiment are actively pursuing CMOS pixel R&D in an ATLAS Demonstrator program pursuing sensor design and characterizations. The goal of this program is to demonstrate that depleted CMOS pixels, with monolithic or hybrid designs, are suited for high rate, fast timing and high radiation operation at LHC. For this a number of technologies have been explored and characterized. In this pr...

ATLAS Cloud R&D

CERN Document Server

Panitkin, S; The ATLAS collaboration; Caballero Bejar, J; Benjamin, D; DiGirolamo, A; Gable, I; Hendrix, V; Hover, J; Kucharczuk, K; Medrano LLamas, R; Love, P; Ohman, H; Paterson, M; Sobie, R; Taylor, R; Walker, R; Zaytsev, A

2014-01-01

The computing model of the ATLAS experiment was designed around the concept of grid computing and, since the start of data taking, this model has proven very successful. However, new cloud computing technologies bring attractive features to improve the operations and elasticity of scientific distributed computing. ATLAS sees grid and cloud computing as complementary technologies that will coexist at different levels of resource abstraction, and two years ago created an R&D working group to investigate the different integration scenarios. The ATLAS Cloud Computing R&D has been able to demonstrate the feasibility of offloading work from grid to cloud sites and, as of today, is able to integrate transparently various cloud resources into the PanDA workload management system. The ATLAS Cloud Computing R&D is operating various PanDA queues on private and public resources and has provided several hundred thousand CPU days to the experiment. As a result, the ATLAS Cloud Computing R&D group has gained...

Analysis facility infrastructure (Tier-3) for ATLAS experiment

CERN Document Server

González de la Hoza, S; Ros, E; Sánchez, J; Amorós, G; Fassi, F; Fernández, A; Kaci, M; Lamas, A; Salt, J

2008-01-01

In the ATLAS computing model the tiered hierarchy ranged from the Tier-0 (CERN) down to desktops or workstations (Tier-3). The focus on defining the roles of each tiered component has evolved with the initial emphasis on the Tier-0 and Tier-1 definition and roles. The various LHC (Large Hadron Collider) projects, including ATLAS, then evolved the tiered hierarchy to include Tier-2’s (Regional centers) as part of their projects. Tier-3 centres, on the other hand, have been defined as whatever an institution could construct to support their Physics goals using institutional and otherwise leveraged resources and therefore have not been considered to be part of the official ATLAS computing resources. However, Tier-3 centres are going to exist and will have implications on how the computing model should support ATLAS physicists. Tier-3 users will want to access LHC data and simulations and will want to enable their resources to support their analysis and simulation work. This document will define how IFIC (Insti...

ATLAS

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Ermoline, I; Sinev, N; Whiteson, D O; Corso radu, A; Huang, J; Werth, M P; Kastoryano, M; Meirose da silva costa, B; Namasivayam, H; Hobbs, J D; Schamberger jr, R D; Guo, F; Potekhin, M; Popovic, D; Gorisek, A; Sokhrannyi, G; Hofsajer, I W; Mandelli, L; Ceradini, F; Graziani, E; Giorgi, F; Zur nedden, M E G; Grancagnolo, S; Volpi, M; Nunes hanninger, G; Rados, P K; Milesi, M; Cuthbert, C J; Black, C W; Fink grael, F; Fincke-keeler, M; Keeler, R; Kowalewski, R V; Berghaus, F O; Qi, M; Davidek, T; Tas, P; Jakubek, J; Duckeck, G; Walker, R; Mitterer, C A; Harenberg, T; Sandvoss, S A; Del peso, J; Llorente merino, J; Gonzalez millan, V; Irles quiles, A; Crouau, M; Gris, P L Y; Liauzu, S; Romano saez, S M; Gallop, B J; Jones, T J; Austin, N C; Morris, J; Duerdoth, I; Thompson, R J; Kelly, M P; Leisos, A; Garas, A; Pizio, C; Venda pinto, B A; Kudin, L; Qian, J; Wilson, A W; Mietlicki, D; Long, J D; Sang, Z; Arms, K E; Rahimi, A M; Moss, J J; Oh, S H; Parker, S I; Parsons, J; Cunitz, H; Vanguri, R S; Sadrozinski, H; Lockman, W S; Martinez-mc kinney, G; Goussiou, A; Jones, A; Lie, K; Hasegawa, Y; Olcese, M; Gilewsky, V; Harrison, P F; Janus, M; Spangenberg, M; De, K; Ozturk, N; Pal, A K; Darmora, S; Bullock, D J; Oviawe, O; Derkaoui, J E; Rahal, G; Sircar, A; Frey, A S; Stolte, P; Rosien, N; Zoch, K; Li, L; Schouten, D W; Catinaccio, A; Ciapetti, M; Delruelle, N; Ellis, N; Farthouat, P; Hoecker, A; Klioutchnikova, T; Macina, D; Malyukov, S; Spiwoks, R D; Unal, G P; Vandoni, G; Petersen, B A; Pommes, K; Nairz, A M; Wengler, T; Mladenov, D; Solans sanchez, C A; Lantzsch, K; Schmieden, K; Jakobsen, S; Ritsch, E; Sciuccati, A; Alves dos santos, A M; Ouyang, Q; Zhou, M; Brock, I C; Janssen, J; Katzy, J; Anders, C F; Nilsson, B S; Bazan, A; Di ciaccio, L; Yildizkaya, T; Collot, J; Malek, F; Trocme, B S; Breugnon, P; Godiot, S; Adam bourdarios, C; Coulon, J; Duflot, L; Petroff, P G; Zerwas, D; Lieuvin, M; Calderini, G; Laporte, D; Ocariz, J; Gabrielli, A; Ohska, T K; Kurochkin, Y; Kantserov, V; Vasilyeva, L; Speransky, M; Smirnov, S; Antonov, A; Bulekov, O; Tikhonov, Y; Sargsyan, L; Vardanyan, G; Budick, B; Kocian, M L; Luitz, S; Young, C C; Grenier, P J; Kelsey, M; Black, J E; Kneringer, E; Jussel, P; Horton, A J; Beaudry, J; Chandra, A; Ereditato, A; Topfel, C M; Mathieu, R; Bucci, F; Muenstermann, D; White, R M; He, M; Urban, J; Straka, M; Vrba, V; Schumacher, M; Parzefall, U; Mahboubi, K; Sommer, P O; Koepke, L H; Bethke, S; Moser, H; Wiesmann, M; Walkowiak, W A; Fleck, I J; Martinez-perez, M; Sanchez sanchez, C A; Jorgensen roca, S; Accion garcia, E; Sainz ruiz, C A; Valls ferrer, J A; Amoros vicente, G; Vives torrescasana, R; Ouraou, A; Formica, A; Hassani, S; Watson, M F; Cottin buracchio, G F; Bussey, P J; Saxon, D; Ferrando, J E; Collins-tooth, C L; Hall, D C; Cuhadar donszelmann, T; Dawson, I; Duxfield, R; Argyropoulos, T; Brodet, E; Livneh, R; Shougaev, K; Reinherz, E I; Guttman, N; Beretta, M M; Vilucchi, E; Aloisio, A; Patricelli, S; Caprio, M; Cevenini, F; De vecchi, C; Livan, M; Rimoldi, A; Vercesi, V; Ayad, R; Mastroberardino, A; Ciapetti, G; Luminari, L; Rescigno, M; Santonico, R; Salamon, A; Del papa, C; Kurashige, H; Homma, Y; Tomoto, M; Horii, Y; Sugaya, Y; Hanagaki, K; Bobbink, G; Kluit, P M; Koffeman, E N; Van eijk, B; Lee, H; Eigen, G; Dorholt, O; Strandlie, A; Strzempek, P B; Dita, S; Stoicea, G; Chitan, A; Leven, S S; Moa, T; Brenner, R; Ekelof, T J C; Olshevskiy, A; Roumiantsev, V; Chlachidze, G; Zimine, N; Gusakov, Y; Grigalashvili, N; Mineev, M; Potrap, I; Barashkou, A; Shoukavy, D; Shaykhatdenov, B; Pikelner, A; Gladilin, L; Ammosov, V; Abramov, A; Arik, M; Sahinsoy, M; Uysal, Z; Azizi, K; Hotinli, S C; Zhou, S; Berger, E; Blair, R; Underwood, D G; Einsweiler, K; Garcia-sciveres, M A; Siegrist, J L; Kipnis, I; Dahl, O; Holland, S; Barbaro galtieri, A; Smith, P T; Parua, N; Franklin, M; Mercurio, K M; Tong, B; Pod, E; Cole, S G; Hopkins, W H; Guest, D H; Severini, H; Marsicano, J J; Abbott, B K; Wang, Q; Lissauer, D; Ma, H; Takai, H; Rajagopalan, S; Protopopescu, S D; Snyder, S S; Undrus, A; Popescu, R N; Begel, M A; Blocker, C A; Amelung, C; Mandic, I; Macek, B; Tucker, B H; Citterio, M; Troncon, C; Orestano, D; Taccini, C; Romeo, G L; Dova, M T; Taylor, G N; Gesualdi manhaes, A; Mcpherson, R A; Sobie, R; Taylor, R P; Dolezal, Z; Kodys, P; Slovak, R; Sopko, B; Vacek, V; Sanders, M P; Hertenberger, R; Meineck, C; Becks, K; Kind, P; Sandhoff, M; Cantero garcia, J; De la torre perez, H; Castillo gimenez, V; Ros, E; Hernandez jimenez, Y; Chadelas, R; Santoni, C; Washbrook, A J; O'brien, B J; Wynne, B M; Mehta, A; Vossebeld, J H; Landon, M; Teixeira dias castanheira, M; Cerrito, L; Keates, J R; Fassouliotis, D; Chardalas, M; Manousos, A; Grachev, V; Seliverstov, D; Sedykh, E; Cakir, O; Ciftci, R; Edson, W; Prell, S A; Rosati, M; Stroman, T; Jiang, H; Neal, H A; Li, X; Gan, K K; Smith, D S; Kruse, M C; Ko, B R; Leung fook cheong, A M; Cole, B; Angerami, A R; Greene, Z S; Kroll, J I; Van berg, R P; Forbush, D A; Lubatti, H; Raisher, J; Shupe, M A; Wolin, S; Oshita, H; Gaudio, G; Das, R; Konig, A C; Croft, V A; Harvey, A; Maaroufi, F; Melo, I; Greenwood jr, Z D; Shabalina, E; Mchedlidze, G; Drechsler, E; Rieger, J K; Blackston, M; Colombo, T

2002-01-01

% ATLAS \\\\ \\\\ ATLAS is a general-purpose experiment for recording proton-proton collisions at LHC. The ATLAS collaboration consists of 144 participating institutions (June 1998) with more than 1750~physicists and engineers (700 from non-Member States). The detector design has been optimized to cover the largest possible range of LHC physics: searches for Higgs bosons and alternative schemes for the spontaneous symmetry-breaking mechanism; searches for supersymmetric particles, new gauge bosons, leptoquarks, and quark and lepton compositeness indicating extensions to the Standard Model and new physics beyond it; studies of the origin of CP violation via high-precision measurements of CP-violating B-decays; high-precision measurements of the third quark family such as the top-quark mass and decay properties, rare decays of B-hadrons, spectroscopy of rare B-hadrons, and $ B ^0 _{s} $-mixing. \\\\ \\\\The ATLAS dectector, shown in the Figure includes an inner tracking detector inside a 2~T~solenoid providing an axial...

Latest results on b-physics from the ATLAS and CMS experiments

CERN Document Server

Pasqualucci, E; The ATLAS collaboration

2013-01-01

This paper briefly reviews some of the latest measurements of the ATLAS and CMS experiments at LHC in the b-physics sector, namely the ones on rare and semi-rare B0(s) decays, the parity violation in the b decay and the CP violation parameters in the Bs --> J/psi (μ+μ−)phi(K+K−) process, some of the measurements on heavy quarkonia systems.

Production experience with the ATLAS Event Service

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00066086; The ATLAS collaboration; Calafiura, Paolo; Childers, John Taylor; De, Kaushik; Guan, Wen; Maeno, Tadashi; Nilsson, Paul; Tsulaia, Vakhtang; van Gemmeren, Peter; Wenaus, Torre

2017-01-01

The ATLAS Event Service (AES) has been designed and implemented for efficient running of ATLAS production workflows on a variety of computing platforms, ranging from conventional Grid sites to opportunistic, often short-lived resources, such as spot market commercial clouds, supercomputers and volunteer computing. The Event Service architecture allows real time delivery of fine grained workloads to running payload applications which process dispatched events or event ranges and immediately stream the outputs to highly scalable Object Stores. Thanks to its agile and flexible architecture the AES is currently being used by grid sites for assigning low priority workloads to otherwise idle computing resources; similarly harvesting HPC resources in an efficient back-fill mode; and massively scaling out to the 50-100k concurrent core level on the Amazon spot market to efficiently utilize those transient resources for peak production needs. Platform ports in development include ATLAS@Home (BOINC) and the Google Comp...

Production Experience with the ATLAS Event Service

CERN Document Server

Benjamin, Douglas; The ATLAS collaboration

2016-01-01

The ATLAS Event Service (ES) has been designed and implemented for efficient running of ATLAS production workflows on a variety of computing platforms, ranging from conventional Grid sites to opportunistic, often short-lived resources, such as spot market commercial clouds, supercomputers and volunteer computing. The Event Service architecture allows real time delivery of fine grained workloads to running payload applications which process dispatched events or event ranges and immediately stream the outputs to highly scalable Object Stores. Thanks to its agile and flexible architecture the ES is currently being used by grid sites for assigning low priority workloads to otherwise idle computing resources; similarly harvesting HPC resources in an efficient back-fill mode; and massively scaling out to the 50-100k concurrent core level on the Amazon spot market to efficiently utilize those transient resources for peak production needs. Platform ports in development include ATLAS@Home (BOINC) and the Goggle Comput...

ATLAS Distributed Computing Operations: Experience and improvements after 2 full years of data-taking

International Nuclear Information System (INIS)

Jézéquel, S; Stewart, G

2012-01-01

This paper summarizes operational experience and improvements in ATLAS computing infrastructure in 2010 and 2011. ATLAS has had 2 periods of data taking, with many more events recorded in 2011 than in 2010. It ran 3 major reprocessing campaigns. The activity in 2011 was similar to 2010, but scalability issues had to be addressed due to the increase in luminosity and trigger rate. Based on improved monitoring of ATLAS Grid computing, the evolution of computing activities (data/group production, their distribution and grid analysis) over time is presented. The main changes in the implementation of the computing model that will be shown are: the optimization of data distribution over the Grid, according to effective transfer rate and site readiness for analysis; the progressive dismantling of the cloud model, for data distribution and data processing; software installation migration to cvmfs; changing database access to a Frontier/squid infrastructure.

ATLAS Distributed Computing Automation

CERN Document Server

Schovancova, J; The ATLAS collaboration; Borrego, C; Campana, S; Di Girolamo, A; Elmsheuser, J; Hejbal, J; Kouba, T; Legger, F; Magradze, E; Medrano Llamas, R; Negri, G; Rinaldi, L; Sciacca, G; Serfon, C; Van Der Ster, D C

2012-01-01

The ATLAS Experiment benefits from computing resources distributed worldwide at more than 100 WLCG sites. The ATLAS Grid sites provide over 100k CPU job slots, over 100 PB of storage space on disk or tape. Monitoring of status of such a complex infrastructure is essential. The ATLAS Grid infrastructure is monitored 24/7 by two teams of shifters distributed world-wide, by the ATLAS Distributed Computing experts, and by site administrators. In this paper we summarize automation efforts performed within the ATLAS Distributed Computing team in order to reduce manpower costs and improve the reliability of the system. Different aspects of the automation process are described: from the ATLAS Grid site topology provided by the ATLAS Grid Information System, via automatic site testing by the HammerCloud, to automatic exclusion from production or analysis activities.

Evolution of the Trigger and Data Acquisition System for the ATLAS experiment

CERN Document Server

Negri, A; The ATLAS collaboration

2012-01-01

The ATLAS experiment at the Large Hadron Collider at CERN relies on a complex and highly distributed Trigger and Data Acquisition (TDAQ) system to gather and select particle collision data at unprecedented energy and rates. The TDAQ is composed of three levels which reduces the event rate from the design bunch-crossing rate of 40 MHz to an average event recording rate of about 200 Hz. The first part of this paper gives an overview of the operational performance of the DAQ system during 2011 and the first months of data taking in 2012. It describes how the flexibility inherent in the design of the system has be exploited to meet the changing needs of ATLAS data taking and in some cases push performance beyond the original design performance specification. The experience accumulated in the TDAQ system operation during these years stimulated also interest to explore possible evolutions, despite the success of the current design. One attractive direction is to merge three systems - the second trigger level (L2), ...

ATLAS Distributed Computing Experience and Performance During the LHC Run-2

Science.gov (United States)

Filipčič, A.; ATLAS Collaboration

2017-10-01

ATLAS Distributed Computing during LHC Run-1 was challenged by steadily increasing computing, storage and network requirements. In addition, the complexity of processing task workflows and their associated data management requirements led to a new paradigm in the ATLAS computing model for Run-2, accompanied by extensive evolution and redesign of the workflow and data management systems. The new systems were put into production at the end of 2014, and gained robustness and maturity during 2015 data taking. ProdSys2, the new request and task interface; JEDI, the dynamic job execution engine developed as an extension to PanDA; and Rucio, the new data management system, form the core of Run-2 ATLAS distributed computing engine. One of the big changes for Run-2 was the adoption of the Derivation Framework, which moves the chaotic CPU and data intensive part of the user analysis into the centrally organized train production, delivering derived AOD datasets to user groups for final analysis. The effectiveness of the new model was demonstrated through the delivery of analysis datasets to users just one week after data taking, by completing the calibration loop, Tier-0 processing and train production steps promptly. The great flexibility of the new system also makes it possible to execute part of the Tier-0 processing on the grid when Tier-0 resources experience a backlog during high data-taking periods. The introduction of the data lifetime model, where each dataset is assigned a finite lifetime (with extensions possible for frequently accessed data), was made possible by Rucio. Thanks to this the storage crises experienced in Run-1 have not reappeared during Run-2. In addition, the distinction between Tier-1 and Tier-2 disk storage, now largely artificial given the quality of Tier-2 resources and their networking, has been removed through the introduction of dynamic ATLAS clouds that group the storage endpoint nucleus and its close-by execution satellite sites. All stable

Big Data Challenges in High Energy Physics Experiments: The ATLAS (CERN) Fast TracKer Approach

CERN Document Server

Sotiropoulou, Calliope Louisa; The ATLAS collaboration

2016-01-01

We live in the era of “Big Data” problems. Massive amounts of data are produced and captured, data that require significant amounts of filtering to be processed in a realistically useful form. An excellent example of a “Big Data” problem is the data processing flow in High Energy Physics experiments, in our case the ATLAS detector in CERN. In the Large Hadron Collider (LHC) 40 million collisions of bunches of protons take place every second, which is about 15 trillion collisions per year. For the ATLAS detector alone 1 Mbyte of data is produced for every collision or 2000 Tbytes of data per year. Therefore what is needed is a very efficient real-time trigger system to filter the collisions (events) and identify the ones that contain “interesting” physics for processing. One of the upgrades of the ATLAS Trigger system is the Fast TracKer system. The Fast TracKer is a real-time pattern matching machine able to reconstruct the tracks of the particles in the inner silicon detector of the ATLAS experim...

Experience in Grid Site Testing for ATLAS, CMS and LHCb with HammerCloud

CERN Document Server

Van der Ster , D; Medrano Llamas, R; Legger , F; Sciaba, A; Sciacca, G; Ubeda Garca , M

2012-01-01

Frequent validation and stress testing of the network, storage and CPU resources of a grid site is essential to achieve high performance and reliability. HammerCloud was previously introduced with the goals of enabling VO- and site-administrators to run such tests in an automated or on-demand manner. The ATLAS, CMS and LHCb experiments have all developed VO plugins for the service and have successfully integrated it into their grid operations infrastructures. This work will present the experience in running HammerCloud at full scale for more than 3 years and present solutions to the scalability issues faced by the service. First, we will show the particular challenges faced when integrating with CMS and LHCb offline computing, including customized dashboards to show site validation reports for the VOs and a new API to tightly integrate with the LHCbDIRAC Resource Status System. Next, a study of the automatic site exclusion component used by ATLAS will be presented along with results for tuning the exclusion p...

Experience in Grid Site Testing for ATLAS, CMS and LHCb with HammerCloud

CERN Multimedia

CERN. Geneva

2012-01-01

Frequent validation and stress testing of the network, storage and CPU resources of a grid site is essential to achieve high performance and reliability. HammerCloud was previously introduced with the goals of enabling VO- and site-administrators to run such tests in an automated or on-demand manner. The ATLAS, CMS and LHCb experiments have all developed VO plugins for the service and have successfully integrated it into their grid operations infrastructures. This work will present the experience in running HammerCloud at full scale for more than 3 years and present solutions to the scalability issues faced by the service. First, we will show the particular challenges faced when integrating with CMS and LHCb offline computing, including customized dashboards to show site validation reports for the VOs and a new API to tightly integrate with the LHCbDIRAC Resource Status System. Next, a study of the automatic site exclusion component used by ATLAS will be presented along with results for tuning the exclusion ...

The evolution of the Trigger and Data Acquisition System in the ATLAS experiment

CERN Document Server

Krasznahorkay, A; The ATLAS collaboration

2013-01-01

The ATLAS experiment, aimed at recording the results of LHC proton-proton collisions, is upgrading its Trigger and Data Acquisition (TDAQ) system during the current LHC first long shutdown. The purpose of such upgrade is to add robustness and flexibility to the selection and the conveyance of the physics data, simplify the maintenance of the infrastructure, exploit new technologies and, overall, make ATLAS data-taking capable of dealing with increasing event rates. The TDAQ system used to date is organised in a three-level selection scheme, including a hardware-based first-level trigger and second- and third-level triggers implemented as separate software systems distributed on commodity hardware nodes. The second-level trigger operates over limited regions of the detector, the so-called Regions-of-Interest (RoI). The third-level trigger deals instead with complete events. While this architecture was successfully operated well beyond the original design goals, the accumulated experience stimulated interest to...

Experience with the Open Source based implementation for ATLAS Conditions Data Management System

CERN Document Server

Amorim, A; Oliveira, C; Pedro, L; Barros, N

2003-01-01

Conditions Data in high energy physics experiments is frequently seen as every data needed for reconstruction besides the event data itself. This includes all sorts of slowly evolving data like detector alignment, calibration and robustness, and data from detector control system. Also, every Conditions Data Object is associated with a time interval of validity and a version. Besides that, quite often is useful to tag collections of Conditions Data Objects altogether. These issues have already been investigated and a data model has been proposed and used for different implementations based in commercial DBMSs, both at CERN and for the BaBar experiment. The special case of the ATLAS complex trigger that requires online access to calibration and alignment data poses new challenges that have to be met using a flexible and customizable solution more in the line of Open Source components. Motivated by the ATLAS challenges we have developed an alternative implementation, based in an Open Source RDBMS. Several issues...

The evolution of the Trigger and Data Acquisition System in the ATLAS experiment

CERN Document Server

Krasznahorkay, A; The ATLAS collaboration

2014-01-01

The ATLAS experiment, aimed at recording the results of LHC proton-proton collisions, is upgrading its Trigger and Data Acquisition (TDAQ) system during the current LHC first long shutdown. The purpose of the upgrade is to add robustness and flexibility to the selection and the conveyance of the physics data, simplify the maintenance of the infrastructure, exploit new technologies and, overall, make ATLAS data-taking capable of dealing with increasing event rates. The TDAQ system used to date is organised in a three-level selection scheme, including a hardware-based first-level trigger and second- and third-level triggers implemented as separate software systems distributed on separate, commodity hardware nodes. While this architecture was successfully operated well beyond the original design goals, the accumulated experience stimulated interest to explore possible evolutions. We will also be upgrading the hardware of the TDAQ system by introducing new elements to it. For the high-level trigger, the current p...

The ATLAS Experiment at the LHC Collider

CERN Document Server

Djama, Fares; The ATLAS collaboration

2017-01-01

The talk shows selected results which illustrate the variety of physics measurements conducted by the ATLAS Collaboration at the LHC. Subdetectors and reconstructed objects are reviewed with their respective performance. Higgs boson and top quark properties are presented as well as electroweak and QCD measurements. Searches are briefly mentioned as they are covered by dedicated talks. The opportunity of the 25th anniversary of the Lomonosov Conference is also taken to look back 25 years ago, at the time of the ATLAS Letter of Intent.

Looking for the Charged Higgs Boson - Simulation Studies for the ATLAS Experiment

CERN Document Server

AUTHOR|(CDS)2073607

2009-01-01

The discovery of a charged Higgs boson (H+) would be an unambiguous sign of physics beyond the Standard Model. This thesis describes preparations for the H+ search with the ATLAS experiment at the Large Hadron Collider at CERN. The H+ discovery potential is evaluated, and tools for H+ searches are developed and refined. The $H^{+} \\to \\tau \

Tau lepton reconstruction with energy flow and the search for R-parity violating supersymmetry at the ATLAS experiment

Energy Technology Data Exchange (ETDEWEB)

Fleischmann, Sebastian

2012-10-15

This thesis investigates the discovery potential of the ATLAS experiment at the Large Hadron Collider (LHC) for R-parity violating (RPV) supersymmetric (SUSY) models in the framework of mSUGRA, where the stau ({tau}) is the lightest supersymmetric particle (LSP). Hence, the LSP is charged and decays in contrast to R-parity conserving models. For the first time in the framework of this RPV model a detailed signal to background analysis is performed for a specific benchmark scenario using a full Monte Carlo simulation of the ATLAS detector. Furthermore a feasibility study for an estimate of the stau LSP mass is given. The fast track simulation FATRAS is a new approach for the Monte Carlo simulation of particles in the tracking systems of the ATLAS experiment. Its results are compared to first data at {radical}(s) = 900 GeV. Additionally, two generic detector simulations are compared to the full simulation. The reconstruction of tau leptons is crucial for many searches for new physics with ATLAS. Therefore, the reconstruction of tracks for particles from tau decays is studied. A novel method, PanTau, is presented for the tau reconstruction in ATLAS. It is based on the energy flow algorithm eflowRec. Its performance is evaluated in Monte Carlo simulations. The dependency of the identification variables on the jet energy are studied in detail. Finally, the energy flow quantities and the identification variables are compared between Monte Carlo simulations and measured multijet events with first ATLAS data at {radical}(s) = 7 TeV.

Tau lepton reconstruction with energy flow and the search for R-parity violating supersymmetry at the ATLAS experiment

International Nuclear Information System (INIS)

Fleischmann, Sebastian

2012-10-01

This thesis investigates the discovery potential of the ATLAS experiment at the Large Hadron Collider (LHC) for R-parity violating (RPV) supersymmetric (SUSY) models in the framework of mSUGRA, where the stau (τ) is the lightest supersymmetric particle (LSP). Hence, the LSP is charged and decays in contrast to R-parity conserving models. For the first time in the framework of this RPV model a detailed signal to background analysis is performed for a specific benchmark scenario using a full Monte Carlo simulation of the ATLAS detector. Furthermore a feasibility study for an estimate of the stau LSP mass is given. The fast track simulation FATRAS is a new approach for the Monte Carlo simulation of particles in the tracking systems of the ATLAS experiment. Its results are compared to first data at √(s) = 900 GeV. Additionally, two generic detector simulations are compared to the full simulation. The reconstruction of tau leptons is crucial for many searches for new physics with ATLAS. Therefore, the reconstruction of tracks for particles from tau decays is studied. A novel method, PanTau, is presented for the tau reconstruction in ATLAS. It is based on the energy flow algorithm eflowRec. Its performance is evaluated in Monte Carlo simulations. The dependency of the identification variables on the jet energy are studied in detail. Finally, the energy flow quantities and the identification variables are compared between Monte Carlo simulations and measured multijet events with first ATLAS data at √(s) = 7 TeV.

ATLAS

Data.gov (United States)

Federal Laboratory Consortium — ATLAS is a particle physics experiment at the Large Hadron Collider at CERN, the European Organization for Nuclear Research. Scientists from Brookhaven have played...

Early operational experience with uranium beams at ATLAS

International Nuclear Information System (INIS)

Pardo, R.C.; Nolen, J.A.; Specht, J.R.

1994-01-01

The first acceleration of a uranium beam using the new ATLAS Positive Ion Injector(PII) took place on July 27, 1992. Since that first run, ATLAS and PII have completely achieved the design goals of the project and now provide high-current heavy-ion beams with energies beyond the Coulomb barrier for the research program. ATLAS routinely and reliably provides low-emittance beams of uranium and other very high-mass ions at energies in excess of 6 MeV/n with available on-target beam intensities exceeding 5 particle nA. The expectation that the beam quality for heavy beams would be significantly better than that of the tandem injector has been fully realized. The longitudinal emittance of beams from the PII is typically one-third that of similar beams from the tandem injector. In the past year ATLAS provided uranium beams for approximately 19% of the total research beam time, while beams with A≥100 were used 33% of the time. The system performance and techniques developed which made for this successful result will be discussed. Improvement projects underway will be presented and future goals described

Support system for ATLAS distributed computing operations

CERN Document Server

Kishimoto, Tomoe; The ATLAS collaboration

2018-01-01

The ATLAS distributed computing system has allowed the experiment to successfully meet the challenges of LHC Run 2. In order for distributed computing to operate smoothly and efficiently, several support teams are organized in the ATLAS experiment. The ADCoS (ATLAS Distributed Computing Operation Shifts) is a dedicated group of shifters who follow and report failing jobs, failing data transfers between sites, degradation of ATLAS central computing services, and more. The DAST (Distributed Analysis Support Team) provides user support to resolve issues related to running distributed analysis on the grid. The CRC (Computing Run Coordinator) maintains a global view of the day-to-day operations. In this presentation, the status and operational experience of the support system for ATLAS distributed computing in LHC Run 2 will be reported. This report also includes operations experience from the grid site point of view, and an analysis of the errors that create the biggest waste of wallclock time. The report of oper...

Project of the ATLAS experiment by LHC of CERN

International Nuclear Information System (INIS)

Andrieux, M.L.; Belhorma, B.; Collot, J.; Saintignon, P. de; Dzahini, D.; Ferrari, A.; Hostachy, J.Y.; Martin, Ph.; Rey-Campagnolle, M.; Belymam, A.; Wielers, B.

1997-01-01

The group is involved in the construction of the liquid argon calorimeter of the ATLAS detector. Following an intense R and D phase, the final detailed design at the ATLAS calorimeter was finalized, written and approved by the LHC committee. ATLAS is now in a pre-construction phase which implies that the group activities are mainly devoted to the installation of the assembly line of the electromagnetic pre-sampler sectors. Our R and D activities on the calorimeter electronics were pursued along two lines: the optimization of the filtering amplifiers and a participation to the development of optical links for data transmission. Liquid argon pollution tests under radiation were also achieved at SARA. They proved the radiation hardness of the liquid argon calorimeter. We recently showed that the search for heavy right-handed neutrinos up to m N < 3 TeV is possible with the ATLAS detector. (authors)

Reconstruction and identification of electrons in the Atlas experiment. Setup of a Tier 2 of the computing grid; Reconstruction et identification des electrons dans l'experience Atlas. Participation a la mise en place d'un Tier 2 de la grille de calcul

Energy Technology Data Exchange (ETDEWEB)

Derue, F

2008-03-15

The origin of the mass of elementary particles is linked to the electroweak symmetry breaking mechanism. Its study will be one of the main efforts of the Atlas experiment at the Large Hadron Collider of CERN, starting in 2008. In most cases, studies will be limited by our knowledge of the detector performances, as the precision of the energy reconstruction or the efficiency to identify particles. This manuscript presents a work dedicated to the reconstruction of electrons in the Atlas experiment with simulated data and data taken during the combined test beam of 2004. The analysis of the Atlas data implies the use of a huge amount of computing and storage resources which brought to the development of a world computing grid. (author)

ATLAS Strip Detector: Operational Experience and Run1-> Run2 Transition

CERN Document Server

Nagai, Koichi; The ATLAS collaboration

2014-01-01

Large hadron collider was operated very successfully during the Run1 and provided a lot of opportunities of physics studies. It currently has a consolidation work toward to the operation at $\\sqrt{s}=14 \\mathrm{TeV}$ in Run2. The ATLAS experiment has achieved excellent performance in Run1 operation, delivering remarkable physics results. The SemiConductor Tracker contributed to the precise measurement of momentum of charged particles. This paper describes the operation experience of the SemiConductor Tracker in Run1 and the preparation toward to the Run2 operation during the LS1.

ATLAS rewards industry

CERN Multimedia

2006-01-01

Showing excellence in mechanics, electronics and cryogenics, three industries are honoured for their contributions to the ATLAS experiment. Representatives of the three award-wining companies after the ceremony. For contributing vital pieces to the ATLAS puzzle, three industries were recognized on Friday 5 May during a supplier awards ceremony. After a welcome and overview of the ATLAS experiment by spokesperson Peter Jenni, CERN Secretary-General Maximilian Metzger stressed the importance of industry to CERN's scientific goals. Close interaction with CERN was a key factor in the selection of each rewarded company, in addition to the high-quality products they delivered to the experiment. Alu Menziken Industrie AG, of Switzerland, was honoured for the production of 380,000 aluminium tubes for the Monitored Drift Tube Chambers (MDT). As Giora Mikenberg, the Muon System Project Leader stressed, the aluminium tubes were delivered on time with an extraordinary quality and precision. Between October 2000 and Jan...

Search for Direct Top Squark Pair Production with the ATLAS Experiment and Studies of the Primary Vertex Reconstruction Performance

CERN Document Server

Abulaiti, Yiming

The ATLAS detector is one of the two largest experiments installed at the Large Hadron Collider at CERN, the European Organization for Nuclear Research. During the first run, the ATLAS detector recorded data at centre of mass energies of 7 TeV and 8 TeV, enabling many precision measurements and new physics searches. One important task in ATLAS is measuring the primary vertex, the interaction point of the hardest proton-proton collision in an event. In this thesis, a study of the primary vertex reconstruction performance in data and simulated events using tt ̄ and Z events is presented. Within the statistics available, the performance in data and simulated events is found to be compatible. Motivated by the limitations of the Standard Model of particle physics, searches for supersymmetric particles are performed with the ATLAS experiment. No signal has been observed so far, and the results are used to set exclusion limits on the masses of the supersymmetric particles. As the exclusion limits are derived from a...

Glance Information System for ATLAS Management

International Nuclear Information System (INIS)

Grael, F F; Maidantchik, C; Évora, L H R A; Karam, K; Moraes, L O F; Cirilli, M; Nessi, M; Pommès, K

2011-01-01

ATLAS Experiment is an international collaboration where more than 37 countries, 172 institutes and laboratories, 2900 physicists, engineers, and computer scientists plus 700 students participate. The management of this teamwork involves several aspects such as institute contribution, employment records, members' appointment, authors' list, preparation and publication of papers and speakers nomination. Previously, most of the information was accessible by a limited group and developers had to face problems such as different terminology, diverse data modeling, heterogeneous databases and unlike users needs. Moreover, the systems were not designed to handle new requirements. The maintenance has to be an easy task due to the long lifetime experiment and professionals turnover. The Glance system, a generic mechanism for accessing any database, acts as an intermediate layer isolating the user from the particularities of each database. It retrieves, inserts and updates the database independently of its technology and modeling. Relying on Glance, a group of systems were built to support the ATLAS management and operation aspects: ATLAS Membership, ATLAS Appointments, ATLAS Speakers, ATLAS Analysis Follow-Up, ATLAS Conference Notes, ATLAS Thesis, ATLAS Traceability and DSS Alarms Viewer. This paper presents the overview of the Glance information framework and describes the privilege mechanism developed to grant different level of access for each member and system.

Glance Information System for ATLAS Management

Science.gov (United States)

Grael, F. F.; Maidantchik, C.; Évora, L. H. R. A.; Karam, K.; Moraes, L. O. F.; Cirilli, M.; Nessi, M.; Pommès, K.; ATLAS Collaboration

2011-12-01

ATLAS Experiment is an international collaboration where more than 37 countries, 172 institutes and laboratories, 2900 physicists, engineers, and computer scientists plus 700 students participate. The management of this teamwork involves several aspects such as institute contribution, employment records, members' appointment, authors' list, preparation and publication of papers and speakers nomination. Previously, most of the information was accessible by a limited group and developers had to face problems such as different terminology, diverse data modeling, heterogeneous databases and unlike users needs. Moreover, the systems were not designed to handle new requirements. The maintenance has to be an easy task due to the long lifetime experiment and professionals turnover. The Glance system, a generic mechanism for accessing any database, acts as an intermediate layer isolating the user from the particularities of each database. It retrieves, inserts and updates the database independently of its technology and modeling. Relying on Glance, a group of systems were built to support the ATLAS management and operation aspects: ATLAS Membership, ATLAS Appointments, ATLAS Speakers, ATLAS Analysis Follow-Up, ATLAS Conference Notes, ATLAS Thesis, ATLAS Traceability and DSS Alarms Viewer. This paper presents the overview of the Glance information framework and describes the privilege mechanism developed to grant different level of access for each member and system.

