Work

Fault-tolerance analysis for an injector of continuous-wave free-electron lasers

Year: 2025

Type: article

Abstract: High-repetition-rate free-electron laser (FEL) facilities such as LCLS-II rely on continuous-wave (cw) injectors to deliver high-quality electron beams to multiple undulator lines simultaneously. Ensuring injector reliability under nonideal conditions is critical for sustained user operations. In this work, we investigate the fault tolerance of a representative cw photoinjector by analyzing its performance under various degraded scenarios, including reduced gun energy, radio-frequency (rf) cavity failures, solenoid field constraints, and early-stage energy gain requirements. Using multiobjective optimization with a genetic algorithm framework (Xopt), we assess achievable beam quality—focusing on transverse emittance and bunch length—across a range of fault conditions. Our results reveal that while certain failures (e.g., buncher off) significantly impact emittance, coordinated adjustments to laser parameters, rf phases, and cavity gradients can still partially recover performance. The injector demonstrates resilience to a variety of perturbations, confirming its robustness for high-demand cw FEL operations.

Source: Physical Review Accelerators and Beams

DOI: 10.1103/zz4w-tvxt

Authors: Zhen Zhang, Yuantao Ding, Feng Zhou

Institution: SLAC National Accelerator Laboratory

Language: English

Topic: Particle Accelerators and Free-Electron Lasers

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: diamond

Funder: U.S. Department of Energy

Award: G303061748