Absolute partial cross sections for electron-impact ionization of CF4from threshold to 1000 eV

Absolute partial cross sections for electron-impact ionization of CF 4 are reported for electron energies from threshold to 1000 eV. The product ions are mass-analysed using a time-of-flight mass spectrometer and detected with a position-sensitive detector whose output demonstrates that all product ions are collected with equal efficiency irrespective of their initial kinetic energies. Data are presented for the production of CF 3 + , CF 2 + , (CF + + CF 3 2+ ), C + , F + and CF 2 2+ and for the total cross section which is obtained as the sum of these partial cross sections. The overall uncertainties in the absolute cross section values are ±5% to ±8%. Data are also presented for formation of (CF + , F + ) and(CF 2 + , F + ) ion pairs. Comparison is made with prior experiments and calculations.