Polarized target developments for GRAAL and prospects

Within the French-Italian GRAAL collaboration, we have constructed a new Polarized HD Target Factory, located at IPN Orsay. The primary objective is to produce polarized HD targets (HYDILE project) for photoproduction experiments with the GRAAL polarized real photon beams. The expected properties of the target and the results already obtained for the polarization of HD samples at Orsay will be given. They open new possibilities to measure polarization observables on the Proton, the Neutron and the Deuteron. All simple and most double polarization measurements for the photoproduction of the pseudoscalar mesons (pi, K and eta) and the vector meson omega could be measured. Polarized total cross sections concerning the isovector Drell-Hearn Gerasimov Sum Rule, related to the proton neutron difference, could be measured with minimum systematic uncertainties, the target containing both polarized protons and neutrons. Increasing the GRAAL photon energy up to 2 GeV with an appropriate UV laser would give access to unknown polarization observables of the eta' and phi mesons photoproduction processes.