Geant4 application to X and Gamma-ray Telescopes B.Ferrero Merlino 1, D.Favretto 2, R. Giannitrapani 2, F.Longo 2, R.Nartallo 3, P.Nieminen 3, A.Pfeiffer 1, M.G.Pia 2, G.Santin 2 (1) CERN (2) INFN (3) ESA/ESTEC

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

X and Gamma Astrophysics Gamma Ray Bursts: a puzzle being solved (since 1997)

Gamma-ray Bursts (Credit NASA)(Credit BeppoSAX team)(Credit NASA/CNR/L.Piro et al.)

Geant4 and Space Applications Source detection Different energy bands Several mechanisms Different detectors Design and optimisation of satellites

Geant4 and Space Applications Background Simulation Different sources (radioactive decay, cosmic origin, detector noise, …)

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

Geometry and Physics for an X-ray Telescope Mirrors, Focal plane detectors Cosmic Ray generation & Focusing Coded mask imaging Photoelectric effect Credit: NASA Credit: ESA

Geometry and Physics for a generic Gamma Telescope Tracker, Calorimeter, Anticoincidence Gamma Conversion Electron Tracking Multiple Scattering Delta-ray production Charged particle tracking

Detectors geometry Ni Conical mirrors (7.5 m) Gold coating Silicon Detectors (50  m) Lead converter Si detectors (400  m) CsI calorimeter Plastic anticoincidence

Visualization Lot’s 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

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

Histogramming and Analysis

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

AGILE & GLAST Real Gamma Ray Experiments

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...

XML