ATLAS Cloud R&D

Science.gov (United States)

Panitkin, Sergey; Barreiro Megino, Fernando; Caballero Bejar, Jose; Benjamin, Doug; Di Girolamo, Alessandro; Gable, Ian; Hendrix, Val; Hover, John; Kucharczyk, Katarzyna; Medrano Llamas, Ramon; Love, Peter; Ohman, Henrik; Paterson, Michael; Sobie, Randall; Taylor, Ryan; Walker, Rodney; Zaytsev, Alexander; Atlas Collaboration

2014-06-01

The computing model of the ATLAS experiment was designed around the concept of grid computing and, since the start of data taking, this model has proven very successful. However, new cloud computing technologies bring attractive features to improve the operations and elasticity of scientific distributed computing. ATLAS sees grid and cloud computing as complementary technologies that will coexist at different levels of resource abstraction, and two years ago created an R&D working group to investigate the different integration scenarios. The ATLAS Cloud Computing R&D has been able to demonstrate the feasibility of offloading work from grid to cloud sites and, as of today, is able to integrate transparently various cloud resources into the PanDA workload management system. The ATLAS Cloud Computing R&D is operating various PanDA queues on private and public resources and has provided several hundred thousand CPU days to the experiment. As a result, the ATLAS Cloud Computing R&D group has gained a significant insight into the cloud computing landscape and has identified points that still need to be addressed in order to fully utilize this technology. This contribution will explain the cloud integration models that are being evaluated and will discuss ATLAS' learning during the collaboration with leading commercial and academic cloud providers.

Taus at ATLAS

Energy Technology Data Exchange (ETDEWEB)

Demers, Sarah M. [Yale Univ., New Haven, CT (United States). Dept. of Physics

2017-12-06

The grant "Taus at ATLAS" supported the group of Sarah Demers at Yale University over a period of 8.5 months, bridging the time between her Early Career Award and her inclusion on Yale's grant cycle within the Department of Energy's Office of Science. The work supported the functioning of the ATLAS Experiment at CERN's Large Hadron Collider and the analysis of ATLAS data. The work included searching for the Higgs Boson in a particular mode of its production (with a W or Z boson) and decay (to a pair of tau leptons.) This was part of a broad program of characterizing the Higgs boson as we try to understand this recently discovered particle, and whether or not it matches our expectations within the current standard model of particle physics. In addition, group members worked with simulation to understand the physics reach of planned upgrades to the ATLAS experiment. Supported group members include postdoctoral researcher Lotte Thomsen and graduate student Mariel Pettee.

Development and Tests of the Event Filter for the ATLAS Experiment

CERN Document Server

Bosman, M; Negri, A; Segura, E; Sushkov, S; Touchard, F; Wheeler, S J; 14th IEEE - NPSS Real Time Conference 2005 Nuclear Plasma Sciences Society

2005-01-01

The Trigger and Data Acquisition (TDAQ) System of the ATLAS Experiment comprises three stages of event selection. The Event Filter (EF) is the third level trigger and is software implemented. Its primary goal is the final selection of interesting events with reduction of the event rate down to ~200 Hz acceptable by the mass storage. The EF System will be implemented as a set of independent commodity components Sub-Farms, each connected to the Event Builder subsystem to receive full events and on the other side to the Sub-Farm Output nodes, where the selected events are forwarded to mass storage. A distinctive feature of the Event Filter is its ability to use the full event data for selection directly based on the offline reconstruction and analysis algorithms. Besides the main duties on event triggering and data transportation, the EF is also able to provide additional functionalities, like monitoring of the selected events and online calibration of the ATLAS detectors. Significant design improvements are cur...

The Atlas pulsed power facility for high energy density physics experiments

CERN Document Server

Miller, R B; Barr, G W; Bowman, D W; Cochrane, J C; Davis, H A; Elizondo, J M; Gribble, R F; Griego, J R; Hicks, R D; Hinckley, W B; Hosack, K W; Nielsen, K E; Parker, J V; Parsons, M O; Rickets, R L; Salazar, H R; Sánchez, P G; Scudder, D W; Shapiro, C; Thompson, M C; Trainor, R J; Valdez, G A; Vigil, B N; Watt, R G; Wysocki, F J; Kirbie, H C

1999-01-01

The Atlas facility, now under construction at Los Alamos National Laboratory (LANL), will provide a unique capability for performing high-energy-density experiments in support of weapon-physics and basic-research programs. Here, the authors describe how the primary element of Atlas is a 23-MJ capacitor bank, comprised of 96 separate Marx generators housed in 12 separate oil-filled tanks, surrounding a central target chamber. Each tank will house two, independently- removable maintenance units, with each maintenance unit consisting of four Marx modules. Each Marx module has four capacitors that can each be charged to a maximum of 60 kilovolts. When railgap switches are triggered, the Marx modules erect to a maximum of 240 kV. The parallel discharge of these 96 Marx modules will deliver a 30-MA current pulse with a 4-5-ys risetime to a cylindrical, imploding liner via 24 vertical, tri-plate, oil-insulated transmission lines. An experimental program for testing and certifying all Marx and transmission line compo...

Reconstruction of tau lepton decays and applications in the ATLAS experiment

Energy Technology Data Exchange (ETDEWEB)

Wagner, Peter [Rheinische Friedrich-Wilhelms-Universitaet Bonn (Germany)

2016-07-01

Final states with hadronically decaying tau leptons play an important part in the physics programme of the ATLAS experiment. Examples are measurements of Standard Model processes, evidence of the Higgs-boson Yukawa couplings to tau leptons, and searches for new physics phenomena, such as Supersymmetry. These analyses depended on robust tau reconstruction and excellent particle identification algorithms that provided suppression of backgrounds from jets, electrons and muons. I present a new ''particle flow'' method of reconstructing the individual charged and neutral hadrons in tau decays with the ATLAS detector which leads to a significant improvement in the tau energy and directional resolution. It further gives access to the individual charged and neutral hadron four-momenta and offers a high purity decay mode selection. These features will play a particularly important role in analyses that exploit tau spin information, such as a measurement of the CP mixture of the Higgs boson in H → ττ decays.

Commissioning of the ATLAS Insertable B-Layer and first operation experience

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00439451; Dobos, Daniel; Rembser, Christoph

Todays research in particle physics offers a wide field of opportunities for scientists from a variety of different subjects. Discoveries can only be made, with hundreds up to thousands of people working together in collaborations. Designing high precision detectors that can be up to several stories tall, followed by production, construction, commissioning and successful operation is only achievable with the combined effort of skilled and experienced detector physicists and engineers, while the vast amount of data recorded with those detectors calls for specialists in data analysis which are able to find the needle in a haystack or in other words the higgs in a sea of underground events. One of the biggest science collaborations worldwide is the ATLAS collaboration with more than 5000 members from around 180 institutes. ATLAS is one of four big particle physics experiments at the LHC. Its tracking system has been upgraded with a new innermost layer, referred to as Insertable B-Layer (IBL), in 2014. This thesi...

Development of a Next Generation Concurrent Framework for the ATLAS Experiment

CERN Document Server

Leggett, Charles; The ATLAS collaboration; Calafiura, Paolo; Wynne, Benjamin; Malon, David; Lampl, Walter

2015-01-01

The ATLAS experiment has successfully used its Gaudi/Athena software framework for data taking and analysis during the first LHC run, with billions of events successfully processed. However, the design of Gaudi/Athena dates from early 2000 and the software and the physics code has been written using a single threaded, serial design. This programming model has increasing difficulty in exploiting the potential of current CPUs, which offer their best performance only through taking full advantage of multiple cores and wide vector registers. Future CPU evolution will intensify this trend, with core counts increasing and memory per core falling. With current memory consumption for 64 bit ATLAS reconstruction in a high luminosity environment approaching 4GB, it will become impossible to fully occupy all cores in a machine without exhausting available memory. However, since maximizing performance per watt will be a key metric, a mechanism must be found to use all cores as efficiently as possible. In this paper we re...

Development of a Next Generation Concurrent Framework for the ATLAS Experiment

CERN Document Server

Leggett, Charles; The ATLAS collaboration; Lampl, Walter; Malon, David; Stewart, Graeme; Wynne, Benjamin

2015-01-01

The ATLAS experiment has successfully used its Gaudi/Athena software framework for data taking and analysis during the first LHC run, with billions of events successfully processed. However, the design of Gaudi/Athena dates from early 2000 and the software and the physics code has been written using a single threaded, serial design. This programming model has increasing difficulty in exploiting the potential of current CPUs, which offer their best performance only through taking full advantage of multiple cores and wide vector registers. Future CPU evolution will intensify this trend, with core counts increasing and memory per core falling. With current memory consumption for 64 bit ATLAS reconstruction in a high luminosity environment approaching 4GB, it will become impossible to fully occupy all cores in a machine without exhausting available memory. However, since maximising performance per watt will be a key metric, a mechanism must be found to use all cores as efficiently as possible. In this paper we re...

Experience with highly-parallel software for the storage system of the ATLAS Experiment at CERN

CERN Document Server

Colombo, T; The ATLAS collaboration

2012-01-01

The ATLAS experiment is observing proton-proton collisions delivered by the LHC accelerator at a centre of mass energy of 7 TeV. The ATLAS Trigger and Data Acquisition (TDAQ) system selects interesting events on-line in a three-level trigger system in order to store them at a budgeted rate of several hundred Hz, for an average event size of ~1.2 MB. This paper focuses on the TDAQ data-logging system and in particular on the implementation and performance of a novel SW design, reporting on the effort of exploiting the full power of recently installed multi-core hardware. In this respect, the main challenge presented by the data-logging workload is the conflict between the largely parallel nature of the event processing, especially the recently introduced on-line event-compression, and the constraint of sequential file writing and checksum evaluation. This is furtherly complicated by the necessity of operating in a fully data-driven mode, to cope with continuously evolving trigger and detector configurations. T...

11 August 2008 - Member of the House of Councillors M. Naito (The National Diet of Japan, The Democratic Party of Japan) visiting the ATLAS experiment control room with Collaboration Spokesperson P. Jenni and ATLAS Muon Project Leader G. Mikenberg. Family photograph with CERN Japanese scientists in front of the ATLAS surface building.

CERN Multimedia

Maximilien Brice

2008-01-01

11 August 2008 - Member of the House of Councillors M. Naito (The National Diet of Japan, The Democratic Party of Japan) visiting the ATLAS experiment control room with Collaboration Spokesperson P. Jenni and ATLAS Muon Project Leader G. Mikenberg. Family photograph with CERN Japanese scientists in front of the ATLAS surface building.

Beyond the Standard Model Higgs boson searches using the ATLAS Experiment

CERN Document Server

Tsukerman, Ilya; The ATLAS collaboration

2014-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond the Standard Model (BSM) Higgs boson searches are outlined. The results are interpreted in well-motivated BSM Higgs frameworks.

Experience ATLAS on the surface

CERN Multimedia

2009-01-01

The new high-tech ATLAS Visitor Centre was officially inaugurated on 23 February. Located next to the ATLAS control centre at Point 1, it boasts some technology to rival its neighbour. var flash_video_player=get_video_player_path(); insert_player_for_external('Video/Public/Movies/2009/CERN-MOVIE-2009-004/CERN-MOVIE-2009-004-0753-kbps-640x360-25-fps-audio-64-kbps-44-kHz-stereo', 'mms://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-004/CERN-MOVIE-2009-004-Multirate-200-to-753-kbps-640x360-25-fps.wmv', 'false', 533, 300, 'https://mediastream.cern.ch/MediaArchive/Video/Public/Movies/2009/CERN-MOVIE-2009-004/CERN-MOVIE-2009-004-posterframe-640x360-at-10-percent.jpg', '1164774', true, 'Video/Public/Movies/2009/CERN-MOVIE-2009-004/CERN-MOVIE-2009-004-0600-kbps-maxH-360-25-fps-audio-128-kbps-48-kHz-stereo.mp4'); Watch the video! The centre is overflowing with fun, interactive activities. Juliette Davenne, lef...

Event visualization in ATLAS

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00211497; The ATLAS collaboration; Boudreau, Joseph; Konstantinidis, Nikolaos; Martyniuk, Alex; Moyse, Edward; Thomas, Juergen; Waugh, Ben; Yallup, David

2017-01-01

At the beginning, HEP experiments made use of photographical images both to record and store experimental data and to illustrate their findings. Then the experiments evolved and needed to find ways to visualize their data. With the availability of computer graphics, software packages to display event data and the detector geometry started to be developed. Here, an overview of the usage of event display tools in HEP is presented. Then the case of the ATLAS experiment is considered in more detail and two widely used event display packages are presented, Atlantis and VP1, focusing on the software technologies they employ, as well as their strengths, differences and their usage in the experiment: from physics analysis to detector development, and from online monitoring to outreach and communication. Towards the end, the other ATLAS visualization tools will be briefly presented as well. Future development plans and improvements in the ATLAS event display packages will also be discussed.

Short description of BMS/BMF MDT chamber production for the muon spectrometer of the ATLAS experiment

International Nuclear Information System (INIS)

Barashkov, A.V.; Glonti, G.L.; Gongadze, A.L.; Gongadze, I.B.; Gostkin, M.I.; Gus'kov, A.V.; Dedovich, D.V.; Demichev, M.A.; Evtukhovich, P.G.; Elagin, A.L.; Zhemchugov, A.S.; Il'yushenko, E.N.; Kotov, S.A.; Kotova, T.I.; Korolevich, Ya.V.; Kruchonok, V.G.; Krumshtejn, Z.V.; Kuznetsov, N.K.; Lomidze, D.D.; Nikolaev, K.V.; Potrap, I.N.; Rudenko, T.O.; Kharchenko, D.V.; Tskhadadze, Eh.G.; Chepurnov, V.F.; Shelkov, G.A.; Shiyakova, M.M.; Shcherbakov, A.A.; Podkladkin, S.Yu.

2005-01-01

The method of assembly of the MDT chambers for the muon spectrometer of the ATLAS experiment is described. During 2000-2004 ∼ 25000 drift tubes were produced at the DLNP, JINR. The tubes were assembled into 84 muon chambers of BMS/BMF type, one of the six main types for the barrel part of the ATLAS muon spectrometer. Particle momenta must be measured in the ATLAS spectrometer with very high precision (2% at 100 GeV/c and 10% at 1000 GeV/c), which required to produce the coordinate detectors with very high (∼80 μm) precision. We describe the method of assembly of large-scale 5-10 m 2 muon chambers with the signal wire mean deviation from the nominal position less than 20 μm

An Associative Memory Chip for the Trigger System of the ATLAS Experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00380893; The ATLAS collaboration; Liberali, Valentino; Crescioli, Francesco; Beretta, Matteo; Frontini, Luca; Annovi, Alberto; Stabile, Alberto

2017-01-01

The AM06 is the 6th version of a large associative memory chip designed in 65 nm CMOS tech- nology. The AM06 operates as a highly parallel ASIC processor for pattern recognition in the ATLAS experiment at CERN. It is the core of the Fast TracKer electronic system, which is tai- lored for on-line track finding in the trigger system of the ATLAS experiment. The Fast TracKer system is able to process events up to 100 MHz in real time. The AM06 is a complex chip, and it has been designed combining full-custom memory arrays, standard logic cells and IP blocks. It contains memory banks that store data organized in 18 bit words; a group of 8 words is called a pattern. The chip silicon area is 168 mm2; it contains 421 millions of transistors and it stores 217 patterns. Moreover, the associative memory is suitable also for other interdisciplinary appli- cations (i.e., general purpose image filtering and analysis). In the near future we plan to design a more powerful and flexible chip in 28 nm CMOS technology.

ATLAS Distributed Computing

CERN Document Server

Schovancova, J; The ATLAS collaboration

2011-01-01

The poster details the different aspects of the ATLAS Distributed Computing experience after the first year of LHC data taking. We describe the performance of the ATLAS distributed computing system and the lessons learned during the 2010 run, pointing out parts of the system which were in a good shape, and also spotting areas which required improvements. Improvements ranged from hardware upgrade on the ATLAS Tier-0 computing pools to improve data distribution rates, tuning of FTS channels between CERN and Tier-1s, and studying data access patterns for Grid analysis to improve the global processing rate. We show recent software development driven by operational needs with emphasis on data management and job execution in the ATLAS production system.

The Next Generation ATLAS Production System

CERN Document Server

Borodin, Mikhail; The ATLAS collaboration; Golubkov, Dmitry; Klimentov, Alexei; Maeno, Tadashi; Mashinistov, Ruslan; Vaniachine, Alexandre

2015-01-01

The ATLAS experiment at LHC data processing and simulation grows continuously, as more data and more use cases emerge. For data processing the ATLAS experiment adopted the data transformation approach, where software applications transform the input data into outputs. In the ATLAS production system, each data transformation is represented by a task, a collection of many jobs, dynamically submitted by the ATLAS workload management system (PanDA/JEDI) and executed on the Grid, clouds and supercomputers. Patterns in ATLAS data transformation workflows composed of many tasks provided a scalable production system framework for template definitions of the many-tasks workflows. User interface and system logic of these workflows are being implemented in the Database Engine for Tasks (DEFT). Such development required using modern computing technologies and approaches. We report technical details of this development: database implementation, server logic and Web user interface technologies.

A Slice of ATLAS

CERN Document Server

2004-01-01

An entire section of the ATLAS detector is being assembled at Prévessin. Since May the components have been tested using a beam from the SPS, giving the ATLAS team valuable experience of operating the detector as well as an opportunity to debug the system.

Recent Results from the ATLAS Experiment

CERN Document Server

Djama, Fares; The ATLAS collaboration

2015-01-01

A selection of recent Run 1 ATLAS results and first preliminary results from Run 2 are shown. Overview plots on Higgs properties, top measurements and SUSY searches are presented as well as recent QCD and electroweak measurements.

A first-level calorimeter trigger for the ATLAS experiment

International Nuclear Information System (INIS)

Perera, V.; Edwards, J.; Gee, N.

1995-01-01

In the RD27 collaboration the authors have carried out system studies on the implementation of the first level calorimeter trigger processor system for the ATLAS experiment to be mounted at the Large Hadron Collider (LHC) at CERN. A demonstrator trigger system operated successfully with the RD3 and RD33 calorimeters at the full 40 MHz LHC bunch crossing (BC) rate. The prototype application-specific integrated circuits (ASICs) in this system each processed data from only a single trigger cell and its environment, which would lead to an extremely large system for ATLAS. Using eight-bit parallel data even the use of ASICs, processing multiple trigger cells would demand unacceptably large numbers of input pins and module connections. Initial studies of this I/O problem produced a solution based on asynchronous transmission of zero-suppressed and BC-tagged data on 160 Mbit/s serial links. This approach appeared to be feasible but would have introduced additional latency of about 20 BCs. Further studies have led to the design of a fully-synchronous calorimeter trigger processor system using commercial high-speed optical links. The links will terminate in multi-chip modules (MCMs) incorporating custom-designed integrated optics, and the trigger algorithms will be implemented in ASICs

Computational and mathematical methods in brain atlasing.

Science.gov (United States)

Nowinski, Wieslaw L

2017-12-01

Brain atlases have a wide range of use from education to research to clinical applications. Mathematical methods as well as computational methods and tools play a major role in the process of brain atlas building and developing atlas-based applications. Computational methods and tools cover three areas: dedicated editors for brain model creation, brain navigators supporting multiple platforms, and atlas-assisted specific applications. Mathematical methods in atlas building and developing atlas-aided applications deal with problems in image segmentation, geometric body modelling, physical modelling, atlas-to-scan registration, visualisation, interaction and virtual reality. Here I overview computational and mathematical methods in atlas building and developing atlas-assisted applications, and share my contribution to and experience in this field.

ATLAS's inner detector installed in the heart of the experiment

CERN Multimedia

2006-01-01

The ATLAS collaboration recently celebrated a major engineering milestone, namely the transport and installation of the central part of the inner detector (ID-barrel) into the ATLAS detector. Right: Engineers and technicians work to carefully align and install the inner detector in the centre of ATLAS.Left: The crane used in the carefully coordinated effort by the ATLAS collaboration to lower down the fragile inner detector 100 metres underground to its new home. Many members of the collaboration gathered to witness this moment at Point 1. After years of design, construction and commissioning, the two outer detectors (TRT and SCT) of the inner detector barrel (ID-barrel) were moved from the SR1 cleanroom to the ATLAS cavern. The barrel was moved across the car park from Building 2175 to SX1. Although only a journey of about 100 metres, this required weeks of planning and some degree of luck as far as the weather was concerned. Special measures were in place to minimize shock and vibration during transportati...

Study of the Z Boson Production at the ATLAS Experiment with First Data

CERN Document Server

Schott, Matthias

The ATLAS detector, currently in its final installation phase at CERN, is designed to provide precise measurements of 14 TeV proton-proton collisions at the Large Hadron Collider. The measurements of the cross section and transverse momentum spectrum of the Z boson production at LHC provides first tests of the standard model in a new energy domain and may reveal exotic physics processes. Moreover, the properties of the Z boson resonance and its decay into two muons are known to very high precision from LEP experiments and hence can be used as a physics process for calibration and alignment. The Z boson production is also a common background process for many other physics analyses and must therefore be well understood. This thesis describes a measurement strategy of the cross section s for the process pp->Z->(mu)(mu) at the ATLAS experiment during its startup phase. As a result of this study a precision of d(sigma)/ (sigma) = 0.006(stat) + 0.008(sys) + 0.01 (pdf) is expected for an integrated luminosity of 50 ...

Operational Experience and Performance with the ATLAS Pixel Detector at the Large Hadron Collider

CERN Document Server

Grummer, Aidan; The ATLAS collaboration

2018-01-01

The tracking performance of the ATLAS detector relies critically on its 4-layer Pixel Detector, that has undergone significant hardware and software upgrades to meet the challenges imposed by the higher collision energy, pileup and luminosity that are being delivered by the Large Hadron Collider, with record breaking instantaneous luminosities of 2 x 10^34 cm-2 s-1 recently surpassed. The key status and performance metrics of the ATLAS Pixel Detector are summarised, and the operational experience and requirements to ensure optimum data quality and data taking efficiency will be described, with special emphasis to radiation damage experience. In particular, radiation damage effects will be showed and signs of degradation which are visible but which are not impacting yet the tracking performance (but will): dE/dX, occupancy reduction with integrated luminosity, under-depletion effects with IBL in 2016, effects of annealing that is not insignificant for the inner-most layers. Therefore the offline software strat...

ATLAS End-cap Part II

CERN Multimedia

2007-01-01

The epic journey of the ATLAS magnets is drawing to an end. On Thursday 12 July, the second end-cap of the ATLAS toroid magnet was lowered into the cavern of the experiment with the same degree of precision as the first (see Bulletin No. 26/2007). This spectacular descent of the 240-tonne component, is one of the last transport to be completed for ATLAS.

ATLAS Visitors Centre

CERN Multimedia

claudia Marcelloni

2009-01-01

ATLAS Visitors Centre has opened its shiny new doors to the public. Officially launched on Monday February 23rd, 2009, the permanent exhibition at Point 1 was conceived as a tour resource for ATLAS guides, and as a way to preserve the public’s opportunity to get a close-up look at the experiment in action when the cavern is sealed.

ATLAS rewards industry

CERN Document Server

Maximilien Brice

2006-01-01

For contributing vital pieces to the ATLAS puzzle, three industries were recognized on Friday 5 May during a supplier awards ceremony. After a welcome and overview of the ATLAS experiment by spokesperson Peter Jenni, CERN Secretary-General Maximilian Metzger stressed the importance of industry to CERN's scientific goals. Picture 30 : representatives of the three award-wining companies after the ceremony

AGIS: The ATLAS Grid Information System

Science.gov (United States)

Anisenkov, A.; Di Girolamo, A.; Klimentov, A.; Oleynik, D.; Petrosyan, A.; Atlas Collaboration

2014-06-01

ATLAS, a particle physics experiment at the Large Hadron Collider at CERN, produced petabytes of data annually through simulation production and tens of petabytes of data per year from the detector itself. The ATLAS computing model embraces the Grid paradigm and a high degree of decentralization and computing resources able to meet ATLAS requirements of petabytes scale data operations. In this paper we describe the ATLAS Grid Information System (AGIS), designed to integrate configuration and status information about resources, services and topology of the computing infrastructure used by the ATLAS Distributed Computing applications and services.

Study of the Z boson production at the ATLAS experiment with first data

International Nuclear Information System (INIS)

Schott, M.

2007-06-01

The ATLAS detector, currently in its final installation phase at CERN, is designed to provide precise measurements of 14 TeV proton-proton collisions at the Large Hadron Collider. The measurements of the cross section and transverse momentum spectrum of the Z boson production at LHC provides first tests of the standard model in a new energy domain and may reveal exotic physics processes. Moreover, the properties of the Z boson resonance and its decay into two muons are known to very high precision from LEP experiments and hence can be used as a physics process for calibration and alignment. The Z boson production is also a common background process for many other physics analyses and must therefore be well understood. This thesis describes a measurement strategy of the cross section σ for the process pp→γ/Z→μ + μ - at the ATLAS experiment during its startup phase. As a result of this study a precision of (Δσ)/(σ)∼0.006(stat)±0.008(sys) +0.016 -0.008 (pdf) is expected for an integrated luminosity of 50 pb -1 , assuming a fully operational ATLAS detector, not including uncertainties in the luminosity measurements. A major goal of the approach presented was to minimize the dependence on Monte Carlo simulations. Hence, several methods for the determination of the detector response based on data have been studied. In addition, a strategy for the differential cross section measurement (dσ)/(dp Z T ) of the transverse momentum of the Z boson has been developed. In contrast to a measurement of the total cross section, it is expected that the statistical uncertainty dominates for the given integrated luminosity of 50 pb -1 . The predicted high p T resolution of the ATLAS Inner Detector and the Muon Spectrometer allow for the first observation of interesting parton distribution effects, i.e. the so-called x-broadening, even with the limited statistics expected during the first data taking period.

Study of the Z boson production at the ATLAS experiment with first data

Energy Technology Data Exchange (ETDEWEB)

Schott, M

2007-06-15

The ATLAS detector, currently in its final installation phase at CERN, is designed to provide precise measurements of 14 TeV proton-proton collisions at the Large Hadron Collider. The measurements of the cross section and transverse momentum spectrum of the Z boson production at LHC provides first tests of the standard model in a new energy domain and may reveal exotic physics processes. Moreover, the properties of the Z boson resonance and its decay into two muons are known to very high precision from LEP experiments and hence can be used as a physics process for calibration and alignment. The Z boson production is also a common background process for many other physics analyses and must therefore be well understood. This thesis describes a measurement strategy of the cross section {sigma} for the process pp{yields}{gamma}/Z{yields}{mu}{sup +}{mu}{sup -} at the ATLAS experiment during its startup phase. As a result of this study a precision of ({delta}{sigma})/({sigma}){approx}0.006(stat){+-}0.008(sys){sup +0.016}{sub -0.008}(pdf) is expected for an integrated luminosity of 50 pb{sup -1}, assuming a fully operational ATLAS detector, not including uncertainties in the luminosity measurements. A major goal of the approach presented was to minimize the dependence on Monte Carlo simulations. Hence, several methods for the determination of the detector response based on data have been studied. In addition, a strategy for the differential cross section measurement (d{sigma})/(dp{sup Z}{sub T}) of the transverse momentum of the Z boson has been developed. In contrast to a measurement of the total cross section, it is expected that the statistical uncertainty dominates for the given integrated luminosity of 50 pb{sup -1}. The predicted high p{sub T} resolution of the ATLAS Inner Detector and the Muon Spectrometer allow for the first observation of interesting parton distribution effects, i.e. the so-called x-broadening, even with the limited statistics expected during the

FELIX: The new detector readout system for the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00370160; The ATLAS collaboration

2017-01-01

After the Phase-I upgrades (2019) of the ATLAS experiment, the Front-End Link eXchange (FELIX) system will be the interface between the data acquisition system and the detector front-end and trigger electronics. FELIX will function as a router between custom serial links and a commodity switch network using standard technologies (Ethernet or Infiniband) to communicate with commercial data collecting and processing components. The system architecture of FELIX will be described and the status of the firmware implementation and hardware development currently in progress will be presented.

FELIX: The new detector readout system for the ATLAS experiment

Science.gov (United States)

Ryu, Soo; ATLAS TDAQ Collaboration

2017-10-01

After the Phase-I upgrades (2019) of the ATLAS experiment, the Front-End Link eXchange (FELIX) system will be the interface between the data acquisition system and the detector front-end and trigger electronics. FELIX will function as a router between custom serial links and a commodity switch network using standard technologies (Ethernet or Infiniband) to communicate with commercial data collecting and processing components. The system architecture of FELIX will be described and the status of the firmware implementation and hardware development currently in progress will be presented.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Madsen, Alexander; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the latest results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Vanadia, Marco; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the latest Run 1 results from the ATLAS Experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in wellmotivated BSM Higgs frameworks, including the two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Scutti, Federico; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are summarized. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Nagata, Kazuki; The ATLAS collaboration

2014-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Beyond-the-Standard Model Higgs physics using the ATLAS experiment

CERN Document Server

Ernis, G; The ATLAS collaboration

2014-01-01

The discovery of a Higgs boson with a mass of about 125 GeV has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this talk, the current results from the ATLAS experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well-motivated BSM Higgs frameworks, such as two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Complete distributed computing environment for a HEP experiment: experience with ARC-connected infrastructure for ATLAS

International Nuclear Information System (INIS)

Read, A; Taga, A; O-Saada, F; Pajchel, K; Samset, B H; Cameron, D

2008-01-01

Computing and storage resources connected by the Nordugrid ARC middleware in the Nordic countries, Switzerland and Slovenia are a part of the ATLAS computing Grid. This infrastructure is being commissioned with the ongoing ATLAS Monte Carlo simulation production in preparation for the commencement of data taking in 2008. The unique non-intrusive architecture of ARC, its straightforward interplay with the ATLAS Production System via the Dulcinea executor, and its performance during the commissioning exercise is described. ARC support for flexible and powerful end-user analysis within the GANGA distributed analysis framework is also shown. Whereas the storage solution for this Grid was earlier based on a large, distributed collection of GridFTP-servers, the ATLAS computing design includes a structured SRM-based system with a limited number of storage endpoints. The characteristics, integration and performance of the old and new storage solutions are presented. Although the hardware resources in this Grid are quite modest, it has provided more than double the agreed contribution to the ATLAS production with an efficiency above 95% during long periods of stable operation

Complete distributed computing environment for a HEP experiment: experience with ARC-connected infrastructure for ATLAS

Energy Technology Data Exchange (ETDEWEB)

Read, A; Taga, A; O-Saada, F; Pajchel, K; Samset, B H; Cameron, D [Department of Physics, University of Oslo, P.b. 1048 Blindern, N-0316 Oslo (Norway)], E-mail: a.l.read@fys.uio.no

2008-07-15

Computing and storage resources connected by the Nordugrid ARC middleware in the Nordic countries, Switzerland and Slovenia are a part of the ATLAS computing Grid. This infrastructure is being commissioned with the ongoing ATLAS Monte Carlo simulation production in preparation for the commencement of data taking in 2008. The unique non-intrusive architecture of ARC, its straightforward interplay with the ATLAS Production System via the Dulcinea executor, and its performance during the commissioning exercise is described. ARC support for flexible and powerful end-user analysis within the GANGA distributed analysis framework is also shown. Whereas the storage solution for this Grid was earlier based on a large, distributed collection of GridFTP-servers, the ATLAS computing design includes a structured SRM-based system with a limited number of storage endpoints. The characteristics, integration and performance of the old and new storage solutions are presented. Although the hardware resources in this Grid are quite modest, it has provided more than double the agreed contribution to the ATLAS production with an efficiency above 95% during long periods of stable operation.

High-voltage safety fuses for the transition-radiation tracking detector in the ATLAS experiment

NARCIS (Netherlands)

Voronov, SA; Voronov, YA; Onishchenko, EM; Simakov, AB; Sosnovtsev, VV; Suchkov, SI; Sugrobova, TA

2004-01-01

A safety fuse has been designed for the electrical protection of gas-filled detectors in the ATLAS experiment at CERN (Geneva, Switzerland). The fuse is a polished lithium niobate plate with a titanium strip of 91-kOmega resistance deposited by the photolithographic technique. The forced blow-out

Experience in Grid Site Testing for ATLAS, CMS and LHCb with HammerCloud

International Nuclear Information System (INIS)

Elmsheuser, Johannes; Legger, Federica; Llamas, Ramón Medrano; Sciabà, Andrea; García, Mario Úbeda; Ster, Daniel van der; Sciacca, Gianfranco

2012-01-01

Frequent validation and stress testing of the network, storage and CPU resources of a grid site is essential to achieve high performance and reliability. HammerCloud was previously introduced with the goals of enabling VO- and site-administrators to run such tests in an automated or on-demand manner. The ATLAS, CMS and LHCb experiments have all developed VO plugins for the service and have successfully integrated it into their grid operations infrastructures. This work will present the experience in running HammerCloud at full scale for more than 3 years and present solutions to the scalability issues faced by the service. First, we will show the particular challenges faced when integrating with CMS and LHCb offline computing, including customized dashboards to show site validation reports for the VOs and a new API to tightly integrate with the LHCbDIRAC Resource Status System. Next, a study of the automatic site exclusion component used by ATLAS will be presented along with results for tuning the exclusion policies. A study of the historical test results for ATLAS, CMS and LHCb will be presented, including comparisons between the experiments’ grid availabilities and a search for site-based or temporal failure correlations. Finally, we will look to future plans that will allow users to gain new insights into the test results; these include developments to allow increased testing concurrency, increased scale in the number of metrics recorded per test job (up to hundreds), and increased scale in the historical job information (up to many millions of jobs per VO).

Experience in Grid Site Testing for ATLAS, CMS and LHCb with HammerCloud

Science.gov (United States)

Elmsheuser, Johannes; Medrano Llamas, Ramón; Legger, Federica; Sciabà, Andrea; Sciacca, Gianfranco; Úbeda García, Mario; van der Ster, Daniel

2012-12-01

Frequent validation and stress testing of the network, storage and CPU resources of a grid site is essential to achieve high performance and reliability. HammerCloud was previously introduced with the goals of enabling VO- and site-administrators to run such tests in an automated or on-demand manner. The ATLAS, CMS and LHCb experiments have all developed VO plugins for the service and have successfully integrated it into their grid operations infrastructures. This work will present the experience in running HammerCloud at full scale for more than 3 years and present solutions to the scalability issues faced by the service. First, we will show the particular challenges faced when integrating with CMS and LHCb offline computing, including customized dashboards to show site validation reports for the VOs and a new API to tightly integrate with the LHCbDIRAC Resource Status System. Next, a study of the automatic site exclusion component used by ATLAS will be presented along with results for tuning the exclusion policies. A study of the historical test results for ATLAS, CMS and LHCb will be presented, including comparisons between the experiments’ grid availabilities and a search for site-based or temporal failure correlations. Finally, we will look to future plans that will allow users to gain new insights into the test results; these include developments to allow increased testing concurrency, increased scale in the number of metrics recorded per test job (up to hundreds), and increased scale in the historical job information (up to many millions of jobs per VO).

HEP data for everyone CERN open data and the ATLAS and CMS experiments

CERN Document Server

McCauley, Thomas

2016-01-01

A cornerstone of good scientific practice is to make results available to the public. This is especially true for experiments at the LHC at CERN where public investment in fundamental research is significant and long-standing. As part of their commitment to open access and public engagement the ATLAS and CMS collaborations have made several large datasets available to the public. There are many challenges posed in presenting complex and high-level data to the public in an accessible and meaningful way. We describe the solutions to these challenges, part of which is the creation and use of the CERN Open Data Portal and the content found therein. Furthermore we describe the impact and future plans of the ATLAS and CMS open access efforts including future releases of data and accompanying educational material.

ATLAS DDM integration in ARC

DEFF Research Database (Denmark)

Behrmann, Gerd; Cameron, David; Ellert, Mattias

2008-01-01

The Nordic Data Grid Facility (NDGF) consists of Grid resources running ARC middleware in Denmark, Finland, Norway and Sweden. These resources serve many virtual organisations and contribute a large fraction of total worldwide resources for the ATLAS experiment, whose data is distributed and mana......The Nordic Data Grid Facility (NDGF) consists of Grid resources running ARC middleware in Denmark, Finland, Norway and Sweden. These resources serve many virtual organisations and contribute a large fraction of total worldwide resources for the ATLAS experiment, whose data is distributed...... and managed by the DQ2 software. Managing ATLAS data within NDGF and between NDGF and other Grids used by ATLAS (the Enabling Grids for E-sciencE Grid and the Open Science Grid) presents a unique challenge for several reasons. Firstly, the entry point for data, the Tier 1 centre, is physically distributed...

