Simulating a Positron Converter

TL;DR

This paper presents a fast, portable model for simulating positron production from particle-target interactions, validated against Geant4 simulations, and integrated into the Bmad toolkit for efficient particle physics simulations.

Contribution

A novel, efficient model for simulating positron output distributions that is faster and more portable than direct Geant4 simulations, with integration into Bmad.

Findings

Model accurately reproduces Geant4 particle distributions.

Simulation speed improved by over an order of magnitude.

Successfully incorporated into Bmad toolkit.

Abstract

A model to describe the output particle distribution generated by particles impinging on a planar target has been developed. This model was developed to simulate positron production in the Cornell CESR Linac but can be applied to targets using different types of particles. To model a specific converter target, the output particle distribution is first simulated by tracking particles using the Geant4 toolkit which models the fundamental physics of the conversion process. The Monte Carlo distribution from Geant4 is fitted to a set of functions and the function coefficients are saved for use in simulations. Using the fit functions in a simulation is not only more portable but is also more than an order of magnitude faster than running Geant4. This model has been successfully incorporated into the Bmad simulation toolkit. The output position, angular orientation, and momentum distribution is modeled. Preliminary support for modeling the polarization distribution is also discussed.