Electron beam emitter (20) in particular for sterilization of packaging material comprising a housing (40) and an insert (60) wherein the housing (40) comprises a first annular channel (41) for guiding a medium and wherein the first annular channel (41) at least partially surrounds the insert (60) and is adapted to provide the medium characterized in that the first annular channel (41) is at least partly formed by the insert (60).
