Dynamic pulse-to-pulse thermal load effects in pulse-train-mode self-seeded X-ray free-electron laser

Area of Science:

• Physics
• Optics
• Materials Science

Background:

• Thermal load is a critical issue affecting X-ray free-electron laser (XFEL) performance, impacting brightness and coherence.
• In pulse train mode, crystal monochromators may not reach a steady state, leading to dynamic thermal distortions.

Purpose of the Study:

• To investigate the pulse-to-pulse thermal load effects on spectral transmission curves in XFELs operating in pulse train mode.
• To analyze the impact of these thermal effects on seed quality degradation.
• To provide guidance for the tuning process of XFELs.

Main Methods:

• Simulations or experimental measurements of thermal load distribution.
• Analysis of spectral transmission curves under varying pulse conditions.
• Evaluation of seed quality metrics.

Main Results:

• Demonstration of dynamic thermal distortion in spectral transmission curves due to pulse-to-pulse variations.
• Quantification of seed quality degradation linked to thermal effects.
• Identification of key parameters influencing thermal load and its impact.

Conclusions:

• Pulse train mode introduces unique thermal challenges in XFELs, distinct from uniformly pulsed modes.
• Dynamic thermal distortions significantly affect spectral properties and seed quality.
• The findings offer practical insights for improving XFEL operational stability and tuning strategies.