Study of photon-photon scattering events

We present the design of a photon-photon collider based on conventional Compton gamma sources for the observation of secondary γγ production. Two symmetric electron beams, generated by photocathodes and accelerated in linacs, produce two primary gamma rays through Compton back scattering with two high energy lasers. Tuning the system energy to the energy of the photon-photon cross section maximum, a flux of secondary gamma photons is generated. The process is analyzed by start-to-end simulations from the photocathodes to the propagation of the QED photons towards the detector. The new Monte Carlo code 'Rate Of Scattering Events' (ROSE) has been developed ad hoc for the counting of the QED events. Realistic numbers of the secondary gamma yield, referring to existing or approved set-ups and a discussion of the feasibility of the experiment are presented.