Multi-Threaded Evolution of the Data-Logging System of the ATLAS Experiment at CERN

CERN Document Server

Colombo, T; The ATLAS collaboration

2011-01-01

The ATLAS experiment is currently observing proton-proton collisions delivered by the LHC accelerator at a centre of mass energy of 7 TeV with a peak luminosity of ~1033 cm-2 s-1. The ATLAS Trigger and Data Acquisition (TDAQ) system selects interesting events on-line in a three-level trigger system in order to store them at a budgeted rate of ~200 Hz for an event size of ~1.5 MB. This paper focuses on the TDAQ data-logging system. Its purpose is to receive events from the third level trigger, process them and stream the results into different raw data files according to the trigger decision. The data files are subsequently moved to the central mass storage facility at CERN. The system currently in production has been commissioned in 2007 and has been working smoothly since then. It is however based on an essentially single-threaded design that is anticipated not to cope with the increase in event rate and event size that is foreseen as part of the ATLAS and LHC upgrade programs. This design also severely limi...

Multi-Threaded Evolution of the Data-Logging System of the ATLAS Experiment at CERN

CERN Document Server

Colombo, T; The ATLAS collaboration

2011-01-01

The ATLAS experiment observes proton-proton collisions delivered by the LHC accelerator at a centre of mass energy of 7 TeV with a peak luminosity of ~ 10^33 cm^-2 s^-1 in 2011. The ATLAS Trigger and Data Acquisition (TDAQ) system selects interesting events on-line in a three-level trigger system in order to store them at a budgeted average rate of ~ 400 Hz for an event size of ~1.2 MB. This paper focuses on the TDAQ data-logging system. Its purpose is to receive events from the third level trigger, process them and stream the data into different raw files according to the trigger decision. The system currently in production is based on an essentially single-threaded design that is anticipated not to cope with the increase in event rate and event size foreseen as part of the ATLAS and LHC upgrade programs. This design also severely limits the possibility of performing additional CPU-intensive tasks. Therefore, a novel design able to exploit the full power of multi-core architecture is needed. The main challen...

Probabilistic liver atlas construction.

Science.gov (United States)

Dura, Esther; Domingo, Juan; Ayala, Guillermo; Marti-Bonmati, Luis; Goceri, E

2017-01-13

Anatomical atlases are 3D volumes or shapes representing an organ or structure of the human body. They contain either the prototypical shape of the object of interest together with other shapes representing its statistical variations (statistical atlas) or a probability map of belonging to the object (probabilistic atlas). Probabilistic atlases are mostly built with simple estimations only involving the data at each spatial location. A new method for probabilistic atlas construction that uses a generalized linear model is proposed. This method aims to improve the estimation of the probability to be covered by the liver. Furthermore, all methods to build an atlas involve previous coregistration of the sample of shapes available. The influence of the geometrical transformation adopted for registration in the quality of the final atlas has not been sufficiently investigated. The ability of an atlas to adapt to a new case is one of the most important quality criteria that should be taken into account. The presented experiments show that some methods for atlas construction are severely affected by the previous coregistration step. We show the good performance of the new approach. Furthermore, results suggest that extremely flexible registration methods are not always beneficial, since they can reduce the variability of the atlas and hence its ability to give sensible values of probability when used as an aid in segmentation of new cases.

The ATLAS hadronic tau trigger

International Nuclear Information System (INIS)

Shamim, Mansoora

2012-01-01

The extensive tau physics programs of the ATLAS experiment relies heavily on trigger to select hadronic decays of tau lepton. Such a trigger is implemented in ATLAS to efficiently collect signal events, while keeping the rate of multi-jet background within the allowed bandwidth. This contribution summarizes the performance of the ATLAS hadronic tau trigger system during 2011 data taking period and improvements implemented for the 2012 data collection.

Recent updates on the Standard Model Higgs boson measurements from the ATLAS and CMS experiments

CERN Document Server

Wang, Song-Ming

2017-01-01

This report presents the latest results from the ATLAS and CMS experiments on the measurements of the Standard Model Higgs boson by using the proton-proton collisions produced by the Large Hadron Collider during the first two years of Run 2 data taking.

ATLAS job monitoring in the Dashboard Framework

CERN Document Server

Sargsyan, L; The ATLAS collaboration; Campana, S; Karavakis, E; Kokoszkiewicz, L; Saiz, P; Schovancova, J; Tuckett, D

2012-01-01

Monitoring of the large-scale data processing of the ATLAS experiment includes monitoring of production and user analysis jobs. The Experiment Dashboard provides a common job monitoring solution, which is shared by ATLAS and CMS experiments. This includes an accounting portal as well as real-time monitoring. Dashboard job monitoring for ATLAS combines information from PanDA job processing database, Production system database and monitoring information from jobs submitted through GANGA to Workload Management System (WMS) or local batch systems. Usage of Dashboard-based job monitoring applications will decrease load on the PanDA database and overcome scale limitations in PanDA monitoring caused by the short job rotation cycle in the PanDA database. Aggregation of the task/job metrics from different sources provides complete view of job processing activity in ATLAS scope.

ATLAS job monitoring in the Dashboard Framework

International Nuclear Information System (INIS)

Andreeva, J; Campana, S; Karavakis, E; Kokoszkiewicz, L; Saiz, P; Tuckett, D; Sargsyan, L; Schovancova, J

2012-01-01

Monitoring of the large-scale data processing of the ATLAS experiment includes monitoring of production and user analysis jobs. The Experiment Dashboard provides a common job monitoring solution, which is shared by ATLAS and CMS experiments. This includes an accounting portal as well as real-time monitoring. Dashboard job monitoring for ATLAS combines information from the PanDA job processing database, Production system database and monitoring information from jobs submitted through GANGA to Workload Management System (WMS) or local batch systems. Usage of Dashboard-based job monitoring applications will decrease load on the PanDA database and overcome scale limitations in PanDA monitoring caused by the short job rotation cycle in the PanDA database. Aggregation of the task/job metrics from different sources provides complete view of job processing activity in ATLAS scope.

ATLAS DataFlow Infrastructure: Recent results from ATLAS cosmic and first-beam data-taking

Energy Technology Data Exchange (ETDEWEB)

Vandelli, Wainer, E-mail: wainer.vandelli@cern.c

2010-04-01

The ATLAS DataFlow infrastructure is responsible for the collection and conveyance of event data from the detector front-end electronics to the mass storage. Several optimized and multi-threaded applications fulfill this purpose operating over a multi-stage Gigabit Ethernet network which is the backbone of the ATLAS Trigger and Data Acquisition System. The system must be able to efficiently transport event-data with high reliability, while providing aggregated bandwidths larger than 5 GByte/s and coping with many thousands network connections. Nevertheless, routing and streaming capabilities and monitoring and data accounting functionalities are also fundamental requirements. During 2008, a few months of ATLAS cosmic data-taking and the first experience with the LHC beams provided an unprecedented test-bed for the evaluation of the performance of the ATLAS DataFlow, in terms of functionality, robustness and stability. Besides, operating the system far from its design specifications helped in exercising its flexibility and contributed in understanding its limitations. Moreover, the integration with the detector and the interfacing with the off-line data processing and management have been able to take advantage of this extended data taking-period as well. In this paper we report on the usage of the DataFlow infrastructure during the ATLAS data-taking. These results, backed-up by complementary performance tests, validate the architecture of the ATLAS DataFlow and prove that the system is robust, flexible and scalable enough to cope with the final requirements of the ATLAS experiment.

ATLAS DataFlow Infrastructure: Recent results from ATLAS cosmic and first-beam data-taking

International Nuclear Information System (INIS)

Vandelli, Wainer

2010-01-01

The ATLAS DataFlow infrastructure is responsible for the collection and conveyance of event data from the detector front-end electronics to the mass storage. Several optimized and multi-threaded applications fulfill this purpose operating over a multi-stage Gigabit Ethernet network which is the backbone of the ATLAS Trigger and Data Acquisition System. The system must be able to efficiently transport event-data with high reliability, while providing aggregated bandwidths larger than 5 GByte/s and coping with many thousands network connections. Nevertheless, routing and streaming capabilities and monitoring and data accounting functionalities are also fundamental requirements. During 2008, a few months of ATLAS cosmic data-taking and the first experience with the LHC beams provided an unprecedented test-bed for the evaluation of the performance of the ATLAS DataFlow, in terms of functionality, robustness and stability. Besides, operating the system far from its design specifications helped in exercising its flexibility and contributed in understanding its limitations. Moreover, the integration with the detector and the interfacing with the off-line data processing and management have been able to take advantage of this extended data taking-period as well. In this paper we report on the usage of the DataFlow infrastructure during the ATLAS data-taking. These results, backed-up by complementary performance tests, validate the architecture of the ATLAS DataFlow and prove that the system is robust, flexible and scalable enough to cope with the final requirements of the ATLAS experiment.

ATLAS-AWS

International Nuclear Information System (INIS)

Gehrcke, Jan-Philip; Stonjek, Stefan; Kluth, Stefan

2010-01-01

We show how the ATLAS offline software is ported on the Amazon Elastic Compute Cloud (EC2). We prepare an Amazon Machine Image (AMI) on the basis of the standard ATLAS platform Scientific Linux 4 (SL4). Then an instance of the SLC4 AMI is started on EC2 and we install and validate a recent release of the ATLAS offline software distribution kit. The installed software is archived as an image on the Amazon Simple Storage Service (S3) and can be quickly retrieved and connected to new SL4 AMI instances using the Amazon Elastic Block Store (EBS). ATLAS jobs can then configure against the release kit using the ATLAS configuration management tool (cmt) in the standard way. The output of jobs is exported to S3 before the SL4 AMI is terminated. Job status information is transferred to the Amazon SimpleDB service. The whole process of launching instances of our AMI, starting, monitoring and stopping jobs and retrieving job output from S3 is controlled from a client machine using python scripts implementing the Amazon EC2/S3 API via the boto library working together with small scripts embedded in the SL4 AMI. We report our experience with setting up and operating the system using standard ATLAS job transforms.

ATLAS book wins the IPPY awards

CERN Multimedia

Abha Eli Phoboo

2014-01-01

Hunting the Higgs, published by Papadakis Publishers in collaboration with the ATLAS experiment has won the Bronze prize in the Science category of the Independent Publisher Book Awards (see here). The Award ceremony will be held on 28 May in New York on the eve of the BookExpo America (see here).   “Ours is a souvenir book that gives viewers a glimpse of the discovery of the Higgs boson and the collaborative effort behind it of thousands of scientists in ATLAS,” says Claudia Marcelloni, communications officer of the ATLAS Experiment, who worked on the book with freelance science writer Colin Barras. “The science is noble and the collaboration heartwarming, and the IPPY Award is a great way to celebrate the mind-blowing story of human achievement.” Hunting the Higgs is the inside story of the ATLAS experiment at the Large Hadron Collider. It tells the journey of the experiment, from before the detector was born to the announcement of the discovery of t...

Searches for Dark Matter at the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00143063; The ATLAS collaboration

2015-01-01

Abstract. Searches for strongly produced dark matters in events with jets, photons, heavy-flavor quarks or massive gauge bosons recoiling against large missing transverse momentum in ATLAS are presented. These "MET+X" signatures provide powerful probes to dark matter production at the LHC, allowing us to interpret results in terms of effective field theory and/or simplified models with pair production of Weakly Interactions Particles. Recent ATLAS results on dark matter searches at LHC Run I and the connection to astroparticle physics are discussed.

The ATLAS SCT: Commissioning Experience and SLHC Upgrade

OpenAIRE

Mitrevski, J

2008-01-01

The ATLAS Semiconductor Tracker (SCT) has been installed, and fully connected to electrical, optical and cooling services. Commissioning has been performed both with calibration data and cosmic ray events. The cosmics were used to align the detector, measure the hit efficiency and set the timing. The SCT is now ready to take data when the LHC turns on this autumn. At the same time, it is clear that the present ATLAS tracker will need to be renewed for projected luminosity upgrade of the LHC, ...

ATLAS end-cap detector

CERN Multimedia

Maximilien Brice

2003-01-01

Three scientists from the Institute of Nuclear Phyiscs at Novossibirsk with one of the end-caps of the ATLAS detector. The end-caps will be used to detect particles produced in the proton-proton collisions at the heart of the ATLAS experiment that are travelling close to the axis of the two beams.

Development of the ATLAS simulation framework

International Nuclear Information System (INIS)

DellAcqua, A.; Stavrianakou, M.; Amako, K.; Kanzaki, J.; Morita, Y.; Murakami, K.; Sasaki; Kurashige, H.; Rimoldi, A.; Saeki, T.; Ueda, I.; Tanaka, S.; Yoshida, H.

2001-01-01

Object-oriented (OO) approach is the key technology to develop a software system in the LHC/ATLAS experiment. The authors developed a OO simulation framework based on the Geant4 general-purpose simulation toolkit. Because of complexity of simulation in ATLAS, the authors paid most attention to the scalability in the design. Although the first target to apply this framework is to implement the ATLAS full detector simulation program, there is no experiment-specific code in it, therefore it can be utilized for the development of any simulation package, not only for HEP experiments but also for various different research domains. The authors discuss our approach of design and implementation of the framework

Radiation tolerant optical links for the readout of the ATLAS experiment

CERN Document Server

Pearce, M

2000-01-01

The ATLAS experiment will use radiation tolerant optical links to transfer data to and from sub-detector systems. The link specifications can be broadly divided into two classes, represented by the inner tracking detectors and the electromagnetic calorimeter. A feature common to all the readout links is the use of vertical cavity surface emitting laser diodes coupled to multimode optical fibres. Results from the development for both of these environments are reviewed with particular attention bring paid to irradiation studies. (8 refs).

Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00211509

2016-01-01

Large area Micromegas (MM) detectors will be employed for the Muon Spectrometer upgrade of the ATLAS experiment at the LHC. A total surface of about $150m^2$ of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules. Each module covers a surface area of approximately 2 to $3 m^2$ for a total active area of $1200 m^2$. Together with the small- strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the planned 2018/19 shutdown. This upgrade will mantain a low pt threshold for single muons and provides excellent tracking capabilities for the HL-LHC phase. The NSW project requires fully efficient MM chambers with spatial resolution down to $100 \\mu m$, at rate capability up to about $15kHz/cm^2$ and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking capability is provided by the intrinsic spatial resolution combined with a challengi...

Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

CERN Document Server

Iodice, Mauro; The ATLAS collaboration

2015-01-01

The Micromegas (MICRO MEsh GAseous Structure) have been proven along the years to be reliable detectors with excellent space resolution and high rate capability. Large area Micromegas will be employed for the first time in high-energy physics for the Muon Spectrometer upgrade of the ATLAS experiment at CERN LHC. A total surface of about 150 m$^2$ of the forward regions of the Muon Spectrometer will be equipped with 8 layers of Micromegas modules. Each module covers a surface from 2 to 3 m$^2$ for a total active area of 1200 m$^2$. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the 2018/19 shutdown. The breakthroughs and developments of this type of Micro Pattern Gas Detector will be reviewed, along with the path towards the construction of the modules, which will take place in several production sites starting in 2015. An overview of the detector performances obtained in the rec...

Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

CERN Document Server

Iodice, M; The ATLAS collaboration

2014-01-01

The Micromegas (MICRO MEsh GAseous Structure) chambers have been proven along the years to be reliable detectors with excellent space resolution and high rate capability. Large area Micromegas will be employed for the first time in high-energy physics for the Muon Spectrometer upgrade of the ATLAS experiment at CERN LHC. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer will be equipped with 8 layers of Micromegas modules. Each module covers a surface from 2 to 3 m2 for a total active area of 1200 m2. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the 2018/19 shutdown. The principles of operation and recent developments of this type of Micro Pattern Gas Detector will be reviewed, along with our plans towards the construction of the modules, which will take place in several production sites. An overview of the detector performances obtained in the re...

Micromegas Detectors for the Muon Spectrometer Upgrade of the ATLAS Experiment

CERN Document Server

Bianco, Michele; The ATLAS collaboration

2015-01-01

Large area Micromegas (MM) detectors will be employed for the Muon Spectrometer upgrade of the ATLAS experiment at the LHC. A total surface of about 150 m2 of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MM modules. Each module covers a surface area of approximately 2 to 3 m$^{2}$ for a total active area of 1200 m$^{2}$. Together with the small-strips Thin Gap Chambers, they will compose the two New Small Wheels, which will replace the innermost stations of the ATLAS Endcap Muon tracking system in the planned 2018/19 shutdown. This upgrade will maintain a low pt threshold for single muons and provides excellent tracking capabilities for the HL- LHC phase. The NSW project requires fully efficient MM chambers with spatial resolution down to 100 $ \\mu m$, a rate capability up to about 15 kHz/cm$^{2}$ and operation in a moderate (highly inhomogeneous) magnetic field up to B=0.3 T. The required tracking capability is provided by the intrinsic spatial resolution combined with a cha...

ATLAS Cloud Computing R&D project

CERN Document Server

Panitkin, S; The ATLAS collaboration; Caballero Bejar, J; Benjamin, D; DiGirolamo, A; Gable, I; Hendrix, V; Hover, J; Kucharczuk, K; Medrano LLamas, R; Ohman, H; Paterson, M; Sobie, R; Taylor, R; Walker, R; Zaytsev, A

2013-01-01

The computing model of the ATLAS experiment was designed around the concept of grid computing and, since the start of data taking, this model has proven very successful. However, new cloud computing technologies bring attractive features to improve the operations and elasticity of scientific distributed computing. ATLAS sees grid and cloud computing as complementary technologies that will coexist at different levels of resource abstraction, and two years ago created an R&D working group to investigate the different integration scenarios. The ATLAS Cloud Computing R&D has been able to demonstrate the feasibility of offloading work from grid to cloud sites and, as of today, is able to integrate transparently various cloud resources into the PanDA workload management system. The ATLAS Cloud Computing R&D is operating various PanDA queues on private and public resources and has provided several hundred thousand CPU days to the experiment. As a result, the ATLAS Cloud Computing R&D group has gained...

Monolithic pixel development in 180 nm CMOS for the outer pixel layers in the ATLAS experiment

CERN Document Server

Kugathasan, Thanushan; Buttar, Craig; Berdalovic, Ivan; Blochet, Bastien; Cardella, Roberto Calogero; Dalla, Marco; Egidos Plaja, Nuria; Hemperek, Tomasz; Van Hoorne, Jacobus Willem; Maneuski, Dima; Marin Tobon, Cesar Augusto; Moustakas, Konstantinos; Mugnier, Herve; Musa, Luciano; Pernegger, Heinz; Riedler, Petra; Riegel, Christian; Rousset, Jerome; Sbarra, Carla; Schaefer, Douglas Michael; Schioppa, Enrico Junior; Sharma, Abhishek; Snoeys, Walter; Solans Sanchez, Carlos; Wang, Tianyang; Wermes, Norbert

2017-01-01

The ATLAS experiment at CERN plans to upgrade its Inner Tracking System for the High-Luminosity LHC in 2026. After the ALPIDE monolithic sensor for the ALICE ITS was successfully implemented in a 180 nm CMOS Imaging Sensor technology, the process was modified to combine full sensor depletion with a low sensor capacitance (≈ 2.5fF), for increased radiation tolerance and low analog power consumption. Efficiency and charge collection time were measured with comparisons before and after irradiation. This paper summarises the measurements and the ATLAS-specific development towards full-reticle size CMOS sensors and modules in this modified technology.

The ATLAS Women's Network: one year of activities

CERN Multimedia

Paula Eerola

The idea for an ATLAS Women's Network was born during the ATLAS overview week in October 2005, when a few of us discussed our experiences and were pondering about what we could do. We felt that it was important to increase the visibility of women working in ATLAS in order to make a better and more effective use of the ATLAS human resources, that is, make sure that women are duly included at all levels. Furthermore, it is our belief that making ATLAS a better working environment for female collaborators and other female co-workers will benefit both us and the collaboration as a whole. On the individual level, all of us thought that we could benefit from peer support and experience sharing, and an ATLAS Women's Network could facilitate this by developing contacts between the ATLAS Women in ATLAS Institutes worldwide. Finally, we thought that it was important to increase the number of women studying physics and working in the field of physics research by identifying gender barriers in the career paths of women i...

Conference Report: The First ATLAS.ti User Conference

Directory of Open Access Journals (Sweden)

Jeanine C. Evers

2014-01-01

Full Text Available This report on the First ATLAS.ti User Conference shares our impressions and experiences as longstanding ATLAS.ti users and trainers about the First ATLAS.ti User Conference in Berlin 2013. The origins, conceptual principles and development of the program are outlined, the conference themes discussed and experiences shared. Finally, the future of the program is discussed. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1401197

Evolution of the Trigger and Data Acquisition System in the ATLAS experiment

CERN Document Server

Kama, Sami; The ATLAS collaboration

2012-01-01

The ATLAS detector is designed to observe proton-proton collisions delivered by the LHC accelerator. The ATLAS Trigger and Data Acquisition (TDAQ) system is responsible for the selection and the conveyance of physics data, reducing the rate of stored events from the initial 40 MHz LHC frequency to several hundreds Hz. The TDAQ system is organised in a three-level selection scheme, including a hardware-based first-level trigger and second- and third-level triggers implemented as software systems distributed on commodity hardware nodes. The second-level trigger operates over limited regions of the detector, the so-called Regions-of-Interest (RoI). The last selection step deals instead with complete events. In the current design, the second and third trigger levels are separate systems. While this architecture was successfully operated well beyond the original design goals, the accumulated experience stimulated interest to explore possible evolutions. One attractive direction is to merge the second and third tri...

Evolution of the Trigger and Data Acquisition System in the ATLAS experiment

CERN Document Server

Kama, S; The ATLAS collaboration

2012-01-01

The ATLAS detector is designed to observe proton-proton collisions delivered by the LHC accelerator. The ATLAS Trigger and Data Acquisition (TDAQ) system is responsible for the selection and the conveyance of physics data, reducing the rate of stored events from the initial $40\\MHz$ LHC frequency to several hundreds Hz. The TDAQ system is organized in a three-level selection scheme, including a hardware-based first-level trigger and second- and third-level triggers implemented as software systems distributed on commodity hardware nodes. The second-level trigger operates over limited regions of the detector, the so-called Regions-of-Interest (RoI). The last selection step deals instead with complete events. In the current design, the second and third trigger levels are separate systems. While this architecture was successfully operated well beyond the original design goals, the accumulated experience stimulated interest to explore possible evolutions. One attractive direction is to merge the second and third t...

Beyond-the-Standard Model Higgs Physics using the ATLAS Experiment

CERN Document Server

Vanadia, Marco; The ATLAS collaboration

2015-01-01

The discovery of a Higgs boson with a mass of about 125 GeV/$\\rm{c^2}$ has prompted the question of whether or not this particle is part of a larger and more complex Higgs sector than that envisioned in the Standard Model. In this report, the latest Run 1 results from the ATLAS Experiment on Beyond-the-Standard Model (BSM) Higgs searches are outlined. Searches for additional Higgs bosons are presented and interpreted in well motivated BSM Higgs frameworks, including the two-Higgs-doublet Models and the Minimal and Next to Minimal Supersymmetric Standard Model.

Robustness studies of the photomultipliers reading out TileCal, the central hadron calorimeter of the ATLAS experiment

CERN Document Server

Di Gregorio, Giulia; The ATLAS collaboration

2018-01-01

TileCal, the hadron calorimeter of the ATLAS experiment in LHC, is a 10000 channel detector readout by photomultipliers (PMTs). A challenging goal is to understand whether the full sample of PMTs installed at the beginning of the ATLAS detector operation can be used until completion of the High-Luminosity Large Hadron Collider (HL-LHC) program or not. For this reason, a reliable study of the PMT robustness against ageing is required. Detailed studies modelling the PMT response variation as a function of the integrated anode charge were done.

Spectroscopy and decay properties with b-hadrons at the ATLAS experiment

CERN Document Server

Toms, Konstantin; The ATLAS collaboration

2015-01-01

We present the latest results from the ATLAS experiment on hadron decays and spectroscopy, including observation of the B_c(2S) state, production of the B_c+ meson, branching ratio measurements of B_c->J/psiD(), extraction of fragmentation fractions fs/fd via reconstructed Bs->J/psiPhi and Bd->J/psiK decays, and studies of the decay properties of the Lambda_b. We also present the results of searches for the Xb, the bottomonium counterpart to the X(3872) exotic charmonium state.

The ATLAS distributed analysis system

OpenAIRE

Legger, F.

2014-01-01

In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During...

Track Reconstruction in the ATLAS Experiment The Deterministic Annealing Filter

CERN Document Server

Fleischmann, S

2006-01-01

The reconstruction of the trajectories of charged particles is essential for experiments at the LHC. The experiments contain precise tracking systems structured in layers around the collision point which measure the positions where particle trajectories intersect those layers. The physics analysis on the other hand mainly needs the momentum and direction of the particle at the estimated creation or reaction point. It is therefore needed to determine these parameters from the initial measurements. At the LHC one has to deal with high backgrounds while even small deficits or artifacts can reduce the signal or may produce additional background after event selection. The track reconstruction does not only contain the estimation of the track parameters, but also a pattern recognition deciding which measurements belong to a track and how many particle tracks can be found. Track reconstruction at the ATLAS experiment suffers from the high event rate at the LHC resulting in a high occupancy of the tracking devices. A...

PeptideAtlas

Data.gov (United States)

U.S. Department of Health & Human Services — PeptideAtlas is a multi-organism, publicly accessible compendium of peptides identified in a large set of tandem mass spectrometry proteomics experiments. Mass...

Two new wheels for ATLAS

CERN Multimedia

2002-01-01

Juergen Zimmer (Max Planck Institute), Roy Langstaff (TRIUMF/Victoria) and Sergej Kakurin (JINR), in front of one of the completed wheels of the ATLAS Hadronic End Cap Calorimeter. A decade of careful preparation and construction by groups in three continents is nearing completion with the assembly of two of the four 4 m diameter wheels required for the ATLAS Hadronic End Cap Calorimeter. The first two wheels have successfully passed all their mechanical and electrical tests, and have been rotated on schedule into the vertical position required in the experiment. 'This is an important milestone in the completion of the ATLAS End Cap Calorimetry' explains Chris Oram, who heads the Hadronic End Cap Calorimeter group. Like most experiments at particle colliders, ATLAS consists of several layers of detectors in the form of a 'barrel' and two 'end caps'. The Hadronic Calorimeter layer, which measures the energies of particles such as protons and pions, uses two techniques. The barrel part (Tile Calorimeter) cons...

ATLAS@Home looks for CERN volunteers

CERN Multimedia

Rosaria Marraffino

2014-01-01

ATLAS@Home is a CERN volunteer computing project that runs simulated ATLAS events. As the project ramps up, the project team is looking for CERN volunteers to test the system before planning a bigger promotion for the public.   The ATLAS@home outreach website. ATLAS@Home is a large-scale research project that runs ATLAS experiment simulation software inside virtual machines hosted by volunteer computers. “People from all over the world offer up their computers’ idle time to run simulation programmes to help physicists extract information from the large amount of data collected by the detector,” explains Claire Adam Bourdarios of the ATLAS@Home project. “The ATLAS@Home project aims to extrapolate the Standard Model at a higher energy and explore what new physics may look like. Everything we’re currently running is preparation for next year's run.” ATLAS@Home became an official BOINC (Berkeley Open Infrastructure for Network ...

Experience with C++ Code Quality in ATLAS

CERN Document Server

Roe, Shaun; The ATLAS collaboration; Snyder, Scott; Martin-Haugh, Stewart; Obreshkov, Emil; Stewart, Graeme

2015-01-01

An explanation of tools used for code quality checking in Atlas offline software, including results and responses is given. The principle tools covered are: Coverity, cppcheck, 'include what you use', Undefined Behaviour Sanitizer

ATLAS cloud R and D

International Nuclear Information System (INIS)

Panitkin, Sergey; Bejar, Jose Caballero; Hover, John; Zaytsev, Alexander; Megino, Fernando Barreiro; Girolamo, Alessandro Di; Kucharczyk, Katarzyna; Llamas, Ramon Medrano; Benjamin, Doug; Gable, Ian; Paterson, Michael; Sobie, Randall; Taylor, Ryan; Hendrix, Val; Love, Peter; Ohman, Henrik; Walker, Rodney

2014-01-01

The computing model of the ATLAS experiment was designed around the concept of grid computing and, since the start of data taking, this model has proven very successful. However, new cloud computing technologies bring attractive features to improve the operations and elasticity of scientific distributed computing. ATLAS sees grid and cloud computing as complementary technologies that will coexist at different levels of resource abstraction, and two years ago created an R and D working group to investigate the different integration scenarios. The ATLAS Cloud Computing R and D has been able to demonstrate the feasibility of offloading work from grid to cloud sites and, as of today, is able to integrate transparently various cloud resources into the PanDA workload management system. The ATLAS Cloud Computing R and D is operating various PanDA queues on private and public resources and has provided several hundred thousand CPU days to the experiment. As a result, the ATLAS Cloud Computing R and D group has gained a significant insight into the cloud computing landscape and has identified points that still need to be addressed in order to fully utilize this technology. This contribution will explain the cloud integration models that are being evaluated and will discuss ATLAS' learning during the collaboration with leading commercial and academic cloud providers.

The new Level-1 Topological Trigger for the ATLAS experiment at the Large Hadron Collider

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00047907; The ATLAS collaboration

2017-01-01

At the CERN Large Hadron Collider, the world’s most powerful particle accelerator, the ATLAS experiment records high-energy proton collision to investigate the properties of fundamental particles. These collisions take place at a 40 MHz, and the ATLAS trigger system selects the interesting ones, reducing the rate to 1 kHz, allowing for their storage and subsequent offline analysis. The ATLAS trigger system is organized in two levels, with increasing degree of details and of accuracy. The first level trigger reduces the event rate to 100 kHz with a decision latency of less than 2.5 micro seconds. It is composed of the calorimeter trigger, muon trigger and central trigger processor. A new component of the first-level trigger was introduced in 2015: the Topological Processor (L1Topo). It allows to use detailed real-time information from the Level-1 calorimeter and muon systems, to compute advanced kinematic quantities using state of the art FPGA processors, and to select interesting events based on several com...

Development of large size Micromegas detectors for the upgrade of the ATLAS experiments

CERN Document Server

Bianco, Michele

2014-01-01

The luminosity upgrade of the Large Hadron Collider at CERN f oresees a luminosity increase by a factor 3 compared to the LHC luminosity design value. To c ope with the corresponding rate increase, the Muon System of the ATLAS experiment at CER N needs to be upgraded. In the first station of the high rapidity region, micromegas det ectors have been chosen as the main tracking chambers but will, at the same time, also contribut e to the trigger. We describe the R&D; efforts that led to the construction of the first (1 × 2.4 m 2 ) large micromegas detectors at CERN and outline the next steps towards the construction of the 12 00 m 2 of micromegas detectors for the ATLAS upgrade. The technical solutions, adopted in the c onstruction of the chamber as well as results on the detector performance with cosmic rays are s hown.

Evolution and experience with the ATLAS Simulation at Point1 Project

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00389536; The ATLAS collaboration; Brasolin, Franco; Kouba, Tomas; Schovancova, Jaroslava; Fazio, Daniel; Di Girolamo, Alessandro; Scannicchio, Diana; Twomey, Matthew Shaun; Wang, Fuquan; Zaytsev, Alexander; Lee, Christopher

2017-01-01

The Simulation at Point1 project is successfully running standard ATLAS simulation jobs on the TDAQ HLT resources. The pool of available resources changes dynamically, therefore we need to be very effective in exploiting the available computing cycles. We present our experience with using the Event Service that provides the event-level granularity of computations. We show the design decisions and overhead time related to the usage of the Event Service. The improved utilization of the resources is also presented with the recent development in monitoring, automatic alerting, deployment and GUI.

Evolution and experience with the ATLAS simulation at Point1 project

CERN Document Server

Ballestrero, Sergio; The ATLAS collaboration; Fazio, Daniel; Di Girolamo, Alessandro; Kouba, Tomas; Lee, Christopher; Scannicchio, Diana; Schovancova, Jaroslava; Twomey, Matthew Shaun; Wang, Fuquan; Zaytsev, Alexander

2016-01-01

The Simulation at Point1 project is successfully running traditional ATLAS simulation jobs on the TDAQ HLT resources. The pool of available resources changes dynamically, therefore we need to be very effective in exploiting the available computing cycles. We will present our experience with using the Event Service that provides the event-level granularity of computations. We will show the design decisions and overhead time related to the usage of the Event Service. The improved utilization of the resources will also be presented with the recent development in monitoring, automatic alerting, deployment and GUI.

Update on the search for the Higgs boson by the ATLAS and CMS experiments at CERN

CERN Multimedia

CERN. Geneva

2011-01-01

Update on the search for the Higgs boson by the ATLAS and CMS experiments at CERN Geneva, 6 December 2011.  A seminar will be held at CERN on 13 December at which the ATLAS and CMS experiments will present the status of their searches for the Standard Model Higgs boson.  These results will be based on the analysis of considerably more data than those presented at the summer conferences, sufficient to make significant progress in the search for the Higgs boson, but not enough to make any conclusive statement on the existence or non-existence of the Higgs. The seminar begins at 14:00 CET. The auditorium in which the seminar will be held is reserved for CERN personnel and researchers from the laboratory’s user community, but a video stream will be relayed to another auditorium in which scientists will be on hand to answer questions. At 16:30 CET CERN management and representatives of the two experiments will be available to take questions from the media. Journalists wishing to a...

ATLAS MPGD production status

CERN Document Server

Schioppa, Marco; The ATLAS collaboration

2018-01-01

Micromegas (MICRO MEsh GAseous Structure) chambers are Micro-Pattern Gaseous Detectors designed to provide a high spatial resolution and reasonable good time resolution in highly irradiated environments. In 2007 an ambitious long-term R\\&D activity was started in the context of the ATLAS experiment, at CERN: the Muon ATLAS Micromegas Activity (MAMMA). After years of tests on prototypes and technology breakthroughs, Micromegas chambers were chosen as tracking detectors for an upgrade of the ATLAS Muon Spectrometer. These novel detectors will be installed in 2020 at the end of the second long shutdown of the Large Hadron Collider, and will serve mainly as precision detectors in the innermost part of the forward ATLAS Muon Spectrometer. Four different types of Micromegas modules, eight layers each, up to $3 m^2$ area (of unprecedented size), will cover a surface of $150 m^2$ for a total active area of about $1200 m^2$. With this upgrade the ATLAS muon system will maintain the full acceptance of its excellent...

ATLAS Operations: Experience and Evolution in the Data Taking Era

CERN Document Server

Ueda, I; The ATLAS collaboration; Goossens, L; Stewart, G; Jezequel, S; Nairz, A; Negri, G; Campana, S; Di Girolamo, A

2011-01-01

This paper summarises the operational experience and improvements of the ATLAS hierarchical multi-tier computing infrastructure in the past year leading to taking and processing of the first collisions in 2009 and 2010. Special focus will be given to Tier-0 which is responsible, among other things, for a prompt processing of the raw data coming from the online DAQ system and is thus critical part of the chain. We will give an overview of the Tier-0 architecture, and improvements based on the operational experience. Emphasis will be put on the new developments, namely the Task Management System opening Tier-0 to expert users and Web 2.0 monitoring and management suite. We then overview the achieved performances with the distributed computing system, discuss observed data access patterns over the grid and describe how we used this information to improve analysis rates.

ATLAS distributed computing operation shift teams experience during the discovery year and beginning of the long shutdown 1

International Nuclear Information System (INIS)

Sedov, Alexey; Girolamo, Alessandro Di; Negri, Guidone; Sakamoto, Hiroshi; Schovancová, Jaroslava; Smirnov, Iouri; Vartapetian, Armen; Yu, Jaehoon

2014-01-01

ATLAS Distributed Computing Operation Shifts evolve to meet new requirements. New monitoring tools as well as operational changes lead to modifications in organization of shifts. In this paper we describe the structure of shifts, the roles of different shifts in ATLAS computing grid operation, the influence of a Higgs-like particle discovery on shift operation, the achievements in monitoring and automation that allowed extra focus on the experiment priority tasks, and the influence of the Long Shutdown 1 and operational changes related to the no beam period.

Atlas event production on the EGEE infrastructure

CERN Document Server

Espinal, X; Perini, L; Rod, W

2007-01-01

ATLAS is one of the four LHC (Large Hadron Collider) experiments at CERN, is devoted to study proton-proton and ion-ion collisions at 14TeV. ATLAS collaboration is composed of about 2000 scientists spread around the world. The activity of the experiment requirements for next year is of about 300TB of storage and a CPU power of about 13 Mski2sk, and is relying on GRID philosophy and EGEE infrastructure. Simulated events are distributed over EGEE by the Atlas production system. Data has to be processed and must be accessible by a huge number of scientists for analysis. The throughput of data for Atlas experiment is expected to be of 320 MB/s with an integrated amount of data per year of ~10Pb. The processing and storage need a distributed share of resources, spread worldwide and interconnected with GRID technologies as the requirements are so demanding for the LHC. In that sense event production is the way to produce, process and store data for analysis before the experiment startup, and is performed in a distr...

Evolution of the ReadOut System of the ATLAS experiment

CERN Document Server

Borga, A; The ATLAS collaboration; Joos, M; Schumacher, J; Tremblet, L; Vandelli, W; Vermeulen, J; Werner, P; Wickens, F

2014-01-01

The ReadOut System (ROS) is a central and essential part of the ATLAS data-acquisition system. It receives and buffers event data accepted from all sub-detectors and first-level trigger subsystems. Event data are subsequently forwarded to the High-Level Trigger system and Event Builder via a GbE-based network. The ATLAS ROS will be completely renewed in view of the demanding conditions expected during LHC Run 2 and Run 3. The new ROS will consist of roughly 100 Linux-based 2U-high rack-mounted server PCs, each equipped with 2 PCIe I/O cards and four 10GbE interfaces. The FPGA-based PCIe I/O cards, developed by the ALICE collaboration, will be configured with ATLAS-specific firmware, called RobinNP. They will provide connectivity to about 2000 point-to-point optical links conveying the ATLAS event data. This dense configuration provides an excellent test bench for studying I/O efficiency and challenges in current COTS PC architectures with non-uniform memory and I/O access paths. In this paper the requirements...

