Speaker
Summary
The high granularity of the ATLAS calorimeter and the large
number of expected
particles per event require a clustering algorithm that is able
to suppress
noise and pile-up efficiently. Therefore the topo cluster
reconstruction is the
essential first step in the hadronic calibration. The
identification of
electromagnetic components within a hadronic cluster using
cluster shape
variables is the next step in the hadronic calibration procedure.
Finally the
energy density of individual cells is used to assign the proper
weight to
correct for the invisible energy deposits of hadrons due to the
non-compensating
nature of the ATLAS calorimeter and to correct for energy losses
in material non
instrumented with read-out.
The weighting scheme employs the energy density in individual
cells. Therefore
the validation of the MC simulation, which is used to define the
weighting
parameters and energy correction algorithms, is an essential step
in the
hadronic calibration procedure.
Pion data, obtained in a beam test corresponding to the
pseudorapidity region
$2.5<|\eta|<4.0$ in ATLAS and in the energy range $E \le
200~\GeV$, have been
compared with MC simulations, using the full ATLAS hadronic
calibration
procedure.
