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Simulation Project Overview

Simulation Project Overview. Gabriele Cosmo, CERN/PH-SFT http://lcgapp.cern.ch/project/simu LCG-PEB Meeting November 30, 2004. Simulation Project. Simulation framework Interface to multiple simulation engines (Geant4, Fluka) and geometry models exchange Geant4 team participating

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Simulation Project Overview

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  1. Simulation Project Overview Gabriele Cosmo, CERN/PH-SFT http://lcgapp.cern.ch/project/simu LCG-PEB Meeting November 30, 2004

  2. Simulation Project • Simulation framework • Interface to multiple simulation engines (Geant4, Fluka) and geometry models exchange • Geant4 team participating • Aligned with and responding to needs from LHC experiments, physics validation, simulation framework • Fluka team participating • Framework integration, physics validation • Simulation physics validation subproject • Assess adequacy of simulation and physics environment for LHC and provide the feedback to drive needed improvements • Generator services subproject • Generator librarian; common event files; validation/test suite; development when needed (HEPMC, etc.) Witold Pokorski John Apostolakis Alfredo Ferrari Alberto Ribon Paolo Bartalini

  3. Project Organization Geant4 Project Fluka Project Experiment Validation MC4LHC Simulation Project Leader Subprojects Framework Geant4 Fluka integration Physics Validation Shower Param Generator Services WP WP WP WP WP Work packages WP WP WP WP WP WP WP WP

  4. Simulation Framework – General goals • Support the physics validation activities and test beam simulations • Provide flexible infrastructure for efficient development and for usage of detector simulation applications • Provide means for interchanging geometry descriptions between different applications • Provide flexible, LCG-oriented interfaces to simulation toolkits • Agreed approach: set up a simulation infrastructure based on Geant4 and Fluka via Flugg (which uses the Geant4 geometry) • Existing Geant4 benchmarks/simulation-validation setups can be run with Fluka with minimum effort • Idea of creating a generic framework for Geant4 and Fluka for full detector simulation setups abandoned due to lack of strong interest from the experiments (except for ALICE which has its own solution based on VMC) • Interest in having a common tool to be applied for specific physics validation studies • Geant4/Fluka physics validation will be treated on a case by case basis

  5. Simulation Framework – Status & plans • Complete Geant4+Fluka+Flugg setups to meet physics validation needs • First example of usage for test-beam validation studies provided (pixel detector simulation) • New use-case examples to be provided, together with proper documentation and guidelines. Expected removal of PEMF pre-processing stage in Fluka • Extensions to Flugg to meet the best achievable level of automation • Establish a persistent exchange format for geometry descriptions: GDML • Development motivated by several use-cases: • Debugging, visualization, XML-based, readability, low-overhead geometry exchange, … • Status after recent developments: • Schema complete enough to describe realistic geometries like the LHCb detector • The Geant4 reader/writer has been developed and tested on realistic (LHCb) geometries • Immediate plan: • Further extend the schema to support more complex geometries (ATLAS and CMS) • Short/Medium term: • Implement reader/writer for Root • Developed concrete milestones reflecting the program above • The program described makes maximum use of existing work • Manpower currently assigned to the project is just 0.5 FTEs !

  6. Simulation Framework – Longer Term • Increasing interest from different experiments in Python-based frameworks (because of large flexibility) • LCG tools (LCGDict/PyLCGDict) provide excellent starting point for development/study of ‘pythonized’ simulation applications • First tests (creating LCGDict for Geant4 and running Geant4 via PyLCGDict) look very promising • Geant4 expressed interest in the Python technology • Require revision of public interfaces and classes exposure safety • LCG tools (Pool/Root) could also be applied as persistency mechanism • Simulation environment • Provide a working example of Python based (Geant4) simulation application using LCGDict and PyLCGDict • Investigate the possibility of using LCG persistency framework also for geometry descriptions