Evolution of the ReadOut System of the ATLAS experiment

CERN Document Server

Borga, A; The ATLAS collaboration; Green, B; Kugel, A; Joos, M; Panduro Vazquez, W; Schumacher, J; Teixeira-Dias, P; Tremblet, L; Vandelli, W; Vermeulen, J; Werner, P; Wickens, F

2014-01-01

The ReadOut System (ROS) is a central and essential part of the ATLAS DAQ system. It receives and buffers data of events accepted by the first-level trigger from all subdetectors and first-level trigger subsystems. Event data are subsequently forwarded to the High-Level Trigger system and Event Builder via a 1 GbE-based network. The ATLAS ROS is completely renewed in view of the demanding conditions expected during LHC Run 2 and Run 3, to replace obsolete technologies and space constraints require it to be compact. The new ROS will consist of roughly 100 Linux-based 2U high rack mounted server PCs, each equipped with 2 PCIe I/O cards and two four 10 GbE interfaces. The FPGA-based PCIe I/O cards, developed by the ALICE collaboration, will be configured with ATLAS-specific firmware, the so-called RobinNP firmware. They will provide the connectivity to about 2000 optical point-to-point links conveying the ATLAS event data. This dense configuration provides an excellent test bench for studying I/O efficiency and ...

An important step for the ATLAS toroid magnet

CERN Multimedia

2000-01-01

The ATLAS experiment's prototype toroid coil arrives at CERN from the CEA laboratory in Saclay on 6 October. The world's largest superconducting toroid magnet is under construction for the ATLAS experiment. A nine-metre long fully functional prototype coil was delivered to CERN at the beginning of October and has since been undergoing tests in the West Area. Built mainly by companies in France and Italy under the supervision of engineers from the CEA-Saclay laboratory near Paris and Italy's INFN-LASA, the magnet is a crucial step forward in the construction of the ATLAS superconducting magnet system. Unlike any particle detector that has gone before, the ATLAS detector's magnet system consists of a large toroidal system enclosing a small central solenoid. The barrel part of the toroidal system will use eight toroid coils, each a massive 25 metres in length. These will dwarf the largest toroids in the world when ATLAS was designed, which measure about six metres. So the ATLAS collaboration decided to build a...

Design, construction, quality checks and test results of first resistive-Micromegas read-out boards for the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00215943; The ATLAS collaboration; Kuger, Fabian

2015-01-01

The development work carried out at CERN to push the Micromegas technology to a new frontier is now coming to an end. The construction of the first read-out boards for the upgrade of the ATLAS muon system will demonstrate in full-scale the feasibility of this ambitious project. The read-out boards, representing the heart of the detector, are manufactured in industries, making the Micromegas for ATLAS the first MPGD for a large experiment with a relevant part industrially produced. The boards are 50 cm wide and up to 220 cm long, carrying copper strips 315 μm wide with 415 μm pitch. Interconnected resistive strips, having the same pattern as the copper strips, provide spark protection. The boards are completed by the creation of cylindrical pillars 128 μm high, 280 μm in diameter and arranged in a triangular array 7 mm aside. The total number of boards to be produced for ATLAS is 2048 of 32 different types. We will review the main design parameters of the read-out boards for the ATLAS Micromegas, following...

Pixel electronics for the ATLAS experiment

International Nuclear Information System (INIS)

Fischer, P.

2001-01-01

The ATLAS experiment at LHC will use 3 barrel layers and 2x5 disks of silicon pixel detectors as the innermost elements of the semiconductor tracker. The basic building blocks are pixel modules with an active area of 16.4 mmx60.8 mm which include an n + on n-type silicon sensor and 16 VLSI front-end (FE) chips. Every FE chip contains a low power, high speed charge sensitive preamplifier, a fast discriminator, and a readout system which operates at the 40 MHz rate of LHC. The addresses of hit pixels (as well as a low resolution pulse height information) are stored on the FE chips until arrival of a level 1 trigger signal. Hits are then transferred to a module controller chip (MCC) which collects the data of all 16 FE chips, builds complete events and sends the data through two optical links to the data acquisition system. The MCC receives clock and data through an additional optical link and provides timing and configuration information for the FE chips. Two additional chips are used to amplify and decode the pin diode signal and to drive the VCSEL laser diodes of the optical links

Selected Results from the ATLAS Experiment on its 25th Anniversary

CERN Document Server

Djama, Fares; The ATLAS collaboration

2018-01-01

The Lomonosov Conference and the ATLAS Collaboration celebrated their 25th anniversaries at a few week interval. This gave us the opportunity to present a brief history of ATLAS and to discuss some of its more important results.

The one-armed ATLAS Forward Proton detector

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00372192; Lange, Joern

The ATLAS experiment at the European Laboratory for Particle Physics (CERN), Geneva, has been taking data successfully since the Large Hadron Collider (LHC) accelerator started operations in 2010. Since then, it has been generating proton-proton collisions to study the frontiers of particle physics, at a centre of mass energy of 7-8 TeV first and, more recently, 13 TeV. However, the experiment is in constant evolution: detectors ageing due to radiation damage, increasing collision rates and pile-up, and new scientific objectives often require upgrades of the ATLAS detectors. These ever-growing challenges motivate the continued research and development of new detector technologies. To enhance the physics search of the experiment the ATLAS collaboration recently added a forward detector to identify intact protons that emerge from LHC collisions at very shallow angles. The ATLAS Forward Proton (AFP) detector enables the identification of diffractive processes and, ultimately, of central exclusive events, thus al...

FELIX: the new detector readout system for the ATLAS experiment

CERN Document Server

Bauer, Kevin Thomas; The ATLAS collaboration

2017-01-01

Starting in 2018 during the planned shutdown of the LHC, the ATLAS experiment at CERN will be deploying new optical link technology (GigaBit Transceiver links) connecting the front end electronics. The Front-End LInk eXchange (FELIX) will provide an infrastructure for the new GBT links to connect to the rest of the Trigger and Data Acquisition (TDAQ) system. FELIX is a PC-based system designed to route data and commands to and from the GBT links and a Commercial Off-The Shelf (COTS) network. In this paper, the FELIX system is described and the design of the hardware prototype and core software is presented.

Searches for beyond the Standard Model physics with boosted topologies in the ATLAS experiment using the Grid-based Tier-3 facility at IFIC-Valencia

CERN Document Server

Villaplana Pérez, Miguel; Vos, Marcel

Both the LHC and ATLAS have been performing well beyond expectation since the start of the data taking by the end of 2009. Since then, several thousands of millions of collision events have been recorded by the ATLAS experiment. With a data taking efficiency higher than 95% and more than 99% of its channels working, ATLAS supplies data with an unmatched quality. In order to analyse the data, the ATLAS Collaboration has designed a distributed computing model based on GRID technologies. The ATLAS computing model and its evolution since the start of the LHC is discussed in section 3.1. The ATLAS computing model groups the different types of computing centers of the ATLAS Collaboration in a tiered hierarchy that ranges from Tier-0 at CERN, down to the 11 Tier-1 centers and the nearly 80 Tier-2 centres distributed world wide. The Spanish Tier-2 activities during the first years of data taking are described in section 3.2. Tier-3 are institution-level non-ATLAS funded or controlled centres that participate presuma...

Simulation of top quark production for the ATLAS experiment at sqrt(s) = 13 TeV

CERN Document Server

The ATLAS collaboration

2016-01-01

This note summarises the Monte Carlo simulation setup for the pair and single production of top quarks for the ATLAS experiment at the LHC for sqrt(s)=13 TeV. In addition to the settings available and recommended for analyses using the 2015 dataset, the anticipated setup for 2016 analysis is also discussed.

Recent Multiboson measurements with the ATLAS experiment

CERN Multimedia

CERN. Geneva

2016-01-01

Measurements of the cross sections of the production of two electroweak gauge bosons constitute stringent tests of the electroweak sector of the Standard Model and provide a model-independent means to search for new physics at the TeV scale. We present recent ATLAS measurements of inclusive and differential cross sections for WW, WZ, ZZ and Z + photon at centre of mass energies of 8 TeV and 13 TeV. Large next-to-next-to-leading order QCD corrections were recently calculated and are confronted with the measurements. We also present recent ATLAS measurements of inclusive cross sections for electroweak production of WZ + 2 jets and production of Z + di-photon at 8 TeV. Differential distributions sensitive to anomalous triple and quartic gauge couplings have been studied and limits on new physics have been derived.

ATLAS Silicon Microstrip Tracker Operation and Performance

CERN Document Server

Rosendahl, P L; The ATLAS collaboration

2012-01-01

The Semi-Conductor Tracker (SCT) is a silicon microstrip detector part of the ATLAS experiment at the CERN Large Hadron Collider (LHC). Together with the rest for the ATLAS Inner Detector (ID) it provides vital precision tracking information of charged particles. In this paper the performance and operational status of the SCT in the last two years of ATLAS data taking are reviewed.

The ATLAS detector control system

International Nuclear Information System (INIS)

Schlenker, S.; Arfaoui, S.; Franz, S.

2012-01-01

The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC), constructed to study elementary particle interactions in collisions of high-energy proton beams. Twelve different sub-detectors as well as the common experimental infrastructure are supervised by the Detector Control System (DCS). The DCS enables equipment supervision of all ATLAS sub-detectors by using a system of more that 130 server machines running the industrial SCADA product PVSS. This highly distributed system reads, processes and archives of the order of 10 6 operational parameters. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, and manage the communication with external systems such as the LHC. First, this contribution describes the status of the ATLAS DCS and the experience gained during the LHC commissioning and the first physics data taking operation period. Secondly, the future evolution and maintenance constraints for the coming years and the LHC high luminosity upgrades are outlined. (authors)

The ATLAS Detector Control System

CERN Document Server

Schlenker, S; Kersten, S; Hirschbuehl, D; Braun, H; Poblaguev, A; Oliveira Damazio, D; Talyshev, A; Zimmermann, S; Franz, S; Gutzwiller, O; Hartert, J; Mindur, B; Tsarouchas, CA; Caforio, D; Sbarra, C; Olszowska, J; Hajduk, Z; Banas, E; Wynne, B; Robichaud-Veronneau, A; Nemecek, S; Thompson, PD; Mandic, I; Deliyergiyev, M; Polini, A; Kovalenko, S; Khomutnikov, V; Filimonov, V; Bindi, M; Stanecka, E; Martin, T; Lantzsch, K; Hoffmann, D; Huber, J; Mountricha, E; Santos, HF; Ribeiro, G; Barillari, T; Habring, J; Arabidze, G; Boterenbrood, H; Hart, R; Marques Vinagre, F; Lafarguette, P; Tartarelli, GF; Nagai, K; D'Auria, S; Chekulaev, S; Phillips, P; Ertel, E; Brenner, R; Leontsinis, S; Mitrevski, J; Grassi, V; Karakostas, K; Iakovidis, G.; Marchese, F; Aielli, G

2011-01-01

The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC), constructed to study elementary particle interactions in collisions of high-energy proton beams. Twelve different sub-detectors as well as the common experimental infrastructure are supervised by the Detector Control System (DCS). The DCS enables equipment supervision of all ATLAS sub-detectors by using a system of >130 server machines running the industrial SCADA product PVSS. This highly distributed system reads, processes and archives of the order of 106 operational parameters. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, and manage the communication with external systems such as the LHC. This contribution firstly describes the status of the ATLAS DCS and the experience gained during the LHC commissioning and the first physics data taking operation period. Secondly, the future evolution and maintenance constraints for the coming years an...

LUCID A Cherenkov Tube Based Detector for Monitoring the ATLAS Experiment Luminosity

CERN Document Server

Sbrizzi, A

2007-01-01

The LUCID (LUminosity Cherenkov Integrating Detector) apparatus is composed by two symmetric arms deployed at about 17 m from the ATLAS interaction point. The purpose of this detector, which will be installed in january 2008, is to monitor the luminosity delivered by the LHC machine to the ATLAS experiment. An absolute luminosity calibration is needed and it will be provided by a Roman Pot type detector with the two arms placed at about 240 m from the interaction point. Each arm of the LUCID detector is based on an aluminum vessel containing 20 Cherenkov tubes, 15 mm diameter and 1500 mm length, filled with C4F10 radiator gas at 1.5 bar. The Cherenkov light generated by charged particles above the threshold is collected by photomultiplier tubes (PMT) directly placed at the tubes end. The challenging aspect of this detector is its readout in an environment characterized by the high dose of radiation (about 0.7 Mrad/year at 10^33cm^2 s^-1) it must withstand. In order to fulfill these radiation hardness requirem...

Experience with Intel's many integrated core architecture in ATLAS software

International Nuclear Information System (INIS)

Fleischmann, S; Neumann, M; Kama, S; Lavrijsen, W; Vitillo, R

2014-01-01

Intel recently released the first commercial boards of its Many Integrated Core (MIC) Architecture. MIC is Intel's solution for the domain of throughput computing, currently dominated by general purpose programming on graphics processors (GPGPU). MIC allows the use of the more familiar x86 programming model and supports standard technologies such as OpenMP, MPI, and Intel's Threading Building Blocks (TBB). This should make it possible to develop for both throughput and latency devices using a single code base. In ATLAS Software, track reconstruction has been shown to be a good candidate for throughput computing on GPGPU devices. In addition, the newly proposed offline parallel event-processing framework, GaudiHive, uses TBB for task scheduling. The MIC is thus, in principle, a good fit for this domain. In this paper, we report our experiences of porting to and optimizing ATLAS tracking algorithms for the MIC, comparing the programmability and relative cost/performance of the MIC against those of current GPGPUs and latency-optimized CPUs.

Analysis Facility infrastructure (TIER3) for ATLAS High Energy physics experiment

International Nuclear Information System (INIS)

Gonzalez de la Hoz, S.; March, L.; Ros, E.; Sanchez, J.; Amoros, G.; Fassi, F.; Fernandez, A.; Kaci, M.; Lamas, A.; Salt, J.

2007-01-01

ATLAS project has been asked to define the scope and role of Tier-3 resources (facilities or centres) within the existing ATLAS computing model, activities and facilities. This document attempts to address these questions by describing Tier-3 resources generally, and their relationship to the ATLAS Software and Computing Project. Originally the tiered computing model came out of MONARC (see http://monarc.web.cern.ch/MONARC/) work and was predicated upon the network being a scarce resource. In this model the tiered hierarchy ranged from the Tier-0 (CERN) down to the desktop or workstation (Tier 3). The focus on defining the roles of each tiered component has evolved with the initial emphasis on the Tier-0 (CERN) and Tier-1 (National centres) definition and roles. The various LHC projects, including ATLAS, then evolved the tiered hierarchy to include Tier-2s (Regional centers) as part of their projects. Tier-3s, on the other hand, have (implicitly and sometime explicitly) been defined as whatever an institution could construct to support their Physics goals using institutional and otherwise leveraged resources and therefore have not been considered to be part of the official ATLAS Research Program computing resources nor under their control, meaning there is no formal MOU process to designate sites as Tier-3s and no formal control of the program over the Tier-3 resources. Tier-3s are the responsibility of individual institutions to define, fund, deploy and support. However, having noted this, we must also recognize that Tier-3s must exist and will have implications for how our computing model should support ATLAS physicists. Tier-3 users will want to access data and simulations and will want to enable their Tier-3 resources to support their analysis and simulation work. Tiers 3s are an important resource for physicists to analyze LHC (Large Hadron Collider) data. This document will define how Tier-3s should best interact with the ATLAS computing model, detail the

Search for high mass resonances in the dimuon channel using the muon spectrometer of the atlas experiment at CERN

International Nuclear Information System (INIS)

Helsens, C.

2009-06-01

This thesis covers the search of new neutral gauge bosons decaying into a pair of muons in the ATLAS detector. The Large Hadron Collider (LHC) at CERN will produce parton collisions with very high center of mass energy and may produce Z' predicted by many theories beyond the standard model. Such a resonance should be detected by the ATLAS experiment. For the direct search of Z' decaying into two muons, a small number of events is enough for its discovery, which is possible with the first data. We shall study in particular the effects of the muon spectrometer alignment on high p T tracks and on the Z' discovery potential in the ATLAS experiment. The discovery potentials computed with this method have been officially approved by the ATLAS collaboration and published. At the start of the LHC operation, the muon spectrometer alignment will not have reached the nominal performances. This analysis aims at optimizing the discovery potential of ATLAS for a Z' boson in this degraded initial conditions. The impact on track reconstruction of a degraded alignment is estimated with simulated high p T tracks. Results are given in terms of reconstruction efficiency, momentum and invariant mass resolutions, charge identification and sensitivity to discovery or exclusion. With the first data, an analysis using only the muon spectrometer in stand alone mode will be very useful. Finally, a study on how to determine the initial geometry of the spectrometer (needed for its absolute alignment) is performed. This study uses straight tracks without a magnetic field and also calculates the beam time necessary for reaching a given accuracy of the alignment system. (author)

Search for New Physics Processes with Heavy Quark Signatures in the ATLAS Experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00388427

A program involving searches for new physics with heavy quark final states using data from the ATLAS experiment at the LHC is presented here. The signal and expected backgrounds for the decay $B_{s}→μ^{+} μ^{-} μ^{+} μ^{-}$, a rare decay whose branching ratio may be enhanced by the presence of certain Beyond the Standard Model processes, are studied, and the groundwork is laid for a future analysis. Possible mediators include horizontal gauge bosons, supersymmetry via sgoldstinos, and interactions with the hidden sector. To this end, a set of twelve triggers have been selected and studied, and their efficiency figures of merit have been calculated. A truth trigger efficiency study was performed in order to determine if new triggers should be installed for the analysis. The backgrounds have been studied, and a mass window technique was used to reduce their amplitude relative to the signal. A proposal to improve the efficiency of some of the ATLAS High-Level B-physics Triggers, based on refining the selec...

Simulation of physics in the presence of pile-up at the ATLAS experiment

CERN Document Server

Haas, A; The ATLAS collaboration

2012-01-01

We are now in a regime where we observe substantial multiple proton-proton collisions within each filled LHC bunch-crossing and also multiple filled bunch-crossings within the sensitive time window of the ATLAS detector. This will increase with increased luminosity in the near future. Including these effects in Monte Carlo simulation poses significant computing challenges. We present a description of the standard approach used by the ATLAS experiment and details of how we manage the conflicting demands of keeping the background dataset size as small as possible while minimizing the effect of background event re-use. We also present details of the methods used to minimize the memory footprint of these digitization jobs, to keep them within the grid limit, despite combining the information from thousands of simulated events at once. We also describe an alternative approach, known as Overlay. Here, the actual detector conditions are sampled from raw data using a special zero-bias trigger, and the simulated physi...

Experience with the custom-developed ATLAS Offline Trigger Monitoring Framework and Reprocessing Infrastructure

CERN Document Server

Bartsch, V

2012-01-01

After about two years of data taking with the ATLAS detector manifold experience with the custom-developed trigger monitoring and reprocessing infrastructure could be collected. The trigger monitoring can be roughly divided into online and offline monitoring. The online monitoring calculates and displays all rates at every level of the trigger and evaluates up to 3000 data quality histograms. The physics analysis relevant data quality information is being checked and recorded automatically. The offline trigger monitoring provides information depending of the physics motivated different trigger streams after a run has finished. Experts are checking the information being guided by the assessment of algorithms checking the current histograms with a reference. The experts are recording their assessment in a so-called data quality defects which are used to select data for physics analysis. In the first half of 2011 about three percent of all data had an intolerable defect resulting from the ATLAS trigger system. T...

ATLAS Operations: Experience and Evolution in the Data Taking Era

International Nuclear Information System (INIS)

Ueda, I

2011-01-01

This paper summarises the operational experience and improvements of the ATLAS hierarchical multi-tier computing infrastructure in the past year leading to taking and processing of the first collisions in 2009 and 2010. Special focus will be given to the Tier-0 which is responsible, among other things, for a prompt processing of the raw data coming from the online DAQ system and is thus a critical part of the chain. We will give an overview of the Tier-0 architecture, and improvements based on the operational experience. Emphasis will be put on the new developments, namely the Task Management System opening Tier-0 to expert users and Web 2.0 monitoring and management suite. We then overview the achieved performances with the distributed computing system, discuss observed data access patterns over the grid and describe how we used this information to improve analysis rates.

The ATLAS experience and its relevance to the data acquisition of the BM@N experiment at the NICA complex

International Nuclear Information System (INIS)

Tomiwa, K G; Mellado, B; Slepnev, I; Bazylev, S

2016-01-01

The quest to understand the world around us has increased the size of high energy physics experiments and the processing rate of the data output from high energy experiments. The Large Hadron Collider is the largest experimental set-up known, with ATLAS detector as one of the detectors built to record proton-proton collision at about 10 PB/s (Petabit/s) around the LHC interaction point. With the Phase-II upgrade in 2022 this data output will increase by at least 10 times higher than those of today due to luminosity increase, this poses a serious challenge on processing and storage of the data. Also the BM@N fixed target experiment is expected to have event size of about 80,000 bytes/Event, leading to huge amount of data output to be processed in real time. Experimentalists handle these challenges by developing High-throughput electronic, with the capability of processing and reducing big data to scientific data in real time. One of these high-throughput electronics is the Super Readout Driver (sROD) and ARM-based processing unit (PU) developed for ATLAS TileCal detector by the University of the Witwatersrand. The sROD is designed to process data from Tile Calorimeter at 40 MHz. This work takes a look at the architecture of the data acquisition (DAQ) system of the BM@N detectors and the adaptation of the high-throughput systems to last stage of the BM@N DAQ system. (paper)

Analysis of $B^{0}_{d} \\to K^{*0}\\mu^{+}\\mu^{-}$ Decay with the ATLAS Experiment

CERN Document Server

Usanova, Anna

ATLAS is a general-purpose experiment at the Large Hadron Collider. Beside other goals, it also aims at the study of B -hadrons. B -physics offers a large number of channels that can provide information about some fundamental properties of our universe. Among them, the B 0 d ! K 0 + - decay is sensitive to the potential presence of particles that are not predicted by the Standard Model. Such ”new physics” effects can be observed indirectly by studying angular distributions of the B 0 d ! K 0 + - decay products. This thesis describes the analysis of 4.9 fb - 1 of data produced in the proton-proton collisions at the centre-of-mass energy p s = 7 TeV at the LHC in the year 2011 and recorded by the ATLAS detector. The main steps of analysis are described, such as the selection of the signal events, the data fit procedure and the estimation of uncertainties. The obtained results are compared with other experiments and with the Standard Model prediction.

Distributed analysis in ATLAS using GANGA

International Nuclear Information System (INIS)

Elmsheuser, Johannes; Brochu, Frederic; Egede, Ulrik; Reece, Will; Williams, Michael; Gaidioz, Benjamin; Maier, Andrew; Moscicki, Jakub; Vanderster, Daniel; Lee, Hurng-Chun; Pajchel, Katarina; Samset, Bjorn; Slater, Mark; Soroko, Alexander; Cowan, Greig

2010-01-01

Distributed data analysis using Grid resources is one of the fundamental applications in high energy physics to be addressed and realized before the start of LHC data taking. The needs to manage the resources are very high. In every experiment up to a thousand physicists will be submitting analysis jobs to the Grid. Appropriate user interfaces and helper applications have to be made available to assure that all users can use the Grid without expertise in Grid technology. These tools enlarge the number of Grid users from a few production administrators to potentially all participating physicists. The GANGA job management system (http://cern.ch/ganga), developed as a common project between the ATLAS and LHCb experiments, provides and integrates these kind of tools. GANGA provides a simple and consistent way of preparing, organizing and executing analysis tasks within the experiment analysis framework, implemented through a plug-in system. It allows trivial switching between running test jobs on a local batch system and running large-scale analyzes on the Grid, hiding Grid technicalities. We will be reporting on the plug-ins and our experiences of distributed data analysis using GANGA within the ATLAS experiment. Support for all Grids presently used by ATLAS, namely the LCG/EGEE, NDGF/NorduGrid, and OSG/PanDA is provided. The integration and interaction with the ATLAS data management system DQ2 into GANGA is a key functionality. An intelligent job brokering is set up by using the job splitting mechanism together with data-set and file location knowledge. The brokering is aided by an automated system that regularly processes test analysis jobs at all ATLAS DQ2 supported sites. Large numbers of analysis jobs can be sent to the locations of data following the ATLAS computing model. GANGA supports amongst other things tasks of user analysis with reconstructed data and small scale production of Monte Carlo data.

Readout and Trigger for the AFP Detector at the ATLAS Experiment

CERN Document Server

Kocian, Martin; The ATLAS collaboration

2018-01-01

AFP, the ATLAS Forward Proton consists of silicon detectors at 205 m and 217 m on each side of ATLAS. In 2016 two detectors in one side were installed. The FEI4 chips are read at 160 Mbps over the optical fibers. The DAQ system uses a FPGA board with Artix chip and a mezzanine card with RCE data processing module based on a Zynq chip with ARM processor running Linux. In this contribution we give an overview of the AFP detector with the commissioning steps taken to integrate with the ATLAS TDAQ. Furthermore first performance results are presented.

Summary of the ATLAS experiment's sensitivity to supersymmetry after LHC Run 1 - interpreted in the phenomenological MSSM

