the besiii offline software
DESCRIPTION
The BESIII Offline Software. Weidong Li Institute of High Energy Physics, Beijing Workshop on the cooperation of PRC-US in HEP 16 June 2006. BESIII Experiment. Main Drift Chamber (MDC): xy = 130 m P/P = 0.5 %@1 GeV dE/dx = 6-7 %. Super-conducting Magnet: 1.0 Tesla. - PowerPoint PPT PresentationTRANSCRIPT
The BESIII Offline Software
Weidong Li
Institute of High Energy Physics, Beijing
Workshop on the cooperation of PRC-US in HEP
16 June 2006
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BESIII Experiment
Muon Chamber (MUC) :
RPC based
TOF System :T = 90 ps barrel
110 ps endcap
Main Drift Chamber (MDC) :
xy = 130 m
P/P = 0.5 %@1 GeV
dE/dx = 6-7 %
EM Calorimeter (EMC) : E/E = 2.5 % @ 1 GeV
z, = 0.6 cm @ 1 GeV
Super-conducting Magnet: 1.0 Tesla
3
Software Environment Underlying framework
GAUDI (originally developed by LHCb)
Simulation
GEANT4
Other external LIBs:
CERNLIB, CLHEP, ROOT, AIDA, XercesC, GDML …
Database: MySQL
Computer language: C++ (BESII legacy code written in Fortran )
Operation system:
SLC3/ gcc3.2.3
Reused part of code from Belle, BaBar, ATLAS,GLAST
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CMT and CVS
Release area
CVSWork area
sources
Installation area
binaries
packagepackagepackagepackagepackagepackagegenerated
cmt
packagepackagepackagepackagepackagepackage cmt
ExternalExternal
External
External
Internal software
External software HEP software
Public domain software
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Gaudi Infrastructure
The application has an ApplicationMgr and it creates and initializes a set of services.
The EventLoopMgr controls the main physics event loop and schedules execution of algorithms.
We have implemented many BESIII specific Algorithms and Services.
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Framework
GeometryGDML
Data
ExecutionExecution SequenceSequence
Raw Data
RootDstCnvSvc
RawDataCnvSvc
TofGeomSvc
MdcRec
TofRec
MucRec
DST Data
Event Data
Service
EmcRec
Detector DataDetector Data FlowFlow
Event DataEvent Data FlowFlow
NavigationSvc
MagneticFieldSvc
PartPropSvc
MdcGeomSvc
EmcGeomSvc
MucGeomSvc
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Event Data HEPEVT Data
Kinematics information only
RAW Data Delivered by DAQ for reconstruction
Byte stream format
Simulated Event Data Contain digits, hits and other MC truth
information
Root format/byte stream format
REC & DST Data Reconstructed Data is event data written
as output of reconstruction procedure
DST Data is a reduced event representation suitable for analysis
Both in ROOT format
RAW DataRAW DataSimulatedSimulated
Event DataEvent Data
GeneratorGenerator
HEPEVTHEPEVT DataData
G4 SimulationG4 Simulation
ReconstructionReconstruction
REC & DSTREC & DST DataData
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Simulation (1) MDC
TOF Scintillator (EJ200)
Wrapping materials (Al + PVF)
PMT (R5924)
•Stereo layers: Hype
•Stereo Cells :TwistTube
•Axial layers: Tube Solid •Tube & Endplate constructed use Tube solid
barrel end-cap
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Simulation (2) EMC
G4Trap & G4IrregBox
Added cables,support system
Digitization: readout
electronics is simulated
MUC Detector description detailed to
a single strip
One dimension read-out
Efficiency added according to
position of pad
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Simulation (3)
Generators are legacy code from BES/BESII experiment
Generators communicate with detector simulation through Gaudi Transient Data Store.
Generator(BesGenModule)
Simulation(BesSim)
Reconstruction(MdcPatRec...)
KineInform.
