The ATLAS detector at the LHC

The biggest existing multi-purpose particle detector, ATLAS, is now built and running at CERN. Details of the different subdetectors were presented, together with expected performance aspects. The performance achievements obtained during the two real data-taking periods of ATLAS, cosmics rays and single beam runs of the LHC in fall 2008, were outlined

Temperature Behaviour and Uniformity of SCT Barrels during Assembly and Reception Testing

This note presents temperature studies of the barrel SemiConductor Tracker (SCT) modules during the barrel assembly at Oxford University and the barrel reception at CERN. At Oxford, warm and/or cold tests have been performed on each of the four SCT barrels comprising a total of 2112 silicon strip modules. After macro-assembly, the barrels were shipped to CERN where reception tests took place before the inner detector integration phase. We present the temperature uniformity of the different barrels under changing operating conditions. Estimates of the errors contributing to the temperature measurements will be discussed. We introduce corrections for several systematic effects. We finally identify modules operating at higher temperatures and discuss possible reasons for their deteriorated thermal performance

Development and Characterisation of a Gas System and its Associated Slow-Control System for an ATLAS Small-Strip Thin Gap Chamber Testing Facility

A quality assurance and performance qualification laboratory was built at McGill University for the Canadian-made small-strip Thin Gap Chamber (sTGC) muon detectors produced for the 2019-2020 ATLAS experiment muon spectrometer upgrade. The facility uses cosmic rays as a muon source to ionise the quenching gas mixture of pentane and carbon dioxide flowing through the sTGC detector. A gas system was developed and characterised for this purpose, with a simple and efficient gas condenser design utilizing a Peltier thermoelectric cooler (TEC). The gas system was tested to provide the desired 45 vol% pentane concentration. For continuous operations, a state-machine system was implemented with alerting and remote monitoring features to run all cosmic-ray data-acquisition associated slow-control systems, such as high/low voltage, gas system and environmental monitoring, in a safe and continuous mode, even in the absence of an operator.Comment: 23 pages, LaTeX, 14 figures, 4 tables, proof corrections for Journal of Instrumentation (JINST), including corrected Fig. 8b

The Data Acquisition and Calibration System for the ATLAS Semiconductor Tracker

The SemiConductor Tracker (SCT) data acquisition (DAQ) system will calibrate, configure, and control the approximately six million front-end channels of the ATLAS silicon strip detector. It will provide a synchronized bunch-crossing clock to the front-end modules, communicate first-level triggers to the front-end chips, and transfer information about hit strips to the ATLAS high-level trigger system. The system has been used extensively for calibration and quality assurance during SCT barrel and endcap assembly and for performance confirmation tests after transport of the barrels and endcaps to CERN. Operating in data-taking mode, the DAQ has recorded nearly twenty million synchronously-triggered events during commissioning tests including almost a million cosmic ray triggered events. In this paper we describe the components of the data acquisition system, discuss its operation in calibration and data-taking modes and present some detector performance results from these tests

Searches for supersymmetry and exotics phenomena with the ATLAS detector

Searches for new physics beyond the Standard Model are performed using the p-p LHC data collected with the ATLAS detector in 2011 at 7 TeV and in 2012 at 8 TeV centre-of-mass energy. Various production modes for supersymmetric (SUSY) particles are considered: strong production of squarks and gluinos, weak production of sleptons and gauginos, R-parity violating decays and long-lived particles. No significant deviation from the Standard Model processes is observed and limits are set on different flavours of SUSY, such as cMSSM/mSUGRA, pMSSM, GMSB and AMSB. Searches for exotic models for BSM physics are performed, probing for a large variety of well-motivated models, such as heavy gauge resonances, excited fermions, extra-dimensions, exotic Higgs models and new quarks. As in the case of SUSY searches, no excess is observed above the SM background and limits are obtained for the models mentioned above. © 2013 IOP Publishing Ltd

Searches for electroweak production of supersymmetric charginos, neutralinos and sleptons with the ATLAS detector

Many supersymmetry models feature charginos, neutralinos and also sleptons with masses less than a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents results from searches for charginos, neutralinos and slepton production in final state events characterized by the presence of leptons, missing transverse momentum and possibly jets

Search for Supersymmetry and Exotic processes with the ATLAS detector

Slides to be presented at the International Workshop on Discovery Physics at the LHC, about Searches for SUSY and Exotics at the ATLAS experiment. Review of the latest results with 8 TeV data alongside important results from the 7 TeV analyses

The detector control system of the ATLAS SemiConductor Tracker during macro-assembly and integration

The ATLAS SemiConductor Tracker (SCT) is one of the largest existing semiconductor detectors. It is situated between the Pixel detector and the Transition Radiation Tracker at one of the four interaction points of the Large Hadron Collider (LHC). During 2006-2007 the detector was lowered into the ATLAS cavern and installed in its final position. For the assembly, integration and commissioning phase, a complete Detector Control System (DCS) was developed to ensure the safe operation of the tracker. This included control of the individual powering of the silicon modules, a bi-phase cooling system and various types of sensors monitoring the SCT environment and the surrounding test enclosure. The DCS software architecture, performance and operational experience will be presented in the view of a validation of the DCS for the final SCT installation and operation phase. © 2008 IOP Publishing Ltd and SISSA