Simulation Project Structure and tasks Simulation Project (G.Cosmo) Coordination Geant4 collaboration Geant4 (J.Apostolakis) LHC-oriented development and support of Geant4 toolkit Fluka (A.Ferrari) LHC-oriented development and support of Fluka FLUKA collaboration Garfield (R.Veenhof) Development, support and interfaces Experiments Validation Physics Validation & Simulation Framework (A.Ribon) Validation of the detector simulation MC engines Generator Services (A.Ribon, W.Pokorski from Feb-2010) Event generators repository, generator validation, HepMC MC4LHC LCG Simulation Project

LCG Generator Services GENSER Structure stable and used by experiments 26 generators installed (most with different versions) Autotools ready for all generators “bootstrap” script ready for building GENSER more easily and everywhere Completed migration to SLC5 Adopted HepMC Analysis Tool for regression testing based on distributions; evaluation of Rivet also for regression testing HepMC New release 2.06.00 in progress, expected in March Nightly builds for testing HepMC in preparation MCDB In use for CMS productions LCG Simulation Project

LCG Physics Validation Main effort to improve the transition between hadronic models in Geant4 Physics Lists with different transition regions: e.g. FTFP_BERT_TRV (as FTFP_BERT but with transition between Fritiof and Bertini between 6 – 8 GeV, instead of 4 – 5 GeV) New combinations of models: e.g. QGSP_FTFP_BERT (like QGSP_BERT, but with Fritiof replacing LEP, transition 6-8 GeV Improvement of Geant4 models (next text slide) Regular feedback from LHC test-beam analyses ATLAS HEC, ATLAS TileCal, CMS HCAL New validation results from CALICE test-beam Very granular calorimeter sensitive to details of hadronic showers LCG Simulation Project

LCG Simulation Project E. Garutti: LCG Phy. Val. meet. 10 June 2009 CALICE Preliminary LCG Simulation Project

Geant4 Hadronic Physics Progress (Release 9.3 – Dec 2009) Improvement of Fritiof-based FTF model Tuning for energies 3-8 GeV Added Reggeon cascade - as back-end Better matching with Bertini New CHIPS hadronic interaction (1st release) Use single model for all Energies => smooth response Improvement and parameter tuning underway Corrected internal cross sections in BERTini At energies below 1 GeV (SLAC Geant4 team) Retuned Multiple Scattering for e+/e- (optional) FTF: As a result the FTFP_BERT physics list now provides smooth energy-response, and agrees at low and high energies with the (best current) physics list QGSP_BERT – but does not have its unphysical dips In Bertini: The nucleon-nucleon and pion-nucleon partial cross-sections used in the Bertini cascade were reviewed and the incorrect cross-sections found below 1 GeV were fixed. This results in slightly improved agreement with data below 1 GeV. LCG Simulation Project

Geant4: Performance and Support Computing Performance Support and patching Reduced number of memory allocations In geometry, hadronics (reports of ATLAS, CMS) Reduced number of costly field calls Adapting stepper created by ATLAS Support for issues in LHC experiment productions patches Will provide patches for 9.2 until December 2010 Fixes Some CPU improvements LCG Simulation Project

Current LCG Simulation manpower As of Feb 2010 Geant4 6.70 (5.70) Infrastructure, performance, management (approx) 1.55 Electromagnetic / Hadronic Physics effort (approx) 4.40 (3.40) Geometry, tracking, biasing (approx) 0.75 CERN staff (3.50 -> 3.20), CERN fell./assoc./stud. (3.20 -> 2.50) Physics validation & Framework 1.00 (0.80) Validation specific to experiments 0.00 Generator services 2.40 management, documentation/release 0.30 GENSER dev., Validation, MCDB 2.10 Fluka Garfield (interface library to Geant4) 0.20 Management 0.25 Total   10.55 (9.35) 9.85 in July 2009 (x.xx) Manpower as of July 2010 LCG Simulation Project