Digi &McTruth
Event
Gen
McTruth
Digi
Recon
Dst
Algorithm Transient Data Store
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2
3
4
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Reconstruction Algorithms
Sub-detector Reconstruction Algorithms
MDC
MdcPatRec : tracking algorithm based on BaBar software
TrkReco: tracking algorithm based on Belle software
MdcDedxAlg: calculating dE/dx information for MDC tracks.
KalFit: track fitting algorithm using the Kalman Filter method.
TOF TofRec: calculates the flight time of charged particles.
Calorimeter EmcRec: a clustering algorithm for EM Calorimeter.
Muon Chamber MucRec: tracking algorithm for Muon Chamber
Other Algorithms
T0 Calculation: determining the event start time T0.
Tack Extrapolation: considering particles’ deflection in the magnetic field and the ionization energy loss of particles in the material.
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Recon. and simulation algorithms retrieve calibration data from calibration data store
Meta-data stored in database contains: path, valid run interval
Calibration constants are stored in ROOT files
Calibration
Calibration constants
(ROOT)
MySQLdatabase
CalibFuncSvc
Calibration Data
Service
Reconstructionalgorithm
CalibRootCnvSvc
Simulationalgorithm
GUIClient
CalibrationAlgorithm
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Event Display Tool: BesVis
Based on ROOT, OpenGL, X3D and XML
Support both 2D and 3D view
Operations and controls available through menu and toolbar items
Recently MCTruth information was added.
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Physics Analysis Software Analysis Object Builder
Particle Identification
Kinematics Fitting
Vertex Finding
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Major Releases BESIII alpha release
integration with BOOST simulation
Running the reconstruction chain for MDC, TOF, EMC and MUC can be achieved in the BESIII Gaudi framework.
EDM for both Raw Data and reconstructed data developed. Completion of fully functional Event Data I/O.
Status: published in May, 2005
BESIII beta release Simulation and reconstruction chain functions reasonably well and can
successfully process thousands of events.
Common physics analysis tools and utilities available.
Physics study can start.
Status: published in November, 2005
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Event Data Flow
HepEvt McTruthG4Event
HitsDigitsRawDataCnvSvcBES I I I RawData
Generator EventConverters Simulation
Digitization
ReconstructionAlgorithms
CalibrationFucSvc RecHits RecTracks
AnalysisTools DstTracksHistograms
Ntuples
RootDstCnvSvcDstData
Rec2DstAlg
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Performance (1)
TOF reconstruction eff. ~99%
(1GeV electron)
time resolution: ~110 pstime (ns)
entr
ies
MDC momentum and spatial resolution
σxy = 110 μm,
δpt/pt = 0.4% (1GeV μ)
dE/dx= ~6% 1 GeV π
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Performance (2)
MUC Recon. efficiency: ~ 99% @
1GeV
Ratio of fake μ < 10% for π
4E/E=[(p0/E) (p1/ E) p2]%
EMC
σE/E ≈ 2.8%@1GeV
σz = 0.6 cm @1GeV
0
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20
30
40
50
60
70
80
90
100
0. 5 0. 7 0. 9 1. 1 1. 3 1. 5
mu-90pi -90mu-70pi -70mu-50pi =50mu-40pi -40mu-30pi -30
μ efficiency
π(fake μ )
90 7050
40
30
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BESIII Software Timeline
20032002 2007
2004 2005 2006
Reconstruction Algorithms
Analysis Tools
Calibration and Database Data Challengeand
PerformanceTunning
Event Display
G4 Detector Simulation
BESF framework
BESIII Gaudi framework
Digitization
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Ongoing Activities Detector alignment survey
Mixing of background events
Reconstruction performance optimization
Studies of algorithms’ robustness With background pileup
miss-alignment
Non-uniform magnetic field
Data Challenges
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Summary BESIII has successfully adopted GAUDI application
framework.
Based on Gaudi, the BESIII offline software was developed Simulation
Calibration and reconstruction
Physics analysis
Data challenge and software performance optimization are the major task for 2006.