BESIII Simulation Status

Z.Y. Deng M. He H.M. Liu Y.J. Mao Z.Y. You Y.Yuan

BES Annual MeetingJune 1, 2005

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Outline

Introduction

Current status

Performance

Future work

Summary

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GeometryGeant4

Tracking

DetectorDigitization

Response

Hitobjects

EventGENBESGenerator

HepEvtformat

Raw dataMC truth

BOOST Project (BESIII Object Oriented Simulation Tool)

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BOOST Project (BESIII Object Oriented Simulation Tool)

Components Generator Particles and physics processes Magnetic field Material MC truth Data I/O User interface Geometry Hits recording Digitization

sub-detector parts

common parts

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boost/ bes/ common part src/ source c++ codes include/ header files

gen/ … event generators phy/ … physics processes tru/ … MC truth gmk/ … common makefiles mac/ … common card files dat/ … geometry data files exe/ … main program for execution doc/ … documentations mdc/ … main drift chamber tof/ … time of fight emc/ … electromagnetic calorimeter muc/ … muon chamber

BOOST code structure

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BOOST Project (BESIII Object Oriented Simulation Tool)

Developers Liu Huaimin: common parts Yuan Ye: MDC Deng Ziyan: TOF & common parts Fu Chengdong/He Miao: EMC Peking University: MUC & xml geometry

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BOOST Project (BESIII Object Oriented Simulation Tool)

Phase 1: Framework prototype, simple geometry with hit Finished, BOOST prototype realized in May,2003

Phase 2: Detailed detector with simple digitization Finished, now digits and MC truth output can be used for

reconstruction

Phase 3: Detailed digitization, data/MC comparisons In progress, need information from beam test and data.

A long-term work!

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Geant4 and BOOST releasesGeant4

Release 6.1 March, 2004 Release 6.2 June, 2004 Release 7.0 December, 2004 Patch of 7.0 February, 2005

BOOST (mantained by cvs) ‘boost-1-0’ (March, 2004) -----Geant4.6.1 ‘boost-1-1’ (June, 2004) -----Geant4.6.2 …… ‘boost-2-0’ (February, 2005) ----Geant4.7.0 ‘boost-2-1’ (May, 2005) ----- Geant4.7.0+p01

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BOOST Current Statusgeometry

Detailed BESIII geometry is constructed in BOOST

Geometry added since last annual meeting Accurate stereo cells in MDC New End-cap EMC SCM (Super-Conducting Magnet )

BESIII Geometry in XML format Geometry in BOOST now can also be constructed with XML Simulation, reconstruction, event display will share the same BES

III geometry See detailed information in Mao Yajun’s report

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BOOST Current Status MDC stereo cell

Accurate description New class (J4TwistedTubs) introduced all stereo wire cells are constructed

Display for checking Twisted tube can’t be displayed directly hit positions in stereo cell used 3D scatter plot with ROOT package

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BOOST Current Status end-cap EMC geometry

Quadrangular crystal Irregular boxoid Can’t be described by existing classe

s in Geant4 releases New class (G4IrregBox) introduced

Pentangular crystal Divided into 2 boxoids 2 boxoids share the same copy numb

er

quadrangular crystal

pentangular crystal

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BOOST Current Status end-cap EMC geometry

construct all crystals in one sector

Place other sectors through rotation and reflection

Rotate east end-cap to place west end-cap

end-cap EMC

sector

rotation

reflection

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BOOST Current Statusgeometry

From boost-2-1

barrel: MDC, TOF, EMC, SCM, MUC end-cap: TOF, EMC, MUC

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BOOST Current Statusgenerator

genbes: (BESII generator system) Generate events in an ASCII file which supports HEPEVT inter

face with Geant4

The same user interface as BESII• genbes.cards , genbes.user

All BESII generators can be used in BOOST

tester: (single-particle generator for debugging) Shoot particles of given type to a given direction with given kinetic energy Users can randomize above quantities

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BOOST Current Statusgenerator: howl

J/ψKs Ks π+π-π+π-

Hits in MDC

Hits in barrel TOF(no threshold cut)

Hits in end-cap TOF

Hits in end-cap MUC

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BOOST Current Statusgenerator: rhopi

J/ψρπ π+π-

Hits in barrel MUC(π- punch through)

Shower in EMC

gamma

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BOOST Current Statusprocesses & magnetic field & material

Physics processes BesPhysicsList constructed with Geant4 classes Many hadronic models installed, LHEP, LHEP-GN, Q

GSP-GN, …… More research on them needed to choose suitable

ones for BESIII physicsMagnetic field

1 Tesla uniform magnetic field defined inside SCMMaterial

All materials needed in BOOST defined in XML

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BOOST Current Statushits and digitization

