Hyperthermal surface ionization in a time-of-flight mass spectrometer

An apparatus is described which couples hyperthermal surface ionization (HS I) 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 scat tering process is accelerated from a specially-designed ion source into a r eflectron time-of-flight mass spectrometer. In this way features of HSI suc h as high ionization yield and tunable degree of fragmentation are combined with the advantages of the time-of-flight mass spectrometer, namely its hi gh transmission, its in principle unlimited mass range, and the simultaneou s detection of the entire mass range. The resulting instrument thereby open s up hyperthermal surface ionization to applications demanding high tempora l resolution.