In order to face the challenging experimental conditions at the HL-LHC, the ATLAS detector will be equipped with new sets of both front-end and off-detector electronics and a new trigger and data ...acquisition system able to cope with the expected event rates and pile-up levels. The large number of detector channels, huge volumes of input and output data, short time available to process and transmit data, harsh radiation environment and the need of low power consumption, all impose great challenges on the design and operation of the electronic systems.
A module of the ATLAS electromagnetic barrel liquid argon calorimeter was exposed to the CERN electron test-beam at the H8 beam line upgraded for precision momentum measurement. The available ...energies of the electron beam ranged from 10 to 245
GeV. The electron beam impinged at one point corresponding to a pseudo-rapidity of
η
=
0.687
and an azimuthal angle of
φ
=
0.28
in the ATLAS coordinate system. A detailed study of several effects biasing the electron energy measurement allowed an energy reconstruction procedure to be developed that ensures a good linearity and a good resolution. Use is made of detailed Monte Carlo simulations based on GEANT4 which describe the longitudinal and transverse shower profiles as well as the energy distributions. For electron energies between 15 and 180
GeV the deviation of the measured incident electron energy over the beam energy is within 0.1%. The systematic uncertainty of the measurement is about 0.1% at low energies and negligible at high energies. The energy resolution is found to be about 10%
·
E
for the sampling term and about 0.2% for the local constant term.
Response uniformity of the ATLAS liquid argon electromagnetic calorimeter Aharrouche, M.; Colas, J.; Di Ciaccio, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2007, Letnik:
582, Številka:
2
Journal Article
Recenzirano
Odprti dostop
The construction of the ATLAS electromagnetic liquid argon calorimeter modules is completed and all the modules are assembled and inserted in the cryostats. During the production period four barrel ...and three endcap modules were exposed to test beams in order to assess their performance, ascertain the production quality and reproducibility, and to scrutinize the complete energy reconstruction chain from the readout and calibration electronics to the signal and energy reconstruction. It was also possible to check the full Monte Carlo simulation of the calorimeter. The analysis of the uniformity, resolution and extraction of constant term is presented. Typical non-uniformities of
5
‰
and typical global constant terms of
6
‰
are measured for the barrel and endcap modules.
In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the ...calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50–60
(
mrad
)
/
E
(
GeV
)
. The
π
0
rejection has been measured to be about 3.5 for 90% photon selection efficiency at
p
T
=
50
GeV
/
c
.
e–
π
separation studies have indicated that a pion fake rate of (0.07–0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40
GeV.
ATLAS B-physics performance Tartarelli, G.F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/1998, Letnik:
408, Številka:
1
Journal Article
Recenzirano
We review the ATLAS B-physics program to be performed at the LHC collider at CERN. By exploiting a multi-purpose detector and a flexible triggering system, the ATLAS Collaboration expects to take ...full advantage of the large LHC bb̄ cross section, especially during the first years of low-luminosity running. Simulation results are presented here for some of these studies, with particular focus on CP-violation results, B
s mixing and rare leptonic decays of B mesons.
The response of the ATLAS electromagnetic calorimeter to muons has been studied in this paper. Results on signal over noise ratio, assessment of the detector response uniformity, and position ...resolution are presented. The possibility to study fine details of the structure of the detector through its response to muons is illustrated on a specific example. Finally, the performance obtained on muons in test-beam is used to estimate the detector uniformity and time alignment precision that will be reachable after the commissioning of the ATLAS detector with cosmic rays.
The Phase-I trigger readout electronics upgrade of the ATLAS Liquid Argon calorimeters enhances the physics reach of the experiment during the upcoming operation at increasing Large Hadron Collider ...luminosities. The new system, installed during the second Large Hadron Collider Long Shutdown, increases the trigger readout granularity by up to a factor of ten as well as its precision and range. Consequently, the background rejection at trigger level is improved through enhanced filtering algorithms utilizing the additional information for topological discrimination of electromagnetic and hadronic shower shapes. This paper presents the final designs of the new electronic elements, their custom electronic devices, the procedures used to validate their proper functioning, and the performance achieved during the commissioning of this system.
During summer and fall 2004, the response of a full slice of the ATLAS barrel detector to different particles was studied in controlled beam. One module of the ATLAS liquid argon barrel ...calorimeter—identical to the production modules and read out by the final front-end and back-end electronics—was used for electromagnetic calorimetry. This paper presents and discusses the electron performance of the LAr barrel calorimeter, including linearity, uniformity, and resolution with different amounts of material upstream the calorimeter and energies ranging from 1 to 250
GeV.
The ATLAS Detector Control System Lantzsch, K; Arfaoui, S; Franz, S ...
Journal of physics. Conference series,
01/2012, Letnik:
396, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The ATLAS experiment is one of the multi-purpose experiments at the Large Hadron Collider (LHC) at CERN, constructed to study elementary particle interactions in collisions of high-energy proton ...beams. Twelve different sub detectors as well as the common experimental infrastructure are controlled and monitored by the Detector Control System (DCS) using a highly distributed system of 140 server machines running the industrial SCADA product PVSS. Higher level control system layers allow for automatic control procedures, efficient error recognition and handling, manage the communication with external systems such as the LHC controls, and provide a synchronization mechanism with the ATLAS data acquisition system. Different databases are used to store the online parameters of the experiment, replicate a subset used for physics reconstruction, and store the configuration parameters of the systems. This contribution describes the computing architecture and software tools to handle this complex and highly interconnected control system.
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