FEL performance achieved at PAL-XFEL using a three-chicane bunch compression scheme.

Area of Science:

• Accelerator Physics
• Free-Electron Laser (FEL) Technology
• High-Brightness Electron Beams

Background:

• Free-electron lasers (FELs) require precisely controlled electron beams for optimal performance.
• Bunch compression is critical for achieving the high peak currents necessary for FEL lasing.
• Coherent synchrotron radiation (CSR) effects can degrade electron beam quality during compression.

Purpose of the Study:

• To evaluate the performance of the novel three-chicane bunch compression (3-BC) scheme at the PAL-XFEL.
• To assess the impact of radiofrequency (RF) jitter on electron beam stability within the 3-BC scheme.
• To compare the 3-BC scheme with traditional two-chicane bunch compression methods.

Main Methods:

• Implementation and operation of the first-ever three-chicane bunch compressor in an FEL facility.
• Conducting start-to-end simulations to model the effects of RF jitter on electron beam dynamics.
• Utilizing the high-performance linac RF system for stable electron beam generation.

Main Results:

• The 3-BC scheme effectively mitigates CSR effects, enabling superior electron beam quality.
• Simulations demonstrate improved electron beam performance with the 3-BC scheme compared to the two-chicane scheme under RF jitter.
• Consistent achievement of unprecedented operational stability: <15 fs arrival timing jitter, <10% transverse position jitter, and <5% FEL intensity jitter.

Conclusions:

• The three-chicane bunch compression scheme is a highly effective method for enhancing FEL performance and stability.
• The 3-BC scheme offers increased flexibility in system configuration and improved mitigation of detrimental effects like CSR.
• PAL-XFEL's advanced RF system and the 3-BC scheme enable reliable, stable operation crucial for cutting-edge FEL applications.