SCT Geometry Status: December 2000 Christopher.Lester@cern.ch

1. SCT Geometry Status: December 2000Christopher.Lester@cern.ch Christopher.Lester@cern.ch

2. 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. Christopher.Lester@cern.ch

3. 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. Christopher.Lester@cern.ch

4. Barrel SCT Geometry Christopher.Lester@cern.ch

5. Forward SCT Geometry Christopher.Lester@cern.ch

6. AGDD_XmlFileBuilder 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” Christopher.Lester@cern.ch

7. Where is the geometry generated? • All code is available in the ATLAS offline software repository under: /afs/cern.ch/atlas/software/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 Christopher.Lester@cern.ch

8. 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” (Dell’Acqua et al) • Some/all of the above may result in next version of geometry being very different from current ! Christopher.Lester@cern.ch

9. 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 Jo’s 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 ….. Christopher.Lester@cern.ch

10. 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 Related work: SCT Modules Christopher.Lester@cern.ch

11. 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. Christopher.Lester@cern.ch