  7. Geant4 in production • Three LHC experiments (ATLAS, CMS, LHCb) now using it successfully in production • OSCAR (CMS), Gauss (LHCb) and ATLAS’s Geant4-based simulation programs are the production tools • OSCAR and Gauss have replaced G3 based simulation • Substantial productions (numbers from Oct 20th Application Area Meeting presentations) • ATLAS DC2 (summer 2004) produced 12M events • Oscar (CMS) : 35 M pp interaction events, and first 100 Pb-Pb events • Gauss (LHCb): Over 200 M events simulated • In production use demonstrated low crash rate (and decreasing with new releases) • Rate decreasing from 1/10K events (5.2, CMS) to 1 per Million events (6.1, LHCb) • G4 team addressed issues found in test productions • The Geant4 LCG/SI sub-project and the Geant4 Collaboration • LCG/SI/G4 responsible for CERN/LHC participation in Geant4 • Work plan integrated with overall Geant4 plan • Geometry and tracking in field, Physics: hadronic and electromagnetic, testing and release, coordination • Collaborating closely on validation, infrastructure and robustness • With Physics Valid. on validation, and with Framework on geometry exchange • Worked on shared infrastructure (testing, portal) with SPI: bonsai, Savannah • With experiment simulation and physics teams on robustness, integration and validation

  8. Geant4: 2004 goals • Feb 2004 – Savannah/SPI prototype portal for problem reporting system for Geant4 • Prototype and assessment delivered; under evaluation in the Geant4 Collaboration • Mar 2004 - Release 6.1 (Contributions in several areas) • focused on improving production usage in LCG experiments • Jun 2004 – Scheduled release 6.2 (Contributions) • focused on better use of computing resources, including performance and memory use, and refinements to specific physics models, persistency and windows support • Sep 2004 - Development release • included additional geometry volume registration, refinements to physics models • supported CLHEP 1.9, and still compatible with CLHEP 1.8 • Oct 2004 - First consolidated acceptance suite for LHC applications • Suite of simplified test-beam setups created, and being deployed • Dec 2004 - Release 7.0 (Contributions) • Release 7.0 contributions focus on improvement of physics models and additional geometry functionality • Dec 2004 - Prototypes & Process Improvements • prototype 3D string fragmentation; ensure maintenance and improve examples, system tests and physics lists • Dec 2004 - Geant4 validation in LHC production (added May 2004) • documenting results, response to feedback, status of production use of Geant4

  9. Geant4: 2004 highlights • Geant4 reliability in production: crash rate low and decreasing • CMS (Geant4 5.2, 1 crash per 10,000 events) • ATLAS (Geant4 6.0 patch1, ~1 crash per 1 Million events) • LHCb (Geant4 6.1, ~1-2 crashes per 1 Million events) • Support and maintenance • Addressing issues found in LHC experiment production • providing high job ‘robustness’ (less than ~1 per mille job failures in 6.1, 6.2) • Code improvements to help identify problem conditions • In hadronics and geometry (Geant4, releases 6.0 & 6.1) • Creation of ‘statistical testing’ suite • Automated physics comparisons in simple test-beam-like setups • Being deployed for validation of release 7.0 (December 2004) • Requires significant computer resources • New and improved physics models • And improvements in EM & hadronics (Geant4, releases 6.1 & 6.2) • Refinements & more functionality in kernel • E.g. enabling experiments to easily construct detectors • Reflections, divisions, … • New fast shower capability (a-la GFLASH) • Integrating efforts in LHC experiments into Geant4 toolkit • New addition, just scheduled for Geant4, release 7.0

  10. Geant4: potential future goals • Provide continued support and maintenance • Address queries on physics, geometry, tracking issues • Solve problems and respond to other issues / reports • Sustain existing physics use cases and enable emerging LHC-related uses • Enhance physics • Address requirements for sub-1% EM stability and precision • Address precision needs for combined calorimetry in full detector simul. / LHC exp. • Address issues of pre-calibration using Monte Carlo (ATLAS) • Further enable use of radiation studies, addressing needs for data and physics lists • Improve and extend ‘automated’ release validation • Extend and refine comparisons • Within available computing resources • Address requirements for geometry and improved persistency • Improvements to Boolean solids, to address robustness issues • Enable exchange format (GDML) and ‘direct’ persistency (POOL/ROOT) for Geant4 • Address new requirements for radiation applications • Improve ‘standard’ tallying and extend with additional observables • Continue to improve CPU performance • Address hot spots identified in 2004 and bring new tools into use

  11. Geant4: manpower in 2004 • Effort currently • 9.0 FTE from Staff/ Associates /Fellows • ~1.0 visitors • Expertise and effort are required to address ‘expert’ inquiries • Need to maintain expertise • Balance between support/maintenance and development • Increased effort on support and maintenance • New requirements necessitate refinements & developments. • Continuity of effort depends • On the expected continued availability of associates & fellows. Move of 0.25 FTEs to simulation project leadership pushed some geometry deliverables to 2005

