Preliminary results with the crystal ball at MAMI

A new set of experiments on meson photoproduction up to beam energies of 1.5 GeV is being planned for the MAMI-C accelerator in Mainz (Germany).The experimental apparatus consists of the Crystal Ball multiphoton spectrometer together with the TAPS detector as a forward wall and a central tracker based on the DAPHNE-type cylindrical wire chambers and a central tracker. This configuration provides a geometrical acceptance approaching the full acceptance with good energy and angular resolutions for photons as well as a good angular resolution for charged particles.Using this set-up, a first round of experiments have already been performed at the existing MAMI-B facility (photon energies up to 820 MeV) to determine basic properties of hadrons like the magnetic moment of the Δ+(1232) resonance, branching ratios/upper limits for various rare and forbidden eta-meson decays, test of low-energy theorems for single pion photoproduction. (author)