Test of the first BIL tracking chamber for the ATLAS muon spectrometer Avolio, G.; Bagnaia, P.; Baroncelli, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2004, Volume:
523, Issue:
3
Journal Article
Peer reviewed
The first Barrel Inner Large chamber of the Monitored Drift Tube (MDT) tracking detector for the muon spectrometer of the ATLAS experiment has been tested with a high-energy muon beam. After a ...description of the MDT characteristics, we present the test beam experimental set-up, the data analysis techniques and discuss the results. The chamber was operated with a Ar(93%)–CO
2(7%) gas mixture at 3-bar pressure. The performance studies include the chamber calibration, the single-tube resolution, efficiency and electronic noise, and their behaviour as a function of the high-voltage setting and discriminator threshold.
The ATLAS trigger and data acquisition (TDAQ) is a distributed, multi trigger level, data-acquisition system, mostly made of off-the-shelf processing units organized in a farm. In its final ...configuration the system will account more than 2000 nodes, having heterogeneous capabilities and network connections, due to the TDAQ program for rolling expansions and upgrades. In this paper we present how we dealt with the farm heterogeneity during the proton-proton collisions of 2010 and 2011: a period characterized by changing working conditions, and constantly increasing LHC instantaneous luminosity. We describe a graphical tool to balance the computing-power and bandwidth sharing across the trigger farms, a data-flow monitoring daemon that provides high-level resource-aware data-flow operational information and the evolution of data-flow communication protocols.
A practical strategy is presented and successfully implemented to determine form factors in the time-like but unphysical (below threshold) region using dispersion relations, in a model independent ...way without any bias towards expected resonances. Space and time-like data have been employed along with a regularization scheme to unfold and solve the integral equations. Remarkably, resonance structures with peaks for the
ϱ(770),
ϱ′(1600) and a structure near the
N
N
threshold are automatically generated. The Φ peak is invisible thus refuting suggestions about any sizeable
s
s
content in the nucleon.
The ATLAS Muon Trigger "Slice" Sidoti, A.; Bellomo, M.; Biglietti, M. ...
IEEE transactions on nuclear science,
02/2008, Volume:
55, Issue:
1
Journal Article
Peer reviewed
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.
We have measured the cross section σ(e+e−→π+π−γ) at an energy W=mϕ=1.02 GeV with the KLOE detector at the electron–positron collider DAΦNE. From the dependence of the cross section on the invariant ...mass of the two-pion system, we extract σ(e+e−→π+π−) for the mass range 0.35<s<0.95 GeV2. From this result, we calculate the pion form factor and the hadronic contribution to the muon anomaly, aμ.
The QCAL tile calorimeter of KLOE Adinolfi, M; Ambrosino, F; Antonelli, M ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2002, Volume:
483, Issue:
3
Journal Article
Peer reviewed
The quadrupole tile calorimeters of KLOE (QCAL) are two compact detectors placed close to the interaction point and surrounding the focusing quadrupoles. Their purpose is to increase the hermeticity ...of KLOE calorimetry. Each QCAL consists of a sampling structure of lead plates and scintillator tiles with wavelength shifter (WLS) fibers and mesh photomultiplier readout arranged in 16 azimuthal sectors. The arrangement of WLS fibers allows the measurement of the longitudinal position of the showers from time of flight. In this paper we describe the QCAL design and assembly and present preliminary results obtained with both cosmic rays and photons from K
L decays. The time and energy calibration procedures are also discussed in detail.
We have measured the ratio Rϕ=BR(ϕ→η′γ)/BR(ϕ→ηγ) by looking for the radiative decays ϕ→η′γ and ϕ→ηγ into the final states π+π−7γ and 7γ, respectively, in a sample of ∼1.4×109ϕ mesons produced at the ...Frascati ϕ factory. We obtain Rϕ=(4.77±0.09stat±0.19syst)×10−3, from which we derive BR(ϕ→η′γ)=(6.20±0.11stat±0.25syst)×10−5. Assuming the η′ has zero gluonium content, we extract the pseudoscalar mixing angle in the quark-flavor basis, φP=(41.4±0.3stat±0.7syst±0.6th)°. Combining the value of Rϕ with other constraints, we estimate the fractional gluonium content of the η′ to be Z2=0.14±0.04 and the mixing angle to be φP=(39.7±0.7)°.
The ATLAS collaboration at CERN operated a combined test beam (CTB) from May until November 2004. The prototype of ATLAS data acquisition system (DAQ) was used to integrate other subsystems into a ...common CTB setup. Data were collected synchronously from all the ATLAS detectors, which represented nine different detector technologies. Electronics and software of the first level trigger were used to trigger the setup. Event selection algorithms of the high level trigger were integrated with the system and were tested with real detector data. The possibility to operate a remote Event Filter farm synchronized with the ATLAS Trigger and Data Acquisition System (TDAQ) was also tested. Event data, as well as detector conditions data, were made available for offline analysis
The KLOE electromagnetic calorimeter Adinolfi, M; Ambrosino, F; Antonelli, A ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2002, Volume:
482, Issue:
1-2
Journal Article
Peer reviewed
The KLOE detector was designed primarily for the study of CP violation in neutral kaon decays at DAΦNE, the Frascati φ-factory. The detector consists of a tracker and an electromagnetic calorimeter. ...A lead-scintillating-fiber sampling calorimeter satisfies best the requirements of the experiment, providing adequate energy resolution and superior timing accuracy. We describe in the following the construction of the calorimeter, its calibration and how the calorimeter information is used to obtain energy, point of entry and time of the arrival of photons, electrons and charged particles. With e+e− collision data at DAΦNE for an integrated luminosity of some 2pb−1 we find for electromagnetic showers, an energy resolution of 5.7%/E(GeV) and a time resolution of 54/E(GeV) ps. We also present a measurement of efficiency for low energy photons.
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