Update G4builder issues

1
Update G4builder issues

• Talk written almost entirely by
• Stan Bentvelsen
• with a few updates from
• Christopher Lester
• ATLAS G4 Workshop
• December 2000

CAMBRIDGE
2
G4builder Goal

• Client of the AGDD generic model
• Automatically create Geant4 geometry from AGDD
  xml files
• Material definitions also from AGDD xml
• Generic (i.e. Detector NON-specific)

• Provide set of tools to examine geometry
• Visualization using DAWN
• HBOOK histograms with observables as function of
  (?,?)
• radiation length
• track length
• step-counter
• ....

3
G4builder Remarks

• No Mother envelope volumes are required in
  AGDD
• so an iterative method is implemented to
  calculate the mother-envelopes
• effective slow-down of tracking of particles
  (estimate factor 6)
• but still generic!

• Better use could be made of AGDD features
• no use is made of envelopes where users HAVE
  defined them.
• no identifier scheme
• But most of Stack is implemented
• Stacks of boxes tubes
• Stacks of stack
• Stacks of compositions

4
G4builder Remarks

• libG4Builder
• G4Builder methods are encapsulated in one
  library. In principle you just link to this.
• Readout geometries and sensitive detectors
• must be written by user in standard way.
  G4Builder joins them to physical geometry!

• Tweaking
• users wishing to generate a specialised
  geometry (eg non-standard step length in a
  particular volume) may do so in a standard way
• Bug fixes
• Rotation directions fixed (hopefully!)
• AGDD-boolean operations are now permitted

5
G4builder Usage

• Two valid AGDD xml files are read-in
• Material_AGDD.xml
• ATLAS_AGDD.xml
• The complete geometry inside volume ATLAS is
  constructed.

• May choose to view geometry using DAWN program.
• Use DAWN to format the picture
• rotation, zoom, re-coloring, style, postscript
  output

6
G4builder SCT Modules

• Szymon Gadomski fires muons through SCT barrel
  modules created by the G4Builder.
• Particle step length in the silicon is varied and
  results compared to testbeam.

7
CHAOS Accumulator

• CHAOS a 2D grid generator
• set (?,?) start, step and stop values
• spread option randomly generate in bin (??,??)
  n tracks
• set particle ID, energy, vertex.
• Available as UI commands

• StepAccumulator
• Define register observable in header file
• Automatic accumulation during each G4Step
• Separated for detector and material names
• Interfaced to Hbook histogram Manager
• Useful tool to inspect AGDD geometry

DellAcqua
8
Geantinos in SCT

• An AGDD geometry file for the SCT barrel exists
• equivalent DICE geometry
• Scan geantinos in (?,?) to determine
  characteristics of the SCT geometry
• StepAccumulator

9
SCT materials

• Scan ? (0-90o) at fixed value of ? (0)
• Accumulate the radiation- and track length
• Display for various material
• cabling and mounting boards clearly visible

10
Material in SCT
support
Copperalumium
Scintillator

• Determine
• radiation length
• track length
• step-counter
• Function of ?

11
G4builder remarks

• Find the source code for version v4
  (compliant to AGDD v4)
• /afs/cern.ch/atlas/software/cvs/offline/Simulation
  /G4Utilities/G4Builder
• Checkout the software and try
• make install
• make test (should run a little example)