STAR  Computing  Simulation  
Current Status the STAR Simulation Software

This page is intended for posting of the currently existing problems and/or action items pertaining to the STAR simulation software and is subject to periodic updates.

2004 News

  • K.Schweda: request for the ISTB detector geom update
  • A.Wetzler: ongoing work on the analysis of gamma conversions in the TPC gas and the inner detector, consultations held
  • Hal Spinka and Dave Underwood start project on the extra material description behind the TPC, discussions held
  • C.Mironov starts a project on a new geometry description for e-RHIC, assistance given
  • New code submissions from SSD group (Christelle Roy, Lilian Martin), revision, test run.
  • A comparative analysis of the various XML schemas for the detector description (in particular AGDD vs GDML) has been accomplished
  • Yuri Fisyak starts a project to convert the existing STAR geometry into TGeo cint macros, and then to refactor those manually
  • Preparation for the VMC workshop at CERN
  • Sunil Manohar Dogra [] joins the VMC geometry project
  • The VMC workshop at CERN: presented ideas by the STAR computing group in the area of VMC code restructuring and geometry description
  • CHEP'04 -- presented the VMC project on behalf of STAR
  • Online documentation improved
  • Cu-Cu test run, pending CTB data problem in the chain
  • Simulation waves completed
  • Geometry description improved in the area of SSD and the readout cage of the FTPC
  • First cut of the geometry description for the new tracking detectors (pixel based) has been done
  • Valeri Fine: work on Qt and event display
  • Virtual Monte Carlo evaluation and design work under way. Tests of the Geant to Root geometry conversion, and tracking comparison have been done. System of classes has been designed for the VMC implementation at STAR. Rough version of the TPC geometry coded in TGeo
  • Job submission via Grid commences
  • New inner detector (ISTB), work with K.Schweda, in progress
  • Root workshop takes place in Palo Alto, California. New progress has been reported in the Virtual Monte Carlo area, and help from the Root team is enlisted, in order to star developing the VMC platform for STAR
  • First test run of VMC is done with "real" STAR TPC geometry, converted from Geant 3.21 to Root format using the ustility created by the STAR members.
  • Transition to the new layout of the simulation software is under way. The new executable is codenamed "starsim". It's an evolution of the previously used "staf/gstar", with much better code organization and versioning, and results in the unified code base between root4star and starsim.

2003 News

  • AuAu200 Hijing run has been completed, and contains the following datasets, 40k events each:
    1. Pure Hijing events
    2. J/Psi decays
    3. J/Psi decays mixed into underlying Hijing events
    4. Upsilon decays
    5. Upsilon decays mixed into underlying Hijing events
    6. Omega decays
    7. Omega decays mixed into underlying Hijing events

  • Changes have been made to the layout of many detector subsystems in STAR, including the SVTT, PHMD, BTOF, CALB, ECAL, SISD. Added teh first version of the PIXL detector and modified PIPE.
  • The Hijing 1.382 production run is progressing and we now have roughly a million events produced and reconstructed.
  • Pythia run has been completed with total statistics of approximately 1.5M events.
  • The Hijing 1.382 production run is being repeated due to various problems discovered recently in the Ntuple based event generator interface, addition testing thereof, and the fact that a large part of the previously attempted run was done with a wrong verison of executable.
  • More contacts are made with the developers of the CMS DDD group regarding the possible reuse of their XML based detector description system.
  • Work started on the Technical Requirements Document for the XML based detector geometry description in STAR.
  • There are currently about 50k Pythia events produced waiting evaluation by the members of the various detector subsystems groups, before we proceed to a larger run.
  • We are planning a substantial Pythia 6.203 min-bias run of approximately 1 to 2 million events. The ballpark value for the time per event in such simulation is approx. 10 seconds. This makes for 115 CPU/days for 1 million events, which is not at all unreasonable.
  • The pilot project aiming to use the XML geometry description for the STAR detector has been presented and discussed at the CHEP'03 conference in San Diego.
  • Due to recent code enhancements, the "subprocess id" from the Pythia event generator, is now propagating through the Monte Carlo and reconstruction chain.
  • We have made a transition from the older version of Hijing, 1.33, to the newer one, 1.382. Substantial statistics have been generated with 1.33 for the d-Au run and these will be still helpful to most analyses done on the detector subsystems.

    The main improvement in the newer version is in the updated formula for the deutron wave functions, which is likely to have effect in most peripheral collision, due to the different effective size of the deutron.

  • The "new" Hijing statistics is being generated via production of the actual events files output by the event generator, as opposed to the "on the fly" mode of operation used earlier. That would lead to some saving should we need to rerun the statistics with updated geometry (which is indeed the case right now).
  • Based on request from FTPC group and some others, a dedicated "wide Z" MC run has been done, whereby the size of the diamond (beam corssing) is considerably larger than the one used in the main simulation runs. In practice this means the sigma of 80 cm and no hard cuts on Z. This is based on the observation of the actual diamond size, as reconstructed from the data, and the need in the FTPC group to study reconstruction at extreme values of Z.

    There have been at least 170,000 events generated under these conditions, and those have been reportedly reconstructed and successfully used in the analysis.

  • Due to the diligence of Joanna Kiryluk and Akio Ogawa, a small defect was discovered in the geometry layout of the BBC, whereby due the "ONLY" Geant attribute (set by default) certain hits were lost in this counter. The correction has been made and the Hijing 1.382 of the statistics will be run with the corrected version.
  • Work in progress: based on the study done by Ian Johnson, it has been confirmed that theere is some material associated with SVT, which is missing from our Geant model, however detailed. A new comparison of data and MC provides some guidelines for improving that geometry description.
  • The FTPC geometry (the "supogeo.g" file) will need to be updated as the current version seems obsolete and plain incorrect. That does not have effect on the quality of the Monte Carlo data due to the small amount of material involved, as a study has shown.

2002 News

  • A simple script has been created for mixing "Phase Space" tracks into events produced with event generators
  • It has been confirmed that the failure of the Geisha simulation in the current production version of STAF was due to a faulty build of the STAF earlier this year. The STAF has been rebuilt with gcc version 2.95.2 and is being tested now, with no apparent problems.
  • A decision was made to not tie ourself to gcc 2.96 for building STAF/GSTAR simulation software, partly because this is bound to eventually change anyway, and partly because this version produces problems with the executable (the infamous infinite loop).
  • It is now easier to run the Pythia event generator from STAF.
  • There has been a bug in the geometry.g file that prevented the flag which activates hadronic shower simulation in GEANT from being propagated in all volumes of the detector. This has been fixed on 12/10/2002. It necessary, however, to use the following flag in your sim: GCALOR_ON

    Usage example:
    detp geom year2003 gcalor_on

  • GCALOR requires a few data files for it's proper functioning. The files have been deposited in CVS and reside in the path pams/sim/gphysdata. The GCALOR software, which we can't modify, was written in such a way that it will look for these files in the directory from which the binary image was started. Therefore, the files should either be present in the directory where the user runs STAF, or have symbolic links in that directory.
  • gcc version 2.95.2 has been installed locally, but there are some compilation problems (likely due to wrong standard header files) that need to be resolved.
  • November 18: Maxim Potekhin joins the STAR collaboration to lead the Monte Carlo simulation effort.

Last updated by Maxim Potekhin on 12/03/2004