European Organization for Nuclear Research GDML “Geometry Description for GEANT4 and ROOT” by Daniele Francesco Kruse University of Rome “Tor Vergata”

Why GDML? A short answer and a summary of the following presentation Because we need a standard detector geometry description language ...a short answer Summary of the presentation Who uses GDML? How does it work? What is my job here at CERN? What have I done???

Geant4 REAL EVENT SIMULATION A toolkit to simulate the interactions of particles with matter REAL EVENT Particle collision inside the ATLAS detector SIMULATION Computer simulated collision using detector geometry and beam description in Geant4 Geant4 Why ? 1) Correctness of Design know if the detector design is good for what you want to discover 2) Correctness of Theory and Model compare your model with what you have in reality (correct theory?)

An Object-Oriented Data Analysis Framework ROOT An Object-Oriented Data Analysis Framework Analyse the enormous amount of data generated by LHC experiments - The Challenge - Simulation and Real Events Analyse data both during simulation and real experiments - The Geometry Package ROOT can also be used for simulation purposes if combined with other simulation software - Visualization Tools

GDML Geant4 ROOT GDML LHC Computing Grid (LCG) Applications Geometry Description Markup Language LHC Computing Grid (LCG) Applications Geant4 ROOT ... to provide a common geometry data exchange format GDML

Geometry Description Markup Language GDML Geometry Description Markup Language Define Materials <material name=“Oxygen” Z=“8”> <D value=“0.00143”> <atom value=“16.0”> </material> Define Solids <box name=“MyBox” x=“5” y=“10” z=“10”/> <tube name=“TheTube” rmin=“8” rmax=“9” z=“3”/> <sphere name=“Ball” rmin=“8” rmax=“9”/> Define Structure <volume name=“Detector”> <materialref=“Oxygen”> <solidref=“Ball”> </volume> (you can then put this volume in a mother volume)

The Binding with ROOT and Geant4 The Interface The Binding with ROOT and Geant4 Input GDML file R O T G D M L R O T G e a n t 4 C P G D M L Output GDML File

My job@CERN The Binding with ROOT and Geant4 The Geant4 – GDML Binding C++ (good performance) Support for the exportation of new solids Multiple GDML files support (input & output) Output formatting (element names) The ROOT – GDML Binding Python (flexible and easy to upgrade) Support for new complex solids (Xtru, Arb8, etc...) I/O System refinement

Work in progress... Things that are still on my agenda and will be ready soon... CPPGDML Core Extensions Add support for the <matrix> tag Add support for flow-control tags such as <loop> ROOT GDML Import Tuning Enhance performance GDML Schema Upgrade Refine solids’ definitions Add support for the <matrix> and <loop> tags

what was this all about? what have I done for CERN? Conclusions what was this all about? what have I done for CERN? 1) GDML is more flexible now because you can: - use many new kinds of solids in your geometry description - split huge geometry info into smaller GDML modular files 2) ROOT is now able to correctly and efficiently read/write GDML files 3) Geant4 and ROOT have now got a means to share their geometry information

That’s All Folks! Many Thanks to: Witold Pokorski (my supervisor) for his help and understanding during these 2 months My good Friends at CERN for the great times we had together and to All of You for your kind Attention...