Monte Carlo modelling of the linear Breit-Wheeler process within the GEANT4 framework

TL;DR

This paper introduces a Monte Carlo module for the Geant4 simulation toolkit to model the linear Breit-Wheeler process, enabling efficient detection experiment simulations and demonstrating its application in a specific high-energy photon collision scenario.

Contribution

A novel Monte Carlo module for Geant4 that models the linear Breit-Wheeler process with enhanced efficiency using Gaussian process regression.

Findings

The module can increase calculation speed by up to 1000 times.

It successfully models a realistic high-energy photon collision experiment.

The simulation predicts over one Breit-Wheeler pair per shot in the tested scenario.

Abstract

A linear Breit-Wheeler module for the code Geant4 has been developed. This allows signal-to-noise ratio calculations of linear Breit-Wheeler detection experiments to be performed within a single framework. The interaction between two photon sources is modelled by treating one as a static field, then photons from the second source are sampled and tracked through the field. To increase the efficiency of the module, we have used a Gaussian process regression, which can lead to an increase in the calculation rate by a factor of up to 1000. To demonstrate the capabilities of this module, we use it to perform a parameter scan, modelling an experiment based on that recently reported by Kettle et al. [1]. We show that colliding $50\,$fs duration $\gamma$-rays, produced through bremsstrahlung emission of a $100\,$pC, $2\,$GeV laser wakefield accelerator beam, with a $50\,$ps X-ray field, generated by a germanium burn-through foil heated to temperatures $>\,150\,$eV, this experiment is capable of producing $>1\,$ Breit-Wheeler pair per shot.