update g4builder issues talk written almost entirely by stan bentvelsen with a few updates from...

Update G4builder issuesTalk written almost entirely by

Stan Bentvelsenwith a few updates from

Christopher Lester

ATLAS G4 WorkshopDecember 2000

CAMBRIDGE

December 2000 Stan Bentvelsen / Christopher Lester 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• ....


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


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


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


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.


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

Dell’Acqua


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’


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


Material in SCT

Determine– radiation length– track length– step-counter

Function of

Scintillator

Copper+alumium

support


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)

update g4builder issues talk written almost entirely by stan bentvelsen with a few updates from...

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