With the luminosity upgrade of the LHC machine (SLHC, Super-LHC), the Muon system of the ATLAS experiment at CERN will also need a detector upgrade in the highest rapidity region. MAMMA, Muon ATLAS ...Micromegas Activity, is an ongoing R&D activity with the aim to develop large detectors based on the bulk-Micromegas technology for use in the ATLAS Muon Spectrometer. Micromegas is a good potential candidate for the construction of large muon chambers that combine trigger and tracking capability and can sustain high particle rates expected at the SLHC. A medium size Micromegas prototype, in scale 1:10 of the final chambers, has been built and evaluated in the laboratory and in beam tests at CERN. Results from the analysis of test-beam data are presented. The results indicate that large size Micromegas is a viable candidate for ATLAS Muon upgrade
The ATLAS Muon Spectrometer is designed to provide efficient and precise stand-alone momentum measurement for muons of momentum up to O (1 TeV/c). The fluctuations of the muon energy loss in the ...material upstream of the Muon Spectrometer could deteriorate the physics performance, which requires the momentum to be determined at the interaction point. A method to account for this energy loss using the calorimeter information is presented. The method provides an estimate of the energy loss on an event-by-event basis thus reducing the statistical fluctuations. The improvement in the momentum resolution by the significant suppression of the non-Gaussian tails of the energy loss is demonstrated using simulated single muon data. The performance of the method on physics samples with muons in the final state is also briefly discussed.
A PMT-Block test bench Adragna, P.; Antonaki, A.; Boudagov, I. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2006, Letnik:
564, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The front-end electronics of the ATLAS hadronic calorimeter (Tile Cal) is housed in a unit, called
PMT-Block. The PMT-Block is a compact instrument comprising a light mixer, a PMT together with its ...divider and a
3-in-1 card, which provides shaping, amplification and integration for the signals. This instrument needs to be qualified before being assembled on the detector. A PMT-Block test bench has been developed for this purpose. This test bench is a system which allows fast, albeit accurate enough, measurements of the main properties of a complete PMT-Block. The system, both hardware and software, and the protocol used for the PMT-Blocks characterization are described in detail in this report. The results obtained in the test of about 10
000 PMT-Blocks needed for the instrumentation of the ATLAS (LHC-CERN) hadronic Tile Calorimeter are also reported.
We have measured the response of an array of ATLAS muon spectrometer drift tubes to fast neutrons, produced by a t(d,n)/sup 4/He reaction at the 5.5-MV TANDEM Van de Graaff accelerator of the ...National Centre of Scientific Research "Demokritos." The setup consisted of 24 drift tubes in a 6/spl times/4 arrangement. The neutron energy was 18.3 MeV. The anode wire voltage varied from 2200 to 2800 V. For a neutron flux of about 2.75 kHz/cm/sup 2/, the drift tube sensitivity to 18.3-MeV neutrons ranged from 0.031% to 0.606% for anode voltages between 2200 and 2800 V, respectively.
This paper describes the definition of maximum-likelihood equivalent estimators of the Trilinear Gauge Couplings which include detector effects. The asymptotic properties of these estimators as well ...as their unbiasedness and efficiency when dealing with finite statistical samples are demonstrated by Monte Carlo experimentation, using simulated events corresponding to the reaction
e
+
e
−→
q
q
̄
lν
at 172
GeV. Emphasis is given to the determination of the expected efficiencies in extracting the
α
W
φ
,
α
W and
α
B
φ
couplings from LEPII data, which in this particular case found to be close to the maximum possible.
This paper describes the use of weighted Monte Carlo events to accurately approximate integrals of functions of the experimentally measured kinematical vectors and their dependence on physical ...parameters. This technique is demonstrated in estimating the evolution of cross-sections, efficiencies, measured kinematical distributions and mean values as functions of the Trilinear Gauge Couplings.
ATLAS (a toroidal LHC apparatus) is a general purpose experiment that will start its operation at the large hadron collider (LHC) at CERN in 2007. The ATLAS detector is designed to explore numerous ...physics processes by recording, measuring, and investigating the products emerging from proton-proton collisions at energies up to 14 TeV. High-precision muon momentum measurement (dp/p/spl sim/10% at p/sub T/=1 TeV/c) over large areas using monitored drift tube (MDT) chambers is crucial for the ATLAS experiment. More than 1200 MDT chambers, consisting of approximately 370 000 drift tubes, will provide a total coverage of 5500 m/sup 2/. Three Greek universities have taken the responsibility to construct 130 barrel inner small (BIS)-MDT chambers using 30 000 drift tubes of /spl sim/1.7 m length that have been quality tested before assembly. The design of the muon drift tubes aims at high detection efficiency (>95%) and a spatial single tube resolution of <80 /spl mu/m. This paper describes the cosmic ray test setup, which has been instrumented in order to verify that the BIS-MDT chamber Module-0 fulfills its design requirements. The analysis of its data shows that the chamber meets these requirements; it has low noise levels, uniform drift properties, good spatial resolution, and high particle detection efficiency.
The hadronic part of the electron structure function F2e has been measured for the first time, using e+e− data collected by the DELPHI experiment at LEP, at centre-of-mass energies of ...s=91.2–209.5 GeV. The data analysis is simpler than that of the measurement of the photon structure function. The electron structure function F2e data are compared to predictions of phenomenological models based on the photon structure function. It is shown that the contribution of large target photon virtualities is significant. The data presented can serve as a cross-check of the photon structure function F2γ analyses and help in refining existing parameterisations.
This paper describes two generalization schemes of the Optimal Variables technique in estimating simultaneously two Trilinear Gauge Couplings. The first is an iterative procedure to perform a ...two-dimensional fit using the linear terms of the expansion of the probability density function with respect to the corresponding couplings, whilst the second is a clustering method of probability distribution representation in five dimensions. The pair production of W's at 183
GeV center of mass energy, where one W decays leptonically and the other hadronically, was used to demonstrate the optimal properties of the proposed estimation techniques.
This paper describes the extension of the Modified Observables technique in estimating simultaneously more than one Trilinear Gauge Couplings. The optimal properties, unbiasedness and consistent ...error estimation of this method are demonstrated by Monte Carlo experimentation using lvjj four-fermion final state topologies. Emphasis is given in the determination of the expected sensitivities in estimating the
λ
γ−Δ
g
z
1 and Δ
k
γ−Δ
g
z
1 pair of couplings with data from the 183 GeV LEPII run.
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