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The Tile Calorimeter of the ATLAS detector
The ATLAS detector [5] is a general purpose detector
at the Large Hadron
collider of CERN. It spans a length of 42 m, a diameter of 25 m and weighs a
heavy 7000 tons. Proton bunches are accelerated within the 27 km long LHC
tunnels and two beams are sent towards each other, which collide at the
interaction point at the centre of the detector. Various
particl e fragments result
from the collisions and interact with the various detector layers.
The ATLAS detector contains four main components which each play a
significant role in reconstructing the original collision in order for new physics
to be probed. These are the inner detector, the calorimeters, the muon
spectrometer and the magnetic system. A schematic representation of the ATLAS
detector is shown in Figure 2-1.
Figure 2-1: A computer generated image of the ATLAS detector [ATLAS Experiment ©
2013 CERN]
The Inner Detector (ID) is situated closest to the beam pipe . It consists of three
sub-detectors;
the Pixel detector, the Semi-Conductor Tracker (SCT) and the
Transition Radiation Tracker (TRT), and is surrounded by a superconducting
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solenoid magnet which generates a 2 Tesla magnetic field. The ID is used for
measuring the tracks of charged particles that emerge from th e collisions. The
tracks are curved due to the influence
of the magnetic field , enabling their
momenta to be determined.
Surrounding the ID concentrically are the Electromagnetic Calorimeters and the
Tile Calorimeter, hadronic end-cap and forward calorimeters. The Calorimeters
are based on “Sampling Calorimeter” technologies and are used to measure the
energy of both charged and neutral particles. The calorimeters are designed to
contain all electromagnetic and hadronic
showers developing within them, and
only neutrinos and muons manage to exit from these layers.
The Muon spectrometer surrounds the calorimeters and operates within a
magnetic field generated by eight toroidal magnets. The Muon spectrometer
measures the tracks of muons as they are bent by th is magnetic field. Neutrino’s
pass through ATLAS undetected.
A schematic of how the different particles interact through a wedge in the ATLAS
detector is shown in Figure 2-2. A more detailed description of how each sublayer
works in order to detect or track particles is provided in Appendix A.
The interactions of the various particles,
resulting from the collision, with the
different detector layers generate a huge amount of data. The ATLAS detector
therefore incorporates a trigger and data acquisition (DAQ) system in order to
only record events containing physics potential. T his three level system uses
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