Simulation Framework
and
XML Detector Description
for the
CMS Experiment
ARCE Pedro1,2, BANERJEE Sunanda3, BOCCALI Tomasso4, CASE Michael5, De ROECK
Albert2, LARA Vicente2, LIENDL Martin2,6, NIKITENKO Alexander7, SCHRODER
Matthias2, STRAESSNER Arno2, Van LINGEN Frank2, WELLISCH Hans-Peter2,
WENZEL Hans8
1CIEMAT, Madrid, Spain, 2CERN, Geneva, Switzerland, 3Tata Institute, Bombay, India,
4INFN Bari, Italy, 5UC Davis, USA, 6HEPHY, Vienna, Austria, 7Imperial College, UK,
8Fermilab, Chicago, USA
(for the CMS Collaboration)
ACAT 2002, Moscow, 23th June 2002
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
1
Outline
• GEANT4 simulation framework (OSCAR)
• OSCAR – IGUANA Visualisation
• OSCAR Physics comparison
• GEANT4 Performance comparison
• DDD scope
• Basic aspects and architecture
• Document structuring
• Summary
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
2
CMS Simulation & Reconstruction
CMSIM
CMSjet
Ntuple
ZebraFZ
CMSIM
Monte-Carlo generator
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
User Analysis
ORCA FAMOS
OODB
OSCAR FAMOS
OO world
RAN world
T
R
FO
User Analysis
Monte-Carlo generator
Pedro Arce(CERN/CIEMAT)
3
GEANT4 Simulation (OSCAR)
Geometry:
• All geometry up-to-date
• Currently moving to geometry in XML database, common to
Simulation/Reconstruction/Visualisation
• Detailed checking in progress
 CMS Overlap Detection Tool
GEANT4 expects:
(a) Daughters of the same mother must not intersect each other
(b) Daughters of the same mother must be fully contained in their mother
(c) some refinements of the above in case of replication and
parameterisation
If these conditions hold for every mother-volume and the first level of
daughters therein, the geometry is OK!
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
4
Shoot geantinos
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
5
View of CMS muon system
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Sliced view of CMS barrel detectors
Pedro Arce(CERN/CIEMAT)
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OSCAR
Primary generator:
• CMS particle gun:
• Scan in , , energy
• Random in , , energy
• Interface with HEPEVT ASCII files
• Interface with PYTHIA ntuples
Persistency:
• Hits
• Primary generator particles
• Selected tracks
• Using Objectivity, moving to ROOT
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
7
OSCAR - IGUANA
 Interactive visualisation is done with IGUANA (see poster in
this Conference)
• Visualise any GEANT4 Geometry
• Select by logical volumes / by individual copies / by category
• Show volume/object details/properties
• Picking, slicing
• GEANT4 command line
• A wizard to guide through OSCAR settings
• Integrated with overlap detection
• Adding other extensions is trivial (e.g. GUIs like overlap detection)
• Visualise Tracks
•Visualise magnetic field
• 2D plane that can be rotated
• Field direction as an arrow
• Field intensity as colour
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
8
OSCAR - IGUANA
Overlap detection
Example extension (a trivial wizard)
Queried from plug-in database, loaded on
request and bound to IGUANA G4 Run Manager
Control of arbitrary
GEANT4 tree
Correlated
Picking
IGUANA viewer displaying
OpenInventor scene
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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CMS magnetic field in IGUANA
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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OSCAR
Physics:
• Electromagnetic processes needed at LHC
• Hadronic processes needed at LHC
CMS Physics Technical Design Report is planned to be
written using OSCAR (due december 2004)
OSCAR milestone June 2003:
“Reproduce the physics results of the GEANT3 simulation
with the same performance”
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
11
GEANT4/GEANT3 simu. + ORCA reco.
CMS central tracker
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Single  events
Pedro Arce(CERN/CIEMAT)
12
GEANT4/GEANT3 simu. + ORCA reco.
CMS muon system
phi_sim - phi_rec
ACAT ’02
Single  events
eta_sim - eta_rec
CMS GEANT4 Sim. & Detector Desc.
Pt_sim - Pt_rec
Pedro Arce(CERN/CIEMAT)
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GEANT4/GEANT3 ECAL comparisons
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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OSCAR Time Performance
Full events in full CMS
> 10000 events without crashing
- H, tte, Z
- All CMS geometry
- 3D TOSCA magnetic field
- Production and tracking cuts as in CMSIM
- geant4.4.0.ref02
- Pentium III 850 Mhz, 640 Mb
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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No Tracks
H in all CMS (10 Events)
Initial track energy
- CMSIM (442828 tracks)
• OSCAR (427136 tracks)
No Tracks
MeV
Track length
- CMSIM (442828 tracks)
• OSCAR (427136 tracks)
MeV
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
16
Time performance
- H (10 events)
CMSIM: 439k tracks
OSCAR: 400k tracks
318 seconds
583 seconds (1.83)
- tte (10 events)
CMSIM: 1809k tracks
OSCAR: 1159k tracks
919 seconds
2125 seconds (2.31)
- Z (10 events)
CMSIM: 1105k tracks
OSCAR: 941k tracks
480 seconds
1240 seconds (2.58)
No GEANT4 optimization done yet!
ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
Pedro Arce(CERN/CIEMAT)
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ACAT ’02
CMS GEANT4 Sim. & Detector Desc.
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