CERN Document Server

Aad, Georges; Abdallah, Jalal; Abdinov, Ovsat; Aben, Rosemarie; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Abreu, Ricardo; Abulaiti, Yiming; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Adelman, Jahred; Adomeit, Stefanie; Adye, Tim; Affolder, Tony; Agatonovic-Jovin, Tatjana; Agricola, Johannes; Aguilar-Saavedra, Juan Antonio; Ahlen, Steven; Ahmadov, Faig; Aielli, Giulio; Akerstedt, Henrik; Åkesson, Torsten Paul Ake; Akimov, Andrei; Alberghi, Gian Luigi; Albert, Justin; Albrand, Solveig; Alconada Verzini, Maria Josefina; Aleksa, Martin; Aleksandrov, Igor; Alexa, Calin; Alexander, Gideon; Alexopoulos, Theodoros; Alhroob, Muhammad; Alimonti, Gianluca; Alio, Lion; Alison, John; Alkire, Steven Patrick; Allbrooke, Benedict; Allport, Phillip; Aloisio, Alberto; Alonso, Alejandro; Alonso, Francisco; Alpigiani, Cristiano; Altheimer, Andrew David; Alvarez Gonzalez, Barbara; Άlvarez Piqueras, Damián; Alviggi, Mariagrazia; Amadio, Brian Thomas; Amako, Katsuya; Amaral Coutinho, Yara; Amelung, Christoph; Amidei, Dante; Amor Dos Santos, Susana Patricia; Amorim, Antonio; Amoroso, Simone; Amram, Nir; Amundsen, Glenn; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anders, John Kenneth; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Angelidakis, Stylianos; Angelozzi, Ivan; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aperio Bella, Ludovica; Arabidze, Giorgi; Arai, Yasuo; Araque, Juan Pedro; Arce, Ayana; Arduh, Francisco Anuar; Arguin, Jean-Francois; Argyropoulos, Spyridon; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnold, Hannah; Arratia, Miguel; Arslan, Ozan; Artamonov, Andrei; Artoni, Giacomo; Asai, Shoji; Asbah, Nedaa; Ashkenazi, Adi; Åsman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astalos, Robert; Atkinson, Markus; Atlay, Naim Bora; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Axen, Bradley; Ayoub, Mohamad Kassem; Azuelos, Georges; Baak, Max; Baas, Alessandra; Baca, Matthew John; Bacci, Cesare; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Bagiacchi, Paolo; Bagnaia, Paolo; Bai, Yu; Bain, Travis; Baines, John; Baker, Oliver Keith; Baldin, Evgenii; Balek, Petr; Balestri, Thomas; Balli, Fabrice; Balunas, William Keaton; Banas, Elzbieta; Banerjee, Swagato; Bannoura, Arwa A E; Barak, Liron; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnes, Sarah Louise; Barnett, Bruce; Barnett, Michael; Barnovska, Zuzana; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Bartoldus, Rainer; Barton, Adam Edward; Bartos, Pavol; Basalaev, Artem; Bassalat, Ahmed; Basye, Austin; Bates, Richard; Batista, Santiago Juan; Batley, Richard; Battaglia, Marco; Bauce, Matteo; Bauer, Florian; Bawa, Harinder Singh; Beacham, James Baker; Beattie, Michael David; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Kathrin; Becker, Maurice; Beckingham, Matthew; Becot, Cyril; Beddall, Andrew; Beddall, Ayda; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Beermann, Thomas; Begel, Michael; Behr, Janna Katharina; Belanger-Champagne, Camille; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellerive, Alain; Bellomo, Massimiliano; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bender, Michael; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Bensinger, James; Bentvelsen, Stan; Beresford, Lydia; Beretta, Matteo; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Beringer, Jürg; Bernard, Clare; Bernard, Nathan Rogers; Bernius, Catrin; Bernlochner, Florian Urs; Berry, Tracey; Berta, Peter; Bertella, Claudia; Bertoli, Gabriele; Bertolucci, Federico; Bertsche, Carolyn; Bertsche, David; Besana, Maria Ilaria; Besjes, Geert-Jan; Bessidskaia Bylund, Olga; Bessner, Martin Florian; Besson, Nathalie; Betancourt, Christopher; Bethke, Siegfried; Bevan, Adrian John; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianchini, Louis; Bianco, Michele; Biebel, Otmar; Biedermann, Dustin; Bieniek, Stephen Paul; Biesuz, Nicolo Vladi; Biglietti, Michela; Bilbao De Mendizabal, Javier; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biondi, Silvia; Bjergaard, David Martin; Black, Curtis; Black, James; Black, Kevin; Blackburn, Daniel; Blair, Robert; Blanchard, Jean-Baptiste; Blanco, Jacobo Ezequiel; Blazek, Tomas; Bloch, Ingo; Blocker, Craig; Blum, Walter; Blumenschein, Ulrike; Blunier, Sylvain; Bobbink, Gerjan; Bobrovnikov, Victor; Bocchetta, Simona Serena; Bocci, Andrea; Bock, Christopher; Boehler, Michael; Bogaerts, Joannes Andreas; Bogavac, Danijela; Bogdanchikov, Alexander; Bohm, Christian; Boisvert, Veronique; Bold, Tomasz; Boldea, Venera; Boldyrev, Alexey; Bomben, Marco; Bona, Marcella; Boonekamp, Maarten; Borisov, Anatoly; Borissov, Guennadi; Borroni, Sara; Bortfeldt, Jonathan; Bortolotto, Valerio; Bos, Kors; Boscherini, Davide; Bosman, Martine; Boudreau, Joseph; Bouffard, Julian; Bouhova-Thacker, Evelina Vassileva; Boumediene, Djamel Eddine; Bourdarios, Claire; Bousson, Nicolas; Boutle, Sarah Kate; Boveia, Antonio; Boyd, James; Boyko, Igor; Bozic, Ivan; Bracinik, Juraj; Brandt, Andrew; Brandt, Gerhard; Brandt, Oleg; Bratzler, Uwe; Brau, Benjamin; Brau, James; Braun, Helmut; Breaden Madden, William Dmitri; Brendlinger, Kurt; Brennan, Amelia Jean; Brenner, Lydia; Brenner, Richard; Bressler, Shikma; Bristow, Kieran; Bristow, Timothy Michael; Britton, Dave; Britzger, Daniel; Brochu, Frederic; Brock, Ian; Brock, Raymond; Bronner, Johanna; Brooijmans, Gustaaf; Brooks, Timothy; Brooks, William; Brosamer, Jacquelyn; Brost, Elizabeth; Bruckman de Renstrom, Pawel; Bruncko, Dusan; Bruneliere, Renaud; Bruni, Alessia; Bruni, Graziano; Bruschi, Marco; Bruscino, Nello; Bryngemark, Lene; Buanes, Trygve; Buat, Quentin; Buchholz, Peter; Buckley, Andrew; Buda, Stelian Ioan; Budagov, Ioulian; Buehrer, Felix; Bugge, Lars; Bugge, Magnar Kopangen; Bulekov, Oleg; Bullock, Daniel; Burckhart, Helfried; Burdin, Sergey; Burgard, Carsten Daniel; Burghgrave, Blake; Burke, Stephen; Burmeister, Ingo; Busato, Emmanuel; Büscher, Daniel; Büscher, Volker; Bussey, Peter; Butler, John; Butt, Aatif Imtiaz; Buttar, Craig; Butterworth, Jonathan; Butti, Pierfrancesco; Buttinger, William; Buzatu, Adrian; Buzykaev, Aleksey; Cabrera Urbán, Susana; Caforio, Davide; Cairo, Valentina; Cakir, Orhan; Calace, Noemi; Calafiura, Paolo; Calandri, Alessandro; Calderini, Giovanni; Calfayan, Philippe; Caloba, Luiz; Calvet, David; Calvet, Samuel; Camacho Toro, Reina; Camarda, Stefano; Camarri, Paolo; Cameron, David; Caminal Armadans, Roger; Campana, Simone; Campanelli, Mario; Campoverde, Angel; Canale, Vincenzo; Canepa, Anadi; Cano Bret, Marc; Cantero, Josu; Cantrill, Robert; Cao, Tingting; Capeans Garrido, Maria Del Mar; Caprini, Irinel; Caprini, Mihai; Capua, Marcella; Caputo, Regina; Carbone, Ryne Michael; Cardarelli, Roberto; Cardillo, Fabio; Carli, Tancredi; Carlino, Gianpaolo; Carminati, Leonardo; Caron, Sascha; Carquin, Edson; Carrillo-Montoya, German D; Carter, Janet; Carvalho, João; Casadei, Diego; Casado, Maria Pilar; Casolino, Mirkoantonio; Castaneda-Miranda, Elizabeth; Castelli, Angelantonio; Castillo Gimenez, Victoria; Castro, Nuno Filipe; Catastini, Pierluigi; Catinaccio, Andrea; Catmore, James; Cattai, Ariella; Caudron, Julien; Cavaliere, Viviana; Cavalli, Donatella; Cavalli-Sforza, Matteo; Cavasinni, Vincenzo; Ceradini, Filippo; Cerio, Benjamin; Cerny, Karel; Santiago Cerqueira, Augusto; Cerri, Alessandro; Cerrito, Lucio; Cerutti, Fabio; Cerv, Matevz; Cervelli, Alberto; Cetin, Serkant Ali; Chafaq, Aziz; Chakraborty, Dhiman; Chalupkova, Ina; Chang, Philip; Chapman, John Derek; Charlton, Dave; Chau, Chav Chhiv; Chavez Barajas, Carlos Alberto; Cheatham, Susan; Chegwidden, Andrew; Chekanov, Sergei; Chekulaev, Sergey; Chelkov, Gueorgui; Chelstowska, Magda Anna; Chen, Chunhui; Chen, Hucheng; Chen, Karen; Chen, Liming; Chen, Shenjian; Chen, Shion; Chen, Xin; Chen, Ye; Cheng, Hok Chuen; Cheng, Yangyang; Cheplakov, Alexander; Cheremushkina, Evgenia; Cherkaoui El Moursli, Rajaa; Chernyatin, Valeriy; Cheu, Elliott; Chevalier, Laurent; Chiarella, Vitaliano; Chiarelli, Giorgio; Chiodini, Gabriele; Chisholm, Andrew; Chislett, Rebecca Thalatta; Chitan, Adrian; Chizhov, Mihail; Choi, Kyungeon; Chouridou, Sofia; Chow, Bonnie Kar Bo; Christodoulou, Valentinos; Chromek-Burckhart, Doris; Chudoba, Jiri; Chuinard, Annabelle Julia; Chwastowski, Janusz; Chytka, Ladislav; Ciapetti, Guido; Ciftci, Abbas Kenan; Cinca, Diane; Cindro, Vladimir; Cioara, Irina Antonela; Ciocio, Alessandra; Cirotto, Francesco; Citron, Zvi Hirsh; Ciubancan, Mihai; Clark, Allan G; Clark, Brian Lee; Clark, Philip James; Clarke, Robert; Clement, Christophe; Coadou, Yann; Cobal, Marina; Coccaro, Andrea; Cochran, James H; Coffey, Laurel; Cogan, Joshua Godfrey; Colasurdo, Luca; Cole, Brian; Cole, Stephen; Colijn, Auke-Pieter; Collot, Johann; Colombo, Tommaso; Compostella, Gabriele; Conde Muiño, Patricia; Coniavitis, Elias; Connell, Simon Henry; Connelly, Ian; Consorti, Valerio; Constantinescu, Serban; Conta, Claudio; Conti, Geraldine; Conventi, Francesco; Cooke, Mark; Cooper, Ben; Cooper-Sarkar, Amanda; Cornelissen, Thijs; Corradi, Massimo; Corriveau, Francois; Corso-Radu, Alina; Cortes-Gonzalez, Arely; Cortiana, Giorgio; Costa, Giuseppe; Costa, María José; Costanzo, Davide; Côté, David; Cottin, Giovanna; Cowan, Glen; Cox, Brian; Cranmer, Kyle; Cree, Graham; Crépé-Renaudin, Sabine; Crescioli, Francesco; Cribbs, Wayne Allen; Crispin Ortuzar, Mireia; Cristinziani, Markus; Croft, Vince; Crosetti, Giovanni; Cuhadar Donszelmann, Tulay; Cummings, Jane; Curatolo, Maria; Cúth, Jakub; Cuthbert, Cameron; Czirr, Hendrik; Czodrowski, Patrick; D'Auria, Saverio; D'Onofrio, Monica; Da Cunha Sargedas De Sousa, Mario Jose; Da Via, Cinzia; Dabrowski, Wladyslaw; Dafinca, Alexandru; Dai, Tiesheng; Dale, Orjan; Dallaire, Frederick; Dallapiccola, Carlo; Dam, Mogens; Dandoy, Jeffrey Rogers; Dang, Nguyen Phuong; Daniells, Andrew Christopher; Danninger, Matthias; Dano Hoffmann, Maria; Dao, Valerio; Darbo, Giovanni; Darmora, Smita; Dassoulas, James; Dattagupta, Aparajita; Davey, Will; David, Claire; Davidek, Tomas; Davies, Eleanor; Davies, Merlin; Davison, Peter; Davygora, Yuriy; Dawe, Edmund; Dawson, Ian; Daya-Ishmukhametova, Rozmin; De, Kaushik; de Asmundis, Riccardo; De Benedetti, Abraham; De Castro, Stefano; De Cecco, Sandro; De Groot, Nicolo; de Jong, Paul; De la Torre, Hector; De Lorenzi, Francesco; De Pedis, Daniele; De Salvo, Alessandro; De Sanctis, Umberto; De Santo, Antonella; De Vivie De Regie, Jean-Baptiste; Dearnaley, William James; Debbe, Ramiro; Debenedetti, Chiara; Dedovich, Dmitri; Deigaard, Ingrid; Del Peso, Jose; Del Prete, Tarcisio; Delgove, David; Deliot, Frederic; Delitzsch, Chris Malena; Deliyergiyev, Maksym; Dell'Acqua, Andrea; Dell'Asta, Lidia; Dell'Orso, Mauro; Della Pietra, Massimo; della Volpe, Domenico; Delmastro, Marco; Delsart, Pierre-Antoine; Deluca, Carolina; DeMarco, David; Demers, Sarah; Demichev, Mikhail; Demilly, Aurelien; Denisov, Sergey; Derendarz, Dominik; Derkaoui, Jamal Eddine; Derue, Frederic; Dervan, Paul; Desch, Klaus Kurt; Deterre, Cecile; Deviveiros, Pier-Olivier; Dewhurst, Alastair; Dhaliwal, Saminder; Di Ciaccio, Anna; Di Ciaccio, Lucia; Di Domenico, Antonio; Di Donato, Camilla; Di Girolamo, Alessandro; Di Girolamo, Beniamino; Di Mattia, Alessandro; Di Micco, Biagio; Di Nardo, Roberto; Di Simone, Andrea; Di Sipio, Riccardo; Di Valentino, David; Diaconu, Cristinel; Diamond, Miriam; Dias, Flavia; Diaz, Marco Aurelio; Diehl, Edward; Dietrich, Janet; Diglio, Sara; Dimitrievska, Aleksandra; Dingfelder, Jochen; Dita, Petre; Dita, Sanda; Dittus, Fridolin; Djama, Fares; Djobava, Tamar; Djuvsland, Julia Isabell; Barros do Vale, Maria Aline; Dobos, Daniel; Dobre, Monica; Doglioni, Caterina; Dohmae, Takeshi; Dolejsi, Jiri; Dolezal, Zdenek; Dolgoshein, Boris; Donadelli, Marisilvia; Donati, Simone; Dondero, Paolo; Donini, Julien; Dopke, Jens; Doria, Alessandra; Dova, Maria-Teresa; Doyle, Tony; Drechsler, Eric; Dris, Manolis; Dubreuil, Emmanuelle; Duchovni, Ehud; Duckeck, Guenter; Ducu, Otilia Anamaria; Duda, Dominik; Dudarev, Alexey; Duflot, Laurent; Duguid, Liam; Dührssen, Michael; Dunford, Monica; Duran Yildiz, Hatice; Düren, Michael; Durglishvili, Archil; Duschinger, Dirk; Dutta, Baishali; Dyndal, Mateusz; Eckardt, Christoph; Ecker, Katharina Maria; Edgar, Ryan Christopher; Edson, William; Edwards, Nicholas Charles; Ehrenfeld, Wolfgang; Eifert, Till; Eigen, Gerald; Einsweiler, Kevin; Ekelof, Tord; El Kacimi, Mohamed; Ellert, Mattias; Elles, Sabine; Ellinghaus, Frank; Elliot, Alison; Ellis, Nicolas; Elmsheuser, Johannes; Elsing, Markus; Emeliyanov, Dmitry; Enari, Yuji; Endner, Oliver Chris; Endo, Masaki; Erdmann, Johannes; Ereditato, Antonio; Ernis, Gunar; Ernst, Jesse; Ernst, Michael; Errede, Steven; Ertel, Eugen; Escalier, Marc; Esch, Hendrik; Escobar, Carlos; Esposito, Bellisario; Etienvre, Anne-Isabelle; Etzion, Erez; Evans, Hal; Ezhilov, Alexey; Fabbri, Laura; Facini, Gabriel; Fakhrutdinov, Rinat; Falciano, Speranza; Falla, Rebecca Jane; Faltova, Jana; Fang, Yaquan; Fanti, Marcello; Farbin, Amir; Farilla, Addolorata; Farooque, Trisha; Farrell, Steven; Farrington, Sinead; Farthouat, Philippe; Fassi, Farida; Fassnacht, Patrick; Fassouliotis, Dimitrios; Faucci Giannelli, Michele; Favareto, Andrea; Fawcett, William James; Fayard, Louis; Fedin, Oleg; Fedorko, Wojciech; Feigl, Simon; Feligioni, Lorenzo; Feng, Cunfeng; Feng, Eric; Feng, Haolu; Fenyuk, Alexander; Feremenga, Last; Fernandez Martinez, Patricia; Fernandez Perez, Sonia; Ferrando, James; Ferrari, Arnaud; Ferrari, Pamela; Ferrari, Roberto; Ferreira de Lima, Danilo Enoque; Ferrer, Antonio; Ferrere, Didier; Ferretti, Claudio; Ferretto Parodi, Andrea; Fiascaris, Maria; Fiedler, Frank; Filipčič, Andrej; Filipuzzi, Marco; Filthaut, Frank; Fincke-Keeler, Margret; Finelli, Kevin Daniel; Fiolhais, Miguel; Fiorini, Luca; Firan, Ana; Fischer, Adam; Fischer, Cora; Fischer, Julia; Fisher, Wade Cameron; Flaschel, Nils; Fleck, Ivor; Fleischmann, Philipp; Fletcher, Gareth Thomas; Fletcher, Gregory; Fletcher, Rob Roy MacGregor; Flick, Tobias; Floderus, Anders; Flores Castillo, Luis; Flowerdew, Michael; Formica, Andrea; Forti, Alessandra; Fournier, Daniel; Fox, Harald; Fracchia, Silvia; Francavilla, Paolo; Franchini, Matteo; Francis, David; Franconi, Laura; Franklin, Melissa; Frate, Meghan; Fraternali, Marco; Freeborn, David; French, Sky; Friedrich, Felix; Froidevaux, Daniel; Frost, James; Fukunaga, Chikara; Fullana Torregrosa, Esteban; Fulsom, Bryan Gregory; Fusayasu, Takahiro; Fuster, Juan; Gabaldon, Carolina; Gabizon, Ofir; Gabrielli, Alessandro; Gabrielli, Andrea; Gach, Grzegorz; Gadatsch, Stefan; Gadomski, Szymon; Gagliardi, Guido; Gagnon, Pauline; Galea, Cristina; Galhardo, Bruno; Gallas, Elizabeth; Gallop, Bruce; Gallus, Petr; Galster, Gorm Aske Gram Krohn; Gan, KK; Gao, Jun; Gao, Yanyan; Gao, Yongsheng; Garay Walls, Francisca; Garberson, Ford; García, Carmen; García Navarro, José Enrique; Garcia-Sciveres, Maurice; Gardner, Robert; Garelli, Nicoletta; Garonne, Vincent; Gatti, Claudio; Gaudiello, Andrea; Gaudio, Gabriella; Gaur, Bakul; Gauthier, Lea; Gauzzi, Paolo; Gavrilenko, Igor; Gay, Colin; Gaycken, Goetz; Gazis, Evangelos; Ge, Peng; Gecse, Zoltan; Gee, Norman; Geich-Gimbel, Christoph; Geisler, Manuel Patrice; Gemme, Claudia; Genest, Marie-Hélène; Gentile, Simonetta; George, Matthias; George, Simon; Gerbaudo, Davide; Gershon, Avi; Ghasemi, Sara; Ghazlane, Hamid; Giacobbe, Benedetto; Giagu, Stefano; Giangiobbe, Vincent; Giannetti, Paola; Gibbard, Bruce; Gibson, Stephen; Gignac, Matthew; Gilchriese, Murdock; Gillam, Thomas; Gillberg, Dag; Gilles, Geoffrey; Gingrich, Douglas; Giokaris, Nikos; Giordani, MarioPaolo; Giorgi, Filippo Maria; Giorgi, Francesco Michelangelo; Giraud, Pierre-Francois; Giromini, Paolo; Giugni, Danilo; Giuliani, Claudia; Giulini, Maddalena; Gjelsten, Børge Kile; Gkaitatzis, Stamatios; Gkialas, Ioannis; Gkougkousis, Evangelos Leonidas; Gladilin, Leonid; Glasman, Claudia; Glatzer, Julian; Glaysher, Paul; Glazov, Alexandre; Goblirsch-Kolb, Maximilian; Goddard, Jack Robert; Godlewski, Jan; Goldfarb, Steven; Golling, Tobias; Golubkov, Dmitry; Gomes, Agostinho; Gonçalo, Ricardo; Goncalves Pinto Firmino Da Costa, Joao; Gonella, Laura; González de la Hoz, Santiago; Gonzalez Parra, Garoe; Gonzalez-Sevilla, Sergio; Goossens, Luc; Gorbounov, Petr Andreevich; Gordon, Howard; Gorelov, Igor; Gorini, Benedetto; Gorini, Edoardo; Gorišek, Andrej; Gornicki, Edward; Goshaw, Alfred; Gössling, Claus; Gostkin, Mikhail Ivanovitch; Goujdami, Driss; Goussiou, Anna; Govender, Nicolin; Gozani, Eitan; Grabas, Herve Marie Xavier; Graber, Lars; Grabowska-Bold, Iwona; Gradin, Per Olov Joakim; Grafström, Per; Grahn, Karl-Johan; Gramling, Johanna; Gramstad, Eirik; Grancagnolo, Sergio; Gratchev, Vadim; Gray, Heather; Graziani, Enrico; Greenwood, Zeno Dixon; Grefe, Christian; Gregersen, Kristian; Gregor, Ingrid-Maria; Grenier, Philippe; Griffiths, Justin; Grillo, Alexander; Grimm, Kathryn; Grinstein, Sebastian; Gris, Philippe Luc Yves; Grivaz, Jean-Francois; Grohs, Johannes Philipp; Grohsjean, Alexander; Gross, Eilam; Grosse-Knetter, Joern; Grossi, Giulio Cornelio; Grout, Zara Jane; Guan, Liang; Guenther, Jaroslav; Guescini, Francesco; Guest, Daniel; Gueta, Orel; Guido, Elisa; Guillemin, Thibault; Guindon, Stefan; Gul, Umar; Gumpert, Christian; Guo, Jun; Guo, Yicheng; Gupta, Shaun; Gustavino, Giuliano; Gutierrez, Phillip; Gutierrez Ortiz, Nicolas Gilberto; Gutschow, Christian; Guyot, Claude; Gwenlan, Claire; Gwilliam, Carl; Haas, Andy; Haber, Carl; Hadavand, Haleh Khani; Haddad, Nacim; Haefner, Petra; Hageböck, Stephan; Hajduk, Zbigniew; Hakobyan, Hrachya; Haleem, Mahsana; Haley, Joseph; Hall, David; Halladjian, Garabed; Hallewell, Gregory David; Hamacher, Klaus; Hamal, Petr; Hamano, Kenji; Hamilton, Andrew; Hamity, Guillermo Nicolas; Hamnett, Phillip George; Han, Liang; Hanagaki, Kazunori; Hanawa, Keita; Hance, Michael; Haney, Bijan; Hanke, Paul; Hanna, Remie; Hansen, Jørgen Beck; Hansen, Jorn Dines; Hansen, Maike Christina; Hansen, Peter Henrik; Hara, Kazuhiko; Hard, Andrew; Harenberg, Torsten; Hariri, Faten; Harkusha, Siarhei; Harrington, Robert; Harrison, Paul Fraser; Hartjes, Fred; Hasegawa, Makoto; Hasegawa, Yoji; Hasib, A; Hassani, Samira; Haug, Sigve; Hauser, Reiner; Hauswald, Lorenz; Havranek, Miroslav; Hawkes, Christopher; Hawkings, Richard John; Hawkins, Anthony David; Hayashi, Takayasu; Hayden, Daniel; Hays, Chris; Hays, Jonathan Michael; Hayward, Helen; Haywood, Stephen; Head, Simon; Heck, Tobias; Hedberg, Vincent; Heelan, Louise; Heim, Sarah; Heim, Timon; Heinemann, Beate; Heinrich, Lukas; Hejbal, Jiri; Helary, Louis; Hellman, Sten; Hellmich, Dennis; Helsens, Clement; Henderson, James; Henderson, Robert; Heng, Yang; Hengler, Christopher; Henkelmann, Steffen; Henrichs, Anna; Henriques Correia, Ana Maria; Henrot-Versille, Sophie; Herbert, Geoffrey Henry; Hernández Jiménez, Yesenia; Herten, Gregor; Hertenberger, Ralf; Hervas, Luis; Hesketh, Gavin Grant; Hessey, Nigel; Hetherly, Jeffrey Wayne; Hickling, Robert; Higón-Rodriguez, Emilio; Hill, Ewan; Hill, John; Hiller, Karl Heinz; Hillier, Stephen; Hinchliffe, Ian; Hines, Elizabeth; Hinman, Rachel Reisner; Hirose, Minoru; Hirschbuehl, Dominic; Hobbs, John; Hod, Noam; Hodgkinson, Mark; Hodgson, Paul; Hoecker, Andreas; Hoeferkamp, Martin; Hoenig, Friedrich; Hohlfeld, Marc; Hohn, David; Holmes, Tova Ray; Homann, Michael; Hong, Tae Min; Hopkins, Walter; Horii, Yasuyuki; Horton, Arthur James; Hostachy, Jean-Yves; Hou, Suen; Hoummada, Abdeslam; Howard, Jacob; Howarth, James; Hrabovsky, Miroslav; Hristova, Ivana; Hrivnac, Julius; Hryn'ova, Tetiana; Hrynevich, Aliaksei; Hsu, Catherine; Hsu, Pai-hsien Jennifer; Hsu, Shih-Chieh; Hu, Diedi; Hu, Qipeng; Hu, Xueye; Huang, Yanping; Hubacek, Zdenek; Hubaut, Fabrice; Huegging, Fabian; Huffman, Todd Brian; Hughes, Emlyn; Hughes, Gareth; Huhtinen, Mika; Hülsing, Tobias Alexander; Huseynov, Nazim; Huston, Joey; Huth, John; Iacobucci, Giuseppe; Iakovidis, Georgios; Ibragimov, Iskander; Iconomidou-Fayard, Lydia; Ideal, Emma; Idrissi, Zineb; Iengo, Paolo; Igonkina, Olga; Iizawa, Tomoya; Ikegami, Yoichi; Ikematsu, Katsumasa; Ikeno, Masahiro; Ilchenko, Iurii; Iliadis, Dimitrios; Ilic, Nikolina; Ince, Tayfun; Introzzi, Gianluca; Ioannou, Pavlos; Iodice, Mauro; Iordanidou, Kalliopi; Ippolito, Valerio; Irles Quiles, Adrian; Isaksson, Charlie; Ishino, Masaya; Ishitsuka, Masaki; Ishmukhametov, Renat; Issever, Cigdem; Istin, Serhat; Iturbe Ponce, Julia Mariana; Iuppa, Roberto; Ivarsson, Jenny; Iwanski, Wieslaw; Iwasaki, Hiroyuki; Izen, Joseph; Izzo, Vincenzo; Jabbar, Samina; Jackson, Brett; Jackson, Matthew; Jackson, Paul; Jaekel, Martin; Jain, Vivek; Jakobs, Karl; Jakobsen, Sune; Jakoubek, Tomas; Jakubek, Jan; Jamin, David Olivier; Jana, Dilip; Jansen, Eric; Jansky, Roland; Janssen, Jens; Janus, Michel; Jarlskog, Göran; Javadov, Namig; Javůrek, Tomáš; Jeanty, Laura; Jejelava, Juansher; Jeng, Geng-yuan; Jennens, David; Jenni, Peter; Jentzsch, Jennifer; Jeske, Carl; Jézéquel, Stéphane; Ji, Haoshuang; Jia, Jiangyong; Jiang, Yi; Jiggins, Stephen; Jimenez Pena, Javier; Jin, Shan; Jinaru, Adam; Jinnouchi, Osamu; Joergensen, Morten Dam; Johansson, Per; Johns, Kenneth; Johnson, William Joseph; Jon-And, Kerstin; Jones, Graham; Jones, Roger; Jones, Tim; Jongmanns, Jan; Jorge, Pedro; Joshi, Kiran Daniel; Jovicevic, Jelena; Ju, Xiangyang; Jussel, Patrick; Juste Rozas, Aurelio; Kaci, Mohammed; Kaczmarska, Anna; Kado, Marumi; Kagan, Harris; Kagan, Michael; Kahn, Sebastien Jonathan; Kajomovitz, Enrique; Kalderon, Charles William; Kama, Sami; Kamenshchikov, Andrey; Kanaya, Naoko; Kaneti, Steven; Kantserov, Vadim; Kanzaki, Junichi; Kaplan, Benjamin; Kaplan, Laser Seymour; Kapliy, Anton; Kar, Deepak; Karakostas, Konstantinos; Karamaoun, Andrew; Karastathis, Nikolaos; Kareem, Mohammad Jawad; Karentzos, Efstathios; Karnevskiy, Mikhail; Karpov, Sergey; Karpova, Zoya; Karthik, Krishnaiyengar; Kartvelishvili, Vakhtang; Karyukhin, Andrey; Kasahara, Kota; Kashif, Lashkar; Kass, Richard; Kastanas, Alex; Kataoka, Yousuke; Kato, Chikuma; Katre, Akshay; Katzy, Judith; Kawade, Kentaro; Kawagoe, Kiyotomo; Kawamoto, Tatsuo; Kawamura, Gen; Kazama, Shingo; Kazanin, Vassili; Keeler, Richard; Kehoe, Robert; Keller, John; Kempster, Jacob Julian; Keoshkerian, Houry; Kepka, Oldrich; Kerševan, Borut Paul; Kersten, Susanne; Keyes, Robert; Khalil-zada, Farkhad; Khandanyan, Hovhannes; Khanov, Alexander; Kharlamov, Alexey; Khoo, Teng Jian; Khovanskiy, Valery; Khramov, Evgeniy; Khubua, Jemal; Kido, Shogo; Kim, Hee Yeun; Kim, Shinhong; Kim, Young-Kee; Kimura, Naoki; Kind, Oliver Maria; King, Barry; King, Matthew; King, Samuel Burton; Kirk, Julie; Kiryunin, Andrey; Kishimoto, Tomoe; Kisielewska, Danuta; Kiss, Florian; Kiuchi, Kenji; Kivernyk, Oleh; Kladiva, Eduard; Klein, Matthew Henry; Klein, Max; Klein, Uta; Kleinknecht, Konrad; Klimek, Pawel; Klimentov, Alexei; Klingenberg, Reiner; Klinger, Joel Alexander; Klioutchnikova, Tatiana; Kluge, Eike-Erik; Kluit, Peter; Kluth, Stefan; Knapik, Joanna; Kneringer, Emmerich; Knoops, Edith; Knue, Andrea; Kobayashi, Aine; Kobayashi, Dai; Kobayashi, Tomio; Kobel, Michael; Kocian, Martin; Kodys, Peter; Koffas, Thomas; Koffeman, Els; Kogan, Lucy Anne; Kohlmann, Simon; Kohout, Zdenek; Kohriki, Takashi; Koi, Tatsumi; Kolanoski, Hermann; Kolb, Mathis; Koletsou, Iro; Komar, Aston; Komori, Yuto; Kondo, Takahiko; Kondrashova, Nataliia; Köneke, Karsten; König, Adriaan; Kono, Takanori; Konoplich, Rostislav; Konstantinidis, Nikolaos; Kopeliansky, Revital; Koperny, Stefan; Köpke, Lutz; Kopp, Anna Katharina; Korcyl, Krzysztof; Kordas, Kostantinos; Korn, Andreas; Korol, Aleksandr; Korolkov, Ilya; Korolkova, Elena; Kortner, Oliver; Kortner, Sandra; Kosek, Tomas; Kostyukhin, Vadim; Kotov, Vladislav; Kotwal, Ashutosh; Kourkoumeli-Charalampidi, Athina; Kourkoumelis, Christine; Kouskoura, Vasiliki; Koutsman, Alex; Kowalewski, Robert Victor; Kowalski, Tadeusz; Kozanecki, Witold; Kozhin, Anatoly; Kramarenko, Viktor; Kramberger, Gregor; Krasnopevtsev, Dimitriy; Krasny, Mieczyslaw Witold; Krasznahorkay, Attila; Kraus, Jana; Kravchenko, Anton; Kreiss, Sven; Kretz, Moritz; Kretzschmar, Jan; Kreutzfeldt, Kristof; Krieger, Peter; Krizka, Karol; Kroeninger, Kevin; Kroha, Hubert; Kroll, Joe; Kroseberg, Juergen; Krstic, Jelena; Kruchonak, Uladzimir; Krüger, Hans; Krumnack, Nils; Kruse, Amanda; Kruse, Mark; Kruskal, Michael; Kubota, Takashi; Kucuk, Hilal; Kuday, Sinan; Kuehn, Susanne; Kugel, Andreas; Kuger, Fabian; Kuhl, Andrew; Kuhl, Thorsten; Kukhtin, Victor; Kukla, Romain; Kulchitsky, Yuri; Kuleshov, Sergey; Kuna, Marine; Kunigo, Takuto; Kupco, Alexander; Kurashige, Hisaya; Kurochkin, Yurii; Kus, Vlastimil; Kuwertz, Emma Sian; Kuze, Masahiro; Kvita, Jiri; Kwan, Tony; Kyriazopoulos, Dimitrios; La Rosa, Alessandro; La Rosa Navarro, Jose Luis; La Rotonda, Laura; Lacasta, Carlos; Lacava, Francesco; Lacey, James; Lacker, Heiko; Lacour, Didier; Lacuesta, Vicente Ramón; Ladygin, Evgueni; Lafaye, Remi; Laforge, Bertrand; Lagouri, Theodota; Lai, Stanley; Lambourne, Luke; Lammers, Sabine; Lampen, Caleb; Lampl, Walter; Lançon, Eric; Landgraf, Ulrich; Landon, Murrough; Lang, Valerie Susanne; Lange, J örn Christian; Lankford, Andrew; Lanni, Francesco; Lantzsch, Kerstin; Lanza, Agostino; Laplace, Sandrine; Lapoire, Cecile; Laporte, Jean-Francois; Lari, Tommaso; Lasagni Manghi, Federico; Lassnig, Mario; Laurelli, Paolo; Lavrijsen, Wim; Law, Alexander; Laycock, Paul; Lazovich, Tomo; Le Dortz, Olivier; Le Guirriec, Emmanuel; Le Menedeu, Eve; LeBlanc, Matthew Edgar; LeCompte, Thomas; Ledroit-Guillon, Fabienne Agnes Marie; Lee, Claire Alexandra; Lee, Shih-Chang; Lee, Lawrence; Lefebvre, Guillaume; Lefebvre, Michel; Legger, Federica; Leggett, Charles; Lehan, Allan; Lehmann Miotto, Giovanna; Lei, Xiaowen; Leight, William Axel; Leisos, Antonios; Leister, Andrew Gerard; Leite, Marco Aurelio Lisboa; Leitner, Rupert; Lellouch, Daniel; Lemmer, Boris; Leney, Katharine; Lenz, Tatjana; Lenzi, Bruno; Leone, Robert; Leone, Sandra; Leonidopoulos, Christos; Leontsinis, Stefanos; Leroy, Claude; Lester, Christopher; Levchenko, Mikhail; Levêque, Jessica; Levin, Daniel; Levinson, Lorne; Levy, Mark; Lewis, Adrian; Leyko, Agnieszka; Leyton, Michael; Li, Bing; Li, Haifeng; Li, Ho Ling; Li, Lei; Li, Liang; Li, Shu; Li, Xingguo; Li, Yichen; Liang, Zhijun; Liao, Hongbo; Liberti, Barbara; Liblong, Aaron; Lichard, Peter; Lie, Ki; Liebal, Jessica; Liebig, Wolfgang; Limbach, Christian; Limosani, Antonio; Lin, Simon; Lin, Tai-Hua; Linde, Frank; Lindquist, Brian Edward; Linnemann, James; Lipeles, Elliot; Lipniacka, Anna; Lisovyi, Mykhailo; Liss, Tony; Lissauer, David; Lister, Alison; Litke, Alan; Liu, Bo; Liu, Dong; Liu, Hao; Liu, Jian; Liu, Jianbei; Liu, Kun; Liu, Lulu; Liu, Miaoyuan; Liu, Minghui; Liu, Yanwen; Livan, Michele; Lleres, Annick; Llorente Merino, Javier; Lloyd, Stephen; Lo Sterzo, Francesco; Lobodzinska, Ewelina; Loch, Peter; Lockman, William; Loebinger, Fred; Loevschall-Jensen, Ask Emil; Loew, Kevin Michael; Loginov, Andrey; Lohse, Thomas; Lohwasser, Kristin; Lokajicek, Milos; Long, Brian Alexander; Long, Jonathan David; Long, Robin Eamonn; Looper, Kristina Anne; Lopes, Lourenco; Lopez Mateos, David; Lopez Paredes, Brais; Lopez Paz, Ivan; Lorenz, Jeanette; Lorenzo Martinez, Narei; Losada, Marta; Lösel, Philipp Jonathan; Lou, XinChou; Lounis, Abdenour; Love, Jeremy; Love, Peter; Lu, Nan; Lubatti, Henry; Luci, Claudio; Lucotte, Arnaud; Luedtke, Christian; Luehring, Frederick; Lukas, Wolfgang; Luminari, Lamberto; Lundberg, Olof; Lund-Jensen, Bengt; Lynn, David; Lysak, Roman; Lytken, Else; Ma, Hong; Ma, Lian Liang; Maccarrone, Giovanni; Macchiolo, Anna; Macdonald, Calum Michael; Maček, Boštjan; Machado Miguens, Joana; Macina, Daniela; Madaffari, Daniele; Madar, Romain; Maddocks, Harvey Jonathan; Mader, Wolfgang; Madsen, Alexander; Maeda, Junpei; Maeland, Steffen; Maeno, Tadashi; Maevskiy, Artem; Magradze, Erekle; Mahboubi, Kambiz; Mahlstedt, Joern; Maiani, Camilla; Maidantchik, Carmen; Maier, Andreas Alexander; Maier, Thomas; Maio, Amélia; Majewski, Stephanie; Makida, Yasuhiro; Makovec, Nikola; Malaescu, Bogdan; Malecki, Pawel; Maleev, Victor; Malek, Fairouz; Mallik, Usha; Malon, David; Malone, Caitlin; Maltezos, Stavros; Malyshev, Vladimir; Malyukov, Sergei; Mamuzic, Judita; Mancini, Giada; Mandelli, Beatrice; Mandelli, Luciano; Mandić, Igor; Mandrysch, Rocco; Maneira, José; Manfredini, Alessandro; Manhaes de Andrade Filho, Luciano; Manjarres Ramos, Joany; Mann, Alexander; Manousakis-Katsikakis, Arkadios; Mansoulie, Bruno; Mantifel, Rodger; Mantoani, Matteo; Mapelli, Livio; March, Luis; Marchiori, Giovanni; Marcisovsky, Michal; Marino, Christopher; Marjanovic, Marija; Marley, Daniel; Marroquim, Fernando; Marsden, Stephen Philip; Marshall, Zach; Marti, Lukas Fritz; Marti-Garcia, Salvador; Martin, Brian Thomas; Martin, Tim; Martin, Victoria Jane; Martin dit Latour, Bertrand; Martinez, Mario; Martin-Haugh, Stewart; Martoiu, Victor Sorin; Martyniuk, Alex; Marx, Marilyn; Marzano, Francesco; Marzin, Antoine; Masetti, Lucia; Mashimo, Tetsuro; Mashinistov, Ruslan; Masik, Jiri; Maslennikov, Alexey; Massa, Ignazio; Massa, Lorenzo; Mastrandrea, Paolo; Mastroberardino, Anna; Masubuchi, Tatsuya; Mättig, Peter; Mattmann, Johannes; Maurer, Julien; Maxfield, Stephen; Maximov, Dmitriy; Mazini, Rachid; Mazza, Simone Michele; Mc Goldrick, Garrin; Mc Kee, Shawn Patrick; McCarn, Allison; McCarthy, Robert; McCarthy, Tom; McCubbin, Norman; McFarlane, Kenneth; Mcfayden, Josh; Mchedlidze, Gvantsa; McMahon, Steve; McPherson, Robert; Medinnis, Michael; Meehan, Samuel; Mehlhase, Sascha; Mehta, Andrew; Meier, Karlheinz; Meineck, Christian; Meirose, Bernhard; Mellado Garcia, Bruce Rafael; Meloni, Federico; Mengarelli, Alberto; Menke, Sven; Meoni, Evelin; Mercurio, Kevin Michael; Mergelmeyer, Sebastian; Mermod, Philippe; Merola, Leonardo; Meroni, Chiara; Merritt, Frank; Messina, Andrea; Metcalfe, Jessica; Mete, Alaettin Serhan; Meyer, Carsten; Meyer, Christopher; Meyer, Jean-Pierre; Meyer, Jochen; Meyer Zu Theenhausen, Hanno; Middleton, Robin; Miglioranzi, Silvia; Mijović, Liza; Mikenberg, Giora; Mikestikova, Marcela; Mikuž, Marko; Milesi, Marco; Milic, Adriana; Miller, David; Mills, Corrinne; Milov, Alexander; Milstead, David; Minaenko, Andrey; Minami, Yuto; Minashvili, Irakli; Mincer, Allen; Mindur, Bartosz; Mineev, Mikhail; Ming, Yao; Mir, Lluisa-Maria; Mistry, Khilesh; Mitani, Takashi; Mitrevski, Jovan; Mitsou, Vasiliki A; Miucci, Antonio; Miyagawa, Paul; Mjörnmark, Jan-Ulf; Moa, Torbjoern; Mochizuki, Kazuya; Mohapatra, Soumya; Mohr, Wolfgang; Molander, Simon; Moles-Valls, Regina; Monden, Ryutaro; Mönig, Klaus; Monini, Caterina; Monk, James; Monnier, Emmanuel; Montalbano, Alyssa; Montejo Berlingen, Javier; Monticelli, Fernando; Monzani, Simone; Moore, Roger; Morange, Nicolas; Moreno, Deywis; Moreno Llácer, María; Morettini, Paolo; Mori, Daniel; Mori, Tatsuya; Morii, Masahiro; Morinaga, Masahiro; Morisbak, Vanja; Moritz, Sebastian; Morley, Anthony Keith; Mornacchi, Giuseppe; Morris, John; Mortensen, Simon Stark; Morton, Alexander; Morvaj, Ljiljana; Mosidze, Maia; Moss, Josh; Motohashi, Kazuki; Mount, Richard; Mountricha, Eleni; Mouraviev, Sergei; Moyse, Edward; Muanza, Steve; Mudd, Richard; Mueller, Felix; Mueller, James; Mueller, Ralph Soeren Peter; Mueller, Thibaut; Muenstermann, Daniel; Mullen, Paul; Mullier, Geoffrey; Murillo Quijada, Javier Alberto; Murray, Bill; Musheghyan, Haykuhi; Musto, Elisa; Myagkov, Alexey; Myska, Miroslav; Nachman, Benjamin Philip; Nackenhorst, Olaf; Nadal, Jordi; Nagai, Koichi; Nagai, Ryo; Nagai, Yoshikazu; Nagano, Kunihiro; Nagarkar, Advait; Nagasaka, Yasushi; Nagata, Kazuki; Nagel, Martin; Nagy, Elemer; Nairz, Armin Michael; Nakahama, Yu; Nakamura, Koji; Nakamura, Tomoaki; Nakano, Itsuo; Namasivayam, Harisankar; Naranjo Garcia, Roger Felipe; Narayan, Rohin; Narrias Villar, Daniel Isaac; Naumann, Thomas; Navarro, Gabriela; Nayyar, Ruchika; Neal, Homer; Nechaeva, Polina; Neep, Thomas James; Nef, Pascal Daniel; Negri, Andrea; Negrini, Matteo; Nektarijevic, Snezana; Nellist, Clara; Nelson, Andrew; Nemecek, Stanislav; Nemethy, Peter; Nepomuceno, Andre Asevedo; Nessi, Marzio; Neubauer, Mark; Neumann, Manuel; Neves, Ricardo; Nevski, Pavel; Newman, Paul; Nguyen, Duong Hai; Nickerson, Richard; Nicolaidou, Rosy; Nicquevert, Bertrand; Nielsen, Jason; Nikiforou, Nikiforos; Nikiforov, Andriy; Nikolaenko, Vladimir; Nikolic-Audit, Irena; Nikolopoulos, Konstantinos; Nilsen, Jon Kerr; Nilsson, Paul; Ninomiya, Yoichi; Nisati, Aleandro; Nisius, Richard; Nobe, Takuya; Nomachi, Masaharu; Nomidis, Ioannis; Nooney, Tamsin; Norberg, Scarlet; Nordberg, Markus; Novgorodova, Olga; Nowak, Sebastian; Nozaki, Mitsuaki; Nozka, Libor; Ntekas, Konstantinos; Nunes Hanninger, Guilherme; Nunnemann, Thomas; Nurse, Emily; Nuti, Francesco; O'Brien, Brendan Joseph; O'grady, Fionnbarr; O'Neil, Dugan; O'Shea, Val; Oakham, Gerald; Oberlack, Horst; Obermann, Theresa; Ocariz, Jose; Ochi, Atsuhiko; Ochoa, Ines; Ochoa-Ricoux, Juan Pedro; Oda, Susumu; Odaka, Shigeru; Ogren, Harold; Oh, Alexander; Oh, Seog; Ohm, Christian; Ohman, Henrik; Oide, Hideyuki; Okamura, Wataru; Okawa, Hideki; Okumura, Yasuyuki; Okuyama, Toyonobu; Olariu, Albert; Olivares Pino, Sebastian Andres; Oliveira Damazio, Denis; Olszewski, Andrzej; Olszowska, Jolanta; Onofre, António; Onogi, Kouta; Onyisi, Peter; Oram, Christopher; Oreglia, Mark; Oren, Yona; Orestano, Domizia; Orlando, Nicola; Oropeza Barrera, Cristina; Orr, Robert; Osculati, Bianca; Ospanov, Rustem; Otero y Garzon, Gustavo; Otono, Hidetoshi; Ouchrif, Mohamed; Ould-Saada, Farid; Ouraou, Ahmimed; Oussoren, Koen Pieter; Ouyang, Qun; Ovcharova, Ana; Owen, Mark; Owen, Rhys Edward; Ozcan, Veysi Erkcan; Ozturk, Nurcan; Pachal, Katherine; Pacheco Pages, Andres; Padilla Aranda, Cristobal; Pagáčová, Martina; Pagan Griso, Simone; Paganis, Efstathios; Paige, Frank; Pais, Preema; Pajchel, Katarina; Palacino, Gabriel; Palestini, Sandro; Palka, Marek; Pallin, Dominique; Palma, Alberto; Pan, Yibin; Panagiotopoulou, Evgenia; Pandini, Carlo Enrico; Panduro Vazquez, William; Pani, Priscilla; Panitkin, Sergey; Pantea, Dan; Paolozzi, Lorenzo; Papadopoulou, Theodora; Papageorgiou, Konstantinos; Paramonov, Alexander; Paredes Hernandez, Daniela; Parker, Michael Andrew; Parker, Kerry Ann; Parodi, Fabrizio; Parsons, John; Parzefall, Ulrich; Pasqualucci, Enrico; Passaggio, Stefano; Pastore, Fernanda; Pastore, Francesca; Pásztor, Gabriella; Pataraia, Sophio; Patel, Nikhul; Pater, Joleen; Pauly, Thilo; Pearce, James; Pearson, Benjamin; Pedersen, Lars Egholm; Pedersen, Maiken; Pedraza Lopez, Sebastian; Pedro, Rute; Peleganchuk, Sergey; Pelikan, Daniel; Penc, Ondrej; Peng, Cong; Peng, Haiping; Penning, Bjoern; Penwell, John; Perepelitsa, Dennis; Perez Codina, Estel; Pérez García-Estañ, María Teresa; Perini, Laura; Pernegger, Heinz; Perrella, Sabrina; Peschke, Richard; Peshekhonov, Vladimir; Peters, Krisztian; Peters, Yvonne; Petersen, Brian; Petersen, Troels; Petit, Elisabeth; Petridis, Andreas; Petridou, Chariclia; Petroff, Pierre; Petrolo, Emilio; Petrucci, Fabrizio; Pettersson, Nora Emilia; Pezoa, Raquel; Phillips, Peter William; Piacquadio, Giacinto; Pianori, Elisabetta; Picazio, Attilio; Piccaro, Elisa; Piccinini, Maurizio; Pickering, Mark Andrew; Piegaia, Ricardo; Pignotti, David; Pilcher, James; Pilkington, Andrew; Pin, Arnaud Willy J; Pina, João Antonio; Pinamonti, Michele; Pinfold, James; Pingel, Almut; Pires, Sylvestre; Pirumov, Hayk; Pitt, Michael; Pizio, Caterina; Plazak, Lukas; Pleier, Marc-Andre; Pleskot, Vojtech; Plotnikova, Elena; Plucinski, Pawel; Pluth, Daniel; Poettgen, Ruth; Poggioli, Luc; Pohl, David-leon; Polesello, Giacomo; Poley, Anne-luise; Policicchio, Antonio; Polifka, Richard; Polini, Alessandro; Pollard, Christopher Samuel; Polychronakos, Venetios; Pommès, Kathy; Pontecorvo, Ludovico; Pope, Bernard; Popeneciu, Gabriel Alexandru; Popovic, Dragan; Poppleton, Alan; Pospisil, Stanislav; Potamianos, Karolos; Potrap, Igor; Potter, Christina; Potter, Christopher; Poulard, Gilbert; Poveda, Joaquin; Pozdnyakov, Valery; Pralavorio, Pascal; Pranko, Aliaksandr; Prasad, Srivas; Prell, Soeren; Price, Darren; Price, Lawrence; Primavera, Margherita; Prince, Sebastien; Proissl, Manuel; Prokofiev, Kirill; Prokoshin, Fedor; Protopapadaki, Eftychia-sofia; Protopopescu, Serban; Proudfoot, James; Przybycien, Mariusz; Ptacek, Elizabeth; Puddu, Daniele; Pueschel, Elisa; Puldon, David; Purohit, Milind; Puzo, Patrick; Qian, Jianming; Qin, Gang; Qin, Yang; Quadt, Arnulf; Quarrie, David; Quayle, William; Queitsch-Maitland, Michaela; Quilty, Donnchadha; Raddum, Silje; Radeka, Veljko; Radescu, Voica; Radhakrishnan, Sooraj Krishnan; Radloff, Peter; Rados, Pere; Ragusa, Francesco; Rahal, Ghita; Rajagopalan, Srinivasan; Rammensee, Michael; Rangel-Smith, Camila; Rauscher, Felix; Rave, Stefan; Ravenscroft, Thomas; Raymond, Michel; Read, Alexander Lincoln; Readioff, Nathan Peter; Rebuzzi, Daniela; Redelbach, Andreas; Redlinger, George; Reece, Ryan; Reeves, Kendall; Rehnisch, Laura; Reichert, Joseph; Reisin, Hernan; Rembser, Christoph; Ren, Huan; Renaud, Adrien; Rescigno, Marco; Resconi, Silvia; Rezanova, Olga; Reznicek, Pavel; Rezvani, Reyhaneh; Richter, Robert; Richter, Stefan; Richter-Was, Elzbieta; Ricken, Oliver; Ridel, Melissa; Rieck, Patrick; Riegel, Christian Johann; Rieger, Julia; Rifki, Othmane; Rijssenbeek, Michael; Rimoldi, Adele; Rinaldi, Lorenzo; Ristić, Branislav; Ritsch, Elmar; Riu, Imma; Rizatdinova, Flera; Rizvi, Eram; Rizzo, Thomas Gerard; Robertson, Steven; Robichaud-Veronneau, Andree; Robinson, Dave; Robinson, James; Robson, Aidan; Roda, Chiara; Roe, Shaun; Røhne, Ole; Rolli, Simona; Romaniouk, Anatoli; Romano, Marino; Romano Saez, Silvestre Marino; Romero Adam, Elena; Rompotis, Nikolaos; Ronzani, Manfredi; Roos, Lydia; Ros, Eduardo; Rosati, Stefano; Rosbach, Kilian; Rose, Peyton; Rosendahl, Peter Lundgaard; Rosenthal, Oliver; Rossetti, Valerio; Rossi, Elvira; Rossi, Leonardo Paolo; Rosten, Jonatan; Rosten, Rachel; Rotaru, Marina; Roth, Itamar; Rothberg, Joseph; Rousseau, David; Royon, Christophe; Rozanov, Alexandre; Rozen, Yoram; Ruan, Xifeng; Rubbo, Francesco; Rubinskiy, Igor; Rud, Viacheslav; Rudolph, Christian; Rudolph, Matthew Scott; Rühr, Frederik; Ruiz-Martinez, Aranzazu; Rurikova, Zuzana; Rusakovich, Nikolai; Ruschke, Alexander; Russell, Heather; Rutherfoord, John; Ruthmann, Nils; Ryabov, Yury; Rybar, Martin; Rybkin, Grigori; Ryder, Nick; Saavedra, Aldo; Sabato, Gabriele; Sacerdoti, Sabrina; Saddique, Asif; Sadrozinski, Hartmut; Sadykov, Renat; Safai Tehrani, Francesco; Saha, Puja; Sahinsoy, Merve; Saimpert, Matthias; Saito, Tomoyuki; Sakamoto, Hiroshi; Sakurai, Yuki; Salamanna, Giuseppe; Salamon, Andrea; Salazar Loyola, Javier Esteban; Saleem, Muhammad; Salek, David; Sales De Bruin, Pedro Henrique; Salihagic, Denis; Salnikov, Andrei; Salt, José; Salvatore, Daniela; Salvatore, Pasquale Fabrizio; Salvucci, Antonio; Salzburger, Andreas; Sammel, Dirk; Sampsonidis, Dimitrios; Sanchez, Arturo; Sánchez, Javier; Sanchez Martinez, Victoria; Sandaker, Heidi; Sandbach, Ruth Laura; Sander, Heinz Georg; Sanders, Michiel; Sandhoff, Marisa; Sandoval, Carlos; Sandstroem, Rikard; Sankey, Dave; Sannino, Mario; Sansoni, Andrea; Santoni, Claudio; Santonico, Rinaldo; Santos, Helena; Santoyo Castillo, Itzebelt; Sapp, Kevin; Sapronov, Andrey; Saraiva, João; Sarrazin, Bjorn; Sasaki, Osamu; Sasaki, Yuichi; Sato, Koji; Sauvage, Gilles; Sauvan, Emmanuel; Savage, Graham; Savard, Pierre; Sawyer, Craig; Sawyer, Lee; Saxon, James; Sbarra, Carla; Sbrizzi, Antonio; Scanlon, Tim; Scannicchio, Diana; Scarcella, Mark; Scarfone, Valerio; Schaarschmidt, Jana; Schacht, Peter; Schaefer, Douglas; Schaefer, Ralph; Schaeffer, Jan; Schaepe, Steffen; Schaetzel, Sebastian; Schäfer, Uli; Schaffer, Arthur; Schaile, Dorothee; Schamberger, R Dean; Scharf, Veit; Schegelsky, Valery; Scheirich, Daniel; Schernau, Michael; Schiavi, Carlo; Schillo, Christian; Schioppa, Marco; Schlenker, Stefan; Schmieden, Kristof; Schmitt, Christian; Schmitt, Sebastian; Schmitt, Stefan; Schneider, Basil; Schnellbach, Yan Jie; Schnoor, Ulrike; Schoeffel, Laurent; Schoening, Andre; Schoenrock, Bradley Daniel; Schopf, Elisabeth; Schorlemmer, Andre Lukas; Schott, Matthias; Schouten, Doug; Schovancova, Jaroslava; Schramm, Steven; Schreyer, Manuel; Schuh, Natascha; Schultens, Martin Johannes; Schultz-Coulon, Hans-Christian; Schulz, Holger; Schumacher, Markus; Schumm, Bruce; Schune, Philippe; Schwanenberger, Christian; Schwartzman, Ariel; Schwarz, Thomas Andrew; Schwegler, Philipp; Schweiger, Hansdieter; Schwemling, Philippe; Schwienhorst, Reinhard; Schwindling, Jerome; Schwindt, Thomas; Sciacca, Gianfranco; Scifo, Estelle; Sciolla, Gabriella; Scuri, Fabrizio; Scutti, Federico; Searcy, Jacob; Sedov, George; Sedykh, Evgeny; Seema, Pienpen; Seidel, Sally; Seiden, Abraham; Seifert, Frank; Seixas, José; Sekhniaidze, Givi; Sekhon, Karishma; Sekula, Stephen; Seliverstov, Dmitry; Semprini-Cesari, Nicola; Serfon, Cedric; Serin, Laurent; Serkin, Leonid; Serre, Thomas; Sessa, Marco; Seuster, Rolf; Severini, Horst; Sfiligoj, Tina; Sforza, Federico; Sfyrla, Anna; Shabalina, Elizaveta; Shamim, Mansoora; Shan, Lianyou; Shang, Ruo-yu; Shank, James; Shapiro, Marjorie; Shatalov, Pavel; Shaw, Kate; Shaw, Savanna Marie; Shcherbakova, Anna; Shehu, Ciwake Yusufu; Sherwood, Peter; Shi, Liaoshan; Shimizu, Shima; Shimmin, Chase Owen; Shimojima, Makoto; Shiyakova, Mariya; Shmeleva, Alevtina; Shoaleh Saadi, Diane; Shochet, Mel; Shojaii, Seyedruhollah; Shrestha, Suyog; Shulga, Evgeny; Shupe, Michael; Shushkevich, Stanislav; Sicho, Petr; Sidebo, Per Edvin; Sidiropoulou, Ourania; Sidorov, Dmitri; Sidoti, Antonio; Siegert, Frank; Sijacki, Djordje; Silva, José; Silver, Yiftah; Silverstein, Samuel; Simak, Vladislav; Simard, Olivier; Simic, Ljiljana; Simion, Stefan; Simioni, Eduard; Simmons, Brinick; Simon, Dorian; Sinervo, Pekka; Sinev, Nikolai; Sioli, Maximiliano; Siragusa, Giovanni; Sisakyan, Alexei; Sivoklokov, Serguei; Sjölin, Jörgen; Sjursen, Therese; Skinner, Malcolm Bruce; Skottowe, Hugh Philip; Skubic, Patrick; Slater, Mark; Slavicek, Tomas; Slawinska, Magdalena; Sliwa, Krzysztof; Smakhtin, Vladimir; Smart, Ben; Smestad, Lillian; Smirnov, Sergei; Smirnov, Yury; Smirnova, Lidia; Smirnova, Oxana; Smith, Matthew; Smith, Russell; Smizanska, Maria; Smolek, Karel; Snesarev, Andrei; Snidero, Giacomo; Snyder, Scott; Sobie, Randall; Socher, Felix; Soffer, Abner; Soh, Dart-yin; Sokhrannyi, Grygorii; Solans, Carlos; Solar, Michael; Solc, Jaroslav; Soldatov, Evgeny; Soldevila, Urmila; Solodkov, Alexander; Soloshenko, Alexei; Solovyanov, Oleg; Solovyev, Victor; Sommer, Philip; Song, Hong Ye; Soni, Nitesh; Sood, Alexander; Sopczak, Andre; Sopko, Bruno; Sopko, Vit; Sorin, Veronica; Sosa, David; Sosebee, Mark; Sotiropoulou, Calliope Louisa; Soualah, Rachik; Soukharev, Andrey; South, David; Sowden, Benjamin; Spagnolo, Stefania; Spalla, Margherita; Spangenberg, Martin; Spanò, Francesco; Spearman, William Robert; Sperlich, Dennis; Spettel, Fabian; Spighi, Roberto; Spigo, Giancarlo; Spiller, Laurence Anthony; Spousta, Martin; St Denis, Richard Dante; Stabile, Alberto; Staerz, Steffen; Stahlman, Jonathan; Stamen, Rainer; Stamm, Soren; Stanecka, Ewa; Stanescu, Cristian; Stanescu-Bellu, Madalina; Stanitzki, Marcel Michael; Stapnes, Steinar; Starchenko, Evgeny; Stark, Jan; Staroba, Pavel; Starovoitov, Pavel; Staszewski, Rafal; Steinberg, Peter; Stelzer, Bernd; Stelzer, Harald Joerg; Stelzer-Chilton, Oliver; Stenzel, Hasko; Stewart, Graeme; Stillings, Jan Andre; Stockton, Mark; Stoebe, Michael; Stoicea, Gabriel; Stolte, Philipp; Stonjek, Stefan; Stradling, Alden; Straessner, Arno; Stramaglia, Maria Elena; Strandberg, Jonas; Strandberg, Sara; Strandlie, Are; Strauss, Emanuel; Strauss, Michael; Strizenec, Pavol; Ströhmer, Raimund; Strom, David; Stroynowski, Ryszard; Strubig, Antonia; Stucci, Stefania Antonia; Stugu, Bjarne; Styles, Nicholas Adam; Su, Dong; Su, Jun; Subramaniam, Rajivalochan; Succurro, Antonella; Sugaya, Yorihito; Suk, Michal; Sulin, Vladimir; Sultansoy, Saleh; Sumida, Toshi; Sun, Siyuan; Sun, Xiaohu; Sundermann, Jan Erik; Suruliz, Kerim; Susinno, Giancarlo; Sutton, Mark; Suzuki, Shota; Svatos, Michal; Swiatlowski, Maximilian; Sykora, Ivan; Sykora, Tomas; Ta, Duc; Taccini, Cecilia; Tackmann, Kerstin; Taenzer, Joe; Taffard, Anyes; Tafirout, Reda; Taiblum, Nimrod; Takai, Helio; Takashima, Ryuichi; Takeda, Hiroshi; Takeshita, Tohru; Takubo, Yosuke; Talby, Mossadek; Talyshev, Alexey; Tam, Jason; Tan, Kong Guan; Tanaka, Junichi; Tanaka, Reisaburo; Tanaka, Shuji; Tannenwald, Benjamin Bordy; Tannoury, Nancy; Tapia Araya, Sebastian; Tapprogge, Stefan; Tarem, Shlomit; Tarrade, Fabien; Tartarelli, Giuseppe Francesco; Tas, Petr; Tasevsky, Marek; Tashiro, Takuya; Tassi, Enrico; Tavares Delgado, Ademar; Tayalati, Yahya; Taylor, Frank; Taylor, Geoffrey; Taylor, Pierre Thor Elliot; Taylor, Wendy; Teischinger, Florian Alfred; Teixeira Dias Castanheira, Matilde; Teixeira-Dias, Pedro; Temming, Kim Katrin; Temple, Darren; Ten Kate, Herman; Teng, Ping-Kun; Teoh, Jia Jian; Tepel, Fabian-Phillipp; Terada, Susumu; Terashi, Koji; Terron, Juan; Terzo, Stefano; Testa, Marianna; Teuscher, Richard; Theveneaux-Pelzer, Timothée; Thomas, Juergen; Thomas-Wilsker, Joshuha; Thompson, Emily; Thompson, Paul; Thompson, Ray; Thompson, Stan; Thomsen, Lotte Ansgaard; Thomson, Evelyn; Thomson, Mark; Thun, Rudolf; Tibbetts, Mark James; Ticse Torres, Royer Edson; Tikhomirov, Vladimir; Tikhonov, Yury; Timoshenko, Sergey; Tiouchichine, Elodie; Tipton, Paul; Tisserant, Sylvain; Todome, Kazuki; Todorov, Theodore; Todorova-Nova, Sharka; Tojo, Junji; Tokár, Stanislav; Tokushuku, Katsuo; Tollefson, Kirsten; Tolley, Emma; Tomlinson, Lee; Tomoto, Makoto; Tompkins, Lauren; Toms, Konstantin; Torrence, Eric; Torres, Heberth; Torró Pastor, Emma; Toth, Jozsef; Touchard, Francois; Tovey, Daniel; Trefzger, Thomas; Tremblet, Louis; Tricoli, Alessandro; Trigger, Isabel Marian; Trincaz-Duvoid, Sophie; Tripiana, Martin; Trischuk, William; Trocmé, Benjamin; Troncon, Clara; Trottier-McDonald, Michel; Trovatelli, Monica; Truong, Loan; Trzebinski, Maciej; Trzupek, Adam; Tsarouchas, Charilaos; Tseng, Jeffrey; Tsiareshka, Pavel; Tsionou, Dimitra; Tsipolitis, Georgios; Tsirintanis, Nikolaos; Tsiskaridze, Shota; Tsiskaridze, Vakhtang; Tskhadadze, Edisher; Tsukerman, Ilya; Tsulaia, Vakhtang; Tsuno, Soshi; Tsybychev, Dmitri; Tudorache, Alexandra; Tudorache, Valentina; Tuna, Alexander Naip; Tupputi, Salvatore; Turchikhin, Semen; Turecek, Daniel; Turra, Ruggero; Turvey, Andrew John; Tuts, Michael; Tykhonov, Andrii; Tylmad, Maja; Tyndel, Mike; Ueda, Ikuo; Ueno, Ryuichi; Ughetto, Michael; Ugland, Maren; Ukegawa, Fumihiko; Unal, Guillaume; Undrus, Alexander; Unel, Gokhan; Ungaro, Francesca; Unno, Yoshinobu; Unverdorben, Christopher; Urban, Jozef; Urquijo, Phillip; Urrejola, Pedro; Usai, Giulio; Usanova, Anna; Vacavant, Laurent; Vacek, Vaclav; Vachon, Brigitte; Valderanis, Chrysostomos; Valencic, Nika; Valentinetti, Sara; Valero, Alberto; Valery, Loic; Valkar, Stefan; Vallecorsa, Sofia; Valls Ferrer, Juan Antonio; Van Den Wollenberg, Wouter; Van Der Deijl, Pieter; van der Geer, Rogier; van der Graaf, Harry; van Eldik, Niels; van Gemmeren, Peter; Van Nieuwkoop, Jacobus; van Vulpen, Ivo; van Woerden, Marius Cornelis; Vanadia, Marco; Vandelli, Wainer; Vanguri, Rami; Vaniachine, Alexandre; Vannucci, Francois; Vardanyan, Gagik; Vari, Riccardo; Varnes, Erich; Varol, Tulin; Varouchas, Dimitris; Vartapetian, Armen; Varvell, Kevin; Vazeille, Francois; Vazquez Schroeder, Tamara; Veatch, Jason; Veloce, Laurelle Maria; Veloso, Filipe; Velz, Thomas; Veneziano, Stefano; Ventura, Andrea; Ventura, Daniel; Venturi, Manuela; Venturi, Nicola; Venturini, Alessio; Vercesi, Valerio; Verducci, Monica; Verkerke, Wouter; Vermeulen, Jos; Vest, Anja; Vetterli, Michel; Viazlo, Oleksandr; Vichou, Irene; Vickey, Trevor; Vickey Boeriu, Oana Elena; Viehhauser, Georg; Viel, Simon; Vigne, Ralph; Villa, Mauro; Villaplana Perez, Miguel; Vilucchi, Elisabetta; Vincter, Manuella; Vinogradov, Vladimir; Vivarelli, Iacopo; Vives Vaque, Francesc; Vlachos, Sotirios; Vladoiu, Dan; Vlasak, Michal; Vogel, Marcelo; Vokac, Petr; Volpi, Guido; Volpi, Matteo; von der Schmitt, Hans; von Radziewski, Holger; von Toerne, Eckhard; Vorobel, Vit; Vorobev, Konstantin; Vos, Marcel; Voss, Rudiger; Vossebeld, Joost; Vranjes, Nenad; Vranjes Milosavljevic, Marija; Vrba, Vaclav; Vreeswijk, Marcel; Vuillermet, Raphael; Vukotic, Ilija; Vykydal, Zdenek; Wagner, Peter; Wagner, Wolfgang; Wahlberg, Hernan; Wahrmund, Sebastian; Wakabayashi, Jun; Walder, James; Walker, Rodney; Walkowiak, Wolfgang; Wang, Chao; Wang, Fuquan; Wang, Haichen; Wang, Hulin; Wang, Jike; Wang, Jin; Wang, Kuhan; Wang, Rui; Wang, Song-Ming; Wang, Tan; Wang, Tingting; Wang, Xiaoxiao; Wanotayaroj, Chaowaroj; Warburton, Andreas; Ward, Patricia; Wardrope, David Robert; Washbrook, Andrew; Wasicki, Christoph; Watkins, Peter; Watson, Alan; Watson, Ian; Watson, Miriam; Watts, Gordon; Watts, Stephen; Waugh, Ben; Webb, Samuel; Weber, Michele; Weber, Stefan Wolf; Webster, Jordan S; Weidberg, Anthony; Weinert, Benjamin; Weingarten, Jens; Weiser, Christian; Weits, Hartger; Wells, Phillippa; Wenaus, Torre; Wengler, Thorsten; Wenig, Siegfried; Wermes, Norbert; Werner, Matthias; Werner, Per; Wessels, Martin; Wetter, Jeffrey; Whalen, Kathleen; Wharton, Andrew Mark; White, Andrew; White, Martin; White, Ryan; White, Sebastian; Whiteson, Daniel; Wickens, Fred; Wiedenmann, Werner; Wielers, Monika; Wienemann, Peter; Wiglesworth, Craig; Wiik-Fuchs, Liv Antje Mari; Wildauer, Andreas; Wilkens, Henric George; Williams, Hugh; Williams, Sarah; Willis, Christopher; Willocq, Stephane; Wilson, Alan; Wilson, John; Wingerter-Seez, Isabelle; Winklmeier, Frank; Winter, Benedict Tobias; Wittgen, Matthias; Wittkowski, Josephine; Wollstadt, Simon Jakob; Wolter, Marcin Wladyslaw; Wolters, Helmut; Wosiek, Barbara; Wotschack, Jorg; Woudstra, Martin; Wozniak, Krzysztof; Wu, Mengqing; Wu, Miles; Wu, Sau Lan; Wu, Xin; Wu, Yusheng; Wyatt, Terry Richard; Wynne, Benjamin; Xella, Stefania; Xu, Da; Xu, Lailin; Yabsley, Bruce; Yacoob, Sahal; Yakabe, Ryota; Yamada, Miho; Yamaguchi, Daiki; Yamaguchi, Yohei; Yamamoto, Akira; Yamamoto, Shimpei; Yamanaka, Takashi; Yamauchi, Katsuya; Yamazaki, Yuji; Yan, Zhen; Yang, Haijun; Yang, Hongtao; Yang, Yi; Yao, Weiming; Yap, Yee Chinn; Yasu, Yoshiji; Yatsenko, Elena; Yau Wong, Kaven Henry; Ye, Jingbo; Ye, Shuwei; Yeletskikh, Ivan; Yen, Andy L; Yildirim, Eda; Yorita, Kohei; Yoshida, Rikutaro; Yoshihara, Keisuke; Young, Charles; Young, Christopher John; Youssef, Saul; Yu, David Ren-Hwa; Yu, Jaehoon; Yu, Jiaming; Yu, Jie; Yuan, Li; Yuen, Stephanie P; Yurkewicz, Adam; Yusuff, Imran; Zabinski, Bartlomiej; Zaidan, Remi; Zaitsev, Alexander; Zalieckas, Justas; Zaman, Aungshuman; Zambito, Stefano; Zanello, Lucia; Zanzi, Daniele; Zeitnitz, Christian; Zeman, Martin; Zemla, Andrzej; Zeng, Qi; Zengel, Keith; Zenin, Oleg; Ženiš, Tibor; Zerwas, Dirk; Zhang, Dongliang; Zhang, Fangzhou; Zhang, Guangyi; Zhang, Huijun; Zhang, Jinlong; Zhang, Lei; Zhang, Ruiqi; Zhang, Xueyao; Zhang, Zhiqing; Zhao, Xiandong; Zhao, Yongke; Zhao, Zhengguo; Zhemchugov, Alexey; Zhong, Jiahang; Zhou, Bing; Zhou, Chen; Zhou, Lei; Zhou, Li; Zhou, Mingliang; Zhou, Ning; Zhu, Cheng Guang; Zhu, Hongbo; Zhu, Junjie; Zhu, Yingchun; Zhuang, Xuai; Zhukov, Konstantin; Zibell, Andre; Zieminska, Daria; Zimine, Nikolai; Zimmermann, Christoph; Zimmermann, Stephanie; Zinonos, Zinonas; Zinser, Markus; Ziolkowski, Michael; Živković, Lidija; Zobernig, Georg; Zoccoli, Antonio; zur Nedden, Martin; Zurzolo, Giovanni; Zwalinski, Lukasz

