Description
Laser-driven plasma X-ray sources are attractive for High Energy Density Science, particularly for diagnosing Inertial Confinement Fusion implosions and resolving the influence of hydrodynamic instabilities such as Rayleigh-Taylor growth. For these applications, an effective source must combine high spatial resolution (< 50 um) with photon energies reaching several hundred keV, sufficient to probe within the gold hohlraum. Betatron radiation generated in Laser-Wakefield Acceleration is especially compelling because it’s resolution is typically 10s of microns, depending on laser and plasma conditions. In this study, we evaluate the spectral extent and spatial resolution of betatron emission produced in a plasma-waveguide enhanced LWFA configuration, parameters that have not previously been characterized for this regime. We will present measurements obtained during an August 2025 campaign at the ELBA end station of ELI Beamlines using the HAPLS laser system (800 nm, 30 fs, 15 J, .2 Hz), including the resulting X-ray flux, critical energy, and source size. These measurements also offer new experimental insight into wakefield behavior under this enhancement scheme for LWFA, particularly into electron beam trajectories reflected in the observed betatron source size. Previous studies have shown that limited flux and substantial shot-to-shot variability have hindered the broader use of betatron X-rays compared with more established platforms such as X-ray tubes and synchrotron facilities. By exploring the role of a plasma waveguide on LWFA X-ray source generation, we seek to clarify how deliberate shaping of electron beam properties within a laser wakefield can control X-ray source performance and determine its suitability for targeted applications.
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344, supported by the LDRD program under tracking code 25-ERD-010 and the Foster-Brown Fellowship. LLNL-ABS-2013664
