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BESIII Simulation Status Z.Y. Deng M. He H.M. Liu Y.J. Mao Z.Y. You Y.Yuan BES Annual Meeting June 1, 2005
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2/34 Outline Introduction Current status Performance Future work Summary
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3/34 Geometry Geant4 Tracking Detector Digitization Response Hit objects Event GENBES Generator HepEvt format Raw data MC truth BOOST Project ( BESIII Object Oriented Simulation Tool)
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4/34 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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5/34 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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6/34 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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7/34 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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8/34 Geant4 and BOOST releases Geant4 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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9/34 BOOST Current Status geometry 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 BESIII geometry See detailed information in Mao Yajun’s report
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10/34 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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11/34 BOOST Current Status end-cap EMC geometry Quadrangular crystal Irregular boxoid Can’t be described by existing classes in Geant4 releases New class (G4IrregBox) introduced Pentangular crystal Divided into 2 boxoids 2 boxoids share the same copy number quadrangular crystal pentangular crystal
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12/34 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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13/34 BOOST Current Status geometry From boost-2-1 barrel: MDC, TOF, EMC, SCM, MUC end-cap: TOF, EMC, MUC
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14/34 BOOST Current Status generator genbes: (BESII generator system) Generate events in an ASCII file which supports HEPEVT interface 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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15/34 BOOST Current Status generator: howl J/ψ K s K s 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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16/34 BOOST Current Status generator: rhopi J/ψ ρπ π + π - Hits in barrel MUC (π- punch through) Shower in EMC gamma
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17/34 BOOST Current Status processes & magnetic field & material Physics processes BesPhysicsList constructed with Geant4 classes Many hadronic models installed, LHEP, LHEP-GN, QGSP-GN, …… More research on them needed to choose suitable ones for BESIII physics Magnetic field 1 Tesla uniform magnetic field defined inside SCM Material All materials needed in BOOST defined in XML
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18/34 BOOST Current Status hits 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 discrimination EMC waveform added Simulate main amplifier output Provide risetime to eliminate noise No noise, so not used now MUC Digit information added
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19/34 BOOST Current Status MC 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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20/34 BOOST Current Status MC 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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21/34 BOOST Current Status Data 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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22/34 BOOST Current Status User 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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23/34 BOOST Performance Speed 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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24/34 BOOST Performance Speed CPU time (s) for one event Besfarm7 (PIII/933) EventSIMBESBOOST ee -> uu 0.1220.189 J/ψ->ρ π 0.4710.763 ee -> ee 0.7361.224 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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25/34 BOOST Performance MDC P distribution (1GeV/c e-) σ p =6.1MeV P distribution (1GeV/c mu-) σ p =5.8MeV Reconstruction result using BOOST data sample
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26/34 1GeV/c e- vertical incidence total energy loss in one scintillator ( 5cm width ) BOOST Performance TOF
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27/34 BOOST Performance TOF e- 1GeV/c Z=0 : forward TDC resolution = 121ps backward TDC resolution = 122ps T : 1/sqrt(Q) time-walk forward backward
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28/34 BOOST Performance TOF e μ π k p Randomly generate particles: e-, mu-, pi-, kaon-, proton Momentum: uniform between 0-1.6 GeV/c Only intrinsic time resolution
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29/34 BOOST Performance EMC total energy loss of pi- e-
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30/34 BOOST Performance MUC Probability of single particle(μπ) entering MUC
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31/34 BOOST Integration to BOSS framework Different developing environment BOOST On besfarm Configured with gmake Based on GEANT4 BOSS On koala Configured with CMT Based on GAUDI Integration Status BOOSTAlg algorithm/packages created 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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32/34 Future Work Move developing environment from besfarm to lxplus Magnetic field mapping Physics validation, optimization Data I/O Objectivity? Raw data in online format, MC-Truth format? Background, noise? Detailed detector response
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33/34 Summary Detailed BESIII detector is built in BOOST All BESII generators can be used in BOOST Raw data/MC-truth data are successfully used in reconstruction Friendly user interface BOOST integrated into BOSS Prototype of TOF detailed digitization is realized More to do about detector response !
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34/34 Thank you !
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