Simulating a Positron Converter

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.