Pion Showers in the CALICE AHCAL Prototype

In this note we present results from the data collected with the CALICE Analogue Hadronic Calorimeter (AHCAL) during the 2007 test beam at the CERN SPS. The data analyzed correspond to events collected using negative pion beams in the energy range 8 - 80 GeV. Detailed investigations of the shower properties in pion beam data are described and compared with results obtained with Geant 4 based Monte Carlo simulations. This is possible due to the high granularity of the scintillator-steel AHCAL prototype. The pion interaction length in the material mix of the AHCAL has been compared between simulations with several Geant 4 physics lists and measured data at different beam energies. A comparison between data and simulation in the longitudinal shower shape and the energy density is presented and the differences found are discussed.