Hits recording Finished last year

digitization MDC

• Drift distance-> drift time• dE/dx• Wire resolution added• Simple background added

TOF• Detailed digitization• Light emission & light propagation• PMT response & threshold discrimin

ation

EMC • waveform added• Simulate main amplifier output• Provide risetime to eliminate no

ise• No noise, so not used now

MUC• Digit information added

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BOOST Current StatusMC truth

Purpose To provide truth information for

reconstruction debugging Similar to MCMADE in BESII

What to save True state of the particles and their

association with detector response• Particle

• particles from generator • uninterrupted decayed daughters

• Detector response• hits in sub-detectors associated with particles

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BOOST Current StatusMC truth

Track and vertex (associated with particle)

Track • PDGcode• charge• original vertex• terminal vertex• four-momentum• decayed daughters

Vertex• parent track• position • time

truth hits (associated with track)

Considering demand of each reconstruction developer

MDC• Hit history

TOF• First-hit

EMC• Total energy loss

MUC• Hit history

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BOOST Current StatusData I/O

Ascii data I/O It’s temporary, but useful in software (SIM + REC) development

Ascii data format fixed for the moment

MC truth (TRUTH) & Raw data (DIGI) included in one file

• EVHEAD• TRACKTRUTH, VERTEXTRUTH• MDCTRUTH, MDCDIGI• TOFTRUTH, TOFDIGI• EMCTRUTH, EMCDIGI• MUCTRUTH, MUCDIGI

Users can turn on/off TRUTH and DIGI part of each sub-detector in run cards

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BOOST Current StatusUser interface

Friendly to both users and developers source ~dengzy/.boostenv cvs co boost edit boost.cards & boost.user more controls in run cards

Run background/terminal/interactive/PBS job freely boost -b/-t/-i/-q use ‘boost –h’ for detail

Reconstruction developers can generate needed data files themselves

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BOOST PerformanceSpeed

From LHC experience G4 direct comparison with G3 G4 is slower (1.5~2) than G3 G4 tracking particle to 0 energy

Compared with SIMBES SIMBES (G3/BESII), BOOST (G4/BESIII)

How to compare Similar cuts

• CUTE CUTM (10KeV), range cuts (1mm) Same platform (Besfarm7) Physics events used (dimuon, rhopi, bhabha)

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BOOST PerformanceSpeed

CPU time (s) for one eventBesfarm7 (PIII/933)

Event SIMBES BOOST

ee -> uu 0.122 0.189

J/ψ->ρπ 0.471 0.763

ee -> ee 0.736 1.224

BOOST 1.5 times slower than SIMBES

More to do about speed improvement Threshold cut in digitization Speed of hadronic models to be compared

Stable (no crash for 100,000 events)

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BOOST PerformanceMDC

P distribution (1GeV/c e-)

σp =6.1MeV

P distribution (1GeV/c mu-)

σ p=5.8MeV

Reconstruction result using BOOST data sample

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1GeV/c e- vertical incidence

total energy loss in one scintillator (5cm width)

BOOST PerformanceTOF

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BOOST PerformanceTOF

e- 1GeV/c Z=0 : forward TDC resolution = 121ps backward TDC resolution = 122ps

T : 1/sqrt(Q)

time-walkforward

backward

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BOOST PerformanceTOF

e

μπ

kp

Randomly generate particles: e-, mu-, pi-, kaon-, protonMomentum: uniform between 0-1.6 GeV/cOnly intrinsic time resolution

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BOOST PerformanceEMC

total energy loss of pi- e-

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BOOST PerformanceMUC

Probability of single particle(μπ) entering MUC

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BOOST Integration to BOSSframework

Different developing environment BOOST

• On besfarm• Configured with gmak

e• Based on GEANT4

BOSS• On koala• Configured with CMT• Based on GAUDI

Integration Status BOOSTAlg algorithm/packages c

reated in BOSS

Key functions of BOOST realized in BOSS

Interface of saving data to TDS is ok

Codes imported into cvs

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Future Work

Move developing environment from besfarm to lxplus

Magnetic field mappingPhysics validation, optimizationData I/O

Objectivity? Raw data in online format, MC-Truth format?

Background, noise?Detailed detector response

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Summary

Detailed BESIII detector is built in BOOSTAll BESII generators can be used in BOOSTRaw data/MC-truth data are successfully

used in reconstructionFriendly user interfaceBOOST integrated into BOSSPrototype of TOF detailed digitization is

realizedMore to do about detector response !

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Thank you !