In order to ensure that the resistive plate chambers used in the ATLAS experiment will not show, during their operation, any abnormal aging effect which could degrade their performances, an aging ...test is being performed at X5-GIF, CERN's gamma irradiation facility. In this paper, the latest results are presented, together with an example of successful damage recovery technique.
The ATLAS RPC Level-1 muon trigger: design and simulation Carlino, G.; Conventi, F.; Bocci, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2004, Letnik:
533, Številka:
1-2
Journal Article
Recenzirano
The three-levels ATLAS trigger system has been designed to reduce the initial LHC interactions rate from 1GHz to ∼100Hz in order to allow permanent data storage. This result must be achieved ...preserving the less probable physics signals against a large background therefore providing a challenge task for the trigger and DAQ system. The Level-1 muon trigger in the barrel region of the Muon Spectrometer is provided by Resistive Plate Chambers (RPC) working in avalanche mode. More than 1000 RPC Units of different sizes will be installed covering a surface of about 3650m2 with a 350,000 readout channels. A detailed simulation of the Level-1 has been developed in order to optimize the trigger logic design and to study his performances. A description of the Level-1 trigger in the barrel and preliminary results of his performances will be presented.
Ageing test of the ATLAS RPCs at X5-GIF Aielli, G.; Alviggi, M.; Ammosov, V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2004, Letnik:
533, Številka:
1-2
Journal Article
Recenzirano
An ageing test of three ATLAS production RPC stations is in course at X5-GIF, the CERN irradiation facility. The chamber efficiencies are monitored using cosmic rays triggered by a scintillator ...hodoscope. Higher statistics measurements are made when the X5 muon beam is available. We report here the measurements of the efficiency versus operating voltage at different source intensities, up to a maximum counting rate of about 700Hz/cm2. We describe the performance of the chambers during the test up to an overall ageing of 4 ATLAS equivalent years corresponding to an integrated charge of 0.12C/cm2, including a safety factor of 5.
The proton-proton beam crossing at the LHC accelerator at CERN will have a rate of 40 MHz at the project luminosity. The ATLAS Trigger System has been designed in three levels in order to select only ...interesting physics events reducing from that rate of 40 MHz to the foreseen storage rate of about 200 Hz. The First Level reduces the output rate to about 100 kHz. The ATLAS Muon Spectrometer has been designed to perform stand-alone triggering and measurement of Muon transverse momentum up to 1 TeV/c with good resolution (from 3% at 10 GeV/c up to 10% at 1 TeV/c). In the Barrel region of the Muon Spectrometer the Level-1 trigger is given by means of three layers of resistive plate chamber detectors (RPC): a gaseous detector working in avalanche mode composed by two plates of high-resistivity bakelite and two orthogonal planes of read-out strips. The logic of the Level-1 barrel Muon trigger is based on the search of patterns of RPC hits in the three layers consistent with a high transverse momentum Muon track originated from the interaction vertex. The associated trigger electronics is based on dedicated processors, the Coincidence Matrix boards, performing space coincidences and time gates and providing the RPC readout as well. A detailed simulation of the ATLAS Experiment and of both 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 define the hardware set-up such as the cabling of both the trigger detectors and the trigger electronics modules. A description of both the Level-1 Muon Trigger system in the barrel and the RPC detectors, with their cosmic rays quality tests, will be presented together with the trigger performances and rates calculations evaluated for Muons over a wide range of p T and preliminary studies on the impact of accidental triggers due to low energy background particles in the experimental area
The ATLAS Muon Trigger "Slice" Sidoti, A.; Bellomo, M.; Biglietti, M. ...
IEEE transactions on nuclear science,
02/2008, Letnik:
55, Številka:
1
Journal Article
Recenzirano
The ATLAS experiment at the Large Hadron Collider (LHC) will face the challenge of selecting interesting candidate events in proton-proton collisions at 14 TeV center of mass energy, while rejecting ...the enormous number of background events. The trigger system architecture is organized in three levels. From a bunch crossing rate of 40 MHz, the First Level trigger, hardware implemented, will reduce this rate to around ~75 kHz. Then the software based High Level Trigger (HLT), composed by the Second Level Trigger and the Event Filter reduces the rate to 200 Hz. In this paper, we will present the implementation of the muon trigger ldquoslice,rdquo signal efficiencies, background rejection rates, and system performances (execution time, memory consumption, etc.) for online muon selection based on Monte Carlo simulations and results obtained on real events collected during cosmic data taking runs.
The trigger chambers of the ATLAS muon spectrometer: production and tests ALOISIO, A; ALVIGGI, M; BIGLIETTI, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2004, Letnik:
535, Številka:
1-2
Journal Article
Muon identification (MUID) and high-momentum measurement accuracy is crucial to fully exploit the physics potential that will be accessible with the ATLAS experiment at the LHC. The muon energy of ...physics interest ranges in a large interval from few GeV, where the b-physics studies dominate the physics program, up to the highest values that could indicate the presence of new physics. The muon detection system of the ATLAS detector is characterized by two high-precision tracking systems, namely the inner detector (ID) and the muon spectrometer, (MS) plus a thick calorimeter that ensures a safe hadron absorption filtering with high-purity muons with energy above 3 GeV. In order to combine the muon tracks reconstructed in the ID and the MS, a MUID object-oriented software package has been developed. The purpose of the MUID procedure is to associate tracks found in the MS with the corresponding ID track and calorimeter information in order to identify muons at their production vertex with optimum parameter resolution. The performance of these two combined systems has been evaluated with Monte Carlo studies using single muons of fixed-transverse momentum and with full physics events.
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 brief description of the Atlas Trigger, in particular of the Level-1 Muon Trigger in the barrel, and the results of the trigger simulation will be given.
The RPC detectors in the L3 experiment at LEP work as a trigger system for the Forward–Backward Muon Spectrometer. It consists of 192 bi-gap RPCs working in streamer mode. We monitored the behaviour ...of the system over seven years of data taking at LEP. To investigate the ageing of the RPCs after this long-term operation, we report the main results obtained from 1994 to 2000, together with the results of tests performed on some RPC chambers in our test site in Napoli with cosmic rays after the dismantling of L3.
Cosmic ray test station for ATLAS RPC Alviggi, M; Canale, V; Caprio, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2003, Letnik:
508, Številka:
1-2
Journal Article
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