2,723 research outputs found
The First Year at LHC: Diffractive Physics
At the LHC, diffractive physics will be explored by the dedicated experiment
TOTEM whose Technical Design Report has been approved in Summer 2004. The
experimental programme will be carried out partly in TOTEM standalone mode for
purely forward phenomena like elastic scattering, and partly in collaboration
with CMS for processes requiring a full rapidity coverage. ATLAS and ALICE are
interested in diffraction for a later stage.
This article presents the TOTEM/CMS running scenario for diffractive physics
in the first year of LHC. We discuss which processes are within reach and with
which statistics they can be measured.Comment: 11 pages, 7 figures; proceedings of "Physics at LHC", July 2004,
Vienna; to be published in a supplement of the Czechoslovak Journal of
Physic
TOTEM: Prospects for Total Cross-Section and Luminosity Measurements
With the installation of the T1 telescope and the Roman Pot stations at 147 m
from IP5, the detector apparatus of the TOTEM experiment has been completed
during the technical stop in winter 2010/2011. After the commissioning of the
dedicated beam optics with beta* = 90 m, a first measurement of the total pp
cross-section sigma_tot and -- simultaneously -- the luminosity L will be
possible in the upcoming running season 2011. The precision envisaged is 3 %
and 4 % for sigma_tot and L, respectively. An ultimate beam optics
configuration with beta* ~ 1 km will later reduce the uncertainty to the 1 %
level.Comment: 4 pages, 4 figures; presented at the LHC Lumi Days: LHC Workshop on
LHC Luminosity Calibration, 13-14 January 2011, CERN, Geneva, Switzerland,
pp. 7-1
Estimation and analysis of the machine-induced background at the TOTEM roman pot detectors in the IR5 of the LHC
The problem of background generation in the experimental insertion IR5 of the LHC during machine operation in the dedicated TOTEM mode with low intensity beams and the specially designed β* = 1540 m optics is discussed. The sources of the machine-induced background in the IR5 forward physics areas are identified and their relative importance is evaluated. The results of the background simulation in the IR5 are presented, based on the most recent estimates of the residual gas density for TOTEM beam conditions. The methods for background analysis and rejection are explained
Performance of the ATLAS Precision Muon Chambers under LHC Operating Conditions
For the muon spectrometer of the ATLAS detector at the large hadron collider
(LHC), large drift chambers consisting of 6 to 8 layers of pressurized drift
tubes are used for precision tracking covering an active area of 5000 m2 in the
toroidal field of superconducting air core magnets. The chambers have to
provide a spatial resolution of 41 microns with Ar:CO2 (93:7) gas mixture at an
absolute pressure of 3 bar and gas gain of 2?104. The environment in which the
chambers will be operated is characterized by high neutron and background with
counting rates of up to 100 per square cm and second. The resolution and
efficiency of a chamber from the serial production for ATLAS has been
investigated in a 100 GeV muon beam at photon irradiation rates as expected
during LHC operation. A silicon strip detector telescope was used as external
reference in the beam. The spatial resolution of a chamber is degraded by 4 ?m
at the highest background rate. The detection efficiency of the drift tubes is
unchanged under irradiation. A tracking efficiency of 98% at the highest rates
has been demonstrated
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