2015-10-21

A summary of the constraints from the ATLAS experiment on $R$-parity conserving supersymmetry is presented. Results from 22 separate ATLAS searches are considered, each based on analysis of up to 20.3 fb$^{-1}$ of proton-proton collision data at the centre-of-mass energy of $\\sqrt{s}$ = 7 and 8 TeV at the Large Hadron Collider.  The results are interpreted in the context of the 19-parameter phenomenological minimal supersymmetric standard model, in which the lightest supersymmetric particle is a neutralino, taking into account constraints from previous precision electroweak and flavour measurements as well as from dark matter related measurements.  The results are presented in terms of constraints on supersymmetric particle masses and are compared to limits from simplified models. The impact of ATLAS searches on parameters such as the dark matter relic density, the couplings of the observed Higgs boson, and the degree of electroweak fine-tuning is also shown.  Spectra for surviving supersymmetry model ...

PanDA: distributed production and distributed analysis system for ATLAS

International Nuclear Information System (INIS)

Maeno, T

2008-01-01

A new distributed software system was developed in the fall of 2005 for the ATLAS experiment at the LHC. This system, called PANDA, provides an integrated service architecture with late binding of jobs, maximal automation through layered services, tight binding with ATLAS Distributed Data Management system [1], advanced error discovery and recovery procedures, and other features. In this talk, we will describe the PANDA software system. Special emphasis will be placed on the evolution of PANDA based on one and half year of real experience in carrying out Computer System Commissioning data production [2] for ATLAS. The architecture of PANDA is well suited for the computing needs of the ATLAS experiment, which is expected to be one of the first HEP experiments to operate at the petabyte scale

ATLAS Grid Workflow Performance Optimization

CERN Document Server

Elmsheuser, Johannes; The ATLAS collaboration

2018-01-01

The CERN ATLAS experiment grid workflow system manages routinely 250 to 500 thousand concurrently running production and analysis jobs to process simulation and detector data. In total more than 300 PB of data is distributed over more than 150 sites in the WLCG. At this scale small improvements in the software and computing performance and workflows can lead to significant resource usage gains. ATLAS is reviewing together with CERN IT experts several typical simulation and data processing workloads for potential performance improvements in terms of memory and CPU usage, disk and network I/O. All ATLAS production and analysis grid jobs are instrumented to collect many performance metrics for detailed statistical studies using modern data analytics tools like ElasticSearch and Kibana. This presentation will review and explain the performance gains of several ATLAS simulation and data processing workflows and present analytics studies of the ATLAS grid workflows.

PanDA: A New Paradigm for Distributed Computing in HEP Through the Lens of ATLAS and other Experiments

CERN Document Server

De, K; The ATLAS collaboration; Maeno, T; Nilsson, P; Wenaus, T

2014-01-01

Experiments at the Large Hadron Collider (LHC) face unprecedented computing challenges. Heterogeneous resources are distributed worldwide, thousands of physicists analyzing the data need remote access to hundreds of computing sites, the volume of processed data is beyond the exabyte scale, and data processing requires more than a billion hours of computing usage per year. The PanDA (Production and Distributed Analysis) system was developed to meet the scale and complexity of LHC distributed computing for the ATLAS experiment. In the process, the old batch job paradigm of computing in HEP was discarded in favor of a far more flexible and scalable model. The success of PanDA in ATLAS is leading to widespread adoption and testing by other experiments. PanDA is the first exascale workload management system in HEP, already operating at a million computing jobs per day, and processing over an exabyte of data in 2013. We will describe the design and implementation of PanDA, present data on the performance of PanDA a...

QCD in Higgs and BSM Results from the ATLAS and CMS Experiments

CERN Document Server

Tompkins, Lauren; The ATLAS collaboration

2015-01-01

Advances in theoretical calculations of QCD processes and modeling of colored objects have underpinned the success of the ATLAS and CMS Run I LHC measurements of the Higgs boson and searches for physics beyond the Standard Model. In this talk, I will cover selected recent results from the two experiments which illustrate the ways in which QCD calculations and models are used. I will additionally highlight areas in which uncertainties from these calculations and models are comparable to the experimental uncertainties, motivating further theoretical work.

Tester of the TRT front-end electronics for the ATLAS-experiment

CERN Document Server

Hajduk, Z; Kisielewski, B; Kotarba, A; Malecki, P; Natkaniec, Z; Olszowska, J; Ostrowicz, W; Krupinska, G

2000-01-01

The VME based tester for front-end electronics of the TRT (Transition Radiation Tracker) detector of the ATLAS-LHC experiment at CERN, Geneva, is described. The TRT read-out electronics for 424576 proportional tubes grouped on many thousands of cards requires stringent quality control after assembly and during installation. The tester provides all required data, pulses, timing and power supplies for tested cards. The essential part of the tester is its software that allows for device handling as well as facilitates functional and statistical tests. The prototype, present design as well as the new design for mass production tests are discussed. (17 refs).

The upgraded Pixel Detector of the ATLAS Experiment for Run 2 at the Large Hadron Collider

Energy Technology Data Exchange (ETDEWEB)

Backhaus, M., E-mail: malte.backhaus@cern.ch

2016-09-21

During Run 1 of the Large Hadron Collider (LHC), the ATLAS Pixel Detector has shown excellent performance. The ATLAS collaboration took advantage of the first long shutdown of the LHC during 2013 and 2014 and extracted the ATLAS Pixel Detector from the experiment, brought it to surface and maintained the services. This included the installation of new service quarter panels, the repair of cables, and the installation of the new Diamond Beam Monitor (DBM). Additionally, a completely new innermost pixel detector layer, the Insertable B-Layer (IBL), was constructed and installed in May 2014 between a new smaller beam pipe and the existing Pixel Detector. With a radius of 3.3 cm the IBL is located extremely close to the interaction point. Therefore, a new readout chip and two new sensor technologies (planar and 3D) are used in the IBL. In order to achieve best possible physics performance the material budget was improved with respect to the existing Pixel Detector. This is realized using lightweight staves for mechanical support and a CO{sub 2} based cooling system. This paper describes the improvements achieved during the maintenance of the existing Pixel Detector as well as the performance of the IBL during the construction and commissioning phase. Additionally, first results obtained during the LHC Run 2 demonstrating the distinguished tracking performance of the new Four Layer ATLAS Pixel Detector are presented.

A new experiment-independent mechanism to persistify and serve the detector geometry of ATLAS

Science.gov (United States)

Bianchi, Riccardo Maria; Boudreau, Joseph; Vukotic, Ilija

2017-10-01

The complex geometry of the whole detector of the ATLAS experiment at LHC is currently stored only in custom online databases, from which it is built on-the-fly on request. Accessing the online geometry guarantees accessing the latest version of the detector description, but requires the setup of the full ATLAS software framework “Athena”, which provides the online services and the tools to retrieve the data from the database. This operation is cumbersome and slows down the applications that need to access the geometry. Moreover, all applications that need to access the detector geometry need to be built and run on the same platform as the ATLAS framework, preventing the usage of the actual detector geometry in stand-alone applications. Here we propose a new mechanism to persistify (in software development in general, and in HEP computing in particular, persistifying means taking an object which lives in memory only - for example because it was built on-the-fly while processing the experimental data, - serializing it and storing it on disk as a persistent object) and serve the geometry of HEP experiments. The new mechanism is composed by a new file format and the modules to make use of it. The new file format allows to store the whole detector description locally in a file, and it is especially optimized to describe large complex detectors with the minimum file size, making use of shared instances and storing compressed representations of geometry transformations. Then, the detector description can be read back in, to fully restore the in-memory geometry tree. Moreover, a dedicated REST API is being designed and developed to serve the geometry in standard exchange formats like JSON, to let users and applications download specific partial geometry information. With this new geometry persistification a new generation of applications could be developed, which can use the actual detector geometry while being platform-independent and experiment-independent.

Readout and trigger for the AFP detector at the ATLAS experiment at LHC

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00097773; The ATLAS collaboration; Kocian, Martin; Lopez Paz, Ivan; Avoni, Giulio

2017-01-01

The ATLAS Forward Proton is a new detector system in ATLAS that allows study of events with protons scattered at very small angles. The final design assumes four stations at distances of 205 and 217 m from the ATLAS interaction point on both sides of the detector exploiting the Roman Pot technology. In 2016 two stations in one arm were installed; installation of the other two is planned for 2017. This article describes details of the installed hardware, firmware and software leading to the full integration with the ATLAS central trigger and data acquisition systems.

ATLAS Award for Shield Supplier

CERN Multimedia

2004-01-01

ATLAS technical coordinator Dr. Marzio Nessi presents the ATLAS supplier award to Vojtech Novotny, Director General of Skoda Hute.On 3 November, the ATLAS experiment honoured one of its suppliers, Skoda Hute s.r.o., of Plzen, Czech Republic, for their work on the detector's forward shielding elements. These huge and very massive cylinders surround the beampipe at either end of the detector to block stray particles from interfering with the ATLAS's muon chambers. For the shields, Skoda Hute produced 10 cast iron pieces with a total weight of 780 tonnes at a cost of 1.4 million CHF. Although there are many iron foundries in the CERN member states, there are only a limited number that can produce castings of the necessary size: the large pieces range in weight from 59 to 89 tonnes and are up to 1.5 metres thick.The forward shielding was designed by the ATLAS Technical Coordination in close collaboration with the ATLAS groups from the Czech Technical University and Charles University in Prague. The Czech groups a...

ATLAS EventIndex Data Collection Supervisor and Web Interface

CERN Document Server

Garcia Montoro, Carlos; The ATLAS collaboration; Sanchez, Javier

2016-01-01

The EventIndex project consists in the development and deployment of a complete catalogue of events for the ATLAS experiment [1][2] at the LHC accelerator at CERN. In 2015 the ATLAS experiment has produced 12 billion real events in 1 million files, and 5 billion simulated events in 8 million files. The ATLAS EventIndex is running in production since mid-2015, reliably collecting information worldwide about all produced events and storing them in a central Hadoop infrastructure. A subset of this information is copied to an Oracle relational database. This paper presents two components of the ATLAS EventIndex [3]: its data collection supervisor and its web interface partner.

ATLAS EventIndex Data Collection Supervisor and Web Interface

CERN Document Server

Garcia Montoro, Carlos; The ATLAS collaboration

2016-01-01

The EventIndex project consists in the development and deployment of a complete catalogue of events for the ATLAS experiment at the LHC accelerator at CERN. In 2015 the ATLAS experiment has produced 12 billion real events in 1 million files, and 5 billion simulated events in 8 million files. The ATLAS EventIndex is running in production since mid- 2015, reliably collecting information worldwide about all produced events and storing them in a central Hadoop infrastructure. A subset of this information is copied to an Oracle relational database. These slides present two components of the ATLAS EventIndex: its data collection supervisor and its web interface partner.

Development of Beam Conditions Monitor for the ATLAS experiment

CERN Document Server

Dolenc Kittelmann, Irena; Mikuž, M

2008-01-01

If there is a failure in an element of the accelerator the resulting beam losses could cause damage to the inner tracking devices of the experiments. This thesis presents the work performed during the development phase of a protection system for the ATLAS experiment at the LHC. The Beam Conditions Monitor (BCM) system is a stand-alone system designed to detect early signs of beam instabilities and trigger a beam abort in case of beam failures. It consists of two detector stations positioned at z=±1.84m from the interaction point. Each station comprises four BCM detector modules installed symmetrically around the beam pipe with sensors located at r=55 mm. This structure will allow distinguishing between anomalous events (beam gas and beam halo interactions, beam instabilities) and normal events due to proton-proton interaction by measuring the time-of-flight as well as the signal pulse amplitude from detector modules on the timescale of nanoseconds. Additionally, the BCM system aims to provide a coarse instan...

