Carbon Clusters from a Cs-Sputter Ion Source

Negatively charged carbon clusters have been extracted from a cesium sputter ion source using graphite target material. The energy of the sputtering Cs-beam has been 40 keV and secondary particles are extracted from the ion source at the same energy. The mass distribution of the sputtered particles has been analysed using a high resolution mass spectrometer [2]. Its accessible mass range enables the identification of negative ions with masses up to 330 [amu]. A background current of a few 10-13A and typically 10µA. 12C- current limit the seven decade dynamic range of the system.