Dark Current and Multipacting Capabilities in OPAL: Model Benchmarks and Applications

TL;DR

This paper enhances the OPAL simulation framework with physics models to accurately simulate dark current and multipacting phenomena in RF accelerator structures, enabling better understanding and suppression strategies.

Contribution

It introduces new physics models and boundary handling in OPAL, and benchmarks them against theoretical multipacting models for improved simulation accuracy.

Findings

Models accurately benchmarked against theory

Enhanced simulation capabilities for multipacting

Potential for improved accelerator design and stability

Abstract

Dark current and multiple electron impacts (multipacting), as for example observed in radio frequency (RF) structures of accelerators, are usually harmful to the equipment and the beam quality. These effects need to be suppressed to guarantee efficient and stable operation. Large scale simulations can be used to understand causes and develop strategies to suppress these phenomenas. We extend \opal, a parallel framework for charged particle optics in accelerator structures and beam lines, with the necessary physics models to efficiently and precisely simulate multipacting phenomenas. We added a Fowler-Nordheim field emission model, two secondary electron emission models, developed by Furman-Pivi and Vaughan respectively, as well as efficient 3D boundary geometry handling capabilities. The models and their implementation are carefully benchmark against a non-stationary multipacting theory for the classic parallel plate geometry. A dedicated, parallel plate experiment is sketched.