Start-to-end simulation of self-amplified spontaneous emission free electron lasers from the gun through the undulator

It is widely appreciated that the performance of self-amplified spontaneous emission free-electron lasers (FELs) depends critically on the properties of the drive beam. In view of this, a multi-laboratory collaboration has explored methods and software tools for integrated simulation of the photoinjector, linear accelerator, bunch compressor, and FEL. Rather than create a single code to handle such a system, our goal has been a robust, generic solution wherein pre-existing simulation codes are used sequentially. We have standardized on the use of Argonne National Laboratoryʹs Self-Describing Data Sets file protocol for transfer of data among codes. The simulation codes used are PARMELA, elegant, and GENESIS. We describe the software methodology and its advantages, then provide examples involving Argonneʹs Low-Energy Undulator Test Line and Stanford Linear Accelerator Centerʹs Linac Coherent Light Source. We also indicate possible future direction of this work.