CBM Simulation

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CBM SimulationAnalysis FrameworkCbmroot

• Mohammad Al-Turany Denis Bertini

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CBM Framework Features

• The same framework can be used for Simulation and
  Analysis
• Fully ROOT based
• VMC for simulation
• Geometry Modeller (TGeoManager) for geometry
  definition
• IO scheme (TChain, friend TTrees, TFolders ) for
  persistency
• TTask to organize analysis data flow
• Improved ROOT IO Combined Chaining Friend
  mechanism
• Completely configurable via ROOT macros
• Reuse of HADES Geometry Interface.
• Reuse of HADES Parameter containers.
• Easy to maintain (only ROOT standard services are
  used)
• Event merging before and/or after transport

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CBMROOT is based on The Virtual Monte Carlo (VMC)
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CBM Analysis and Simulation Framework
ROOT
Geant3
Geometry Manager
Virtual MC
Geant4
FLUKA
Magnet
Target
IO Manager
Run Manager
GeoInterface
PIPE
Primary Generator
Cave
Module
STS
Magnetic Field
Urqmd
Detector
Tasks
EVGEN
TRD
Pluto
TOF
Particle Generator
RICH
Delta
Tracking
ASCII
Field Map
digitizers
ECAL
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CBM Analysis and Simulation Framework
ROOT
ROOT FILES Input MC Points, Configuration Output
Hits, Digits, Tracks
Geometry Manager
Virtual MC
IO Manager
Run Manager
GeoInterface
Primary Generator
Module
Magnetic Field
Detector
Tasks
EVGEN
Delta
Tracking
digitizers
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HYDRA Geometry Interface, why ?

• Use the copy mechanism
• reduce the size of ASCII files
• Reduce the number of Volumes in Geant
• Improve Geant tracking performance
• Oracle interface
• Hades geometry table design reusable

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HYDRA Geometry Interface, why ?

• Advantage
• more flexibility different inputs can be used.
• closer to technical drawings and analysis
  coordinate systems
• Disadvantage
• more points than really needed for the basic
  shapes

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Material Geometry Interface

• Geometry/Material CBM
  Geometry TGeoManager
• input
  Builder Interface
• 
  

Oracle DB
CBM Geometry/Material TGeoVolume TGeoNode TGeoMate
rial
CbmGeoInterface CbmGeoRootBuilder
ASCII
ROOT
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Full Simulation-Analysis Chain
Determine particle properties at target vertex
Event Generator
Transport particles through the detector material
Simulation
Transport
SIM
Digitizer
Determine detector response
RAW
Determine physical space point parameters from
detector hits
Storage Levels
Hit Finder
Determine momentum vector and PID for all tracks
Analysis
Reconstruction
Physics Analysis
Calculate physics observables
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Event merging before transport
Event Generator 1
Event Generator 2
UrQMD
Pluto
Transport
Merger
Digitizer
Hit Finder
Reconstruction
Physics Analysis
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Event merging after transport
Event Generator 1
Event Generator 2
Pluto
UrQMD
Transport
Transport
Merger
Digitizer
Hit Finder
Storage at SIM level is more efficient when
digitizers are fast compared to transport
Reconstruction
Physics Analysis
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Tasks and interfaces
SIM
MC POINT
MC POINT
Merger
Data Objects
MC POINT
Tasks
Storage Levels
Digitizer
Input of a taskis from storageor other task
RAW
DIGIT
Hit Finder
HIT
Reconstruction
TRACK
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Adding a detector or a Module ?

