BESIII Offline Software Overview

Weidong Li & Yajun Mao

BESIII Collaboration Meeting, Beijing

12 January 2006

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Infrastructure and Environment Underlying framework

GAUDI (originally developed by LHCb)

Simulation

GEANT4

Other external LIBs:

CERNLIB, CLHEP, ROOT, AIDA, XercesC, GDML …

Database: PGSQL/MySQL

Software configuration management

CMT and CVS

Computer language: C++ (BESII legacy code written in Fortran )

Operation system: Redhat 7.3/gcc3.2

Reused code from Belle, BaBar, ATLAS,GLAST …

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Reconstruction

Calibration &Database

Framework CoreSoftware

Simulaton

Physics AnalysisSoftware

BES III Software

Organization Institutes participating

Institute of High Energy Physics

Peking University

Shandong University

University of Science and Technology of China

Hunan University

Zhejiang University

Joint Institute for Nuclear Research, Russian

Kanglin HeKanglin He

Huaimin LiuHuaimin LiuZepu MaoZepu Mao

Jinfa QiuJinfa QiuWeidong LiWeidong Li

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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

Ascii file 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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Event Data Conversion Services

AlgorithmA

AlgorithmB

AlgorithmC

Data T1

Data T2, T3

Data T2

Data T3, T4

Data T4

Data T5

T1

T5

Real data flow

Apparent data flow

T2

T4

T3

RootDstCnvSvc

RawDataCnvSvc

AsciiFileCnvSvc

REC&DSTData

RawData

Ascii Dump

PersistencyService

TransientData Store

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Detector Description Based GDML (Geometry Description Markup Language), a kind of XML developed

by GEANT4 group.

Peking University group expanded the GEANT4 Schema and developed a new ROOT Schema for BESIII applications.

GDML Detector Description has been used for simulation, event display and MUC reconstruction.

Classes for Simulation

Geometry, Materials,

Alignment…

XML description

Classesfor Reconstruction

Classesfor Event Display

ROOT SchemaROOT Schema

XM

L w

rite

r

GEANT4 Schema

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Access to Geometry Data

TOF

GeomSvc

EMC

GeomSvc

MUC

GeomSvc

MDC

GeomSvc

ApplicationApplication

LayerLayer

TOF

DAO

EMC

DAO

MUC

DAO

MDC

DAO

Database

Geometry, Materials

XML description

Objectsfor Reconstruction

Data AccessData Access

LayerLayer

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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

First version was released in December 2005.

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Simulation Integration BES has ~30 event generators written in Fortran Use C++ Hepevt_Wrapper to access the kinematics information

generated by the generators

Transient Event Store

GeneratorGenerator

SimulatioSimulationn

SimulationSimulation

②②

①①

BOOST (BESIII Objected Oriented Simulation Tool) was originally developed in a independent framework.

Integration with BOOST simulation is based on ATLAS/Athena software.

Currently both BES generators and BOOST have been integrated with the offline framework.

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Calibration Status Framework is based on GLAST calibration infrastructure

Status Developed MDC, TOF and EMC calibration prototype algorithms

Defined calibration data for each sub-detector

Reconstruction algorithms are able to retrieved calibration constants through the framework.

calibUtil interface

Data (persistent)Metadata (persistent)

Dead chns(XML)

CAL calibs(ROOT)MySQL rdbms

Write/registerSearchRead

Signifies “uses” or “accesses”

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Drift Chamber Software Status Simulation

Stereo cells are described by G4TwistTube.

Digitization is based on parameters from test beam data.

The calibration algorithm contains correction to X-T relation, spatial resolution,T0, wire position,

time walk.

Reconstruction algorithms are: TrkReco and MdcPatRec. For single 1 GeV muons, both of them obtain: Efficiency: ~99%

Spatial resolution: ~110 μm

dE/dx resolution: ~6% consistent with detector design report.

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TOF Software Status Simulation

Two-layered structure for Barrel

Digitization takes into account: light production, light propagation and PMT response etc.

Intrinsic time resolution: 85 ps

Calibration & reconstruction Calibration algorithm includes

time correction, effective velocity and attenuation calibration.

