gamma-ray telescopes using conversions to electron-positron pairs: event generators, angular resolution and polarimetry

Abstract

We benchmark various available event generators in Geant4 and EGS5 in the light of ongoing projects for high angular-resolution pair-conversion telescopes. We compare the distributions of key kinematic variables extracted from the geometry of the three final state particles. We validate and use as reference an exact generator using the full 5D differential cross-section of the conversion process. We focus in particular on the effect of the unmeasured recoiling nucleus on the angular resolution. We show that for high resolution trackers, the choice of the generator affects the estimated resolution of the telescope. We also show that the current available generator are unable to describe accurately a linearly polarised photon source.

arXiv commentPublished in Astroparticle Physics (2017)

References in corpus (4)

• Polarimetry of cosmic gamma-ray sources above e+e- pair creation threshold
• Compton Imaging of MeV Gamma-Rays with the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)
• TPC in gamma-ray astronomy above pair-creation threshold
• $\gamma$-ray polarimetry with conversions to $e^{+}{e}^{-}$ pairs: polarization asymmetry and the way to measure it

Cited by in corpus (10)

• Massive Argon Space Telescope (MAST): a concept of heavy time projection chamber for gamma-ray astronomy in the 100 MeV --- 1 TeV energy range
• Performance measurement of HARPO: a Time Projection Chamber as a gamma-ray telescope and polarimeter
• A 5D, polarised, Bethe-Heitler event generator for $\gamma \to e^{+}{e}^{-}$ conversion
• Gamma Ray polarimetry; a new window for the non-thermal Universe
• HARPO, a gas TPC active target for high-performance $\gamma$-ray astronomy; demonstration of the polarimetry of MeV $\gamma$-rays converting to $e^{+}{e}^{-}$ pair
• Gamma-Ray Polarimetry
• Time projection chambers for gamma-ray astronomy
• Linear Polarimetry with $\gamma \to e^{+}{e}^{-}$ conversions
• Pair invariant mass spectrum and polarization asymmetry in the event generation of gamma-ray conversions
• A 5D, polarised, Bethe-Heitler event generator for $\gamma \to {\mu }^{+}{\mu }^{-}$ conversion