Hadron shower decomposition in a highly granular calorimeter
The spatial development of showers induced by positive hadrons with momenta 10-80 GeV in the highly granular CALICE scintillator-steel analogue hadronic calorimeter is analysed. The parametrisation of both longitudinal and radial shower profiles with the two- component functions are fit to the test beam data and simulations using the physics lists QGSP_BERT and FTFP_BERT from GEANT4 version 9.6 patch 01. The shower parameters, describing the longitudinal tail and radial halo, are in good agreement between data and simulations and are similar for pions and protons. For the longitudinal development, the most significant difference between data and simulations is in the relative containment of the separated components. For the radial development, the core slope parameter is underestimated by simulations. The physics list FTFP_BERT gives a very good description of proton showers in the studied energy range and gives better predictions of the pion shower development than QGSP_BERT.
Recent improvements on the description of hadronic interactions in Geant4
We present an overview of recent improvements of hadronic models in Geant4 for the physics configurations (Physics Lists) relevant to applications in high energy experiments. During last year the improvements have concentrated on the study of unphysical discontinuities in calorimeter observables in the transition regions between the models used in Physics Lists. The microscopic origin of these have been investigated, and possible improvements of Geant4 code are currently under validation. In this paper we discuss the status of the latest version of Geant4 with emphasis on the most promising new developments, namely the Fritiof based and CHIPS Physics Lists.
Status of Geant4 hadronic physics for the simulation of LHC experiments at the start of LHC physics program
In this short note we summarize the status of Geant4 hadronic physics for the simulation of LHC experiments, based on an extended physics validation program carried out in the last ten years. The data used come from thintarget published results and LHC test-beam set-ups with electron, pion and proton beams. No LHC collider data are yet utilized; rather, the expectations for the physics quality of Geant4 hadronic simulations for the first analyses at the start of the LHC physics program are discussed. Several physics lists are considered, for Geant4 versions 9.2 (used currently in ATLAS, CMS and LHCb simulations) and 9.3 (latest version, released in December 2009).