  We studied the feasibility of observing light-by-light scattering in a
photon-photon collider based on an existing accelerator complex and a
commercially available laser system. We investigated the statistical
significance of the signal over the QED backgrounds through a Monte Carlo
simulation with a detector model. The study showed that light-by-light
scattering can be observed with a statistical significance of 8 to 10 sigma in
a year of operation, depending on the operating conditions.