• Material definitions
• Geometry definitions
• Create a detector (or Module) subclass
• Create the library

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Simulation Macro

• Load the Libraries
• Create the Run Manager
• Choose Simulation engine
• Choose an output file name
• Create Modules and detectors and add them to the
  Run Manager
• Create and Set the Event generator(s)
• Create and set the Magnetic field
• Initialize and run the simulation

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Simulation Macro loading Libs
// Load basic libraries gROOT-gtLoadMacro("VMC
WORKDIR/gconfig/basiclibs.C") basiclibs()
// Load Cbmroot libraries gSystem-gtLoad("lib
Cbm") gSystem-gtLoad("libPassive")
gSystem-gtLoad("libGen") gSystem-gtLoad("libSts
") gSystem-gtLoad("libTrd") gSystem-gtLoad("li
bTof") gSystem-gtLoad("libRich")
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Simulation Macro

• //create the Run Class
• CBMRun fRun new CBMRun()
• // set the MC version used
• fRun-gtSetName("TGeant4") //for G3 use
  "TGeant3"
• // chose an output file name
• fRun-gtSetOutputFile("test.root")

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Simulation Macro- Create Modules

• CbmModule Cave new CbmCave("WORLD")
• Cave-gtSetGeometryFileName("PASSIVE/CAVE",
  "v03a")
• fRun-gtAddModule(Cave)
• CbmModule Target new CbmTarget("Target")
• Target-gtSetGeometryFileName("PASSIVE/TARGET",
  "v03a")
• fRun-gtAddModule(Target)
• CbmModule Pipe new CbmPIPE("PIPE")
• Pipe-gtSetGeometryFileName("PASSIVE/PIPE",
  "v03a")
• fRun-gtAddModule(Pipe)
• CbmModule Magnet new CbmMagnet("MAGNET")
• Magnet-gtSetGeometryFileName("PASSIVE/MAGNET",
  "v03a")
• fRun-gtAddModule(Magnet)

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Simulation Macro- Create Detectors

• CbmDetector STS new CbmSts("STS", kTRUE)
• STS-gtSetGeometryFileName("STS/STS", "v03c")
• fRun-gtAddModule(STS)
• CbmDetector TOF new CbmTof("TOF", kTRUE )
• TOF-gtSetGeometryFileName("TOF/TOF", "v03_v10")
• fRun-gtAddModule(TOF)
• CbmDetector TRD new CbmTRD("TRD",kFALSE )
• TRD-gtSetGeometryFileName("TRD/TRD", "v04b_9" )
• fRun-gtAddModule(TRD)

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Simulation Macro-Event Generators

• CbmPrimaryGenerator priGen new
  CbmPrimaryGenerator()
• fRun-gtSetGenerator(priGen)
• CbmUrqmdGenerator fGen1 new CbmUrqmdGenerator("0
  0-03fm.100ev.f14")
• CbmPlutoGenerator fGen2 new CbmPlutoGenerator("j
  psi.root")
• CbmParticleGenerator fGen3 new
  CbmParticleGenerator()
• fRun-gtAddGenerator(fGen1)
• fRun-gtAddGenerator(fGen2)
• fRun-gtAddGenerator(fGen3)

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Simulation Macro-Magnetic Field

• // setting a field map
• CbmFieldMap fMagField new CbmFieldMap("FIELD.v03
  b.map")
• // setting a constant field
• CbmConstField fMagFieldnew CbmConstField()
• fMagField-gtSetFieldXYZ(0, 30 ,0 ) // values are
  in kG
• // MinX-75, MinY-40,MinZ-12 ,MaxX75, MaxY40
  ,MaxZ124 )
• fMagField-gtSetFieldRegions(-74, -39 ,-22 , 74, 39
  , 160 ) // values are in cm
• fRun-gtSetField(fMagField)

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Simulation Macro- Run Simulation

• fRun-gtInit() // Initialize the simulation
• Simulation
• 1. Initialize the VMC (Simulation)
• 2. Initialize Tasks (if they are used in
  Simulation)
• fRun-gtRun(NoOfEvent) //Run the Simulation

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CBM Detector Geometry
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Example Rich Detector
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CbmTask

