Figure 5. Schematic diagram of a possible experimental arrangement with strong lasers.

Two counter-propagating 10 PW laser beams are focused by off axis parabolic mirrors on two gas or foam or cluster jets with near-critical-density, generating electron beams (EB), positron beams (PB) and γ-ray beams (GB). The focusing mirrors have small holes in the centre to extract the electrons (e⁻), positrons (e⁺) and γ-rays (γ), and to observe their interactions on axis.