  12. Fluka Integration • Fluka is  an official joint CERN-INFN project since January 2004 • Fluka development is not an LCG activity • Participation involves • Integration of Fluka as a simulation engine in the simulation framework with FLUGG • Physics validation • Working with the physics validation subproject – simple benchmarks, test beam (manpower issues !) • Activity is led by Alfredo Ferrari • Fluka source code public at CERN by end of 2004

  13. Fluka Integration Current developments • Physics • Heavy ions transport and interactions • DPMJET-III interfacedone • Electromagnetic Dissociationdone • Special effects in heavy ion Coulomb interactions in progress • Development of QMD models in progress • Fragmentation • Code structure and user interface (pre-condition for the full release)in progress • Integration of PEMF functionalities in the run time code • Name-oriented advanced input interface • General clean-up • Publication of code documentation as CERN yellow report Man power issues • Physics developments: covered by A.Ferrari and non-CERN collaborators OK • “Complex benchmarks” (test-beams): expertise support from FLUKA team, manpower must come from LCG ? • Code structure and user interface (release oriented) : CERN-AB manpower absorbed by urgent LHC tasks. CERN-PH ending soon critical Struggling to keep the December-January deadline for the public β release of the full code

  14. Physics Validation • Validation based mainly on • Comparisons with LHC detector test beam data • “Simple benchmarks”: thin targets, simple geometries • Coordinates a lot of work being done in the experiments, Geant4, Fluka • Foster cooperation, coherence, completeness • Output of the project • Certification that simulation packages are OK for LHC physics • Understanding strengths/weaknesses/uncertainties of Geant4, Fluka • Contributions to systematic errors of measurements • Recommended optimized physics lists • Simulation benchmark suite for acceptance and performance monitoring • Final report summarizing the work

  15. Physics Validation – Status • Geant4 electromagnetic physics validated at percent level • Simulation physics requirements revisited • First round of hadronic physics validation has been completed, with good results • For the observables, in the case of the simple benchmarks (pixels, neutron double differential, pion absorption) there is a reasonable agreement between data and both Geant4 and Fluka • For the calorimeter test-beams, Geant4 describes well the pion energy resolution, σ/E, and the ratio e/ • The shape of hadronic showers needs some improvement • LCG notes: 1. F.Gianotti et al., CERN-LCG-APP-2004-02 2. A.Ribon, CERN-LCG-APP-2004-09 3. F.Gianotti et al., CERN-LCG-APP-2004-10 4. W.Pokorski, to be released very soon • Monthly meetings presenting and coordinating experiment and project work • Information, results gathering on web page • See: http://lcgapp.cern.ch/project/simu/validation

  16. Physics Validation – Ongoing and Future Work • Validate precision of Geant4 electromagnetic physics at the permil level • More detailed studies of hadronic shower profiles, both at the simulation and experimental (test-beam data) level • Evaluate the possibility to study another simple benchmark, relevant to LHC, to validate both Geant4 and Fluka • Man power could be a problem here! • Complete validation for Fluka in the calorimeter test-beam validations (as it has been done for Geant4) • The adoption of FLUGG and strong interaction with the Simulation Framework project is required here • Geant4 studies of background radiation in the LHC caverns in progress • Will be soon compared with Fluka • Man-power: • People from the experiments are busy with the new test-beam data • From LCG: M. Gallas, W. Pokorski, A. Ribon • all of them involved in other activities! • First version of simulation test and benchmark suite delayed to end 2004 • Physics validation document delayed to June 2005

  17. Physics Validation Manpower • Witek Pokorski ~ 0.4 FTE • simple benchmarks and generic framework (general infrastructure supporting test beam physics validation) • Alberto Ribon ~ 0.5 FTE • project leader, test beam calorimeters with Fluka, simple benchmarks • Giuseppe Daquino (Geant4 team) ~ 0.75 FTE • radiation background simulation with Geant4 (biasing), background studies in the LHCb detector environment • Manuel Gallas Torreira ~ 0.75 FTE • ATLAS combined test-beam simulation • Total ~ 2.4 FTEs • ~ 1.5 FTEs currently shifted to experiments-specific validation activities • ~ 0.9 FTEs dedicated to simple benchmarks, test beam calorimeters and coordination !

