SCT Geometry Status: December 2000 [e-mail]

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SCT Geometry Status December 2000Christopher.Le
ster_at_cern.ch
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SCT Geometry Status

• DISCLAIMER
• These slides are only going to deal with AGDD/XML
  related geometry issues. This talk is only meant
  to describe the work I have been closely involved
  in.
• Where are we now?
• Where are we going?
• Related work.

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Q On the full SCT geometry, where are we now?

• A Largely where we were in August!
• The present AGDD representation of the full SCT
  geometry in Geant4 is still the transcription
  from DICE/AGE of the geometry used for the Inner
  Detector TDR.

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Barrel SCT Geometry
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Forward SCT Geometry
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How is our geometry produced?

• We have a basic set of numbers which parametrise
  the detector. These happen to be stored in an
  XML file called a preXml file.
• We have geometrical knowledge hard coded into a
  C program. This Geometry code can read the
  preXml file and generate an AGDD/XML file.
• The production of a well formed AGDD/XML file is
  made easier by using a set of generic tools
  provided by AGDD_XmlFileBuilder.

• The AGDD_XmlFileBuilder tools ...
• allow AGDD/XML files to be created as a tree in
  memory, rather than as a sequential output stream
• enforce adherence to more AGDD/XML syntax
  requirements than present XML checkers alone
• allow some separation between intent and
  output format

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Where is the geometry generated?

• All code is available in the ATLAS offline
  software repository under /afs/cern.ch/atlas/soft
  ware/cvs/
• In particular
• the SCT specific stuff is in the package
  offline/InDetDetDescr/SCT_AGDD_XmlFileBuilder
• while the generic tools are in the package
  offline/DetectorDescription/AGDD_XmlFileBuilder

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Where are we going? (1)

• AGDD/XML syntax is perhaps about to undergo some
  large changes
• New emphasis
• Detector specific elements may be introduced
• Possible reduction of inter-dependencies within
  AGDD/XML files?
• New features / expectations
• Level-of-detail mechanism (LeCompte et al)
• Envelopes (Laporte et al)
• Surnames (DellAcqua et al)
• Some/all of the above may result in next version
  of geometry being very different from current !

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Where are we going? (2)

• Physical geometry has moved on since ID-TDR.
  Need to update!
• Jo Pater is about to update existing AGE geometry
  to match present best guesses at detector
  configuration.
• The next geometry produced within the AGDD/XML
  framework ought to be
• generated from the same drawings as Jos new
  AGE geometry ...
• but the next AGDD/XML geometry (unlike the
  present one) the should not be a slavish copy of
  AGE. The new geometry should be constructed
  independently. Intended result Better
  AGDD/XML, and no bad habits inherited from age.
• Who will do all of this ? I have to write a
  thesis soon ..

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Related work SCT Modules

• Szymon Gadomski is firing particles through
  simulations of SCT modules
• As a by-product this generates a test of SCT
  geometry within AGDD/XML and G4Builder framework

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Thanks to the G4 Team!

• I would like to thank the Geant4 team for help
  and advice they have given me over the last few
  months in helping me solve problems with these
  geometries.