The fusion reactions and with both deuteron beams polarized will be studied experimentally by a collaboration between the Institut für Kernphysik of Forschungszentrum Jülich (FZJ), Germany, the Laboratory of Cryogenic Techniques, St. Petersburg Nuclear Physics Institute (PNPI), Gatchina, Russia, and the St. Petersburg State University of Information Technologies, Mechanics and Optics (ITMO) in order to analyze the influence of the vector and tensor polarization on the total fusion cross section and the branching to the two reaction channels. The results shall allow to solve the discrepancy between different theoretical predictions. Moreover, the investigation of the reaction rate is of high interest, since it may lead to an increase of the efficiency of the energy generation in fusion power plants. A change of the branching ratio of the two fusion channels, i.e., suppression of neutron production as predicted by a number of theoretical papers, would decrease the radiation damage by neutrons and would allow prolongation of the operation time of a future fusion-reactor generation. The measurements request the knowledge of the polarization of both the deuteron beam and the jet target. With an unpolarized solid-state target, the beam polarization can be determined by studying the angular distributions of the outgoing ions (3He,p,t) with use of the known analyzing powers. Vice versa, additional data for the analyzing powers can be obtained, when the beam polarization is known. This is achieved by an additional (Lamb-shift) polarimeter. The setup of the polarimeter and results of detector tests are described.