  18. Hadronic interactions in ATLAS pixel test-beam A.Ribon LCG-APP-2004-09

  19. e/π ratio

  20. CMS longitudinal shower profile in HCAL for 100 GeV pions

  21. Generator Services • Goal: guarantee the generator support for LHC • WP1 - Generator services library (GENSER) • WP2 - Tuning and validation of event generators • WP3 - Common generator event files, event database (MCDB) • WP4 - Event format, interfaces and particle services • Oversight of MC4LHC • Project Leader: P.Bartalini (Florida). Most of the resources from LCG Russia. • Generator library – GENSER – progressing well • First “production-quality” version 1.0.0 expected for December • ATLAS uses GENSER in production, LHCb and CMS currently validating • Addresses LHC experimentalists and theorists both at CERN and in external laboratories • Supports many MC4LHC-mandated generators, including all first-priority ones • List as of mid-September - GENSER 0_2_0 release: HERWIG (P.Richardson), PYTHIA (T.Sjöstrand), HIJING (X.N. Wang), ISAJET (F.E. Paige), LHAPDF (M.Whalley), ALPGEN (M.Mangano), COMPHEP (A.Sherstnev), EVTGENLHC (P. Robbe), GLAUBER (V.Uzhinsky), FROZEN (PHOTOS, PDFLIB), 10 generators, different versions • In future, to come: CASCADE (H.Jung), DPMJET, MC@NLO, GRACE, MADGRAPH, NEXUS, PHOJET (Z.Was), SFM, TAUOLA, HERWIG++, PYTHIA 7, SHERPA (F.Krauss) • Internal MC4LHC review in March 2004 • Definition of a release policy and roles for the GENSER librarian (A. Pfeiffer, PH/SFT) • Involvement of A.Ribon (LCG) to help the project leader as ‘liaison’ person between MC authors and experiments.

  22. Generator Services - 2 • Tuning and validation of event generators • Advanced proposal for an event generator validation framework • Basic sanity check in standalone way in GENSER sub packages • Physics validation through JetWeb (UK collaboration) • Validation of ALPGEN and HIJING in collaboration with groups in Perugia and Dubna • Common event file production / event database • Event file database MCDB α-version deployed • Core software (MySQL, POOL, CASTOR (RFIO), …) supported by LCG Software Project Infrastructure • Web Interface with dedicated web server: http://mcdb.cern.ch • α version deployed, being extended to support most common browsers • Configuration and book-keeping tested at Fermilab and CMS • Identified production centers (Santander, Oviedo) • Leveraging existing CERN production infrastructure • Event formats and interfaces • HEPML as proposed meta-data format, based on XML for interfacing matrix element generators and showering/hadronization generators • HEPMC as interface between generators and MC simulators • Support the new OO MCs (ThePEG, PYTHIA 7, HERWIG++, SHERPA)

  23. Generator Services Oversight/Review • Review of the subproject conducted in March (M. Mangano chair and MC4LHC chair) with participation from experiment experts and many leading generator authors • Review report end of April with clear elements • Project is delivering what the experiments need • GENSER in production in ATLAS, under validation in CMS and LHCb • Manpower issues to be addressed • Stability in project leader: P.Bartalini (now University of Florida) • Librarian positions: A.Pfeiffer LCG librarian for GENSER and defined release policy • Communication with the generator providers • A.Ribon as ‘liaison’ person between MC authors and experiments • Primary role of Russian collaborators in the “assembly” process of features to be included in sub-packages

  24. Generator Services 2004 (and beyond) Milestones • Jan 2004 – Proposal for MCDB deployment in the LCG environment • Feb 2004 – LHAPDF generator included in generator library • Mar 2004 – Agreed format for event-level generator files • Apr 2004 – COMPHEP, ALPGEN and EVTGEN in GENSER • Jun 2004 – Proposal for generator event production environment • Jul 2004 – Beta version of MCDB in production • Jul 2004 – Proposal for an event generator validation framework • Sep 2004 – Agreement on parton-level event generator file format • Dec 2004 – Generator production framework β-release • Plan extends through 2005-2006 to reach complete, production versions of GENSER, MCDB, validation framework, etc. (in blue those not yet verified) • Mar 2005 - First C++ Monte Carlo fully integrated in GENSER • Jun 2005 - Generator level production framework "beta version 0_1_0" • Jun 2005 - First test of ThePEG and Evtgenlhc integration in Herwig++ • Sep 2005 - Production centre integrated in the grid-middleware • Sep 2005 - Integration of GENSER in JetWeb • Dec 2005 - Generator level production framework "release version 1_0_0" • Mar 2006 - MCDB Integration, experiment specific APIs and management of large files • Jun 2006 - Generator level validation framework beta version

