Abstract
In 2009, the Large Hadron Collider at CERN will collide protons with a center of mass energy of 14 TeV. ATLAS is a general purpose experiment that will allow to explore the wide potential of discovery and achieve high precision measurements. The ATLAS liquid argon calorimeters are presented, with an emphasis on their in situ commissioning using cosmic muons and their response during the first LHC single beam runs on September 2008.
Highlights
In 2009, the Large Hadron Collider at CERN will collide protons with a center of mass energy of 14 TeV
Since summer 2006, cosmic muons data are regurlaly taken in order to check the functionning of the calorimeters, commission trigger and data acquisition systems, and to provide in situ performance measurements[3]
Response to first LHC beams In September 2008, a 450 GeV beam circulated in the Large Hadron Collider; despite the absence of collisions, the presence of collimators located in the LHC beam line at 140 meters from the ATLAS interaction point produced large showers of particles and induced sizable energy deposits in the liquid argon (LAr) calorimeters
Summary
Since summer 2006, cosmic muons data are regurlaly taken in order to check the functionning of the calorimeters, commission trigger and data acquisition systems, and to provide in situ performance measurements[3]. As minimum ionizing particles, deposit few hundred of MeV on average in the electromagnetic calorimeter. On figure 3, are represented the variation of the fitted most probable value (MPV) of the Landau distribution as function of the pseudo rapidity for both the data and Monte Carlo simulation. Monte Carlo describes correctly the relative variation observed in the data, due to the variation of interaction lengths, an overall energy difference of 3% is observed. This difference is lower than the systematic uncertainty on the Monte Carlo energy normalization estimated around 5%. The discrepancy in the range 600ns-750ns is explained by a small variation of the liquid argon gap size, but it does not affect the energy reconstruction, that only uses the peak region (here between 150ns and 250ns)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
