  S-wave photoproduction of pion and kaon pairs on hydrogen is studied. Coupled
channel final state interactions between different pseudoscalar mesons are
included. Effective mass and momentum transfer distributions as well as total
cross sections are calculated. Effective mass distributions in the Born
approximation are structureless but the final state interactions produce peaks
and dips near the energies corresponding to the scalar resonances f0(980) and
f0(1400). Calculations are performed in the effective mass region between the
pion-pion threshold and 1.6 GeV in the range of the momentum transfer squared
up to 2 (GeV/c)^2. The photon energy dependence of the total cross sections is
studied between 2 and 15 GeV. Valuable information on the f0(980) resonance
structure can be extracted from data.
  These calculations are closely related to the experimental program of the
CEBAF accelerator in USA.
