Particle showers in an imaging hadronic calorimeter

The CALICE collaboration has constructed highly granular electromagnetic and hadronic calorimeter prototypes to evaluate technologies for the use in detector systems at a future lepton collider. The hadronic calorimeter consists of 7608 small scintillator cells individually read out with Silicon Photomultipliers. In a combined CALICE test beam program the system has been operated successfully at DESY, CERN and FNAL since 2006 and represents the first large scale tests of these devices in high energy physics experiments. The unprecedented granularity of the detector provides detailed information of the properties of hadronic showers, which helps to constrain hadronic shower models through comparisons with model calculations. Longitudinal shower profiles and the substructure of the showers, compared to a variety of different shower models including decompositions into individual shower components are discussed.