  25. Generator Services – perspectives on required resources • Critical situation of resources for future developments in GENSER • Particularly concerning the new MC generators • Little resources available for the validation activity • Requiring MC experts ! • Long-term resources for user-support required • User-support expected to grow ! • IT-expert for maintenance, MC-expert for development • E.g. - FAQ for GENSER did not start for lack of resources … • See manpower tables for 2004 and estimation for 2005 in appendix

  26. Simulation Project Milestones • 2003/12: Geant4 release 6.0 • 2003/12: Simulation physics requirements revisited • 2003/12: Simulation framework prototype supporting G4 and FLUKA via FLUGG • 2003/12: Proposal for MCDB deployment in the LCG environment • 2004/2: LHAPDF generator included in generator library • 2004/2: First cycle of hadronic physics validation complete • 2004/2: SPI-G4 collaborative infrastructure pilot • 2004/3: Agreement on formats for event generator common samples • 2004/3: Detector description (GDML) proposal to PEB • 2004/03: Geant4 6.1 release - production improvements • 2004/4: COMPHEP, ALPGEN and EVTGEN generators included in GENSER • 2004/5: Review/prioritization of simple benchmarks for simulation physics validation • 2004/6: Proposal for generator event production environment • 2004/6: Geant4 6.2 release - resource usage refinements • 2004/7: Beta version of MCDB in production in the LCG environment • 2004/7: Proposal for an event generator validation framework • 2004/9: Agreement on parton-level event generator file format • 2004/9: Comparison of LHC calorimeters for EM shower development • 2004/10: Geant4 geometry volume registration customization • 2004/10:First consolidated G4 acceptance suite for LHC applications • 2004/12: Generator production framework, β-release • 2004/12: Geant4 physics model prototype concluded • 2004/12: Second iteration of hadronic physics validation complete • 2004/12: Simulation test and benchmark suite available • 2004/12: Geant4 7.0 release - physics models and geometry • 2004/12: Geant4 validation in LHC production • 2005/06: Final physics validation document complete

  27. Simulation Project Major Milestones • 2003/12: Simulation physics requirements revisited • 2003/12: Simulation framework prototype supporting G4 and FLUKA via FLUGG • 2004/2: First cycle of hadronic physics validation complete • 2004/2: SPI-G4 collaborative infrastructure pilot • 2004/3: Agreement on formats for event generator common samples • 2004/5: Review/prioritization of simple benchmarks for simulation physics validation • 2004/6: Geant4 6.2 release - resource usage refinements • 2004/7: Beta version of MCDB in production in the LCG environment • 2004/9: Agreement on parton-level event generator file format • 2004/9: Comparison of LHC calorimeters for EM shower development • 2004/10:First consolidated G4 acceptance suite for LHC applications • 2004/12: Generator production framework, β-release • 2004/12: Second iteration of hadronic physics validation complete • 2004/12: Simulation test and benchmark suite available • 2004/12: Geant4 7.0 release - physics models and geometry • 2004/12: Geant4 validation in LHC production • 2005/06: Final physics validation document complete

  28. Current simulation manpower As of Oct 1

  29. Simulation in the LHC experiments

  30. ALICE Courtesy of A.Morsch

  31. G3 transport G3 User Code G4 transport G4 VMC FLUKA transport FLUKA Reconstruction Virtual Geometrical Modeller Geometrical Modeller (TGeo) Visualisation ALICE – AliRoot Framework • TGeant3 • Currently used in production • TFluka • Implementation completed and interfaced to TGeo • Testing ongoing • TGeant4 • Implementation completed • Interfacing to TGeo planned • Using VMC (Virtual Monte-Carlo) • Plans for 2005 • Validation of the Geometrical Modeller (GM) with Geant3 and Fluka • Extension of the interface to Geant4 • Validation of the Geant4 interface • Validation of new AliRoot simulation with GM, including physics • Phasing out Geant3. • External Generators integrated into AliRoot • HIJING for underlying event simulation • PYTHIA: jets, heavy flavor

