H3+ions gave an abnormally high cross section for dissociation to H2+and a high secondary‐electron yield on copper‐beryllium. These ions were produced by a hydrogen ion source which is excited by a radio frequency voltage and is aperture extracted. To produce these ions this source was operated at low pressure and in a high magnetic field. It is assumed that such ions are vibrationally excited. Production of the various ions was studied as a function of source magnet field, rf voltage, and geometry. In addition to H+, H2+, and H3+, H5+was detected. The secondary‐electron yield of H2+from H3+on H2was measured for different source conditions.