ACD Geometry


  1. Features of ACD geometry in recent GlastRelease tags
  2. To-do list
  3. Pointers to other documents

Features of ACD geometry in use (xmlGeoDbs v1r46p2)

  • Bent tiles are modeled with two boxes
  • Tile sizes and shapes are accurate except that trapezoidal side tiles are approximated by inscribed boxes
  • Screws and screw holes (accurate positions) are implemented for top tiles
  • Shingling (overlap; orientation angle for side rows) is accurately modeled.
  • Ribbon sizes, shapes and positions are reasonably accurate except that, of course, each ribbon has to be modeled as many pieces


  • Trapezoidal prisms for side tiles in rows 1 and 2.  The geometry description is done (as of tag xmlGeoDbs  v1r47, created 29 October) and Acd analysis code has been upgraded to support it, but it has not been systematically tested. The xmlGeoDbs tag has not yet been incorporated in a GlastRelease HEAD build.
  • Screws and screw holes for side tiles.  Awaiting accurate position information
  • Add significant missing mass for BEA

Other documents

See also links to various information concerning the ACD geometry and child pages below, especially the most recent ones.

Geometry status as of January 2006

Geometry status and tests of simulation before DC2 (Oct. 2005)

Old Home of ACD Geometry containing very old information. 

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