  32. ALICE – Physics Validation • Emphasis on simple (thin target) benchmark tests • Thin target benchmark tests represent the only direct way of physics validation • Calorimeter tests lead in the best case to a multi-parameter tuning of MC parameters, but not to a better understanding of the underlying physics • Benchmark tests started by ALICE and continued within the LCG simulation project • Test-beam simulation activities ongoing for ITS, TPC, HMPID • Problem of manpower • Support from LCG requested, but not obtained

  33. ALICE - Status of Simulation ProductionPhysics Data Challenge ‘04 • Test and validate the ALICE Offline computing model: • Produce and analyse ~10% of the data sample collected in a standard data-taking year • Use the entire (complicated) system: AliEn, AliROOT, LCG, Proof… • Dual purpose: test of the software and physics analysis of the produced data for the Alice PPR • Structure: • Logically divided in three phases: • Phase 1 - Production of underlying Pb+Pb events with different centralities (impact parameters) + production of p+p events • Phase 2 - Mixing of signal events with different physics content into the underlying Pb+Pb events (underlying events are reused several times) • Phase 3 – Distributed analysis

  34. ATLAS Courtesy of A.Rimoldi

  35. ATLAS - Status • A Geant4-based simulation suite for the ATLAS experiment is in place (and available to developers) since mid-’03 • Data Challenge phase-2 (summer 2004) • Geant4 -based, ~12M events (leap of faith) • Tests of the ATLAS computing model, distributed production • Running right now • Characteristics • Based on home-grown simulation infrastructure (FADS) • Interfaced to the ATLAS common framework (ATHENA) • Persistency based on POOL • Unified detector description scheme as in ATLAS (GeoModel) • Hand-coded geometries being phased out • ~5 millions of positioned volumes (~300K volume types) • All detectors described to a very high level of detail • Detector configuration chosen at run time • Detailed field map covering the whole detector • Primary numbers from NOVA/MySQL (now from Oracle) • UI currently provided by Geant4 (moving to python) • Several Physics Lists available at any time (QGSP_GN by default) • Very low tracking cuts for precise physics (20-30m in the calorimeters) • About 400Mbytes at run time • ~660secs for Ze+e-, ~770secs for SUSY events (PIV, 2.4Ghz) over the whole rapidity range ||6 • Heavy ions trial successfully done (few full events generated in |eta|<6 or 3.2

  36. ATLAS - Production setup • Physics validation programme helped debugging the sub-detectors in an independent way • 200 talks in a time span of 3 years • Sub-detector integration took several months (2003) • Make sure there are no overlaps and check detector layout • Move to new detector description scheme • Implement missing bits &pieces (services, dead material etc.) • Optimize performance • Running long tests since September 03 • Continuous monitoring helps maintaining the program functional • Set up production environment in the meantime • Currently running Geant4 6.2 for development work and CTB simulation

  37. ATLAS - DC2 production • Slowed down by instability of the production tools • GRID middleware? • Simulation part completed • 12M events • Exceptional Geant4 performance and robustness • Only two jobs crashed b/c of Geant4 problems ! • log file examination pending … • NorduGrid sample (3.5M events) completed with no job failure ! • 35K jobs ! • 1M Ze+e- events without any problem ! • Continuing now with further tests (Tier-0 production…) which are not relevant to Geant4

  38. ATLAS - Future plans • Production for the ATLAS CTB (ongoing) • Continuous production (starting in December) for the physics community • Physics Workshop in Rome, May ’05 • Commissioning • DC-3 • ATLAS “initial” layout • “GeoModel-ization” of the LAr calorimeters • Implementation of missing bits (shielding, support structures…) • Python • General refurbishing

  39. CMS Courtesy of A. De Roeck

  40. CMS - OSCAR • In CMS, OSCAR, the OO simulation program based on the Geant4 toolkit, has successfully replaced its Fortran/Geant3 predecessor. It has been validated and adopted by all CMS detector and physics groups. It has proven robust and performant, easily extensible and configurable • Complete CMS geometry: 1M geometrical volumes • 35M pp interaction events produced • Time ~ 200 sec/event at 2.8 GHz CPU (High ET QCD events) • First 100 PbPb heavy ion events • CMS has now entered sustained-mode production: • 10M physics events/month through the full chain (simulation, digitization, …, DSTs) • OSCAR 3.6.0 released now with G4.6.2 p1 • new validation phase (new field map, new forward detectors, new G4 version, many improvements…) Deploy for mass production next month • Continuing validation of G4 physics (EM+HAD) and performance optimization important. CMS participates in this common effort

