2,345 research outputs found
Performance of a First-Level Muon Trigger with High Momentum Resolution Based on the ATLAS MDT Chambers for HL-LHC
Highly selective first-level triggers are essential to exploit the full
physics potential of the ATLAS experiment at High-Luminosity LHC (HL-LHC). The
concept for a new muon trigger stage using the precision monitored drift tube
(MDT) chambers to significantly improve the selectivity of the first-level muon
trigger is presented. It is based on fast track reconstruction in all three
layers of the existing MDT chambers, made possible by an extension of the
first-level trigger latency to six microseconds and a new MDT read-out
electronics required for the higher overall trigger rates at the HL-LHC. Data
from -collisions at is used to study the
minimal muon transverse momentum resolution that can be obtained using the MDT
precision chambers, and to estimate the resolution and efficiency of the
MDT-based trigger. A resolution of better than is found in all sectors
under study. With this resolution, a first-level trigger with a threshold of
becomes fully efficient for muons with a transverse momentum
above in the barrel, and above in the
end-cap region.Comment: 6 pages, 11 figures; conference proceedings for IEEE NSS & MIC
conference, San Diego, 201
Precision Drift Chambers for the Atlas Muon Spectrometer
ATLAS is a detector under construction to explore the physics at the Large
Hadron Collider at CERN. It has a muon spectrometer with an excellent momentum
resolution of 3-10%, provided by three layers of precision monitored-drift-tube
chambers in a toroidal magnetic field. A single drift tube measures a track
point with a mean resolution close to 100 micron, even at the expected high
neutron and gamma background rates. The tubes are positioned within the chamber
with an accuracy of 20 microns, achieved by elaborate construction and assembly
monitoring procedures.Comment: 3 pages, 2 eps figures, Proceedings for poster at Physics in
Collisions Conference (PIC03), Zeuthen, Germany, June 2003. FRAP1
Large-Scale Production of Monitored Drift Tube Chambers for the ATLAS Muon Spectrometer
Precision drift tube chambers with a sense wire positioning accuracy of
better than 20 microns are under construction for the ATLAS muon spectrometer.
70% of the 88 large chambers for the outermost layer of the central part of the
spectrometer have been assembled. Measurements during chamber construction of
the positions of the sense wires and of the sensors for the optical alignment
monitoring system demonstrate that the requirements for the mechanical
precision of the chambers are fulfilled
Performance of the ATLAS Muon Drift-Tube Chambers at High Background Rates and in Magnetic Fields
The ATLAS muon spectrometer uses drift-tube chambers for precision tracking.
The performance of these chambers in the presence of magnetic field and high
radiation fluxes is studied in this article using test-beam data recorded in
the Gamma Irradiation Facility at CERN. The measurements are compared to
detailed predictions provided by the Garfield drift-chamber simulation
programme
Resolution and Efficiency of the ATLAS Muon Drift-Tube Chambers at High Background Rates
The resolution and efficiency of a precision drift-tube chamber for the ATLAS
muon spectrometer with final read-out electronics was tested at the Gamma
Irradiation Facility at CERN in a 100 GeV muon beam and at photon irradiation
rates of up to 990 Hz/square cm which corresponds to twice the highest
background rate expected in ATLAS. A silicon strip detector telescope was used
as external reference in the beam. The pulse-height measurement of the read-out
electronics was used to perform time-slewing corrections which lead to an
improvement of the average drift-tube resolution from 104 microns to 82 microns
without irradiation and from 128 microns to 108 microns at the maximum expected
rate. The measured drift-tube efficiency agrees with the expectation from the
dead time of the read-out electronics up to the maximum expected rate
Construction and Test of MDT Chambers for the ATLAS Muon Spectrometer
The Monitored Drift Tube (MDT) chambers for the muon spectrometer of the AT-
LAS detector at the Large Hadron Collider (LHC) consist of 3-4 layers of
pressurized drift tubes on either side of a space frame carrying an optical
monitoring system to correct for deformations. The full-scale prototype of a
large MDT chamber has been constructed with methods suitable for large-scale
production. X-ray measurements at CERN showed a positioning accuracy of the
sense wires in the chamber of better than the required 20 ?microns (rms). The
performance of the chamber was studied in a muon beam at CERN. Chamber
production for ATLAS now has started
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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