Construction and test of a transverse superconducting holding magnet

As the resonances in the nucleon excitation spectrum are broad and overlapping, more information than that available from simple unpolarized cross sections is required in order to disentangle them. To this end, experiments with polarized targets and beams are essential in order to study the nucleon internal structure in depth. The additional information is then obtained from the polarization observables in the differential cross section of pseudoscalar meson photoproduction. The development of the frozen spin target technique has provided the possibility to use a polarized target in combination with 4π-detector systems. An internal superconducting holding magnet for transverse polarization has been constructed and tested. It will be employed in the Mainz Frozen Spin Target, which will be used in the near future for scattering experiments at the MAMI accelerator facility in combination with the Crystal Ball-TAPS detector setup.