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Dear Federico Sforza,

The submission of your abstract has been successfully processed.

Abstract submitted: https://indico.cern.ch/userAbstracts.py?confId=192695.

Status of your abstract: https://indico.cern.ch/abstractDisplay.py?abstractId=34&confId=192695.

See below a detailed summary of your submitted abstract:

Conference: Tipp 2014 - Third International Conference on Technology and Instrumentation in Particle Physics

Submitted by: SFORZA, Federico

Submitted on: 24 January 2014 11:28

Title: Upgrade of the ATLAS muon spectrometer with the installation of new precision drift-tube chambers in 2014

Abstract content We present the 2014 upgrade of a section of the muon tracker with drift-tube chambers characterized by a new technology, with smaller tube diameter than the present Monitored Drift-Tube (MDT) chambers. Each new chamber is composed by eight layers of aluminum tubes with a diameter of 15 mm, against to the six layers of 30 mm aluminum tubes used in the corresponding ATLAS MDT chambers. The newly installed chambers allow a simple integration with the services systems, electronic and muon reconstruction software. Furthermore the compact geometry of the chambers allows the installation in problematic regions of the detector structure which are, at present, instrumented with only two MDT stations instead that three as in the optimal case. The new chambers will be installed in the elevator pit area used for access to the ATLAS detector. The instrumentation of this region is possible using a movable detector structure with alignment precise at the level of 30~$\mu m$ and integrated with the rest of the ATLAS muon spectrometer. The momentum resolution for 1~TeV muons will be improved by approximately $30$% in the newly instrumented detector regions.

Summary The 2013-2014 shutdown of the Large Hadron Collider (LHC) at CERN offers the opportunity to improve the performance of the ATLAS detector with the installation of new detector components. However the relatively short time window and the constraints due to the integration of the new components with the existing infrastructure limits the range of available solutions.

We present the upgrade of a section of the ATLAS muon tracker with drift-tube chambers characterized by a new technology, with smaller tube diameter than the present Monitored Drift-Tube (MDT) chambers. The proposed layout balances between maximizing the coverage with muon stations, the tight constraints of the integration with the present infrastructure, and the benefits of using the new stations for detector R&D.

Each new chamber is composed by eight layers of 78 aluminum tubes with a diameter of 15 mm, against to the six layers of 30 mm aluminum tubes used in the corresponding ATLAS MDT chambers. A gold-plated tungsten-rhenium anode wire is tensed at the center of the tubes and its position is known to better than 10~$\mu$m. The design remains fully compatible with the present services, read-out and trigger scheme but the more compact geometry of the chambers allows their installation in problematic regions of the detector structure. The presence of additional tube layers allows for redundancy in the track reconstruction and better noise rejection in the dense tracking environments expected in the future LHC run conditions.

Two new chambers will be installed in the ATLAS detector elevator shaft. This region, covering an area of $\Delta \eta \times\Delta\phi\approx 0.2\times 0.3$ and corresponding to 2% of the ATLAS barrel region, is used to access the inner part of the ATLAS detector and the ease of accessibility must be maintained. This additional challenge has been solved by installing the stations on movable supports and using an optical alignment system, precise at the level of 30~$\mu m$, integrated with the rest of the ATLAS muon spectrometer.

The upgrade will increase the area of the muon spectrometer instrumented with three layers of precision tracking chambers. This will improving the momentum resolution, for 1~TeV muons, by approximately $30$%. The newly installed chambers will also allow for test of the small drift-tube technology during the LHC Run II data taking, starting in 2015, so to prepare for the additional upgrades that will use this technology, planned for the ATLAS phase II.

Primary Authors: KORTNER, Oliver (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D) okortner@cern.ch KROHA, Hubert (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D) kroha@mppmu.mpg.de RICHTER, Robert (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D) robert.richter@cern.ch SCHWEGLER, Philipp (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D) philipp.schwegler@cern.ch SFORZA, Federico (Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut) (D) federico.sforza@cern.ch

Co-authors:

Abstract presenters: SFORZA, Federico

Track classification: Sensors: 1c) Gaseous Detectors Experiments: 2a) Experiments & Upgrades

Presentation type: --not specified--

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