\section{Introduction}

% It shows very briefly how can we proceed to execute
%some basic things like the event generation, reconstruction and data
%analysis. For more details on how AliRoot works and how the experimental
%data can be analyzed, I strongly recommend to read the AliRoot primer~\cite{ALIROOT:doc}
%(the present document is not a substitute of the ``AliRoot primer''
%but an introduction for beginners), and also the AliEn pages~\cite{ALIEN:alien}
%or go directly to the code in~\cite{ALIROOT:svn}. 
%For detailed information on the EMCAL code you can go to the EMCAL offline pages (work in progress)~\cite{EMCAL:doc}.

%I will assume that you have already AliRoot and its environment properly
%installed in your machine, if not, look at \cite{ALIROOT:doc} or to the offline installation page \cite{ALIROOT:install}.
%If you type ``cd \$ALICE\_ROOT'', you will find all the AliRoot
%code. In the directories ``\$ALICE\_ROOT/macros'' and ``\$ALICE\_ROOT/EMCAL/macros'', you will find different examples of macros. All the EMCal
%code is in ``\$ALICE\_ROOT/EMCAL'', in case you want to study
%thoroughly how the simulation, reconstruction and analysis software
%code of the calorimeter work. 

%If we want to generate some data (realistic physics data or just single
%particle to study the performance of the ALICE detectors) or read
%real experimental data, and analyze it with AliRoot, we have to pass
%through three steps: \textbf{simulation}, \textbf{reconstruction}
%and \textbf{analysis}. This steps are explained in the next sections. 

This document is addressed to those who want to work with
EMCal software and the different tasks needed to have the data taken ready to be analyzed. It is divided in 2 blocks: a first one with the description of the procedures needed cook the data and a second one with the reconstruction and simulation offline code.

For a fast introduction on the code and how it works you can have a look to the EMCal for beginners guide \cite{EMCAL:beginners}. Some other interesting references are the AliRoot primer\cite{ALIROOT:doc} , the offline AliRoot page \cite{ALIROOT}, and the installation page from Dario Berzano \cite{ALIROOT:berzano}

\subsection{Mechanical description - Federico}

\subsection{How EMCal works - Terry}

EMCAL basic units are cells/towers (Pb-scintillator sandwich of about 70 layers). We have 12 SuperModules (4 in 2010, 10 in 2011-2012) composed of 24 (phi direction) x 48 (eta direction) cells (except last 2 SuperModules made of 8 cells in phi direction). Particles traversing the calorimeter, in particular photons and electrons, will deposit energy in different towers. The EMCAL reconstruction measures such energy per tower, forms clusters of cells produced by a given particle, and if possible matches them with particles detected by the tracking detectors in front of EMCAL (charged particles).
