16,690 research outputs found
System Test of the ATLAS Muon Spectrometer in the H8 Beam at the CERN SPS
An extensive system test of the ATLAS muon spectrometer has been performed in
the H8 beam line at the CERN SPS during the last four years. This spectrometer
will use pressurized Monitored Drift Tube (MDT) chambers and Cathode Strip
Chambers (CSC) for precision tracking, Resistive Plate Chambers (RPCs) for
triggering in the barrel and Thin Gap Chambers (TGCs) for triggering in the
end-cap region. The test set-up emulates one projective tower of the barrel
(six MDT chambers and six RPCs) and one end-cap octant (six MDT chambers, A CSC
and three TGCs). The barrel and end-cap stands have also been equipped with
optical alignment systems, aiming at a relative positioning of the precision
chambers in each tower to 30-40 micrometers. In addition to the performance of
the detectors and the alignment scheme, many other systems aspects of the ATLAS
muon spectrometer have been tested and validated with this setup, such as the
mechanical detector integration and installation, the detector control system,
the data acquisition, high level trigger software and off-line event
reconstruction. Measurements with muon energies ranging from 20 to 300 GeV have
allowed measuring the trigger and tracking performance of this set-up, in a
configuration very similar to the final spectrometer. A special bunched muon
beam with 25 ns bunch spacing, emulating the LHC bunch structure, has been used
to study the timing resolution and bunch identification performance of the
trigger chambers. The ATLAS first-level trigger chain has been operated with
muon trigger signals for the first time
ATLAS RPC Quality Assurance results at INFN Lecce
The main results of the quality assurance tests performed on the Resistive
Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are
reported and discussed.
Since July 2004, about 270 RPC units has been certified at INFN Lecce site
and delivered to CERN, for being integrated in the final muon station of the
ATLAS barrel region.
We show the key RPC characteristics which qualify the performance of this
detector technology as muon trigger chamber in the harsh LHC enviroments.
These are dark current, chamber efficiency, noise rate, gas volume
tomography, and gas leakage.Comment: Comments: 6 pages, 1 table, 9 figures Proceedings of XXV Physics in
Collision-Prague, Czech Republic, 6-9 July 200
Commissioning of the ATLAS Muon Trigger System with early data
An overview of the early results on commissioning and performance of the ATLAS Muon Trigger System is shown. The ATLAS Muon Trigger has been designed to cope with the high interaction rate expected at the LHC. The presented
performance studies have been obtained using both cosmic-ray and 900GeV collision data
Commissioning of the ATLAS Muon Trigger Selection
The performance of the three-level ATLAS muon trigger as evaluated by using
LHC data is presented. Events have been selected by using only the
hardware-based Level-1 trigger in order to commission and to subsequently
enable the (software-based) selections of the High Level Trigger. Studies
aiming at selecting prompt muons from J/{\psi} and at reducing non prompt muon
contamination have been performed. A brief overview on how the muon triggers
evolve with increasing luminosity is given.Comment: Proceedings of Hadron Collider Physics Symposium 2010, Toronto,
Ontario, Canada, 23 - 27 Aug 2010. 3 pages, 6 figure
A Measurement of the ATLAS Di-Muon Trigger Efficiency in Proton-Proton Collision at TeV
The B physics programme of the ATLAS experiment includes measurements of
production cross sections, searches for rare B-decay signatures which are
sensitive to new physics at the TeV energy scale and studies of CP violation
effects in B-events, such as and
. The key to the detection of these B
signals in ATLAS is to achieve a high trigger efficiency for low-
di-muon events, whilst keeping an acceptable trigger rate. ATLAS developed two
separate approaches for triggering on di-muon events from resonances such as
and Upsilon (). The first approach is to start from a
di-muon trigger selected at Level-1 while the second is based on dedicated
Level-2 algorithms. The performance for these triggers has been studied using
collision data at TeV collected in 2011.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 3 pages, 6 figur
Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √s=13 TeV
The ATLAS experiment at the Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m2. This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb-1 of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using Z boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC.publishedVersio
Performance of the ATLAS Trigger System in 2010
Proton–proton collisions at √s=7 TeV and heavy ion collisions at √sNN=276 TeV were produced by the LHC and recorded using the ATLAS experiment’s trigger system in 2010. The LHC is designed with a maximum bunch crossing rate of 40 MHz and the ATLAS trigger system is designed to record approximately 200 of these per second. The trigger system selects events by rapidly identifying signatures of muon, electron, photon, tau lepton, jet, and B meson candidates, as well as using global event signatures, such as missing transverse energy. An overview of the ATLAS trigger system, the evolution of the system during 2010 and the performance of the trigger system components and selections based on the 2010 collision data are shown. A brief outline of plans for the trigger system in 2011 is presented
Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √s = 13 TeV
The ATLAS experiment at the Large Hadron Collider (LHC) employs a trigger system consisting of a first-level hardware trigger (L1) and a software-based high-level trigger. The L1 muon trigger system selects muon candidates, assigns them to the correct LHC bunch crossing and classifies them into one of six transverse-momentum threshold classes. The L1 muon trigger system uses resistive-plate chambers (RPCs) to generate the muon-induced trigger signals in the central (barrel) region of the ATLAS detector. The ATLAS RPCs are arranged in six concentric layers and operate in a toroidal magnetic field with a bending power of 1.5 to 5.5 Tm. The RPC detector consists of about 3700 gas volumes with a total surface area of more than 4000 m^{2}. This paper reports on the performance of the RPC detector and L1 muon barrel trigger using 60.8 fb^{-1} of proton-proton collision data recorded by the ATLAS experiment in 2018 at a centre-of-mass energy of 13 TeV. Detector and trigger performance are studied using Z boson decays into a muon pair. Measurements of the RPC detector response, efficiency, and time resolution are reported. Measurements of the L1 muon barrel trigger efficiencies and rates are presented, along with measurements of the properties of the selected sample of muon candidates. Measurements of the RPC currents, counting rates and mean avalanche charge are performed using zero-bias collisions. Finally, RPC detector response and efficiency are studied at different high voltage and front-end discriminator threshold settings in order to extrapolate detector response to the higher luminosity expected for the High Luminosity LHC
ATLAS Muon Spectrometer
The muon spectrometer of the ATLAS experiment at the Large Hadron Collider (LHC) at CERN was designed to achieve a momentum resolution of better than 10% at 1 TeV. It consists of three superconducting air-core toroid magnets instrumented with three layers of precision drift chambers and dedicated fast trigger chambers. During the commissioning of the full ATLAS detector in the last year several 100 millions of events of cosmic ray data were recorded. We will report on the status and our experience with the muon precision tracking and trigger chambers, the level-1 trigger, and the spectrometer alignment. The global performance of the muon system will be discussed. The readiness of the ATLAS muon spectrometer for first collisions will be demonstrated
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