Polarimeter 01 10 2011

Introduction

• Used standard Geant4 process G4GammaConversion with an optional G4LivermorePolarizedGammaConversionModel model for polarized photon conversion with all physics processes turned off for electrons and positrons.

• Simulated linearly polarized photon incident on 3mm thick radiator, the polarization is in the plane φ=0. (Note that this model seems to use half plane for photon polarization, may need to simulate with photon linear polarization with φ=180.)

Figures

Azimuthal distribution of electrons from 110 MeV gamma conversions.

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Azimuthal distribution of electrons from 4 GeV gamma conversions. Left plot all energies, right plot is for symmetric pairs.

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Azimuthal distribution of electrons from 9 GeV gamma conversions. Left plot all energies, right plot is for symmetric pairs.

Summary

• Results for 110 MeV incident photon are consistent with the result from what was shown in the publication by the authors of the model.

• Results for 4 GeV incident photon are consistent with the result from what was shown in the the studies by Yerevan group.

• Results for 9 GeV incident photon do not show any asymmetries. Not clear why this is the case.