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

TL;DR

This paper enhances Geant4's electromagnetic physics models for low energy polarised X-/gamma ray transport, validated against synchrotron measurements, improving simulation accuracy for related scientific fields.

Contribution

The work reconfigures Geant4's physics constructor to optimize low energy polarised X-/gamma ray transport modeling, validated against experimental polarimetry data.

Findings

G4LowEPPhysics accurately reproduces experimental polarimetry results within ~5%

Enhanced physics models improve simulation fidelity for low energy polarised gamma rays

Validation against synchrotron measurements confirms the models' reliability

Abstract

The production, application, and/or measurement of polarised X-/gamma rays are key to the fields of synchrotron science and X-/gamma-ray astronomy. The design, development and optimisation of experimental equipment utilised in these fields typically relies on the use of Monte Carlo radiation transport modelling toolkits such as Geant4. In this work the Geant4 "G4LowEPPhysics" electromagnetic physics constructor has been reconfigured to offer a "best set" of electromagnetic physics models for studies exploring the transport of low energy polarised X-/gamma rays. An overview of the physics models implemented in "G4LowEPPhysics", and it's experimental validation against Compton X-ray polarimetry measurements of the BL38B1 beamline at the SPring-8 synchrotron (Sayo, Japan) is reported. "G4LowEPPhysics" is shown to be able to reproduce the experimental results obtained at the BL38B1 beamline (SPring-8) to within a level of accuracy on the same order as Geant4's X-/gamma ray interaction cross-sectional data uncertainty (approximately $\pm$ 5 \%).