Pavel Nevski

STAR simulations STAR simulations

GSTAR frameworkGSTAR framework

OO geometry model OO geometry model

event accessevent access

Pavel Nevski

STAR detector at RHICSTAR detector at RHIC

Pavel Nevski

GSTARGSTAR

– STAR simulation framework since 96STAR simulation framework since 96– has a hierarchical design to clearly separate has a hierarchical design to clearly separate

user code from implementation details user code from implementation details – has improved memory managementhas improved memory management

» elastic ZEBRA (using malloc)elastic ZEBRA (using malloc)

» no limits on number of tracks, vertices, hits etc no limits on number of tracks, vertices, hits etc (apart from physical memory limits) (apart from physical memory limits)

– has built-in interfaces to implementation has built-in interfaces to implementation » Geant3/PAW, MySQL, ROOTGeant3/PAW, MySQL, ROOT

Pavel Nevski

Hierarchical designHierarchical design

Open System Interconnection (OSI) model Open System Interconnection (OSI) model as example: functionality in term of layersas example: functionality in term of layers– basic (physical) layer - platform dependant basic (physical) layer - platform dependant

code, system libraries,graphics etccode, system libraries,graphics etc– low (logical) layer - ZEBRA, DZDOC,HIGSlow (logical) layer - ZEBRA, DZDOC,HIGS– upper (transport) - G3, Paw+Kuip, DB, ROOTupper (transport) - G3, Paw+Kuip, DB, ROOT– system (session) - AGI, ROOT accessors system (session) - AGI, ROOT accessors – user (application) - modules in F, AGI, C++user (application) - modules in F, AGI, C++

Pavel Nevski

STARSTARgeometrygeometry

Modules: 14Modules: 14 Structures: 34Structures: 34 Instances: 45Instances: 45 Parameter Parameter

values: 841values: 841

Pavel Nevski

Database Database BrowserBrowser Versioned Versioned

geometriesgeometries

Pavel Nevski

STAR geometrySTAR geometry Formalized description in specification Formalized description in specification

language, including hits and DB accesslanguage, including hits and DB access Many developers, very detail geometry Many developers, very detail geometry

(almost 2,000 different volumes)(almost 2,000 different volumes) Altogether less then 8000 lines including Altogether less then 8000 lines including

field parameterization , easy to read field parameterization , easy to read No step routine is needed in most of the No step routine is needed in most of the

detectors, no “if statement” problemdetectors, no “if statement” problem

Pavel Nevski

GSTAR performanceGSTAR performance

Fast enough - 30 min/10,000 particles, with Fast enough - 30 min/10,000 particles, with a general 1 MeV cuts a general 1 MeV cuts

Calorimeter cuts tuned with test beam date Calorimeter cuts tuned with test beam date down to 50 KeV down to 50 KeV

Interfaced to all event generatorsInterfaced to all event generators Robust and well debugged production toolRobust and well debugged production tool

Pavel Nevski

Requirements for rOOt interfaceRequirements for rOOt interface

– Flexible, expandable access to geometry Flexible, expandable access to geometry objects from reconstruction programobjects from reconstruction program

– Modern visualization and navigationModern visualization and navigation– Access to hits from a C++ code as if they Access to hits from a C++ code as if they

were normal C++ objectswere normal C++ objects– fun, and even more funfun, and even more fun

Pavel Nevski

New elementsNew elements Initially missing elementsInitially missing elements

– Geometry navigator - trivialGeometry navigator - trivial– Geometry decoder - not so trivial, but feasibleGeometry decoder - not so trivial, but feasible– Volumes and positions separately - TVolumeVolumes and positions separately - TVolume– Volumes as position container - TDatasetVolumes as position container - TDataset– Hit navigator - trivial Hit navigator - trivial – Hit presenter - StGeantHitsHit presenter - StGeantHits

Pavel Nevski

G3 geometry modelG3 geometry model

TDataset

TVolume

TVolumePosition

TVolumePosition list

TVolumeView

TShape

StGeant

TNode

TVolumeView

ctor ctor

Pavel Nevski

View as in G3View as in G3

Pavel Nevski

Geant Hit Access ClassGeant Hit Access Class

class TPoints3DABC(from ROOT G3D)

StGeantHits3D

StGeantHits()...

GetNextHit(Int_t indx)

aghitget()

aghitset()

Pavel Nevski

OpenGL viewerOpenGL viewer

Pavel Nevski

Star Event DisplayStar Event Display

Pavel Nevski

ConclusionsConclusions

Now we have all this done and workingNow we have all this done and working G3 geometry model used in reconstruction G3 geometry model used in reconstruction

– calibrations and parameter organizationcalibrations and parameter organization Looking for a G4 interfaceLooking for a G4 interface