The high heat flux ion beam test facility at Forschungszentrum Jülich can produce peak power densities of 0.14 to 12 kW/cm2 for pulse lengths of 10 ms to 15 s. Longer pulses up to steady-state operation are possible with reduced power. The total ion beam power can be varied between 70 kW and 6 MW at particle energies of 10 to 60 keV. The particles are hydrogen and helium. The beam illuminates a 1300-cm2 area, which allows a large area for materials tests. The rise time of the beam pulses can be adjusted between 2 and 200 ms, and the pulse repetition rate is between 1 and 5 min. The test facility is equipped with a sample manipulator with a vacuum lock that allows a sample size of 15 × 10 cm with active or passive cooling. The extensive diagnostic system of the test stand, originally designed for developing and conditioning the neutral beam ion sources for the Tokamak Experiment for Technology Oriented Research (TEXTOR), and the diagnostic system of the sample manipulator are described. The results of a materials test series performed for the development of wall materials for the Next European Torus/International Thermonuclear Experimental Reactor (NET/ITER) are shown. Possible upgrades of the facility are also discussed.