This paper presents a theoretical and numerical optimization of gamma-quanta sources generated by bremsstrahlung from laser-accelerated electrons in near-critical density plasma. The generation of gamma-quanta is considered across three distinct energy ranges relevant to different applications: 100 keV-1 MeV for radiography, 1–10 MeV for electron–positron pair production, and 10–100 MeV for giant dipole resonance and photonuclear reactions. Using analytical models validated against Geant4 simulations, we investigate the optimal converter material and thickness, as well as electron beam parameters, for two key laser facilities: the PHELIX laser (subpicosecond, intensities up to 1021 W cm−2) and the planned XCELS laser (femtosecond, intensities up to 1023 W cm−2). The optimization considers three complementary figures of merit: the total photon count Nγ, the source size Rγ and the effective brightness Y, with the latter two being critical for applications requiring minimal source size and divergence such as radiography and positron annihilation spectroscopy. Our results provide practical guidance for designing laser-driven gamma-quanta sources tailored to specific applications, demonstrating that near-critical density plasma targets can simultaneously deliver high-charge, high-energy electron beams suitable for efficient gamma-quanta production across all considered energy ranges.
All-optical generation of petawatt gamma radiation via inverse Compton scattering from laser interaction with tube target