gauss - geant4 based simulation for lhcbgeant4.web.cern.ch/sites/geant4.web.cern.ch/files/... ·...

GAUSS - GEANT4 based simulation for LHCb

GEANT4 Workshop2 October 2002W. Pokorski / CERN

02/10/2002 Gauss Application 2

Contents

Introduction to LHCb software

Overview of Gauss project

GiGa – Gaudi interface to GEANT4

Summary


GAUDI – LHCb software framework

all of the LHCb event processing software is built within a framework – Gaudi frameworkseparation between data and algorithmsdata store-centred architectural styleseparation between transient and persistent data

transient as a bridge between other representationsisolation of user codes/algorithms from underlying persistency technologies

components interact through their abstract interfacesalgorithms manipulate dataconversion services change data representations


GAUDI - Object Diagram

Converter

Algorithm

Event DataService

PersistencyService

DataFiles

AlgorithmAlgorithm

Transient Event Store

Detec. DataService

PersistencyService

DataFiles

Transient Detector

Store

MessageService

JobOptionsService

Particle Prop.Service

OtherServices Histogram

ServicePersistency

ServiceDataFiles

TransientHistogram

Store

ApplicationManager

ConverterConverterEventSelector

InteractiveService


GAUDI - Applications

GaudiGaudi

Gaudi ApplicationsGaudi Applications

GaussGauss SimulationSimulation

BrunelBrunel ReconstructionReconstruction

DaVinci DaVinci AnalysisAnalysis

PanoramixPanoramixVisualizationVisualization

PluggablePluggable ComponentsComponents

Event GenerationEvent Generation

GiGa GiGa Detector SimulationDetector Simulation

DigitizationDigitization

GaussGauss

Detector Simulation Detector Simulation GiGaGiGa

GiGa GiGa

GiGa ConversionGiGa Conversion

GiGaGiGa

Embedded Embedded Geant4Geant4Geant4Geant4 control and control and configuration, Actionsconfiguration, Actions

Conversion of Conversion of transienttransientobjects to/from objects to/from Geant4 Geant4 representationrepresentation


Gauss application

Geant4

JobOpts JobOpts

Geant4(GiGa)

DigiAlg

JobOpts

DigitMCDigit

Geometry

HepMCMCParticleMCVertex

MCHit

Generator Detector Simulation Digitization

Cnv

Cnv

Cnv

GiGa

Pythiaetc

Int.face


GiGa overview

GEANT4 Interface for Gaudi Applications orGaudi Interface to GEANT4 Applications

GEANT4 callable and controllable from within GAUDI environment

common detector geometry source used by other applications (reconstruction, visualisation) communication via Transient Stores (Event, Detector Data) as any other service or algorithm in Gaudiuse of common services (ParticlePropertySvc, RandomNumberSvc, MagneticFieldSvc, etc.)


GiGa structure

Geant4

Algorithm

EventService

PersistencyService

DataFiles

AlgorithmAlgorithm

Transient Event Store

Detec. Service

PersistencyService

DataFiles

Transient Detector

Store

ApplicationManager

GiGaService

G4 Hits

G4 Kine

GiGaKine Conversion

Service

CnvCnvConverter

OtherServices

ActionAction

GiGaHits Conversion

Service

G4 Geom

GiGaGeomConversion

Service


GiGa features

it’s a Gaudi serviceprovides access to internal G4 event loop via GiGaRunManagerall interactions with Geant4 only through abstract interfaces of GiGa Serviceminimizes the couplings to Geant4allows loading external physics listsinstantiates (using Abstract Factory pattern) different “actions” (makes them to be plugablecomponents)


GiGa - Geometry Conversion

ConverterConverter ConverterConverter

Geant4Materials

Geant4Geant4MaterialsMaterials Geant4

Volumes

Geant4Geant4VolumesVolumes

VolumesVolumesMaterialsMaterials

Xml description

Xml Cnv

Gaudi transient

store

Geo Conversion Service


Geometry conversion ex. (RICH 1)

XmlàGiGaàG4àOpenGL


GiGa - Kinematics Conversion

Geant4Geant4TrajectoriesTrajectories

Geant4Geant4PrimaryPrimaryVerticesVertices

ConverterConverter ConverterConverter

LHCbLHCbParticlesParticles

LHCbLHCbVerticesVertices

HepMC Event

ConverterConverter

Kine Conversion Service


GiGa – Hits Conversion

Hits Conversion Hits Conversion ServiceService

Geant4Hits

Geant4Geant4HitsHits Geant4

Hits

Geant4Geant4HitsHits Geant4

Hits

Geant4Geant4HitsHits

ConverterConverterConverterConverter

LHCbLHCbEcalEcal HitsHits

LHCb LHCb MuonMuon HitsHits

LHCb LHCb VeloVelo HitsHits

ConverterConverter


Detector Simulation – “physics lists”

physics lists:crucial part of the whole simulation program – will certainly require several tuning iterationsmost of the stuff already implemented in Geant4some specific processes needed implementation

for RICH: photoelectric process (creation of photoelectrons in HPDs), energy loss: in the silicon of HPDs

new feature recently added to GiGa : modular physics listsallows dynamic loading (via jobOptions) of particular physics “sublists”expected to increase flexibility and to make validation easier


Sensitive Detectors & Hits

G4TrackerHits

(Geant4)

GiGaSensDetTracker

lvVolume

(XmlDDDB)

GiGaTrackerHitsCnv

MCHits(/Event/MC/OT/Hits)

Geant4 world

Gaudi world

ProcessHit()

<logvol name="lvU_ActiveLayer" …sensdet="GiGaSensDetTracker/myDet">

creates

invoked when particle passed through the sensitive volume

converts to:


RICH1 with SingleParticleGun

Pion with 7 GeV/c.Cherenkov PhotonsIn Aerogel and C4F10.

RICH1 Event

Rayleigh scatteringSwitched off forIllustration.

S. Easo


RICH1 Hits


Panoramix view of MCHits


Panoramix view of MCHits (2)


Summary

Current Status:we can run GEANT4 simulation with all the subdetectors includedwe are able to produce MCParticles, MCHits(from LHCb event model) and save them in a ROOT filewe are testing/validating subdetector specific code and physics processeswe have started adding digitization algorithms to Gauss


Summary (2)

Planning:by end of the year: to have a complete GEANT4 based simulation application

by the summer: to perform some “test productions”

by … : to definitely move from the old GEANT3 based simulation program to the new one, GEANT4 based

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