Commissioning of the ATLAS pixel detector

International Nuclear Information System (INIS)

Golling, Tobias

2008-01-01

The ATLAS pixel detector is a high precision silicon tracking device located closest to the LHC interaction point. It belongs to the first generation of its kind in a hadron collider experiment. It will provide crucial pattern recognition information and will largely determine the ability of ATLAS to precisely track particle trajectories and find secondary vertices. It was the last detector to be installed in ATLAS in June 2007, has been fully connected and tested in-situ during spring and summer 2008, and is ready for the imminent LHC turn-on. The highlights of the past and future commissioning activities of the ATLAS pixel system are presented

Test Management Framework for the Data Acquisition of the ATLAS Experiment

CERN Document Server

Kazarov, Andrei; The ATLAS collaboration

2017-01-01

Data Acquisition (DAQ) of the ATLAS experiment is a large distributed and inhomogeneous system: it consists of thousands of interconnected computers and electronics devices that operate coherently to read out and select relevant physics data. Advanced testing and diagnostics capabilities of the TDAQ control system are a crucial feature which contributes significantly to smooth operation and fast recovery in case of the problems and, finally, to the high efficiency of the whole experiment. The base layer of the verification and diagnostic functionality is a test management framework. We have developed a flexible test management system that allows the experts to define and configure tests for different components, indicate follow-up actions to test failures and describe inter-dependencies between DAQ or detector elements. This development is based on the experience gained with the previous test system that was used during the first three years of the data taking. We discovered that more emphasis needed to be pu...

Women of ATLAS - International Women's Day 2016

CERN Multimedia

Biondi, Silvia

2016-01-01

Women play key roles in the ATLAS Experiment: from young physicists at the start of their careers to analysis group leaders and spokespersons of the collaboration. Celebrate International Women's Day by meeting a few of these inspiring ATLAS researchers.

Signal generation in highly irradiated silicon microstrip detectors for the ATLAS experiment

International Nuclear Information System (INIS)

Ruggiero, Gennaro

2003-01-01

Silicon detectors are the most diffused tracking devices in High Energy Physics (HEP). The reason of such success can be found in the characteristics of the material together with the existing advanced technology for the fabrication of these devices. Nevertheless in many modem HEP experiments the observation of vary rare events require data taking at high luminosity with a consequent extremely intense hadron radiation field that damages the silicon and degrades the performance of these devices. In this thesis work a detailed study of the signal generation in microstrip detectors has been produced with a special care for the ATLAS semiconductor tracker geometry. This has required a development of an appropriate setup to perform measurements with Transient Current/ Charge Technique. This has allowed studying the evolution of the signal in several microstrips detector samples irradiated at fluences covering the range expected in the ATLAS Semiconductor Tracker. For a better understanding of these measurements a powerful software package that simulates the signal generation in these devices has been developed. Moreover in this thesis it has been also shown that the degradation due to radiation in silicon detectors can be strongly reduced if the data taking is done with detectors operated at 130 K. This makes low temperature operation that benefits of the recovery of the charge collection efficiency in highly irradiated silicon detectors (also known as Lazarus effect) an optimal option for future high luminosity experiments. (author)

The online muon identification of the ATLAS experiment at the LHC

CERN Document Server

Bernard, C; The ATLAS collaboration

2014-01-01

Identifying muons in the busy LHC environment is an important challenge for the ATLAS detector. This paper gives an overview of the ATLAS three-level muon trigger system, summarizing the online performance. In particular it discusses processing time and trigger rates as well as efficiency, resolution and other general performance figures.

The ATLAS distributed analysis system

International Nuclear Information System (INIS)

Legger, F

2014-01-01

In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of Grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During the first run of the LHC, the ATLAS Distributed Analysis (DA) service has operated stably and scaled as planned. More than 1600 users submitted jobs in 2012, with 2 million or more analysis jobs per week, peaking at about a million jobs per day. The system dynamically distributes popular data to expedite processing and maximally utilize resources. The reliability of the DA service is high and steadily improving; Grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters provides user support and communicates user problems to the sites. Both the user support techniques and the direct feedback of users have been effective in improving the success rate and user experience when utilizing the distributed computing environment. In this contribution a description of the main components, activities and achievements of ATLAS distributed analysis is given. Several future improvements being undertaken will be described.

The ATLAS distributed analysis system

Science.gov (United States)

Legger, F.; Atlas Collaboration

2014-06-01

In the LHC operations era, analysis of the multi-petabyte ATLAS data sample by globally distributed physicists is a challenging task. To attain the required scale the ATLAS Computing Model was designed around the concept of Grid computing, realized in the Worldwide LHC Computing Grid (WLCG), the largest distributed computational resource existing in the sciences. The ATLAS experiment currently stores over 140 PB of data and runs about 140,000 concurrent jobs continuously at WLCG sites. During the first run of the LHC, the ATLAS Distributed Analysis (DA) service has operated stably and scaled as planned. More than 1600 users submitted jobs in 2012, with 2 million or more analysis jobs per week, peaking at about a million jobs per day. The system dynamically distributes popular data to expedite processing and maximally utilize resources. The reliability of the DA service is high and steadily improving; Grid sites are continually validated against a set of standard tests, and a dedicated team of expert shifters provides user support and communicates user problems to the sites. Both the user support techniques and the direct feedback of users have been effective in improving the success rate and user experience when utilizing the distributed computing environment. In this contribution a description of the main components, activities and achievements of ATLAS distributed analysis is given. Several future improvements being undertaken will be described.

The ATLAS IBL CO2 Cooling System

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00237783; The ATLAS collaboration; Zwalinski, L.; Bortolin, C.; Vogt, S.; Godlewski, J.; Crespo-Lopez, O.; Van Overbeek, M.; Blaszcyk, T.

2017-01-01

The ATLAS Pixel detector has been equipped with an extra B-layer in the space obtained by a reduced beam pipe. This new pixel detector called the ATLAS Insertable B-Layer (IBL) is installed in 2014 and is operational in the current ATLAS data taking. The IBL detector is cooled with evaporative CO2 and is the first of its kind in ATLAS. The ATLAS IBL CO2 cooling system is designed for lower temperature operation (<-35⁰C) than the previous developed CO2 cooling systems in High Energy Physics experiments. The cold temperatures are required to protect the pixel sensors for the high expected radiation dose up to 550 fb^-1 integrated luminosity.

ATLAS, CMS, LHCb and ALICE Career Networking Event 2015

CERN Multimedia

Marinov, Andrey; Strom, Derek Axel

2015-01-01

A networking event for alumni of the ATLAS, CMS, LHCb and ALICE experiments as well as current ATLAS/CMS/LHCb/ALICE postdocs and graduate students. This event offers an insight into career opportunities outside of academia. Various former members of the ATLAS, CMS, LHCb and ALICE collaborations will give presentations and be part of a panel discussion and elaborate on their experience in companies in a diverse range of fields (industry, finance, IT,...). Details at https://indico.cern.ch/event/440616

Ageing studies of wavelength shifter fibers for the TILECAL/ATLAS experiment

International Nuclear Information System (INIS)

Silva, J.; Maio, A.; Pina, J.; Santos, J.; Saraiva, J.G.

2007-01-01

Natural and accelerated ageing studies for the different components of the TILECAL calorimeter, of the ATLAS experiment, play a central role in forecasting the evolution of the detector's performance throughout its operating life. It is possible that the operation of ATLAS will be extended by 5 years in an upgraded LHC scenario. Such prospect makes these studies even more important, in order to assess the contribution of the natural ageing in relation to the other processes inducing performance loss in the optical components. Among other activities in this LHC/CERN collaboration, the Lisbon calorimetry group is involved in studying the impact of radiation damage and natural ageing in optical characteristics of the TILECAL wavelength shifter (WLS) optical fibers and scintillators, and to reevaluate the light budget of the tile/fiber system. The light yield and the attenuation length of the WLS and scintillating optical fibers are measured using an X-Y table. Results are presented for several sets of WLS optical fibers (Kuraray Y11(200)MSJ) whose characteristics have been monitored since 1999. Most of those 338 fibers are from the mass production for the TILECAL detector: 208 non-aluminized 200 cm fibers, from several production batches, and 128 batch no. 6 aluminized fibers, with lengths ranging from 114 to 207 cm

PanDA: Exascale Federation of Resources for the ATLAS Experiment

CERN Document Server

Barreiro Megino, Fernando Harald; The ATLAS collaboration; Maeno, Tadashi; Wenaus, Torre; Nilsson, Paul; Klimentov, Alexei; Oleynik, Danila; Panitkin, Sergey; Petrosyan, Artem; Vukotic, Ilija

2015-01-01

After a scheduled maintenance and upgrade period, the world’s largest and most powerful machine - the Large Hadron Collider(LHC) - is about to enter its second run at unprecedented energies. In order to exploit the scientific potential of the ma- chine, the experiments at the LHC face computational challenges with enormous data volumes that need to be analysed by thousand of physics users and compared to simulated data. Given diverse funding constraints, the computational resources for the LHC have been deployed in a worldwide mesh of data centres, connected to each other through Grid technologies. The PanDA (Production and Distributed Analysis) system was developed in 2005 for the ATLAS experiment on top of this heterogeneous infrastructure to seamlessly integrate the computational resources and give the users the feeling of a unique system. Since its origins, PanDA has evolved together with upcoming computing paradigms in and outside HEP, such as changes in the networking model, cloud computing and HPC. I...

Distributed processing and analysis of ATLAS experimental data

CERN Document Server

Barberis, D; The ATLAS collaboration

2011-01-01

The ATLAS experiment is taking data steadily since Autumn 2009, collecting close to 1 fb-1 of data (several petabytes of raw and reconstructed data per year of data-taking). Data are calibrated, reconstructed, distributed and analysed at over 100 different sites using the World-wide LHC Computing Grid and the tools produced by the ATLAS Distributed Computing project. In addition to event data, ATLAS produces a wealth of information on detector status, luminosity, calibrations, alignments, and data processing conditions. This information is stored in relational databases, online and offline, and made transparently available to analysers of ATLAS data world-wide through an infrastructure consisting of distributed database replicas and web servers that exploit caching technologies. This paper reports on the experience of using this distributed computing infrastructure with real data and in real time, on the evolution of the computing model driven by this experience, and on the system performance during the first...

Distributed processing and analysis of ATLAS experimental data

CERN Document Server

Barberis, D; The ATLAS collaboration

2011-01-01

The ATLAS experiment is taking data steadily since Autumn 2009, and collected so far over 5 fb-1 of data (several petabytes of raw and reconstructed data per year of data-taking). Data are calibrated, reconstructed, distributed and analysed at over 100 different sites using the World-wide LHC Computing Grid and the tools produced by the ATLAS Distributed Computing project. In addition to event data, ATLAS produces a wealth of information on detector status, luminosity, calibrations, alignments, and data processing conditions. This information is stored in relational databases, online and offline, and made transparently available to analysers of ATLAS data world-wide through an infrastructure consisting of distributed database replicas and web servers that exploit caching technologies. This paper reports on the experience of using this distributed computing infrastructure with real data and in real time, on the evolution of the computing model driven by this experience, and on the system performance during the...

Heavy Ion Physics with the ATLAS Detector at the LHC

International Nuclear Information System (INIS)

Trzupek, A.

2009-01-01

The heavy-ion program at LHC will be pursued by three experiments including ATLAS, a multipurpose detector to study p + p collisions. A report on the potential of the ATLAS detector to uncover new physics in Pb + Pb collisions at energies thirty times larger than energy available at RHIC will be presented. Key aspects of the heavy-ion program of the ATLAS experiment, implied by measurements at RHIC, will be discussed. They include measurement capability of high-p T hadronic and electromagnetic probes, quarkonia as well as elliptic flow and other bulk phenomena. Measurements by the ATLAS experiment will provide crucial information about the formation of a quark-gluon plasma at the new energy scale accessible at the LHC. (author)

Measurement of the Standard Model W+W- production cross-section using the ATLAS experiment on the LHC

International Nuclear Information System (INIS)

Zeman, Martin

2014-01-01

Measurements of di-boson production cross-sections are an important part of the physics programme at the CERN Large Hadron Collider. These physics analyses provide the opportunity to probe the electroweak sector of the Standard Model at the TeV scale and could also indicate the existence of new particles or probe beyond the Standard Model physics. The excellent performance of the LHC through years 2011 and 2012 allowed for very competitive measurements. This thesis provides a comprehensive overview of the experimental considerations and methods used in the measurement of the W + W - production cross-section in proton-proton collisions at √s = 7 TeV and 8 TeV. The treatise covers the material in great detail, starting with the introduction of the theoretical framework of the Standard Model and follows with an extensive discussion of the methods implemented in recording and reconstructing physics events in an experiment of this magnitude. The associated online and offline software tools are included in the discussion. The relevant experiments are covered, including a very detailed section about the ATLAS detector. The final chapter of this thesis contains a detailed description of the analysis of the W-pair production in the leptonic decay channels using the datasets recorded by the ATLAS experiment during 2011 and 2012 (Run I). The analyses use 4.60 fb -1 recorded at √s = 7 TeV and 20.28 fb -1 recorded at 8 TeV. The experimentally measured cross section for the production of W bosons at the ATLAS experiment is consistently enhanced compared to the predictions of the Standard Model at centre-of-mass energies of 7 TeV and 8 TeV. The thesis concludes with the presentation of differential cross-section measurement results. (author) [fr

The ATLAS detector simulation application

International Nuclear Information System (INIS)

Rimoldi, A.

2007-01-01

The simulation program for the ATLAS experiment at CERN is currently in a full operational mode and integrated into the ATLAS common analysis framework, Athena. The OO approach, based on GEANT4, has been interfaced within Athena and to GEANT4 using the LCG dictionaries and Python scripting. The robustness of the application was proved during the test productions since 2004. The Python interface has added the flexibility, modularity and interactivity that the simulation tool requires in order to be able to provide a common implementation of different full ATLAS simulation setups, test beams and cosmic ray applications. Generation, simulation and digitization steps were exercised for performance and robustness tests. The comparison with real data has been possible in the context of the ATLAS Combined Test Beam (2004-2005) and cosmic ray studies (2006)

Work on the ATLAS semiconductor tracker barrel

CERN Multimedia

Maximilien Brice

2005-01-01

Precision work is performed on the semiconductor tracker barrel of the ATLAS experiment. All work on these delicate components must be performed in a clean room so that impurities in the air, such as dust, do not contaminate the detector. The semiconductor tracker will be mounted in the barrel close to the heart of the ATLAS experiment to detect the path of particles produced in proton-proton collisions.

ATLAS Silicon Microstrip Tracker Operation and Performance

CERN Document Server

Nagai, K; The ATLAS collaboration

2012-01-01

The Semi-Conductor Tracker (SCT) is one of the key precision tracking devices in the ATLAS experiment at CERN Large Hadron Collider (LHC). The SCT was constructed of 4088 modules for a total of 6.3 million silicon strips and was installed into the ATLAS experiment in 2007. The SCT has been fully operational since then, and achieves a good tracking performance from the startup of the LHC operation.

Soft QCD at the CMS and ATLAS experiments

CERN Document Server

Veres, Gabor

2016-01-01

A short overview of some of the recent results on soft QCD processes at the LHC will be presented from the ATLAS and CMS experiments. The discussion will proceed starting from the most inclusive to the more differential and rare phenomena. New results include total inelastic cross section measurements; studies of minimum bias collisions (charged particle $\\eta$ and $p_T$ distributions and two-particle correlations in high-multiplicity events); features of the underlying event (multiplicity and $\\Sigma p_T$ distributions in the presence of a high-$p_T$ track, jet, Z boson or $t\\overline{t}$ pair); minijets characterizing the transition between the soft and hard QCD regimes; dijets with a rapidity gap (as a signature of color-singlet exchange); M\\uller-Navelet dijets and their angular decorrelations (as an attempt to search for signs of the BFKL evolution and deviations from DGLAP); and finally, Double Parton Scattering (DPS) studies using various final states (4-jet events, $\\gamma$ + 3 jets, 2 b-jets and 2 je...

Quality of energy consultancy services - Requirements, criteria for evaluation, and a case report; Energieberatungsqualitaet - Anforderungen, Messung und ein Fallbeispiel

Energy Technology Data Exchange (ETDEWEB)

Hausser, K.

1999-07-01

The article initially pictures an optimized model of energy consultancy and continues with explaining an instrument available for quality assessment of services in general, (SERVQUAL), presenting approaches for modifying this tool so as to make it applicable to evaluating the quality of energy consultancy activities. Finally, the capabilities of the modified tool are discussed referring to a case study in an electric utility, the Neckarwerke Stuttgart. (orig./CB) [German] Energieberatung durch Energieversorgungsunternehmen wird in Deutschland fast flaechendeckend angeboten. Im Beitrag wird zuerst aufgezeigt, welche Anforderungen eine optimale Energieberatung erfuellen muss. Danach wird ein Instrument vorgestellt, das die Qualitaet von Dienstleistungen im allgemeinen misst und im Rahmen der o.g. Arbeit so weiterentwickelt wurde, dass es von nun an auch als Instrument zur Messung der Qualitaet von Energieberatung im Besonderen dienen kann: SERVQUAL (von SERVice QUALity). Zuletzt werden die Ergebnisse praesentiert, die in der o.g. Untersuchung unter Anwendung von SERVQUAL bei den Neckarwerken Stuttgart erzielt wurden. (orig./RHM)

Searches for Supersymmetry in ATLAS

CERN Document Server

Cervelli, Alberto; The ATLAS collaboration

2017-01-01

After the discovery of the Higgs boson in ATLAS first run of data taking, and due to the lack of observation of new physics, searches for new particles such as Supersymmetric states are one of the main area of interest for the general purpose detectors operating at LHC. In this talk we will present a review of the searches for Supersymmetric particles, performed by the ATLAS experiment

Summary of non-SM Higgs boson searches from the ATLAS and CMS experiments

International Nuclear Information System (INIS)

Davey, W.

2014-01-01

A review of searches for non-standard Model Higgs bosons conducted at the Large Hadron Collider is presented. The searches use datasets corresponding to integrated luminosities up to 5 fb -1 collected by the ATLAS and CMS experiments during 7 TeV proton-proton collisions. Searches for neutral and charged MSSM Higgs bosons, the light CP-odd neutral Higgs boson of the NMSSM, fermio-phobic Higgs bosons and doubly charged Higgs bosons are conducted. No evidence for these signals have been observed. (author)

A thermosiphon for ATLAS

CERN Multimedia

Rosaria Marraffino

2013-01-01

A new thermosiphon cooling system, designed for the ATLAS silicon detectors by CERN’s EN-CV team in collaboration with the experiment, will replace the current system in the next LHC run in 2015. Using the basic properties of density difference and making gravity do the hard work, the thermosiphon promises to be a very reliable solution that will ensure the long-term stability of the whole system.   Former compressor-based cooling system of the ATLAS inner detectors. The system is currently being replaced by the innovative thermosiphon. (Photo courtesy of Olivier Crespo-Lopez). Reliability is the major issue for the present cooling system of the ATLAS silicon detectors. The system was designed 13 years ago using a compressor-based cooling cycle. “The current cooling system uses oil-free compressors to avoid fluid pollution in the delicate parts of the silicon detectors,” says Michele Battistin, EN-CV-PJ section leader and project leader of the ATLAS thermosiphon....

The Layout and Performance of the Phase-II upgrade of the tracking detector of the ATLAS experiment

CERN Document Server

Ai, Xiaocong; The ATLAS collaboration

2017-01-01

HL-LHC will deliver about 3000 fb-1 of integrated luminosity in over 10 year. This will present an extremely challenging environment to the ATLAS experiment, well beyond that for which it was designed. In ATLAS Phase II upgrade, the Inner Detector will be replace by a new all-silicon Inner Tracker to maintain tracking performance in this high-occupancy environment and to cope with the increase of approximately a factor of ten in the integrated radiation dose. The ITk Detector layout is designed to meet the requirement for identifying charged particles with high efficiency and measuring their properties with high precision in the denser environment. The Layout and performance of the ITk is presented.

Searches for squarks and gluinos with ATLAS

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00394440; The ATLAS collaboration

2017-01-01

One of the most versatile and attractive extensions to the successful yet incomplete Standard Model of particle physics is Supersymmetry - a theory the ATLAS experiment at the Large Hadron Collider is looking for in its recorded data. Due to the nature of proton-proton collisions, the recorded physics events are mainly produced via the strong force. This fact makes searches for the superpartners of the gluon and the quarks particularly promising. This document provides an overview of searches for squarks and gluinos using the ATLAS experiment and describes two of the major analyses in detail. The analysis strategies are outlined, the results discussed and interpreted. Finally, an outlook onto other searches for strongly produced Supersymmetry with ATLAS is given.

The RPC LVL1 trigger system of the muon spectrometer of the ATLAS experiment at LHC

CERN Document Server

Aielli, G; Alviggi, M G; Biglietti, M; Bocci, V; Brambilla, Elena; Camarri, P; Canale, V; Caprio, M A; Cardarelli, R; Carlino, G; Cataldi, G; Chiodini, G; Conventi, F; De Asmundis, R; Della Pietra, M; Della Volpe, D; Di Ciaccio, A; Di Mattia, A; Di Simone, A; Falciano, S; Gorini, E; Grancagnolo, F; Iengo, P; Liberti, B; Luminari, L; Nisati, A; Pastore, F; Patricelli, S; Perrino, R; Petrolo, E; Primavera, M; Sekhniaidze, G; Spagnolo, S; Salamon, A; Santonico, R; Vari, R; Veneziano, Stefano

2004-01-01

The ATLAS Trigger System has been designed to reduce the LHC interaction rate of about 1 GHz to the foreseen storage rate of about 100 Hz. Three trigger levels are applied in order to fulfill such a requirement. A detailed simulation of the ATLAS experiment including the hardware components and the logic of the Level-1 Muon trigger in the barrel of the muon spectrometer has been performed. This simulation has been used not only to evaluate the performances of the system but also to optimize the trigger logic design. In the barrel of the muon spectrometer the trigger will be given by means of resistive plate chambers (RPCs) working in avalanche mode. Before being mounted on the experiment, accurate quality tests with cosmic rays are carried out on each RPC chamber using the test station facility of the INFN and University laboratory of Napoli. All working parameters are measured and the uniformity of the efficiency on the whole RPC surface is required. A summary of the Napoli cosmic rays tests, together with a...

Energy calibration and observation of the Higgs boson in the diphoton decay with the ATLAS experiment

CERN Document Server

Turra, Ruggero; Fanti, M

ATLAS is one of the four main experiments at the LHC proton-proton accelerator at CERN. This thesis describes two correlated topics: the observation for the Higgs boson in the diphoton channel and the Monte Carlo calibration of electrons and photons. The Higgs boson is a particle predicted by the Standard Model to explain the mechanism for electroweak symmetry breaking, giving masses to the particles. A particle compatible with the SM Higgs boson has been discovered by the ATLAS and CMS experiments in 2012. If this new boson is the Higgs boson, all fundamental parameters of the SM are known and, for the first time, it is possible to overconstrain the SM at the electroweak scale and to evaluate its validity. The proton-proton collision datasets used for the diphoton analysis correspond to integrated luminosities of 4.8 fb-1 collected at sqrt(s) = 7 TeV and 13.0 fb-1 collected at sqrt(s) = 8 TeV. The results, for the first time, establish the observation in the diphoton channel alone. The observation has a loca...

Measurement of hydrogen distributions in iron and steel by means of neutron radiography and tomography; Messung von Wasserstoffverteilungen in Eisen und Stahl mittels Neutronenradiographie und -tomographie

Energy Technology Data Exchange (ETDEWEB)

Griesche, Axel; Kannengiesser, Thomas [BAM Bundesanstalt fuer Materialforschung und -pruefung, Berlin (Germany); Kardjilov, Nikolay; Manke, Ingo [Helmholtz-Zentrum Berlin (HZB), Berlin (Germany); Schillinger, Burkhard [Technische Univ. Muenchen, Garching (Germany)

2015-07-01

In recent years, the optimization of the radiography measuring stations at research reactors and in particular the development of the neutron detectors has enabled the measurement of hydrogen distributions with ever higher spatial resolution at the same time more sensitive detection limit. Compared to iron, hydrogen has a high interaction cross-section for neutrons, and thus allows simple radiographic methods of the two and three dimensional visualization of hydrogen distribution in the structure. This allowed us for the first time the measurement of hydrogen diffusion flows in centimeter-thick steel samples with a temporal resolution of 20 s and the quantitative measurement of hydrogen accumulation of crack edges in hydrogen embrittled iron samples. It was also the first gaseous hydrogen detected in the cavities of the cracks and the pressure can be determined. This new quality of information on the microstructure scale granted unprecedented insights for the investigation of damage mechanisms e.g. in the hydrogen embrittlement. By providing local in-situ information that is not accessible by conventional methods such as carrier gas hot extraction, as well as analyzes can be performed in three dimensions with a spatial resolution of 20-30 μm. This article provides examples that use the spatial and temporal resolution of the neutron radiography and tomography to visualize hydrogen distributions in and around cracks and to quantify. The measurements were conducted at the research reactors BER II of HZB in Berlin and FRM II of teh neutron source Heinz Maier-Leibnitz in Garching. (This article contains PowerPoint slides). [German] In den letzten Jahren hat die Optimierung der Radiographie-Messplaetze an Forschungsreaktoren und hier insbesondere die Weiterentwicklung der Neutronendetektoren die Messung von Wasserstoffverteilungen mit immer hoeherer Ortsaufloesung bei gleichzeitig empfindlicherer Nachweisgrenze ermoeglicht. Wasserstoff besitzt im Vergleich zu Eisen

Studies of b-associated production and muonic decays of neutral Higgs bosons at the ATLAS experiment within the Minimal Supersymmetric Standard Model

International Nuclear Information System (INIS)

Warsinsky, Markus

2008-01-01

This thesis presents a Monte Carlo study of neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) decaying into muons at the ATLAS experiment at the CERN Large Hadron Collider. Signal and background processes are simulated using novel Monte Carlo generators that incorporate parts of higher order corrections and are expected to give a more accurate prediction than previous programs. The SHERPA Monte Carlo generator is validated for its use in the analysis and compared to results obtained with other programs. Where possible, the Monte Carlo event samples are normalized to higher order calculations. To increase the available Monte Carlo statistics, this study is based on the ATLAS fast detector simulation ATLFAST. Differences between ATLFAST and the detailed detector simulation of ATLAS are examined, and, where possible, correction procedures are devised. A cut based analysis is performed assuming an integrated luminosity of 30 fb -1 , and optimized with respect to the discovery potential for MSSM Higgs bosons. The systematic uncertainties of the event selection and the Monte Carlo predictions are estimated. A method that can be used to estimate the background from data is presented and evaluated. Last, the discovery potential of the ATLAS experiment in the CP conserving benchmark scenarios of the MSSM is evaluated. One or more of the neutral Higgs bosons of the MSSM can be discovered in the muonic decay mode using 30 fb -1 of data for low masses of the pseudoscalar boson A 0 , if the model parameter tan β is at least 20. For higher masses of the A 0 , tan β would need to be significantly higher to ensure a discovery in the studied decay channel. The sensitivity of ATLAS to MSSM Higgs bosons is multiple times larger than the one of previous and currently running experiments. (orig.)

Studies of b-associated production and muonic decays of neutral Higgs bosons at the ATLAS experiment within the Minimal Supersymmetric Standard Model

Energy Technology Data Exchange (ETDEWEB)

Warsinsky, Markus

2008-09-15

This thesis presents a Monte Carlo study of neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) decaying into muons at the ATLAS experiment at the CERN Large Hadron Collider. Signal and background processes are simulated using novel Monte Carlo generators that incorporate parts of higher order corrections and are expected to give a more accurate prediction than previous programs. The SHERPA Monte Carlo generator is validated for its use in the analysis and compared to results obtained with other programs. Where possible, the Monte Carlo event samples are normalized to higher order calculations. To increase the available Monte Carlo statistics, this study is based on the ATLAS fast detector simulation ATLFAST. Differences between ATLFAST and the detailed detector simulation of ATLAS are examined, and, where possible, correction procedures are devised. A cut based analysis is performed assuming an integrated luminosity of 30 fb{sup -1}, and optimized with respect to the discovery potential for MSSM Higgs bosons. The systematic uncertainties of the event selection and the Monte Carlo predictions are estimated. A method that can be used to estimate the background from data is presented and evaluated. Last, the discovery potential of the ATLAS experiment in the CP conserving benchmark scenarios of the MSSM is evaluated. One or more of the neutral Higgs bosons of the MSSM can be discovered in the muonic decay mode using 30 fb{sup -1} of data for low masses of the pseudoscalar boson A{sup 0}, if the model parameter tan {beta} is at least 20. For higher masses of the A{sup 0}, tan {beta} would need to be significantly higher to ensure a discovery in the studied decay channel. The sensitivity of ATLAS to MSSM Higgs bosons is multiple times larger than the one of previous and currently running experiments. (orig.)

Measurement of the reference channel B±→J/ψK± for the rare decay B0s→μ+μ- with the ATLAS experiment

International Nuclear Information System (INIS)

Gaur, Bakul

2013-01-01

The ATLAS experiment is one of the four major experiments at the Large Hadron Collider (LHC) of CERN, Geneva. The experiment addresses the open questions of particle physics. The decay of the B 0 s meson to two muons is strongly suppressed in the Standard Model (SM). It is a rare decay with an expected branching fraction of 3.56 x 10 -9 . The B 0 s →μ + μ - branching fraction is measured relative to a reference channel, B ± →J/ψK ± . The subject of this thesis is the measurement of the B ± yield. The analysis uses 4.9 fb -1 of ATLAS data collected in the year 2011 at 7 TeV center-of-mass energy. The B ± candidate selection is performed using a multivariate (MVA) technique. The yield is estimated using a two-dimensional unbinned maximum likelihood fit that accounts for the per-event uncertainties. The result is used for the computation of the upper limit on the B 0 s →μ + μ - branching fraction published by the ATLAS collaboration.

Experience with ATLAS MySQL PanDA database service

International Nuclear Information System (INIS)

Smirnov, Y; Wlodek, T; Hover, J; Smith, J; Wenaus, T; Yu, D; De, K; Ozturk, N

2010-01-01

The PanDA distributed production and analysis system has been in production use for ATLAS data processing and analysis since late 2005 in the US, and globally throughout ATLAS since early 2008. Its core architecture is based on a set of stateless web services served by Apache and backed by a suite of MySQL databases that are the repository for all PanDA information: active and archival job queues, dataset and file catalogs, site configuration information, monitoring information, system control parameters, and so on. This database system is one of the most critical components of PanDA, and has successfully delivered the functional and scaling performance required by PanDA, currently operating at a scale of half a million jobs per week, with much growth still to come. In this paper we describe the design and implementation of the PanDA database system, its architecture of MySQL servers deployed at BNL and CERN, backup strategy and monitoring tools. The system has been developed, thoroughly tested, and brought to production to provide highly reliable, scalable, flexible and available database services for ATLAS Monte Carlo production, reconstruction and physics analysis.

Experience with ATLAS MySQL PanDA database service

Energy Technology Data Exchange (ETDEWEB)

Smirnov, Y; Wlodek, T; Hover, J; Smith, J; Wenaus, T; Yu, D [Physics Department, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States); De, K; Ozturk, N [Department of Physics, University of Texas at Arlington, Arlington, TX, 76019 (United States)

2010-04-01

The PanDA distributed production and analysis system has been in production use for ATLAS data processing and analysis since late 2005 in the US, and globally throughout ATLAS since early 2008. Its core architecture is based on a set of stateless web services served by Apache and backed by a suite of MySQL databases that are the repository for all PanDA information: active and archival job queues, dataset and file catalogs, site configuration information, monitoring information, system control parameters, and so on. This database system is one of the most critical components of PanDA, and has successfully delivered the functional and scaling performance required by PanDA, currently operating at a scale of half a million jobs per week, with much growth still to come. In this paper we describe the design and implementation of the PanDA database system, its architecture of MySQL servers deployed at BNL and CERN, backup strategy and monitoring tools. The system has been developed, thoroughly tested, and brought to production to provide highly reliable, scalable, flexible and available database services for ATLAS Monte Carlo production, reconstruction and physics analysis.

A beam halo event of the ATLAS Experiment

CERN Multimedia

ATLAS, Experiment

2014-01-01

Beam halo events: These occur as a single beam of protons is circulating in one direction in LHC, just passing through ATLAS. An outlier particle hits a part of the detector causing a spray of particles.

ATLAS Silicon Microstrip Tracker

CERN Document Server

Haefner, Petra; The ATLAS collaboration

2010-01-01

The SemiConductor Tracker (SCT), made up from silicon micro-strip detectors is the key precision tracking device in ATLAS, one of the experiments at CERN LHC. The completed SCT is in very good shape: 99.3% of the SCT strips are operational, noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector and observed problems, with stress on the sensor and electronics performance. TWEPP Summary In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton- proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The SemiConductor Tracker (SCT) is the key precision tracking device in ATLAS, made up from silicon micro-strip detectors processed in the planar p-in-n technology. The signal from the strips is processed in the front-end ASICS ABCD3TA, working in the binary readout mode. Data i...

Robustness studies of the photomultipliers reading out TileCal, the central hadron calorimeter of the ATLAS experiment

CERN Document Server

Di Gregorio, Giulia; The ATLAS collaboration

2018-01-01

The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibres to photo-multiplier tubes (PMTs), located in the outer part of the calorimeter. The readout is segmented into about 5000 cells, each one being read out by two PMTs in parallel. The detector readout geometry will not be changed for the Phase II of the High Luminosity Large Hadron Collider (HL-LHC) operation. A challenging goal is to understand whether the full sample of PMTs installed at the beginning of the ATLAS detector operation can be used until completion of the HL-LHC program or not. For this reason, a reliable study of the PMT robustness against ageing is required. Detailed studies modelling the PMT response variation as a function of the integrated anode charge were done. The PMT response evoluti...

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

CERN Document Server

Keoshkerian, Houry

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

ATLAS DAQ/HLT rack DCS

International Nuclear Information System (INIS)

Ermoline, Yuri; Burckhart, Helfried; Francis, David; Wickens, Frederick J.

2007-01-01

The ATLAS Detector Control System (DCS) group provides a set of standard tools, used by subsystems to implement their local control systems. The ATLAS Data Acquisition and High Level Trigger (DAQ/HLT) rack DCS provides monitoring of the environmental parameters (air temperatures, humidity, etc.). The DAQ/HLT racks are located in the underground counting room (20 racks) and in the surface building (100 racks). The rack DCS is based on standard ATLAS tools and integrated into overall operation of the experiment. The implementation is based on the commercial control package and additional components, developed by CERN Joint Controls Project Framework. The prototype implementation and measurements are presented

The German National Analysis Facility as a tool for ATLAS analyses

International Nuclear Information System (INIS)

Ehrenfeld, W; Leffhalm, K; Mehlhase, S

2011-01-01

In 2008 the German National Analysis Facility (NAF) at DESY was established. It is attached to and builds on top of DESY Grid infrastructure. The facility is designed to provide the best possible analysis infrastructure for high energy particle physics of the ATLAS, CMS, LHCb and ILC experiments. The Grid and local infrastructure of the NAF is reviewed with a focus on the ATLAS part. Both parts include large scale storage and a batch system. Emphasis is put on ATLAS specific customisation and utilisation of the NAF. This refers not only to the NAF components but also to the different components of the ATLAS analysis framework. Experience from operating and supporting ATLAS users on the NAF is presented in this paper. The ATLAS usage of the different components are shown including some typical use cases of user analysis. Finally, the question is addressed, if the design of the NAF meets the ATLAS expectations for efficient data analysis in the era of LHC data taking.

Exploitation of heterogeneous resources for ATLAS Computing

CERN Document Server

Chudoba, Jiri; The ATLAS collaboration

2018-01-01

LHC experiments require significant computational resources for Monte Carlo simulations and real data processing and the ATLAS experiment is not an exception. In 2017, ATLAS exploited steadily almost 3M HS06 units, which corresponds to about 300 000 standard CPU cores. The total disk and tape capacity managed by the Rucio data management system exceeded 350 PB. Resources are provided mostly by Grid computing centers distributed in geographically separated locations and connected by the Grid middleware. The ATLAS collaboration developed several systems to manage computational jobs, data files and network transfers. ATLAS solutions for job and data management (PanDA and Rucio) were generalized and now are used also by other collaborations. More components are needed to include new resources such as private and public clouds, volunteers' desktop computers and primarily supercomputers in major HPC centers. Workflows and data flows significantly differ for these less traditional resources and extensive software re...

The magnetically driven imploding liner parameter space of the ATLAS capacitor bank

CERN Document Server

Lindemuth, I R; Faehl, R J; Reinovsky, R E

2001-01-01

Summary form only given, as follows. The Atlas capacitor bank (23 MJ, 30 MA) is now operational at Los Alamos. Atlas was designed primarily to magnetically drive imploding liners for use as impactors in shock and hydrodynamic experiments. We have conducted a computational "mapping" of the high-performance imploding liner parameter space accessible to Atlas. The effect of charge voltage, transmission inductance, liner thickness, liner initial radius, and liner length has been investigated. One conclusion is that Atlas is ideally suited to be a liner driver for liner-on-plasma experiments in a magnetized target fusion (MTF) context . The parameter space of possible Atlas reconfigurations has also been investigated.

