Pair creation in collision of $\gamma$--ray beams produced with high intensity lasers

Direct production of electron–positron pairs in two photon collisions, the Breit–Wheeler process, is one of the basic processes in the Universe. However, it has never been observed in laboratory because of absence of the intense gamma-ray sources. Laser induced synchrotron sources emission may open for the first time a way to observe this process. A feasibility of an experimental set–up using a MeV photon source is studied in this paper. We compare several $\gamma$–ray sources, estimate the expected number of electron–positron pairs and competing processes by using numerical simulations including quantum electrodynamic effects.