The design philosophy and a short description of an experimental facility under construction are given. Its purpose is to test targets (diameter of the order of 10 cm) for long-time exposure to a plasma or particle beam of hydrogen at fusion energies and proper flux densities, generated using a multi-aperture ion source as well as a Hall accelerator and an electron-cyclotron RF accelerator. The primary effort will be to concentrate on the problem area around divertor plates. Cryo pumps will provide a background pressure of cold neutral gas ranging from 10 −4 to 10 −1 torr. The target is immersed in a magnetic field of up to 10 kG which serves to more realistically influence plasma conditions at the target. The facility will serve to investigate surface effects on materials of interest for the reactor design. Special emphasis will be placed on the correlation between erosion rates and plasma conditions at the surface of the target.