Speaker
Description
This study investigates a novel approach to enhancing betatron gamma-ray radiation based on laser wakefield acceleration (LWFA) [1, 2], a compact scheme for generating ultrashort, high-energy photon sources. We report the first experimental realization of a hybrid betatron scheme [3] in which electron acceleration and radiation emission stages are spatially decoupled using a two-stage gas target. In the first stage, relativistic electron beams are generated in a low-density helium gas cell driven by multi-petawatt laser pulses [4]. These beams are subsequently injected into a high-density neon gas jet, where strong transverse oscillations within the high-density plasma medium produce bright betatron gamma-rays with critical photon energies approaching 0.5 MeV and fluxes exceeding 10¹⁰ photons per laser shot. Based on an estimated source size of ~5 μm and a pulse duration of ~25 fs, the corresponding peak brilliance reaches ~5 × 1024 photons/s/mm2/mrad2/0.1% BW at 180 keV, representing one of the highest reported brilliance values in this photon energy range. This source was further applied to high-resolution gamma-ray radiography of dense metallic structures, demonstrating its suitability for advanced non-destructive evaluation, time-resolved imaging, and probing of extreme states of matter. The proposed hybrid scheme represents a significant advancement in laser-driven gamma-ray source generation, offering a scalable pathway toward compact, high-brilliance photon sources for fundamental and applied science. [1] A Félicie and A. G. R. Thomas Plasma, “Applications of laser wakefield accelerator-based light sources”, Phys. Control. Fusion 58 103001 (2016) [2] C. Hojbota et al., “High-energy betatron source driven by a 4-PW laser with applications to non-destructive imaging” The European Physical Journal A 59, 247 (2023). [3] J. Ferri et al. “High-Brilliance Betatron γ -Ray Source Powered by Laser-Accelerated Electrons” Phys. Rev. Lett. 120, 254802 (2018). [4] J. H. Sung et al., “4.2 PW, 20 fs Ti:sapphire laser at 0.1 Hz”, Opt. Lett. 42, 2058 (2017).
