Dr
Valentina Fioretti
(INAF/IASF Bologna)
The accuracy of Monte Carlo simulations in reproducing the scientific performance of space telescopes (e.g. angular resolution) is mandatory for a correct design of the mission. This is particularly the case of gamma-ray Compton and pair production trackers, where the reconstruction of the primary photon energy and direction requires the full physical understanding of the particle tracks.
A brand-new Geant4 simulator of the ASI/AGILE space telescope, AGILESim, is built using the customizable BoGEMMS architecture to reproduce the in-flight observation of the Crab system (pulsar plus nebula) in the 100 MeV - 1 GeV energy range. The AGILESim mass model is composed by three instruments: a Tungsten-Silicon tracker (the AGILE/GRID), a CsI(Tl) Mini-Calorimeter (the AGILE MCAL) at the bottom of the tracker, and a Bicron BC-404 plastic scintillator anticoincidence (the AC) surrounding the tracking system. The BoGEMMS simulation output is digitized in post-processing according to the instrument electronic read-out logic, then converted in the AGILE operating data format, and finally analyzed by the standard mission scientific pipeline, including the Kalman filter, as a real observation in space.
The physics validation of the simulation set-up is performed by (i) analytically computing the conversion efficiency of the tracker layers, (ii) reproducing the on-ground measured distribution of the AGILE tracker energy deposits, and (iii) evaluating the Point Spread Function for a simulated observation of a Crab-like source. The AGILESim results are in very good agreement with the real AGILE on-ground and in-flight data. The successful cross-comparison validates the BoGEMMS framework for its application to future gamma-ray trackers (e.g. eASTROGAM).
Summary
A brand-new Geant4 simulator of the ASI/AGILE space telescope, AGILESim, is built using the customizable BoGEMMS architecture to reproduce the in-flight observation of the Crab system (pulsar plus nebula) in the 100 MeV - 1 GeV energy range. The AGILESim mass model is composed by three instruments: a Tungsten-Silicon tracker (the AGILE/GRID), a CsI(Tl) Mini-Calorimeter (the AGILE MCAL) at the bottom of the tracker, and a Bicron BC-404 plastic scintillator anticoincidence (the AC) surrounding the tracking system. The AGILESim results are in very good agreement with the real AGILE on-ground and in-flight data. The successful cross-comparison of the simulation results validates the BoGEMMS framework for its application to future gamma-ray trackers (e.g. eASTROGAM).
