The main goal of this work was to determine the cross-section for photoproduction of omega mesons off neutrons. This cross-section had so far not been measured. It is, however, important for a quantitative understanding of the omega meson-nucleon interaction and for the in-medium properties of omega mesons in nuclei. Up to the time of this thesis all information on this interaction had come from studying the production off protons. The omega photoproduction off hydrogen and deuterium targets was studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The omega meson was identified via the omega -- > pi^0 gamma --> gamma gamma gamma decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems, which allowed photon detection over almost the full solid angle. Charged particles were registered by a scintillating fiber detector in the CB angular region and by plastic veto detectors in front of TAPS in the forward region. Both exclusive (the recoil nucleon was detected) and inclusive (detection of the recoil nucleon not required) analyses have been carried out. Differential and total cross-sections have been derived for omega mesons produced off free protons and off protons and neutrons bound in deuterium. For all cases, a strong forward rise of the differential cross-section, indicative of t-channel production processes, is observed. The cross-section off the bound proton is smaller than the one off the free proton. This difference cannot be attributed to a mere smearing due to the Fermi motion. At incident photon energies close to the production threshold the interaction with the neutron plays a role. Only at higher energies the omega meson production cross-section off the bound proton comes close to that off the free proton. The average cross-sections off the bound proton and the bound neutron are 6.6+-0.1 microbarn and 8.4+-0.2 microbarn, respectively, in the incident photon energy range 1.2-2.0 GeV. For photon energies 1.2-1.6 GeV the production cross-section off the bound neutron is larger than that off the bound proton by about a factor 1.3. In this energy region the excitation and decay of nucleon resonances play a dominant role. A stronger resonance contribution to the cross-section for omega production off the bound neutron compared to off the bound proton is observed. At incident photon energies larger than 1.7 GeV the cross-sections come close to each other, indicating production mechanisms independent of isospin. A deeper understanding of the results would require more detailed model calculations. It is hoped that the present work will motivate further theoretical studies.
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