  41. OSCAR/G4: Performance • CPU time of OSCAR 2.4.5 (with Geant4 5.2 p2) is 2xGEANT3 time, but • much more sophisticated cut/region scheme • more conservative cuts than for CMSIM • more detailed physics in G4 • improvements implemented by G4 team, and by CMS through more optimized access to/use of the (new) magnetic field. • we have now a 20-30% better performance of OSCAR 3.6.0 (with G4.6.2 p1) compared to the version 2.4.5. So now we are at 1.5 x GEANT3; effort is continuing • Memory usage in OSCAR 2.4.5: 220 MB OSCAR vs 100 MB GEANT3 simulation. • further optimization led to ~110 Mb/event for pp (>500 Mb/event for HI) • Crashes occurred with 2.4.5: about 1/10000 for pp events. Mostly hadronic physics (baryon decays, -nuclear intertactions) • latest stress test (800K single particles, 300K full QCD events) showed no single crash ! Many thanks to G4 for help!

  42. CMS – LCG projects • Other LCG projects • GENSER being validated, plan to deploy early 2005 • Use FLUKA via FLUGG if PRS groups in CMS require it • Validation: participate with new 2004 HCAL and ECAL testbeam data (beam energies down to 2 GeV, longitudinal readout) • Future • Production of additional O(100K) events with OSCAR for physics TDR

  43. Validation of the Physics in OSCAR Validation of G4 physics in the context of the LCG study group So far: Comparisons of hadronic test beam data with models in G4 Also: Comparison of EM physics with test beam data CERN-LCG-2004-10 Generally QGSP model adequate Studies of energy resolutions, e/ ratios, and shower profiles

  44. Physics Events with OSCAR SUSY events (LM4 point: leptons, missing ET) View of 180 Higgs ZZevent simulated in CMS Tracker detector Samples of “standard sets” of events now automatically produced for each new release

  45. Ultimate test: Heavy-Ion Collisions • CMSIM: chop event in slices of 100 tracks, run them separately • Needed due to limitations in CMSIM • OSCAR/Geant4 can run full events. • Timing is good/Memory > 500 Mbyte (2GB memory machines used) • Have now run 100 events without problems ~ Timing for the first event with 55K generator tracks The first CMS PbPb event with OSCAR/G4

  46. LHCb Courtesy of G.Corti

  47. LHCb - Simulation status • Gauss, the “new” Gaudi/Geant4 based simulation application has been put in production this year • main simulation engine • has replaced Geant3 based simulation for overall simulation to mimic what will happen in the spectrometer and understand experimental conditions and performance • integrates two independent phases: 1. generation of proton-proton collisions and decays of b hadrons 2. tracking of particles in the detector and interactions with the material production of “hits" when particles cross sensitive detectors • makes use of simulation external engines via dedicated interfaces and services • Pythia, EvtGen, HepMC, Geant4 • based on LHCb Gaudi framework, EventModel and Detector Description • Digitization performed by Boole a different application • Dedicated background studies also performed with FLUKA

  48. LHCb - Gauss status • Gauss is fully operational • complete • all detectors simulated • all information needed in later processing provided • stable • low crash rate, reasonable CPU time • good collaboration with Geant4 team to achieve this ( various iteration before frozen version for DC04 ) • validated as replacement of Geant3 simulation with detailed comparisons • under continuous validation with test beam data to tune physics settings • work in different sub-detectors at different paces based on their needs and data (RICH, ECAL,…) • collaboration with LCG physics validation project • also to use Geant4 for radiation studies

  49. LHCb - Gauss in production (May – August) 186 M Produced Events Phase 1 Completed 3-5 106/day LCG restarted LCG paused Still producing data Geant4 version 6.1 In each job 3 or 4 sets of 500 events produced with Gauss LCG in action 1.8 106/day Data produced in ~ 60 different sites

  50. LHCb - Simulation developments & plans - 1 • Data produced with Gauss in DC04 will be intensively scrutinized in the coming months by many physicists • allow to understand, improve the simulation, fix bugs, identify new needs • Ongoing developments • Validating GENSER as provider of generator libraries • need to be “stable” for use in production • collaborating for LHC version of EvtGen • Adopting and validating new versions of Geant4 as they are available • provide feed back and new requirements to Geant4 • try out new relevant features • Physics validation (tuning) with test beam analysis • RICH, ECAL test beams just completed, analysis in progress

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