Advances in Photoemission and Secondary Emission Models in the MICHELLE Beam Optics Simulation Code

We present advances in the photoemission and secondary emission models and implementations in the MICHELLE charged particle beam optics code. MICHELLE has been developed to include a wide variety of emission models designed to suit a robust set of applications and be customizable to use cases by institutions and groups. In the case of photoemission, there are upgrades to our computational methods to evaluate the Moments model for enhanced computational efficiency. In the case of secondary emission, MICHELLE employs a table-lookup approach that captures the moments of the secondary emission. Upgrades includes not only a more robust secondary particle distribution but a methodology employing the Sandia ITS suite to populate secondary emission tables for materials of interest. The paper highlights these models and features that have evolved over time and identifies cases where they can be applied to improve simulation fidelity or enable new problems to be approached.