Validating polarization effects in γ-rays elastic scattering by Monte Carlo simulation

Abstract

The polarization properties of γ-rays elastically scattered by atoms have become more observable with the development of polarized photon beams. However, systematic studies are required to explore the elastic scattering in the MeV-energy range of the spectrum where Delbrück scattering becomes more significant, especially at large scattering angles. We implement a new Monte Carlo simulation to account for the polarization effects of elastic scattering. The simulation is based on explicit expressions driven in the formalism of Stokes parameters. The scattering amplitudes of Rayleigh, nuclear Thomson, and Delbrück scattering processes are superimposed onto a two orthogonal set of complex amplitudes. This set is then exploited to construct the core of the simulation in such a way that the simulation can handle arbitrary polarization states of the incoming beam and correspondingly generate polarization states of the outgoing beam. We demonstrate how the polarization of scattered photons is affected by the polarization of incoming photons. In addition, we explain the dependence of depolarization on the azimuthal angle.

Rayleigh scattering of a linearly polarized light: scenario of the complete experiment

“…Combing now Eqs. ( 21) and (22) with the corresponding result for the cross section (18) one can extract the magnetic amplitude:…”

“…[17,21]. Recently, the numerical studies of the polarization of the scattered photons in case of initially linear polarized light have been made for hydrogen and hydrogenlike ions [18,19] as well as for ions with more electrons [20,22].…”

“…Despite there are papers devoted to the polarization trans-fer in the Rayleigh scattering [16][17][18][19][20][21][22] and, in particular, in Refs. [16,17] significant steps towards complete experiment description were undertaken, we think that the polarization analysis requires more detailed considerations.…”

An electromagnetic physics constructor for low energy polarised X-/gamma ray transport in Geant4

“…In the release of Geant4 version 8.2 an extensive set of polarised particle transport models were added to complement the existing models for polarised X-/gamma ray photoelectric absorption, Compton scattering, and Rayleigh scattering [33]. Since then new polarised X-/gamma rays transport models have been added for gamma conversion/pair production in 2009 [34] and 2018 [35,36], Compton scattering in 2016 [31], and elastic scattering (Rayleigh, Delbrück and Nuclear Thomson scattering) in 2019 [37].…”

Monte Carlo Simulation of γ − γ Correlation Functions

“…However, all of these attempts considered the scattering of unpolarized photons limited by the specific resonances of some nuclei. Other simulation works were performed by Omer and Hajima [11,12] and Turturica et al [13] on the elastic scattering as a beam background. Nonetheless, the literature is missing a Monte Carlo simulation for γ − γ correlation functions, which are crucial for the nuclear decays.…”