EU-LC Simulation

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EU-LC Simulation Reconstruction
Ties Behnke, DESY

• Full simulation systems status report
• The next steps where do we go from here
• The simulation challenge status report

The ECFA LC simulation group Europe David
Ward, Ties Behnke http//www-zeuthen.de/linear_co
llider
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The mission

• Coordinate the creation of appropriate
  simulation tools
• Coordinate the creation of appropriate
  reconstruction tools
• Provide a frame for the creation of appropriate
  analysis tools

• The boundary conditions
• System should be long lived
• Should be lightweight
• We are not a collaboration commercial software
  is difficult (funding)
• Share across regions as much as possible
• Little to no personpower available

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The ingredients
The data highway IO (persistency) -- files
Generator
Simulator
Reconstructor
Analyser
Detector description
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Full simulation

• BRAHMS
• GEANT3/ f77 based
• TESLA TDR detector updated for recent changes
• Complete simulation (and reconstruction)

• MOKKA
• GEANT4/ C based
• TESLA TDR detector more or less
• No reconstruction framework

• BRAHMS is still the most complete package, but
• MOKKA is quickly getting there, will soon
  replace BRAHMS SIM

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The future of the simulator(s)
MOKKA is our main GEANT4 based full simulation
environment

• GEANT4 based
• light weight, C code
• geometry via mysql and C drivers

Our US collegues are evaluating MOKKA to use it
as a base for their GEANT4 simulation
environment.
Should look at LCD-G4 MOKKA and possible
synergies / common developments
MOKKA developments

• Improve the detector models
• allow for more flexible system concept of user
  plugins
• Watch closely CERN geometry developments (GDML)

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The data highway LCIO

• Need definition of a data model
• What is a hit
• What is a track
• What is a calorimeter cluster
• etc.
• Need a common way to store (persist) objects

ROOT
HBOOK
JAS
Objectivity
Anything else?

• LCIO a simple data model with underlying
  persistency system

Reconstructed quantities objects
Reconstructed Particles Track and cluster
objects
Hit objects
Complexity
Event object
Serial packed files with pointer and block
support
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LCIO LC persistency framework
SIMULATION
RECONSTRUCTION
ANALYSIS
HITS
PARTICLES
OBJECTS
Vertex
JETS
Tracker hits
Tracks
Clusters
Calorimeter Hits
MONTE CARLO INFORMATION
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LCIO Status

• Developed in collaboration between SLAC / DESY /
  LLR (France)
• Common data model / persistemcy framework for LC
  studies
• Simple API to store and retrieve data
• Same API in C, Java (and Fortran)
• Simple underlying IO format (SIO) can be changed
  easily at a later time

• Status
• Development started December 2002
• First public pre-release in March
• First public production release for Montpellier
  LCIO 1.0
• Full C implementation
• Full Java implementation
• Full Fortran implementation
• Hit based data model fully defined,
  reconstructed objetcs still rudimentary

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LCIO Future developments
proposal by Frank Gaede

• reconstruction data model
• refine data model as discussed
• first implementation soon
• add convenient methods and tools
• analyzing the MCParticle tree (graph)
• iterators for MCParticles, e.g. all stable/final
  particles
• analyzing parent/daughter relationships
• adding convenience iterators for LCIO types
• simplify complex C syntax with dynamic_casts
  etc.
• add possibility to store generic user data
• calibration constants etc.
• respond to user requests

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LCIO user extensions I
proposal by Frank Gaede

• want to be able to store data not foreseen in
  LCIO data model
• e.g. calibration constants, prototype data
• impossible to extend the data model for all
  users needs !
• existing LCIntVec and LCFloatVec not very
  convenient and efficient
• still keep LCIO files self contained
• i.e. data should be readable without additional
  software/ user code
• user code independent of file format (SIO)

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LCIO user extensions II
proposal by Frank Gaede

• allow user classes with some restrictions
• subclasses of LCObject -gt store in event
  collections
• properties have to be basic types
• int, float, double
• can be extended to other types and vectors !
• Properties have to be accessible via user class
• data members or
• accessor member functions
• Preprocessor macros for C and Java static
  functions for making class known to LCIO

