[en] The next generation of compact tandem-type DD or DT neutron generators requires a robust electron stripper with high charge exchange efficiency. In this study, stripping foils of various types were tested, and the H^- to H⁺ conversion efficiency, endurance to the heat load, and durability were investigated in terms of suitability in the tandem-type neutron generator. In the experiments, a H^- beam was accelerated to about 180 keV, passes through a stripping foil, and produces a mixed beam of H^-, H⁰, and H⁺. These ions were separated by an electric field, and detected by a movable Faraday cup to determine the conversion efficiency. The experimental results using thin foils of diamond-like carbon, gold, and carbon nano-tubes revealed issues on the robustness. As a new concept, a H^- beam was injected onto a metal surface with an oblique angle, and reflected H⁺ ions are detected. It was found that the conversion efficiency, H⁺ fraction in the reflected particles, depends on the surface condition, with the maximum value of about 90%.