  We report on nonlocal transport in superconductor hybrid structures, with
ferromagnetic as well as normal-metal tunnel junctions attached to the
superconductor. In the presence of a strong Zeeman splitting of the density of
states, both charge and spin imbalance is injected into the superconductor.
While previous experiments demonstrated spin injection from ferromagnetic
electrodes, we show that spin imbalance is also created for normal-metal
injector contacts. Using the combination of ferromagnetic and normal-metal
detectors allows us to directly discriminate between charge and spin injection,
and demonstrate a complete separation of charge and spin imbalance. The
relaxation length of the spin imbalance is of the order of several $\mu$m and
is found to increase with a magnetic field, but is independent of temperature.
We further discuss possible relaxation mechanisms for the explanation of the
spin relaxation length.
