Accurate Modelling of Intrabeam Scattering and its Impact on Photoinjectors for Free-Electron Lasers

Fuente: arXiv
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Main Authors: Lucas, Thomas Geoffrey, Craievich, Paolo, Prat, Eduard, Reiche, Sven, Gjonaj, Erion
Format: Preprint
Published: 2025
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_version_ 1866918153142927360
author Lucas, Thomas Geoffrey
Craievich, Paolo
Prat, Eduard
Reiche, Sven
Gjonaj, Erion
author_facet Lucas, Thomas Geoffrey
Craievich, Paolo
Prat, Eduard
Reiche, Sven
Gjonaj, Erion
contents Intrabeam scattering (IBS) is a fundamental effect that can limit the performance of high-brightness electron machines, yet it has so far been neglected in standard modelling of RF photoinjectors. Recent measurements at SwissFEL reveal that the slice energy spread (SES) in the injector is significantly underestimated by conventional tracking codes. In this work, we present a dedicated Monte Carlo simulation model that accurately predicts the IBS-induced SES growth in the photoinjector of an X-ray free-electron laser. The simulations are benchmarked against SES measurements at the SwissFEL as well as theoretically supported by a new analytical model. The results demonstrate that IBS-induced SES growth occurs throughout the injector, most prominently in the electron source, and must be taken into account when assessing photoinjector performance. We further show that while the 5D brightness is largely conserved, the 6D brightness undergoes notable degradation with propagation, underscoring the need to include IBS in the accurate design and optimization of photoinjectors.
format Preprint
id arxiv_https___arxiv_org_abs_2510_02058
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Accurate Modelling of Intrabeam Scattering and its Impact on Photoinjectors for Free-Electron Lasers
Lucas, Thomas Geoffrey
Craievich, Paolo
Prat, Eduard
Reiche, Sven
Gjonaj, Erion
Accelerator Physics
Intrabeam scattering (IBS) is a fundamental effect that can limit the performance of high-brightness electron machines, yet it has so far been neglected in standard modelling of RF photoinjectors. Recent measurements at SwissFEL reveal that the slice energy spread (SES) in the injector is significantly underestimated by conventional tracking codes. In this work, we present a dedicated Monte Carlo simulation model that accurately predicts the IBS-induced SES growth in the photoinjector of an X-ray free-electron laser. The simulations are benchmarked against SES measurements at the SwissFEL as well as theoretically supported by a new analytical model. The results demonstrate that IBS-induced SES growth occurs throughout the injector, most prominently in the electron source, and must be taken into account when assessing photoinjector performance. We further show that while the 5D brightness is largely conserved, the 6D brightness undergoes notable degradation with propagation, underscoring the need to include IBS in the accurate design and optimization of photoinjectors.
title Accurate Modelling of Intrabeam Scattering and its Impact on Photoinjectors for Free-Electron Lasers
topic Accelerator Physics
url https://arxiv.org/abs/2510.02058