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LCIO user extensions III

• user classes are stored with data description in
  the LCIO files
• data can be read back even if UserClass
  definition not available to the program
• LGenericObject
• allows access to properties, via
• names (convenient)
• indices (faster)
• unknown collections can be analyzed with LCIO
  tools/browser

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LCIO as online data format
Both TPC and calorimeter groups look at LCIO as
online data format
example HCAL calorimeter group at DESY/Hamburg
calorimeter prototype minical
First version of raw data classes have been
defined.
data-MC comparison of energies in minical
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Example Calo hit file (online)
Dump of data file
LCIO can be used online eases access to data and
comparison to MC
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Reconstruction

• BRAHMS/ f77 based reconstruction
• Complete and sophisticated tracking
• Particle flow reconstruction package
• Tools (n-tuple for analysis, interface to main
  packages like ZVTOP, ...)

• OO world
• No coherent reconstruction frame yet
• LCIO allows using f77 based reconstruction
  package on MOKKA output(first version of MOKKA-
  BRAHMS connection released)

We need to move fast towards a OO based
reconstruction framework, to enable
reconstruction program developments!
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Reconstruction
Status of reconstruction packages

• BRAHMS
• sophisticated and complete reconstruction
  software available
• OO based no reconstruction tools available at
  the moment

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Reconstruction
Hits simulated in detector (BRAHMS)
Tracks and Pflow objects reconstructed (BRAHMS
reco)
Plots Karsten Buesser
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The Plan

• Develop a plain C reconstruction framework
• LCIO as data model
• Possibly CGA as geometry access model
• Very simple interface, no fancy interactive
  environment for a start
• Multi language support is no problem (JAVA ...)

Use LCIO ROOT LCIO JAS to provide a simple
user interaction with the reconstruction
At this stage remain independent of any
particular environment (root, JAS, PAW, ...) be
open for future developments be light-weight
(minimise the number of libraries the user needs
to install)
.... but we are still far from this goal...
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Fast Simulation

• SIMDET fast, parametrised Monte Carlo

NEW interface to used track based ZVTOP in
SIMDET improvements to parametrisations

• SGV fast, semi-parametrised Monte Carlo
  (produces hits)

Our US collegues are developing a similar system
NEW interface to ZVTOP in SGV
At the moment, fast simulations work, are
producing physics results but in Europe we have
no project for a modern fast simulator
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Software Outlook
Simulation

• Converge towards GEANT4 based MOKKA simulation
• program should become more flexible and user
  friendly
• Close collaboration with our US collegues on
  simulation establised

IO

• LC specific persistency scheme and data model
  established
• Interface to C, JAVA and Fortran exists
• Common development with our US collegues

Reconstruction

• Next big project
• Digitisation and reconstruction complete in
  BRAHMS
• Much effort needed in OO framework the next
  project

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Towards a simulation challenge
The challenge be able at the end of the current
ECFA study to do a blind analysis challenge
(A. Wagner, Amsterdam)
Software environment see previous slides
Access to data

• Need transparent and flexible access system
• Data volume small compared to LHC, but still
  significant

The plan

• User interface/ interaction use the GRID
  computing model and software

GLOBUS authentication manager

• Storage manager dCache (FNAL and DESY,
  integrated into GRID)

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LC Data depository

• Database interface to data stored under dCache
  at DESY

• Current problems access from outside DESY
  (being worked on)

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Summary

• Software tools present a significant challenge
• Progress on the simulation
• GEANT3 based simulation more stable and complete
• GEANT4 based simulation becoming available
• Common persistency scheme is reality

• Progress on the reconstruction
• BRAHMS based reconstruction exists
• OO reconstruction still in the future
• LCIO input exists
• LCIO output being defined

• Goals
• GEANT4 based simultor
• Simple reconstruction environment independent of
  particular framework
• LCIO as basic data format and model to facilitate
  data exchange
• Management of data sets through GRID like system