• Tasks can be organized into a hierarchy and
  displayed in the browser.
• The CbmTask class is the base class from which
  the tasks are derived.
• To give task functionality, you need to subclass
  the CbmTask class and override
• Init() //Initialization
• Exec(Option_t option)

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Tasks Mechanism

• CbmTask Task1new CbmTask("Task1") CbmTask
  Task2new CbmTask("Task2")
• CbmTask Task3new CbmTask("Task3")
• CbmTask Task4new CbmTask("Task4")
• CbmTask Task5new CbmTask("Task5")
• CbmTask Task6new CbmTask("Task6")
• Task1-gtAdd(Task2)
• Task1-gtAdd(Task3)
• Task2-gtAdd(Task4)
• Task2-gtAdd(Task5)
• Task3-gtAdd(Task6)

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CbmTasks
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Analysis creating a Task

• class CbmITrack public CbmTask
• public
• CbmDITrack(const char name, const char
  title"CBM Task")
• virtual void Init() //Initialization
• virtual void Exec(Option_t
  option) //called for each event
• virtual void Finish() //called for each event
• virtual CbmITrack()
• ClassDef(CbmITrack,1) //CbmITrack

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Analysis Task- Init example

• void CbmITrackInit()
• // Get a pointer to the ROOT Manager ( data
  store )
• CbmRootManager fManager CbmRootManagerInstanc
  e()
• // Get the relevant data for the Task
• // activate in IO the corresponding TTree
  branch
• fListSTSpts(TClonesArray )fManager-gtActivateBr
  anch("STSPoint")
• //Create a new branch in the output file for the
  results
• fHitCollection new TClonesArray("CBMSTSDoubleHi
  t")
• fManager-gtRegister("STSDoubleHit","STS",
  fHitCollection)

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Analysis Task- Exec example

• void CBMITrackExec(Option_t option)
• CBMSTSDoublePoint ptNULL
• CBMSTSDoubleHit hitNULL
• for (int j0 j lt fListSTSpts-gtGetEntries() j
  )
• pt (CBMSTSDoublePoint) fListSTSpts-gtAt(j)
• if (pt ( pt-gtGetDetectorID(0)
  pt-gtGetDetectorID(1)) )
• hit AddHit() hit-gtSetDetectorID(
  pt-gtGetDetectorID(1))
• else continue
• hit-gtSetPos_in( pt-gtGetPos_in() )
• hit-gtSetPos_out( pt-gtGetPos_out() )
• TVector3 xy(gRandom-gtGaus(0,fDx),
  gRandom-gtGaus(0,fDy),0.0)
• hit-gtSetDPos_in( xy )
• hit-gtSetDPos_out( xy )

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Analysis Macro

• gROOT-gtLoadMacro("VMCWORKDIR/gconfig/basiclibs.C
  ")
• basiclibs()
• gSystem-gtLoad("libCbm")
• gSystem-gtLoad("libITrack")
• CBMRun fRun new CBMRun()
• fRun-gtSetInputFile(/d/STS_AuAu25Gev_Urqmd.root")
  
• fRun-gtSetOutputFile(trackOutput.root")
• CBMITrack tr new CBMITrack("Tracking
  Algorithm")
• fRun-gtAddTask(tr)
• fRun-gtInit()
• fRun-gtRun()

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Chaining root files

• Chaining mechanism supported in the Analysis
• //
• CbmRun fRun new CbmRun()
• fRun-gtSetInputFile(myfile1.root)
• fRun-gtAddFile(myfile2.root)
• fRun-gtAddFile(myfile3.root)
• // loop over all entries
• fRun-gtRun()

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Combined Chain Friend (ROOT)

• ROOT IO problem
• //
• TChain ch(cbmsim)
• ch.Add(rich_hit1.root)
• ch.Add(rich_hit2.root)
• TFile f1(Rguidance1.root)
• TFile f2(Rguidance2.root)
• ch.AddFriend(cbmsim, f1)
• ch.AddFriend(cbmsim, f2)
• //
• Does NOT Work !!

