1. Geant4 Simulation Fabrizio Bianchi University of Torino and INFN-Torino SuperB Computing Workshop Frascati, December 17 2008

2. What we have ? • A detailed Geant4 based simulation • Up to the GHit level (no digitization, no electronic response, no reconstruction) • Geometry description mainly from BaBar • Using GDML • Mainly used for machine background study

3. What we want • A detailed Geant4 based simulation including the electronic response and a full reconstruction of the digitization up to the particle candidate level • Require a computing model for SuperB • Something we need to think at • A long way to go • Difficult to deliver full set of tools on the TDR timescale

4. Recent Developments • Geometry Improvements & Bug Fixes • SVT, DCH, EMC End Cap, IFR • See talks in yesterday Detector Full Simulation session • New python based user interface • Simpler than standard G4 macros • Successfully re-implemented Bruno.cc in python • See talk by A. Di Simone

5. Steps on the TDR time scale • Goal is to deliver tools to support background studies and the detector design and optimization • Complementary role respect to fast simulation • Comes into play when fast simulation is not enough • More flexible geometry description • BaBar geometry is extremely detailed, but very difficult to change • Geometry of sub-detectors reused from BaBar is frozen • Should be easy to implement different options for new sub-detectors • Python interface to generate GDML geometry ? AS an alternative to hand writing of GDML files. • (Simplified) description of electronic response to generate digitization • Different electronic options to be considered • Digitization code from BaBar can only be a reference: need a simpler, more flexible tool. • Are digitization needed for the TDR ?

6. Short Term Developments • Should be available for the background study for Paris Workshop • New Interaction Region design • Monte Carlo Truth • Store list of particles entering a sub-detector • Store also the genealogy of particles entering a sub-detector • Useful for background studies

7. On a longer time scale • Interact with detector people • What infos do you need in GHits ? • Do you need digis for TDR • What kind of digis ? • Integration of sub-detectors geometry • Consistency fast-full simulation • Working environment for developers

8. Consistency between fast and detailed simulation • Need to enforce it • Geometry • A unique geometry description • Derive the simplified fast simulation geometry description from the detailed one • Some ideas around, but need to figure out details • B Field

9. Personnel issues