Hyperthermal Surface Ionization in a Time-of-Flight Mass Spectrometer

An apparatus is described which couples hyperthermal surface ionization (HSI) with time-of-flight mass spectrometry. In order to adapt HSI to the non-continuously working time-of-flight mass spectrometer, it is performed in a pulsed supersonic molecular beam. The ion bunch formed by the surface scattering process is accelerated from a specially-designed ion source into a reflectron time-of-flight mass spectrometer. In this way features of HSI such as high ionization yield and tunable degree of fragmentation are combined with the advantages of the time-of-flight mass spectrometer, namely its high transmission, its in principle unlimited mass range, and the simultaneous detection of the entire mass range. The resulting instrument thereby opens up hyperthermal surface ionization to applications demanding high temporal resolution.