The HILITE (High-Intensity Laser-Ion Trap Experiment) setup, currently located at GSI, is a transportable Penning trap designed to study laser-ion-interactions such as multi-photon or tunnel ionization in highly intense laser fields. For that purpose, the setup is equipped with a dedicated ion source to be able to be connected at different laser facilities. To be transparent for the laser, it is essential to locate the ion source off-axis. Therefore, an electrostatic 90° ion beam deflector was implemented, characterized and brought into operation. The characterization was performed experimentally by imaging the beam profile with a Chevron MCP and a phosphor screen supported by SIMION simulations. Such a radial cylindrical deflector produces a characteristic beam profile depending on the voltage differences applied on the outer and inner electrode. Furthermore, a double-focussing effect occurs. The positions of the focal points regarding the correlated applied voltages were investigated as well as the impact of different charge states and kinetic energies of the ions.