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We report the creation of super-high-flux gamma-rays with energy >8 MeV and photo-neutrons via the ($\gamma$,n) reaction near giant dipole resonance energies (8 - 20 MeV), using the ~130 J Texas Petawatt laser to irradiate high-Z (Au, Pt, Re, W) targets of mm - cm thickness, at laser intensities up to ~5x10$^{21}$ W/cm$^2$ . We detected up to ~ several x 10$^{12}$ gamma-rays >8 MeV (~3% of incident laser energy) and ~ 10$^{10}$ photo-neutrons per shot. Due to the short pulse duration and narrow gamma-ray cone (~17$^o$ half-width) around laser forward, the peak emergent gamma-ray flux >8 MeV reached~10$^{27}$ gammas/cm$^2$ /sec, and the peak emergent neutron flux reached ~10$^{20}$ neutrons/cm$^2$ /sec [1]. Such intense gamma-ray and neutron fluxes will facilitate the study of nuclear reactions requiring super-high-flux of gamma-rays or neutrons, such as the creation of r-process elements. These results may also have far-reaching applications for nuclear energy, such as the transmutation of nuclear waste.
This research is supported by DOE DE-SC0021327 at Rice University.
[1] E. Liang et. al. arXiv:2302.06766
