b. The Tile Calorimeter The Tile Calorimeter is responsible for measuring the hadronic component for
energy reconstruction. It consists of a central barrel flanked by two extended
barrels, each containing 64 azimuthally distributed modules. Each module
contains a matrix of 4 mm thick steel plates with 3 mm thick tiles of plastic
scintillators sandwiched in between. The scintillators are coupled to wavelength
shifting optical fibers along two of their edges. These fibers are in t urn connected
to photo-multiplier tubes (PMT’s).
As a high energy hadron passes through the tile modules, it interacts with the
atomic nuclei of the steel absorber, to produce a shower of lower energy particles
(typically quarks and gluons). These particle showers then interact with the
scintillator tiles which absorb energy from the incoming particles and fluoresce
to emit light. This blue emitted light is absorbed by the fibers along the
scintillator edges and emitted at shifted wavelengths near the gree n region. The
PMT’s then detect the green shifted light and the signal is further processed with
readout electronics in order to digitize the data for analysis thereafter [9].
c. The Hadronic End-cap and Forward Calorimeters The hadronic end-caps (HEC) are situated in regions where stringent radiation
environments need to be sustained and therefore utilise liquid argon detectors.
They are housed along with the forward calorimeter (FCAL) and the EMEC in
cryostats. The HEC is composed of two wheels on either side of the detector,
each containing 32 modules composed of copper plates with gaps for the liquid
argon to flow through. The detector works with a similar concept to that of the
EM calorimeter.