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Combined Chain Friend (CbmRoot)

• Make use of our CbmRootManager (IO)
• When the TChain switch to new file
• Clear the global list of friends
• Add the correct next friend to the list
• Update the corresponding pointers (TTree, Friend
  Tree ..)
• Problem is solved
• //
• CbmRun fRun new CbmRun()
• fRun-gtSetInputFile(rich_hit1.root)
• fRun-gtAddFriend(Rguidance1.root)
• fRun-gtAddFile(rich_hit2.root)
• fRun-gtAddFriend(Rguidance2.root)
• //
• fRun-gtInit()
• fRun-gtRun()

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Track Visualization

• In the Simulation macro add
• .........
• fRun-gtSetStoreTraj(kTRUE)
• fRun-gtInit()
• // Set cuts for storing the trajectories
• CbmTrajFilter trajFilter CbmTrajFilterInstan
  ce()
• trajFilter-gtSetStepSizeCut(1) // 1 cm
• trajFilter-gtSetEnergyCut(0., 1.04) // 0 lt
  Etot lt 1.04 GeV
• trajFilter-gtSetStorePrimaries(kFALSE)
• .........

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Example Visualization macro

• gROOT-gtLoadMacro("VMCWORKDIR/gconfig/basiclibs.C"
  )
• basiclibs()
• gSystem-gtLoad("libCbm")
• ......
• TFile file new TFile("test.root")
• TGeoManager geoMan (TGeoManager)
  file-gtGet("CBMGeom")
• TCanvas c1 new TCanvas("c1", "", 100, 100,
  800, 800)
• c1-gtSetFillColor(10)
• geoMan-gtDrawTracks("same/Nneutron")
• geoMan-gtSetVisLevel(3)
• geoMan-gtGetMasterVolume()-gtDraw("same")

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Track Visualization
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Track Visualization
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Code Convention

• CodeWizard is being used as automatic rule
  checker
• Will be integrated with cvs commit

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Hades Simulation using Cbmroot, why?

• Need to simulate heavy system at High energy
• Need external stack for Geant3 internal stack
  capacity reached
• Check data with geant4
• Easy to use CBM framework services
• The Only efforts
• Definition of Detector MC point container
• Field map reader
• Conversion from Lab. MC point definition to
  points defined in the local ref. Frame of the
  sensitive volume
• Modification of some particles physical
  characteristics
• Use of TVirtualMCGspart()

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Hades Simulation
ROOT
Geant3
Geometry Manager
Virtual MC
Geant4
FLUKA
Magnet
Target
IO Manager
Run Manager
GeoInterface
PIPE
Primary Generator
Cave
Module
MDC
Magnetic Field
Urqmd
Detector
Tasks
EVGEN
RICH
Pluto
Particle Generator
SHOWER
Field Map
TOF/TOFINO
ASCII
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Hades Simulation
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Summary

• A VMC based framework for CBM has been
  implemented
• First released in March 2004
• Work on digitizers and full tracking is going on.
• OCT04 release of Cbmroot was used to produce data
  for the progress report
• Packages ( ROOT 4.01/02 , GEANT3/GEANT4.6.2 )
• Tested on
• Red Hat 9.0 (gcc 3.2.2 and icc 8.1)
• Suse 9.0 (gcc 3.3.1)
• Debian (gcc 3.2.3)
• Fedora Core 2 (gcc 3.3.3)
• Binaries are also available for these platforms

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Summary

• Hades spectrometer has been fully integrated
• Gives us the opportunity to tune Geant4
  (cuts/physics list ) to real Data !
• Realistic test of the framework.
• FLUKA simulation will be also possible with no
  efforts !
• CBM Convention rules will be forced via
  CodeWizard very soon
• HADES Parameter containers are implemented and
  ready to use
• The Hades Oracle interface is already available
  and will be integrated within the next months