Device for producing an electron beam includes a housing, which delimits a space that is evacuatable and has an electron beam outlet opening; an inlet structured and arranged for feeding process gas into the space; and a planar cathode and an anode, which are arranged in the space, and between which, a glow discharge plasma is producible by an applied electrical voltage. Ions are accelerateable from the glow discharge plasma onto a surface of the cathode and electrons emitted by the cathode are accelerateable into the glow discharge plasma. The cathode includes a first part made of a first material at least on an emission side, which forms a centrally arranged first surface region of the cathode, and a second part made of a second material, which forms a second surface region of the cathode that encloses the first surface region.