Authors: Alexander Sharmazanashvili, Niko Tsutskiridze
Publisher: Proceedings of TMCE 2016, May 9-13, 2016, Aix-en-Provence, France, edited by I. Horváth, J.-P. Pernot, Z. Rusák
High Energy Physics (HEP) implements simulation for deep and wide range investigation of physics experiments by generating artificial events from the Monte-Carlo (MC) events generators in a format which is identical to the output of the facilities for experiment, detectors. However in some regions of detector data_vs_MC never match perfectly and there are discrepancies. Several reasons can cause it. Primary interest falling down on the investigations to understand how correct is detector representation in simulation. Simulation infrastructure implements GEANT for modelling of geometry. Shapes consistency and detalization is not important while adequateness of volumes and weight of detector components are essential for tracking. Geometry descriptions stored in database in general formats – XML, Oracle tables, etc. Then it is transforming in GEANT during the simulation. There are 2 main reasons of faults of geometry descriptions in simulation: 1/ Difference between simulated and as-built geometry descriptions 2/ Internal inaccuracies of geometry transformations added by simulation software infrastructure itself. For investigation of both reasons CATIA-GEANT interface was built. The aim was to use CATIA as a hub for collection of different geometry descriptions using by simulation and in same time make their comparison to find faults and analyse quality of GEANT simulation infrastructure. Paper represents results of analysis done for the ATLAS experiment at LHC – Large Hadron Collider, CERN, Geneva, Switzerland.