Ultrahigh brilliance quasi-monochromatic MeV γ-rays based on self-synchronized all-optical Compton scattering

Area of Science:

• High-energy physics
• Laser-plasma interactions
• Photonics

Background:

• Inverse Compton scattering is a key method for generating high-energy gamma-rays.
• Previous all-optical Compton scattering sources produced X-rays near 100 keV.
• Compact, high-brightness gamma-ray sources are needed for various scientific and industrial applications.

Purpose of the Study:

• To develop a tunable, quasi-monochromatic MeV gamma-ray source with ultrahigh brilliance.
• To enhance gamma-ray generation efficiency using a cascaded laser wakefield accelerator and optimized electron-photon collision geometry.
• To explore potential applications of the generated MeV gamma-rays.

Main Methods:

• Utilized a cascaded laser wakefield accelerator to generate high-quality, monoenergetic electron beams.
• Implemented head-on collision between electron beams and an intense driving laser pulse reflected from a 20-μm-thick Ti foil.
• Precisely controlled electron acceleration and scattering processes for tunable gamma-ray production.

Main Results:

• Achieved tunable quasi-monochromatic MeV gamma-rays with a 33% full-width at half-maximum.
• Generated a peak brilliance of approximately 3 × 10^22 photons s⁻¹ mm⁻² mrad⁻² 0.1% BW at 1 MeV.
• Demonstrated a brilliance one order of magnitude higher than previously reported MeV-regime sources.

Conclusions:

• The developed compact source offers unprecedented brilliance for MeV gamma-ray generation.
• Potential applications include nuclear resonance fluorescence, advanced X-ray radiology, and ultrafast pump-probe nondestructive inspection.
• This technology represents a significant advancement in compact, high-brightness gamma-ray source development.