Structured storage in ATLAS Distributed Data Management: use cases and experiences

International Nuclear Information System (INIS)

Lassnig, Mario; Garonne, Vincent; Beermann, Thomas; Dimitrov, Gancho; Canali, Luca; Molfetas, Angelos; Zang Donal; Azzurra Chinzer, Lisa

2012-01-01

The distributed data management system of the high-energy physics experiment ATLAS has a critical dependency on the Oracle Relational Database Management System. Recently however, the increased appearance of data warehouselike workload in the experiment has put considerable and increasing strain on the Oracle database. In particular, the analysis of archived data, and the aggregation of data for summary purposes has been especially demanding. For this reason, structured storage systems were evaluated to offload the Oracle database, and to handle processing of data in a non-transactional way. This includes distributed file systems like HDFS that support parallel execution of computational tasks on distributed data, as well as non-relational databases like HBase, Cassandra, or MongoDB. In this paper, the most important analysis and aggregation use cases of the data management system are presented, and how structured storage systems were established to process them.

Role Based Access Control system in the ATLAS experiment

International Nuclear Information System (INIS)

Valsan, M L; Dumitru, I; Darlea, G L; Bujor, F; Dobson, M; Miotto, G Lehmann; Schlenker, S; Avolio, G; Scannicchio, D A; Filimonov, V; Khomoutnikov, V; Zaytsev, A S; Korol, A A; Bogdantchikov, A; Caramarcu, C; Ballestrero, S; Twomey, M

2011-01-01

The complexity of the ATLAS experiment motivated the deployment of an integrated Access Control System in order to guarantee safe and optimal access for a large number of users to the various software and hardware resources. Such an integrated system was foreseen since the design of the infrastructure and is now central to the operations model. In order to cope with the ever growing needs of restricting access to all resources used within the experiment, the Roles Based Access Control (RBAC) previously developed has been extended and improved. The paper starts with a short presentation of the RBAC design, implementation and the changes made to the system to allow the management and usage of roles to control access to the vast and diverse set of resources. The RBAC implementation uses a directory service based on Lightweight Directory Access Protocol to store the users (∼3000), roles (∼320), groups (∼80) and access policies. The information is kept in sync with various other databases and directory services: human resources, central CERN IT, CERN Active Directory and the Access Control Database used by DCS. The paper concludes with a detailed description of the integration across all areas of the system.

The GNAM system in the ATLAS online monitoring framework

Energy Technology Data Exchange (ETDEWEB)

Salvatore, D. [INFN Cosenza and Dip. di Fisica, Universita della Calabria, ponte P. Bucci 31 C, 87036 Rende (Italy)], E-mail: daniela.salvatore@cern.ch; Adragna, P. [Queen Mary, University of London, London (United Kingdom); Bosman, M. [IFAE, Institut de Fisica de Altes Energies, UAB/Barcelona (Spain); Burckhart, D. [CERN, Geneva (Switzerland); Caprini, M. [National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Corso-Radu, A. [University of California Irvine, Irvine, California (United States); Costa, M.J. [CERN, Geneva (Switzerland); Della Pietra, M. [INFN Sezione diNapoli, Napoli (Italy); Dotti, A. [Universita and INFN Pisa, Pisa (Italy); Eschrich, I. [University of California Irvine, Irvine, California (United States); Ferrari, R. [INFN Sezione di Pavia, Pavia (Italy); Ferrer, M.L. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Gaudio, G. [INFN Sezione di Pavia, Pavia (Italy); Hadavand, H. [Southern Methodist University, Dallas (United States); Hauschild, M. [CERN, Geneva (Switzerland); Hillier, S. [University of Birmingham, Birmingham (United Kingdom); Kehoe, B. [Southern Methodist University, Dallas (United States); Kolos, S. [University of California Irvine, Irvine, California (United States); Kordas, K. [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Mcpherson, R. [University of Victoria, Vancouver (Canada)] (and others)

2007-10-15

ATLAS [ATLAS Collaboration, 'ATLAS Technical Proposal', CERN/LHHCC/94-43, LHCC/P2, CERN, Geneva, Switzerland, 1994] is one of the four experiments under construction along the Large Hadron Collider (LHC) ring, which will produce interactions at a center of mass energy of 14 TeV at 40 MHz rate. The detector consists of more than 140 million electronic channels. The challenging experimental environment and the extreme detector complexity impose the necessity of a common scalable distributed monitoring framework, which can be tuned for the optimal use by different ATLAS detectors at the various levels of the ATLAS data flow.

The GNAM system in the ATLAS online monitoring framework

Energy Technology Data Exchange (ETDEWEB)

Salvatore, D. [INFN Cosenza and Dip. di Fisica, Universita della Calabria, ponte P. Bucci 31 C, 87036 Rende (Italy)], E-mail: daniela.salvatore@cern.ch; Adragna, P [Queen Mary, University of London, London (United Kingdom); Bosman, M [IFAE, Institut de Fisica de Altes Energies, UAB/Barcelona (Spain); Burckhart, D [CERN, Geneva (Switzerland); Caprini, M [National Institute for Physics and Nuclear Engineering, Bucharest (Romania); Corso-Radu, A [University of California Irvine, Irvine, California (United States); Costa, M J [CERN, Geneva (Switzerland); Della Pietra, M [INFN Sezione diNapoli, Napoli (Italy); Dotti, A [Universita and INFN Pisa, Pisa (Italy); Eschrich, I [University of California Irvine, Irvine, California (United States); Ferrari, R [INFN Sezione di Pavia, Pavia (Italy); Ferrer, M L [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Gaudio, G [INFN Sezione di Pavia, Pavia (Italy); Hadavand, H [Southern Methodist University, Dallas (United States); Hauschild, M [CERN, Geneva (Switzerland); Hillier, S [University of Birmingham, Birmingham (United Kingdom); Kehoe, B [Southern Methodist University, Dallas (United States); Kolos, S [University of California Irvine, Irvine, California (United States); Kordas, K [INFN Laboratori Nazionali di Frascati, Frascati (Italy); Mcpherson, R [University of Victoria, Vancouver (Canada)

2007-10-15

ATLAS [ATLAS Collaboration, 'ATLAS Technical Proposal', CERN/LHHCC/94-43, LHCC/P2, CERN, Geneva, Switzerland, 1994] is one of the four experiments under construction along the Large Hadron Collider (LHC) ring, which will produce interactions at a center of mass energy of 14 TeV at 40 MHz rate. The detector consists of more than 140 million electronic channels. The challenging experimental environment and the extreme detector complexity impose the necessity of a common scalable distributed monitoring framework, which can be tuned for the optimal use by different ATLAS detectors at the various levels of the ATLAS data flow.

The GNAM system in the ATLAS online monitoring framework

International Nuclear Information System (INIS)

Salvatore, D.; Adragna, P.; Bosman, M.; Burckhart, D.; Caprini, M.; Corso-Radu, A.; Costa, M.J.; Della Pietra, M.; Dotti, A.; Eschrich, I.; Ferrari, R.; Ferrer, M.L.; Gaudio, G.; Hadavand, H.; Hauschild, M.; Hillier, S.; Kehoe, B.; Kolos, S.; Kordas, K.; Mcpherson, R.

2007-01-01

ATLAS [ATLAS Collaboration, 'ATLAS Technical Proposal', CERN/LHHCC/94-43, LHCC/P2, CERN, Geneva, Switzerland, 1994] is one of the four experiments under construction along the Large Hadron Collider (LHC) ring, which will produce interactions at a center of mass energy of 14 TeV at 40 MHz rate. The detector consists of more than 140 million electronic channels. The challenging experimental environment and the extreme detector complexity impose the necessity of a common scalable distributed monitoring framework, which can be tuned for the optimal use by different ATLAS detectors at the various levels of the ATLAS data flow

Development, deployment and operations of ATLAS databases

International Nuclear Information System (INIS)

Vaniachine, A. V.; von der Schmitt, J. G.

2008-01-01

In preparation for ATLAS data taking, a coordinated shift from development towards operations has occurred in ATLAS database activities. In addition to development and commissioning activities in databases, ATLAS is active in the development and deployment (in collaboration with the WLCG 3D project) of the tools that allow the worldwide distribution and installation of databases and related datasets, as well as the actual operation of this system on ATLAS multi-grid infrastructure. We describe development and commissioning of major ATLAS database applications for online and offline. We present the first scalability test results and ramp-up schedule over the initial LHC years of operations towards the nominal year of ATLAS running, when the database storage volumes are expected to reach 6.1 TB for the Tag DB and 1.0 TB for the Conditions DB. ATLAS database applications require robust operational infrastructure for data replication between online and offline at Tier-0, and for the distribution of the offline data to Tier-1 and Tier-2 computing centers. We describe ATLAS experience with Oracle Streams and other technologies for coordinated replication of databases in the framework of the WLCG 3D services

Design and Implementation of the ATLAS Detector Control System

CERN Document Server

Boterenbrood, H; Cook, J; Filimonov, V; Hallgren, B I; Heubers, W P J; Khomoutnikov, V; Ryabov, Yu; Varela, F

2004-01-01

The overall dimensions of the ATLAS experiment and its harsh environment, due to radiation and magnetic field, represent new challenges for the implementation of the Detector Control System. It supervises all hardware of the ATLAS detector, monitors the infrastructure of the experiment, and provides information exchange with the LHC accelerator. The system must allow for the operation of the different ATLAS sub-detectors in stand-alone mode, as required for calibration and debugging, as well as the coherent and integrated operation of all sub-detectors for physics data taking. For this reason, the Detector Control System is logically arranged to map the hierarchical organization of the ATLAS detector. Special requirements are placed onto the ATLAS Detector Control System because of the large number of distributed I/O channels and of the inaccessibility of the equipment during operation. Standardization is a crucial issue for the design and implementation of the control system because of the large variety of e...

A Nuclear Physics Program at the ATLAS Experiment at the CERN Large Hadron Collider

CERN Document Server

Aronson, S H; Gordon, H; Leite, M; Le Vine, M J; Nevski, P; Takai, H; White, S; Cole, B; Nagle, J L

2002-01-01

The ATLAS collaboration has significant interest in the physics of ultra-relativistic heavy ion collisions. We submitted a Letter of Intent to the United States Department of Energy in March 2002. The following document is a slightly modified version of that LOI. More details are available at: http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/SM/ions

An ATLAS Virtual Visit connects physicists at the Town Square of Cracow and physicists of the LHC Experiment in the ATLAS control room; special participation of CERN's General Director, Rolf Heuer and the Director for Research and Scientific Computing, Sergio Bertolucci.

CERN Multimedia

2012-01-01

he 12 Festival of Science "Theory-knowledge-experience...". Fest will be located on the traditional Main Square, which is visited by thousands of citizens and tourists. The Institute of Nuclear Physics as usual participates in this annual event. Our visitors will learn the secrets of the CERN experiments on the Large Hadron Collider - ATLAS, LHCb, ALICE, CMS, find out more about the Higgs particles, antimatter quark-gluon plasma (beeing guided by our scientists and PhD students). One of the attractions will be ATLAS Control Room Virtual Visit. Visiting people will have an opportunity to see how ATLAS is controlled and operated to collect its exciting data and ask questions to scientists and engineers involved in LHC program at CERN. Institute of Nuclear Physics has prepared also several interactive demonstrations of Atomic Force Microscopy, Magnetic Resonance, Hadron Therapy and Crystal Physics.

Hermeticity control system for the BMS/BMF-MDT chambers of the muon spectrometer of ATLAS experiment

International Nuclear Information System (INIS)

Barashkov, A.V.; Glonti, G.L.; Gongadze, A.L.; Dedovich, D.V.; Demichev, M.A.; Zhemchugov, A.S.; Il'yushenko, E.N.; Korolevich, Ya.V.; Kruchonok, V.G.; Lomidze, D.D.; Nikolaev, K.V.; Kharchenko, D.V.; Tskhadadze, Eh.G.; Chepurnov, V.F.; Shelkov, G.A.; Shcherbakov, A.A.

2005-01-01

Description of hermeticity certification of the JINR made muon chambers for the ATLAS experiment is presented. A high precision stand was installed in the production area of the DLNP, JINR. The description of the stand and results of the measurements and the description and results of the second testing of the drift chambers carried out after transportation to CERN are presented

ATLAS DataFlow Infrastructure recent results from ATLAS cosmic and first-beam data-taking

CERN Document Server

Vandelli, W

2010-01-01

The ATLAS DataFlow infrastructure is responsible for the collection and conveyance of event data from the detector front-end electronics to the mass storage. Several optimized and multi-threaded applications fulfill this purpose operating over a multi-stage Gigabit Ethernet network which is the backbone of the ATLAS Trigger and Data Acquisition System. The system must be able to efficiently transport event-data with high reliability, while providing aggregated bandwidths larger than 5 GByte/s and coping with many thousands network connections. Nevertheless, routing and streaming capabilities and monitoring and data accounting functionalities are also fundamental requirements. During 2008, a few months of ATLAS cosmic data-taking and the first experience with the LHC beams provided an unprecedented testbed for the evaluation of the performance of the ATLAS DataFlow, in terms of functionality, robustness and stability. Besides, operating the system far from its design specifications helped in exercising its fle...

Social Media strategy for the ATLAS experiment

CERN Document Server

Nellist, Clara; The ATLAS collaboration

2016-01-01

The ATLAS collaboration uses various social media platforms to communicate the research and achievements of the collaboration to a wider public audience. The strategy to achieve this goal will be presented, with an analysis of the effectiveness as a function of certain factors. A specific focus on the social media approach during the LHC Run II time period in 2015 will be explored.

Physics potential of ATLAS detector with high luminosity

International Nuclear Information System (INIS)

Zhou, Bing

2004-01-01

The ATLAS detector is designed to exploit the full physics potential in the TeV energy region opened up by the Large Hadron Collider at a center of mass energy of 14 TeV with very high luminosities. The physics performance of the ATLAS detector on Higgs, extra-dimension and strong symmetry breaking scenario is summarized in this note. ATLAS experiment has great discovery potential for these new phenomena with high luminosity. Triple gauge couplings are very sensitive for probing new physics at TeV scale. We show that ATLAS can measure these couplings very precisely with high luminosity. (orig.)

Crustal thickness and velocity structure across the Moroccan Atlas from long offset wide-angle reflection seismic data: The SIMA experiment

Science.gov (United States)

Ayarza, P.; Carbonell, R.; Teixell, A.; Palomeras, I.; Martí, D.; Kchikach, A.; Harnafi, M.; Levander, A.; Gallart, J.; Arboleya, M. L.; Alcalde, J.; Fernández, M.; Charroud, M.; Amrhar, M.

2014-05-01

The crustal structure and topography of the Moho boundary beneath the Atlas Mountains of Morocco has been constrained by a controlled source, wide-angle seismic reflection transect: the SIMA experiment. This paper presents the first results of this project, consisting of an almost 700 km long, high-resolution seismic profile acquired from the Sahara craton across the High and the Middle Atlas and the Rif Mountains. The interpretation of this seismic data set is based on forward modeling by raytracing, and has resulted in a detailed crustal structure and velocity model for the Atlas Mountains. Results indicate that the High Atlas features a moderate crustal thickness, with the Moho located at a minimum depth of 35 km to the S and at around 31 km to the N, in the Middle Atlas. Upper crustal shortening is resolved at depth through a crustal root where the Saharan crust underthrusts the northern Moroccan crust. This feature defines a lower crust imbrication that, locally, places the Moho boundary at ˜40-41 km depth in the northern part of the High Atlas. The P-wave velocity model is characterized by relatively low velocities, mostly in the lower crust and upper mantle, when compared to other active orogens and continental regions. These low deep crustal velocities together with other geophysical observables such as conductivity estimates derived from MT measurements, moderate Bouguer gravity anomaly, high heat flow, and surface exposures of recent alkaline volcanism lead to a model where partial melts are currently emplaced at deep crustal levels and in the upper mantle. The resulting model supports the existence of a mantle upwelling as mechanism that would contribute significantly to sustain the High Atlas topography. However, the detailed Moho geometry deduced in this work should lead to a revision of the exact geometry and position of this mantle feature and will require new modeling efforts.

Optimizing the energy measurement of the ATLAS electromagnetic calorimeter

International Nuclear Information System (INIS)

Lampl, W.

2005-12-01

This PhD-thesis addresses the calibration of the ATLAS electromagnetic calorimeter. ATLAS is a high-energy physics experiment at the Large Hadron Collider (LHC) which is currently under construction at CERN in Geneva. LHC and ATLAS are foreseen to start up in 2007. In summer 2004, an extensive beam-test was carried out. This means that individual detector modules are exposed to a particle beam of known energy in order to verify the detector performance. At this occasion, all ATLAS subdetectors where operated together for the first time. The thesis contains a comprehensive description of the ATLAS electromagnetic calorimeter, the reconstruction software and the test-beam experiment that was carried out at CERN in 2004. Furthermore, the physics of the electromagnetic shower is discussed in detail. Data from the test beam as well as a detailed Monte-Carlo simulation are used to develop a novel energy-reconstruction method for the ATLAS EM calorimeter that achieves an excellent energy resolution (sampling term ∼ 11 %) as well as a very good linearity (< 0.4 %). Data taken during the beam test is also used to verify the accuracy of the simulation and to test the new energy-reconstruction method. (author)

Toolkit for data reduction to tuples for the ATLAS experiment

International Nuclear Information System (INIS)

Snyder, Scott; Krasznahorkay, Attila

2012-01-01

The final step in a HEP data-processing chain is usually to reduce the data to a ‘tuple’ form which can be efficiently read by interactive analysis tools such as ROOT. Often, this is implemented independently by each group analyzing the data, leading to duplicated effort and needless divergence in the format of the reduced data. ATLAS has implemented a common toolkit for performing this processing step. By using tools from this package, physics analysis groups can produce tuples customized for a particular analysis but which are still consistent in format and vocabulary with those produced by other physics groups. The package is designed so that almost all the code is independent of the specific form used to store the tuple. The code that does depend on this is grouped into a set of small backend packages. While the ROOT backend is the most used, backends also exist for HDF5 and for specialized databases. By now, the majority of ATLAS analyses rely on this package, and it is an important contributor to the ability of ATLAS to rapidly analyze physics data.

Overview of SUSY results from the ATLAS experiment

Directory of Open Access Journals (Sweden)

Federico Brazzale Simone

2014-04-01

Full Text Available The search for Supersymmetric extensions of the Standard Model (SUSY remains a hot topic in high energy phisycs in the light of the discovery of the Higgs boson with mass of 125 GeV. Supersymmetric particles can cancel out the quadratically-divergent loop corrections to the Higgs boson mass and can explain presence of Dark Matter in the Universe. Moreover, SUSY can unify the gauge couplings of the Standard Model at high energy scales. Under certain theoretical assumptions, some of the super-symmetric particles are preferred to be lighter than one TeV and their discovery can thus be accessible at the LHC. The recent results from searches for Supersymmetry with the ATLAS experiment which utilized up to 21 fb−1 of proton-proton collisions at a center of mass energy of 8 TeV are presented. These searches are focused on inclusive production of squarks and gluinos, on production of third generations squarks, and on electroweak production of charginos and neutralinos. Searches for long-lived particles and R-parity violation are also summarized in the document.

The ATLAS Tier-0 Overview and operational experience

CERN Document Server

Elsing, M; Nairz, A; Negri, G

2010-01-01

Within the ATLAS hierarchical, multi-tier computing infrastructure, the Tier-0 centre at CERN is mainly responsible for prompt processing of the raw data coming from the online DAQ system, to archive the raw and derived data on tape, to register the data with the relevant catalogues and to distribute them to the associated Tier-1 centers. The Tier-0 is already fully functional. It has been successfully participating in all cosmic and commissioning data taking since May 2007, and was ramped up to its foreseen full size, performance and throughput for the cosmic (and short single-beam) run periods between July and October 2008. Data and work flows for collision data taking were exercised in several "Full Dress Rehearsals" (FDRs) in the course of 2008. The transition from an expert to a shifter-based system was successfully established in July 2008. This article will give an overview of the Tier-0 system, its data and work flows, and operations model. It will review the operational experience gained in cosmic, c...

Resistive Micromegas for the Muon Spectrometer Upgrade of the ATLAS Experiment

CERN Document Server

Iodice, Mauro; The ATLAS collaboration

2016-01-01

Large size resistive Micromegas detectors will be employed for the first time in high-energy physics experiments for the Muon Spectrometer upgrade of the ATLAS experiment at CERN. The current innermost stations of the muon endcap system, the Small Wheel, will be upgraded in 2019 to retain the good precision tracking and trigger capabilities in the high background environment expected with the upcoming luminosity increase of the LHC. Along with the small-strip Thin Gap Chambers (sTGC) the “New Small Wheel” will be equipped with eight layers of Micromegas (MM) detectors arranged in multilayers of two quadruplets, for a total of about 1200 m$^2$ detection planes. All quadruplets have trapezoidal shapes with surface areas between 2 and 3 m$^2$. The Micromegas system will provide both trigger and tracking capabilities. In order to achieve a 15% transverse momentum resolution for 1 TeV muons, a challenging mechanical precision is required in the construction for each plane of the assembled modules, with an alig...

Reconstruction of photon conversions in {tau} lepton decays in the ATLAS experiment

Energy Technology Data Exchange (ETDEWEB)

Boehler, Michael

2009-04-15

The ATLAS experiment is one of the experiments at the Large Hadron Collider (LHC) which is designed for the search of new elementary particles. To discover the Higgs boson or precisely measure SUSY scenarios, {tau} lepton final states are very powerful decay channels. Therefore the {tau} lepton decay modes have to be identified correctly. Due to interactions between photons from hadronic decay products of the {tau} lepton and detector material electron-positron pairs (photon conversions) may be produced. These lead to additional charged tracks changing the reconstructed {tau} lepton track multiplicity. To avoid such missidentifications, this thesis introduces an explicit photon conversion identification in the very dense {tau} lepton decay environment. Existing tools had to be modified and a new electron identification method has been developed especially for this task. As a first result, the corrected {tau} lepton track multiplicity is presented. (orig.)

Reconstruction of photon conversions in τ lepton decays in the ATLAS experiment

International Nuclear Information System (INIS)

Boehler, Michael

2009-04-01

The ATLAS experiment is one of the experiments at the Large Hadron Collider (LHC) which is designed for the search of new elementary particles. To discover the Higgs boson or precisely measure SUSY scenarios, τ lepton final states are very powerful decay channels. Therefore the τ lepton decay modes have to be identified correctly. Due to interactions between photons from hadronic decay products of the τ lepton and detector material electron-positron pairs (photon conversions) may be produced. These lead to additional charged tracks changing the reconstructed τ lepton track multiplicity. To avoid such missidentifications, this thesis introduces an explicit photon conversion identification in the very dense τ lepton decay environment. Existing tools had to be modified and a new electron identification method has been developed especially for this task. As a first result, the corrected τ lepton track multiplicity is presented. (orig.)

Search for $B → \\mu^{+}\\mu^{−}$ Decays with the Full Run I Data of The ATLAS Experiment

CERN Document Server

AUTHOR|(SzGeCERN)655651; Vrba, Vaclav; Cerri, Alessandro; Palestini, Sandro

Rare $B_s$ and $B_d$ meson decays into two muons are forbidden at the tree level of the Standard Model. They offer the opportunity to perform genuine probes of Yukawa interactions or Electroweak precision tests and play very important role to find signatures of physics beyond the Standard Model. A brief insight into the theoretical foundations of these decays is given in the introductory section, followed by a section with the ATLAS experiment description, none of which is directly a result of author's own work. The ATLAS Collaboration has been searching for $B_{(s)}^0 \\to \\mu^{+}\\mu^{-}$ decays using merged 2011 $\\sqrt{s} = 7$ TeV and 2012 $\\sqrt{s} = 8$ TeV Full Run I Data sample ($\\approx 25~fb^{-1}$). The analysis procedure has been firmly established and unblinding of the search region of $B_{(s)}^0 \\to \\mu^{+}\\mu^{-}$ is imminent. A sensitivity of the analysis to the $B_s^0 \\to \\mu^{+}\\mu^{-}$ signal is estimated to be $4.7~\\pm~1.0~\\sigma$. The description of the whole ATLAS $B_{(s)}^0 \\to \\mu^{+}\\mu^{-...

The ATLAS Distributed Data Management project: Past and Future

CERN Document Server

Garonne, V; The ATLAS collaboration; Lassnig, M; Molfetas, A; Barisits, M; Beermann, T; Nairz, A; Goossens, L; Barreiro Megino, F; Serfon, C; Oleynik, D; Petrosyan, A

2012-01-01

ATLAS has recorded almost 8PB of RAW data since the LHC started running at the end of 2009. Many more derived data products and complimentary simulation data have also been produced by the collaboration and, in total, 90PB is currently stored in the Worldwide LHC Computing Grid by ATLAS. All this data is managed by the ATLAS Distributed Data Management system, called Don Quijote 2 (DQ2). DQ2 has evolved rapidly to help ATLAS Computing operations manage these large quantities of data across the many grid sites at which ATLAS runs, and to help ATLAS physicists get access to this data. In this paper, we describe new and improved DQ2 services, and the experience of data management operation in ATLAS computing, showing how these services enable the management of petabyte scale computing operations. We also present the concepts of the new version of the ATLAS Distributed Data Management (DDM) system, Rucio.

The ATLAS Distributed Data Management project: Past and Future

International Nuclear Information System (INIS)

Garonne, Vincent; Stewart, Graeme A; Lassnig, Mario; Molfetas, Angelos; Barisits, Martin; Beermann, Thomas; Nairz, Armin; Goossens, Luc; Barreiro Megino, Fernando; Serfon, Cedric; Oleynik, Danila; Petrosyan, Artem

2012-01-01

ATLAS has recorded more than 8 petabyte(PB) of RAW data since the LHC started running at the end of 2009. Many more derived data products and complimentary simulation data have also been produced by the collaboration and, in total, 90PB are currently stored in the Worldwide LHC Computing Grid by ATLAS. All these data are managed by the ATLAS Distributed Data Management system, called Don Quijote 2 (DQ2). DQ2 has evolved rapidly to help ATLAS Computing operations manage these large quantities of data across the many grid sites at which ATLAS runs, and to help ATLAS physicists get access to these data. In this paper, we describe new and improved DQ2 services, and the experience of data management operation in ATLAS computing, showing how these services enable the management of PB scale computing operations. We also present the concepts of the new version of the ATLAS Distributed Data Management (DDM) system, Rucio.

The ATLAS Distributed Data Management project: Past and Future

Science.gov (United States)

Garonne, Vincent; Stewart, Graeme A.; Lassnig, Mario; Molfetas, Angelos; Barisits, Martin; Beermann, Thomas; Nairz, Armin; Goossens, Luc; Barreiro Megino, Fernando; Serfon, Cedric; Oleynik, Danila; Petrosyan, Artem

2012-12-01

ATLAS has recorded more than 8 petabyte(PB) of RAW data since the LHC started running at the end of 2009. Many more derived data products and complimentary simulation data have also been produced by the collaboration and, in total, 90PB are currently stored in the Worldwide LHC Computing Grid by ATLAS. All these data are managed by the ATLAS Distributed Data Management system, called Don Quijote 2 (DQ2). DQ2 has evolved rapidly to help ATLAS Computing operations manage these large quantities of data across the many grid sites at which ATLAS runs, and to help ATLAS physicists get access to these data. In this paper, we describe new and improved DQ2 services, and the experience of data management operation in ATLAS computing, showing how these services enable the management of PB scale computing operations. We also present the concepts of the new version of the ATLAS Distributed Data Management (DDM) system, Rucio.

Status of the uranium upgrade of ATLAS

International Nuclear Information System (INIS)

Bollinger, L.M.; Billquist, P.J.; Bogaty, J.M.; Clifft, B.E.; Markovich, P.; Munson, F.H.; Pardo, R.C.; Shepard, K.W.; Zinkann, G.P.

1991-01-01

The ATLAS Positive Ion Injector (PII) is designed to replace the tandem injector for the ATLAS heavy-ion facility. When the PII project is complete, ATLAS will be able to accelerate all ions through uranium to energies above the Coulomb barrier. PII consists of an ECR ion source on a 350 KV platform and a very low-velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .007c to .05c. the PII project is approximately 75% complete. Beam tests and experiments using the partially completed PII have demonstrated that the technical design goals are being met. The design, construction status, and results of recent operational experience using the PII will be discussed. 10 refs., 2 figs., 1 tab

Status of the uranium upgrade of ATLAS

Energy Technology Data Exchange (ETDEWEB)

Bollinger, L.M.; Billquist, P.J.; Bogaty, J.M.; Clifft, B.E.; Markovich, P.; Munson, F.H.; Pardo, R.C.; Shepard, K.W.; Zinkann, G.P.

1991-01-01

The ATLAS Positive Ion Injector (PII) is designed to replace the tandem injector for the ATLAS heavy-ion facility. When the PII project is complete, ATLAS will be able to accelerate all ions through uranium to energies above the Coulomb barrier. PII consists of an ECR ion source on a 350 KV platform and a very low-velocity superconducting linac. The linac is composed of an independently-phased array of superconducting four-gap interdigital resonators which accelerate over a velocity range of .007c to .05c. the PII project is approximately 75% complete. Beam tests and experiments using the partially completed PII have demonstrated that the technical design goals are being met. The design, construction status, and results of recent operational experience using the PII will be discussed. 10 refs., 2 figs., 1 tab.

Status of the AFP Project in ATLAS

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00224260; The ATLAS collaboration

2017-01-01

Status of the AFP project in the ATLAS experiment is given. In 2016 one arm of the AFP detector was installed and first data have been taken. In parallel with integration of the AFP subdetector into the ATLAS TDAQ nad DCS, beam tests and preparations for the installation of the 2nd arm are performed.

Glance traceability – Web system for equipment traceability and radiation monitoring for the ATLAS experiment

CERN Document Server

Ramos de Azevedo Evora, L H; Pommes, K; Galvão, K K; Maidantchik, C

2010-01-01

During the operation, maintenance, and dismantling periods of the ATLAS Experiment, the traceability of all detector equipment must be guaranteed for logistic and safety matters. The running of the Large Hadron Collider will expose the ATLAS detector to radiation. Therefore, CERN must follow specific regulations from both the French and Swiss authorities for equipment removal, transport, repair, and disposal. GLANCE Traceability, implemented in C++ and Java/Java3D, has been developed to fulfill the requirements. The system registers and associates each equipment part to either a functional position in the detector or a zone outside the underground area through a 3D graphical user interface. Radiation control of the equipment is performed using a radiation monitor connected to the system: the local background gets stored and the threshold is automatically calculated. The system classifies the equipment as non radioactive if its radiation dose does not exceed that limit value. History for both location traceabi...

The Education and Outreach Program of ATLAS

CERN Multimedia

Barnett, M.

2006-01-01

The ATLAS Education and Outreach (E&O) program began in 1997, but the advent of LHC has placed a new urgency in our efforts. Even a year away, we can feel the approaching impact of starting an experiment that could make revolutionary discoveries. The public and teachers are beginning to turn their attention our way, and the newsmedia are showing growing interest in ATLAS. When datataking begins, the interest will peak, and the demands on us are likely to be substantial. The collaboration is responding to this challenge in a number of ways. ATLAS management has begun consultation with experts. The official budget for the E&O group has been growing as have the contributions of many ATLAS institutions. The number of collaboration members joining these efforts has grown, and their time and effort is increasing. We are in ongoing consultation with the CERN Public Affairs Office, as well as the other LHC experiments and the European Particle Physics Outreach Group. The E&O group has expanded the scope...

ATLAS SemiConductor Tracker Operation and Performance

CERN Document Server

Tojo, J; The ATLAS collaboration

2011-01-01

The SemiConductor Tracker (SCT), comprising of silicon micro-strip detectors is one of the key precision tracking devices in the ATLAS Inner Detector. ATLAS is one of the experiments at CERN LHC. The completed SCT is in very good shapes with 99.3% of the SCT’s 4088 modules (a total of 6.3 million strips) are operational. The noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector, its performance and observed problems, with stress on the sensor and electronics performance. In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton-proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The Semi- Conductor Tracker (SCT) is the key precision tracking device in ATLAS, made from silicon micro-strip detectors processed in the planar p-in-n technology. The signals from the stri...

ATLAS Silicon Microstrip Tracker Operation and Performance

CERN Document Server

Yamada, M; The ATLAS collaboration

2011-01-01

The SemiConductor Tracker (SCT), comprising of silicon micro-strip detectors is one of the key precision tracking devices in the ATLAS Inner Detector. ATLAS is one of the experiments at CERN LHC. The completed SCT is in very good shapes with 99.3% of the SCT’s 4088 modules (a total of 6.3 million strips) are operational. The noise occupancy and hit efficiency exceed the design specifications. In the talk the current status of the SCT will be reviewed. We will report on the operation of the detector, its performance and observed problems, with stress on the sensor and electronics performance. In December 2009 the ATLAS experiment at the CERN Large Hadron Collider (LHC) recorded the first proton-proton collisions at a centre-of-mass energy of 900 GeV and this was followed by the unprecedented energy of 7 TeV in March 2010. The Semi-Conductor Tracker (SCT) is the key precision tracking device in ATLAS, made from silicon micro-strip detectors processed in the planar p-in-n technology. The signals from the strip...

Searching possibilities of a composite structure of quarks from the jet studies in the ATLAS experiment: physical and experimental aspects

International Nuclear Information System (INIS)

Brette, Ph.

1996-01-01

This thesis presents the searching possibilities of a composite structure of quark from the jet studies in the ATLAS experiment. ATLAS is one of the major detectors on the LHC, the next proton-proton collider at CERN. The general physic framework of the quark compositeness is first introduced, the its expected search from the contact terms in the channel 2 → 2 is explained. After a description of the ATLAS apparatus and of the prototype of the hadronic scintillating tiles calorimeter, various experimental properties of the hadron calorimeter with respect to the jet measurement are studied. The effect of the non-linearity of the calorimeter response is particularly discussed, including the light red out with the photomultipliers. The laser monitoring system enables a full control of the gain stability of the photomultipliers and of their non-linearity for large signals. Its design and the measured performance are shown. Finally, by considering both the expected performances of the ATLAS detector and the theoretical uncertainties, it appears that the compositeness scale controlled at the LHC, for quarks, should reach 15 to 20 TeV depending upon the luminosity, from jet measurement up to 3 TeV. (author)

Intelligent operations of the data acquisition system of the ATLAS experiment at the LHC

CERN Document Server

Anders, G; The ATLAS collaboration; Lehmann Miotto, G; Magnoni, L

2015-01-01

The ATLAS experiment at the Large Hadron Collider at CERN relies on a complex and highly distributed Trigger and Data Acquisition (TDAQ) system to gather and select particle collision data obtained at unprecedented energy and rates. The Run Control (RC) system is the component steering the data acquisition by starting and stopping processes and by carrying all data-taking elements through well-defined states in a coherent way. Taking into account all the lessons learnt during LHC’s Run 1, the RC has been completely re-designed and re-implemented during the LHC Long Shutdown 1 (LS1) phase. As a result of the new design, the RC is assisted by the Central Hint and Information Processor (CHIP) service that can be truly considered its “brain”. CHIP is an intelligent system able to supervise the ATLAS data taking, take operational decisions and handle abnormal conditions. In this paper the design, implementation and performances of the RC/CHIP system will be described. A particular emphasis will be put on the...

Intelligent operations of the data acquisition system of the ATLAS experiment at the LHC

CERN Document Server

Anders, G; The ATLAS collaboration; Lehmann Miotto, G; Magnoni, L

2014-01-01

The ATLAS experiment at the Large Hadron Collider at CERN relies on a complex and highly distributed Trigger and Data Acquisition (TDAQ) system to gather and select particle collision data obtained at unprecedented energy and rates. The TDAQ system is composed of a large number of hardware and software components (about 3000 machines and more than 15000 concurrent processes at the end of LHC’s Run 1) which in a coordinated manner provide the data-taking functionality of the overall system. The Run Control (RC) system is the component steering the data acquisition by starting and stopping processes and by carrying all data-taking elements through well-defined states in a coherent way (finite state machine pattern). The RC is organized as a hierarchical tree (run control tree) of run controllers following the functional de-composition into systems and sub-systems of the ATLAS detector. Given the size and complexity of the TDAQ system, errors and failures are bound to happen and must be dealt with. The data ac...

Social Media strategy for the ATLAS experiment

CERN Document Server

AUTHOR|(INSPIRE)INSPIRE-00304438; The ATLAS collaboration; Goldfarb, Steven; Shaw, Kate; Thais, Savannah Jennifer

2016-01-01

The ATLAS collaboration uses various social media platforms primarily as a method to communicate the research and achievements of the collaboration to a wider public audience. The strategy to achieve this goal is presented, with an analysis of the effectiveness as a function of certain factors. A specific focus on the social media approach during the LHC Run II time period in 2015 is explored.

Run 2 ATLAS Trigger and Detector Performance

CERN Document Server

Solovyanov, Oleg; The ATLAS collaboration

2018-01-01

The 2nd LHC run has started in June 2015 with a proton-proton centre-of-mass collision energy of 13 TeV. During the years 2016 and 2017, LHC delivered an unprecedented amount of luminosity under the ever-increasing challenging conditions in terms of peak luminosity, pile-up and trigger rates. In this talk, the LHC running conditions and the improvements made to the ATLAS experiment in the course of Run 2 will be discussed, and the latest ATLAS detector and ATLAS trigger performance results from the Run 2 will be presented.

Continuous Software Quality analysis for the ATLAS experiment