Geant 4 application to X and Gammaray Telescopes

Geant 4 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 Geant 4 and space applications for X and Gamma Astrophysics l XRay. Tel and Gamma. Ray. Tel examples l – – l 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 Beppo. SAX team) (Credit NASA/CNR/L. Piro et al. )

Geant 4 and Space Applications Source detection l Different energy bands l Several mechanisms l Different detectors l Design and optimisation of satellites

Geant 4 and Space Applications Background Simulation l Different sources (radioactive decay, cosmic origin, detector noise, …) l

XRay. Tel and Gamma. Ray. Tel examples l Advanced examples in the Geant 4 toolkit (since release 3. 0) l Properties – Advanced features of Geant 4 toolkit – Features of the Low Energy Electromagnetic processes in Geant 4 – Reliability of Geant 4 in a space environment application

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

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) Cs. I calorimeter Plastic anticoincidence

Visualization l Lot’s of graphical drivers – Open. GL • Not interactive, but fast – VRML • A standard for 3 D scene description • Good interactivity (but can be slow) – Post. Script (via DAWN) • Very high quality drawings (suitable for publications) • Can be very slow

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

Histogramming and Analysis

User Interface l Possibility to modify geometry and materials l Source generation algoritmhs (Particle Module, Geant 4 methods) l G 4 user interface capabilities l Histograms operations

AGILE & GLAST l Real Gamma Ray Experiments

XML and Detector Description GLAST collaboration has adopted the XML language for detector description l In house DTD (derived by ATLAS one, but with a lot of modifications) l In house C++ package to interface to the XML file l – Lot of clients for this package • • GEANT 4 VRML Event Display Others. . .

XML