Geant4 application to X and Gamma-ray Telescopes

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Geant4 application to X and Gamma-ray Telescopes

• B.Ferrero Merlino1, D.Favretto2,
• R. Giannitrapani2, F.Longo2, R.Nartallo3,
  P.Nieminen3, A.Pfeiffer1, M.G.Pia2, G.Santin2

(1) CERN (2) INFN (3) ESA/ESTEC
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Outline

• Geant4 and space applications for X and Gamma
  Astrophysics
• XRayTel and GammaRayTel examples
• Geometry and Physics
• Visualisation
• Histogramming
• User Interface
• AGILE GLAST, real experiments
• XML detector description

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X and Gamma Astrophysics
Gamma Ray Bursts a puzzle being solved (since
1997)
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Gamma-ray Bursts
(Credit NASA)
(Credit BeppoSAX team)
(Credit NASA/CNR/L.Piro et al.)
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Geant4 and Space Applications

• Source detection
• Different energy bands
• Several mechanisms
• Different detectors
• Design and optimisation
• of satellites

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Geant4 and Space Applications

• Background Simulation
• Different sources (radioactive
• decay, cosmic origin,
• detector noise, )

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XRayTel and GammaRayTel examples

• Advanced examples in the Geant4 toolkit (since
  release 3.0)
• Properties
• Advanced features of Geant4 toolkit
• Features of the Low Energy Electromagnetic
  processes in Geant4
• Reliability of Geant4 in a space environment
  application

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Geometry and Physics for an X-ray Telescope
Mirrors, Focal plane detectors Cosmic Ray
generation Focusing
Coded mask imaging Photoelectric effect
Credit ESA
Credit NASA
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Geometry and Physics for a generic Gamma
Telescope
Tracker, Calorimeter, Anticoincidence
Gamma Conversion Electron Tracking Multiple
Scattering Delta-ray production Charged particle
tracking
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Detectors geometry
Lead converter Si detectors (400 ?m) CsI
calorimeter Plastic anticoincidence
Ni Conical mirrors (7.5 m) Gold coating Silicon
Detectors (50 ?m)
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Visualization

• Lots of graphical drivers
• OpenGL
• Not interactive, but fast
• VRML
• A standard for 3D scene description
• Good interactivity (but can be slow)
• PostScript (via DAWN)
• Very high quality drawings (suitable for
  publications)
• Can be very slow

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Histogramming and Analisys

• Released version with Lizard using AIDA
• 1d and 2d histograms
• More than one histogram
• Single or multiple views
• Run-based or event-based
• Messenger to choose modality

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Histogramming and Analysis
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User Interface

• Possibility to modify geometry and materials
• Source generation algoritmhs (Particle Module,
  Geant4 methods)
• G4 user interface capabilities
• Histograms operations

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AGILE GLAST

• Real Gamma Ray Experiments

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XML and Detector Description

• GLAST collaboration has adopted the XML language
  for detector description
• In house DTD (derived by ATLAS one, but with a
  lot of modifications)
• In house C package to interface to the XML file
  
• Lot of clients for this package
• GEANT4
• VRML
• Event Display
• Others ...

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XML