  Quasi-free photoproduction of eta-mesons from the deuteron has been measured
at the tagged photon facility of the Mainz microtron MAMI with the photon
spectrometer TAPS for incident photon energies from the production threshold at
630 MeV up to 820 MeV. In a fully exclusive measurement eta-mesons and recoil
nucleons were detected in coincidence. At incident photon energies above the
production threshold on the free nucleon, where final state interaction effects
are negligible, an almost constant ratio of sigma(n)/sigma(p)=0.66+/-0.10 was
found. At lower incident photon energies the ratio rises due to re-scattering
effects. The average ratio agrees with the value extracted from a comparison of
the inclusive d(gamma,eta)X cross section to the free proton cross section via
a participant - spectator model for the deuteron cross section
(sigma(n)/sigma(p)=0.67+/-0.07). The angular dependence of the ratio agrees
with the expected small deviation of neutron and proton cross section from
isotropy due to the influence of the D13(1520) resonance. The energy dependence
of the ratio in the excitation energy range of the S11(1535) resonance
disfavors model predictions which try to explain this resonance as K-Sigma
bound state.
