Geant4 Muon Digitization and Simulation in the ATHENA Framework

The aim of this note is to describe the Muon Digitization software packages, completely re-written to run in the Athena framework and to interface with the Geant4 Muon Spectrometer simulation. The Muon Digitization is the simulation of the Raw Data Objects (RDO), or the electronic output, of the Muon Spectrometer. It consists of two steps: in the first step, the output of the detector simulation, the Muon Hits, is converted to Muon Digits, namely intermediate objects that can be fed into the reconstruction. In the second step, the Muon Digits are converted into RDO, the transient representation of raw data byte stream. We describe the detailed implementation of the first step of the Muon Digitization, where the detector simulation output is â ﾜdigitizedâ into Muon Digits. We describe the fundamentals of the Muon Digitization algorithms, outlining their global structure and the infrastructure for the simulation of piled-up events. We also describe the details of the digitization validation procedures against the Monte Carlo information.