Based on collisions between the 100 PW laser and 8 GeV superconducting linear accelerator under construction in the Shanghai High Repetition Rate X-ray Free Electron Laser and Extreme Light Facility, the construction of GeV-level \(\gamma\) -ray as well as positron beams was proposed according to particle-in-cell simulations. Key processes were considered, involving the nonlinear inverse Compton scattering for \(\gamma\) -ray generation and the multiphoton Breit–Wheeler process for electron–positron pair production. Regardless of laser polarization, the simulations indicated that \(\gamma\) -ray beams achieved energies up to 8 GeV, brilliance of approximately 1027 photons/( \(\textrm{s}\cdot \textrm{mm}^{2}\cdot \textrm{mrad}^{2}\) ), and emittance as low as 0.1 \(\textrm{mm}\cdot \textrm{mrad}\) , whereas positron beams attained energies up to 7 GeV, brilliance of approximately 4 \(\times\) 1024 positrons/( \(\textrm{s}\cdot \textrm{mm}^{2}\cdot \textrm{mrad}^{2}\) ), and emittance as low as 0.1 \(\textrm{mm}\cdot \textrm{mrad}\) . Various applications could benefit from the possible high-energy \(\gamma\) -ray and positron beams, which may potentially be built in SHINE, including validation of the fundamental physics of strong-field quantum electrodynamics theory, nuclear physics, nuclear astrophysics, and imaging.