Reconstruction results have been used in particle identification

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EM Calorimeter Software Status Simulation

End-cap is described by G4IrregBox.

Full simulation of readout electronics is included in digitization.

Energy calibration Digit calibration: converting ADC

channels into energy.

Cluster calibration: correcting non-linearity of readout signals.

Reconstruction ΔE/E = ~2% @1GeV

σz = 0.6 cm @1GeV

4E/E=[(p0/E) (p1/ E) p2]%

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Muon Counter Software Status Simulation

RPC as sensitive detector

Detailed to each read-out strip

Reconstruction Tracking algorithm is

seeded by the tracks extrapolated from MDC.

Searching for hits gap by gap within predefined windows.

Reconstruction efficiency: ~ 99% @ 1GeV

Ext track

Fired strips

Window

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Physics Analysis Software Status Prototype software for physics analysis

Analysis event data model

Analysis event builder

Kinematics fitting

Secondary vertex finding

Particle identification

Physicists already start checking physics performance.

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Online Event Selection Software

Fast reconstruction algorithms and steering prototypes that control event selection have been developed and tested in the online environment.

Accept

Reconstructionalgorithms

Consistentwith criteria

End of AlgSeq

N

N

Y

Reject

Y

Algorithmsequences

StepSequencer

Reconstructionresult

Share the same framework with offline.

Fast reconstruction algorithms shall be executed step by step according to the predefined sequences. In each step, event is rejected if it does not satisfy any selection criteria.

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Release Status BOSS alpha release

integration with BOOST simulation ( done )

Running the reconstruction chain for MDC, TOF, EMC and MUC can be achieved in the BOSS Gaudi framework. ( done )

EDM for both Raw Data and reconstructed data developed. Completion of fully functional Event Data I/O. ( done )

Status: published on 30th of May, 2005

BOSS beta release Simulation and reconstruction chain functions reasonably well and can

successfully process thousands of events. ( done )

Common physics analysis tools and utilities available. ( done )

Physics study in BOSS can start.

Status: published on 17th of November, 2005

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Progress since 2005 Annual Meeting Analysis software development

Analysis event builder (done)

Particle identification (done)

Secondary vertex finding (done)

Calibration infrastructure and algorithm prototypes (done)

Event Display Tool: BesVis (done)

Migration to GDML detector description (done for MUC )

Performance studies (ongoing)

Physics: efficiency and resolution

System: algorithms’ benchmarking and profiling, memory leakage etc.

Cavern backgrounds and realistic detector simulation (ongoing)

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Areas where work is needed Detector alignment, dead/hot channel services

Magnetic field service

Parameters database

Simulation of Level1 hardware trigger

Mixing of background events

Migration to Gaudi v16r4/LCGCMT_35 that has been tested in our target operation system (SLC3).

Analysis software will still evolve based on experience obtained from the current prototype.

Physics study for online Event Filter

Data Challenges

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Data Challenge (1) Motivation

To understand the BESIII computing environment CPU, storage and network requirements, system performances, bottle

necks, etc…

To check and validate the BESIII software

Iterate on a set of Data Challenges of increasing complexity Running ‘simulation’, ‘reconstruction’ and ‘analysis’ on a large scale

Testing calibration procedures

Adding trigger simulation and event filter algorithms

Producing physics results

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Data Challenge (2) It should include

Subsystem tests: simulation, calibration, reconstruction and analysis

Full offline chain test: GenerationGenerationsimulationsimulationdigitizationdigitization

backgroundbackground mixing mixing reconstructionreconstructionanalysisanalysis

Trigger/Event filter/Offline chain testTrigger/Event filter/Offline chain test

Stress tests for scaled systems (10%, 25%…)

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Summary A tremendous amount of progress in 2005

Simulation is in good shape and people are focusing on more and people are focusing on more realistic digitization procedures.realistic digitization procedures.

Calibration Infrastructure and prototype algorithms have been developed.

Reconstruction algorithms are being tuned for better performance.

Physics analysis prototype software are also developed and are being used in physics studies.

Data challenge and software performance optimization are two major tasks this year.

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