Production of H-atom and O-atom beams by a cooled microwave discharge source

A beam of hydrogen and oxygen atoms in the thermal energy range was produced by microwave discharge. The microwave apparatus was used inside a vacuum chamber and therefore required a cooling system. We observed a typical dissociation efficiency of 0.63 from the hydrogen discharge and of 0.73 from a mixture of hydrogen and argon. After coating with concentrated ortho-phosphoric acid, a hydrogen dissociation efficiency as high as 0.82 could be observed. The fraction of dissociated oxygen molecules was measured to be 0.33.