Material Integration Service for the ATLAS Inner Detector

Due to the high rates at the LHC and subsequent design considerations, the material budget of the Inner Detector (ID) is substantial, in some places exceeding one radiation length. A description of the active DetectorElement and passive material (e.g., support structures, readout electronics, cooling infrastructure) is in Detector Description used by the Geant simulation. In order to perform track reconstruction properly, this same description should be drawn upon to provide information about material through which hypothetical particle trajectories traverse within the fiducial volume of the detector. In this note, we present a novel and configurable Material Integration Service (MIS) which accomplishes this by drawing upon the Geant4 detector description.