Absolute partial cross sections for electron-impact ionization of SF6 from threshold to 1000 eV

Absolute partial cross sections for electron-impact ionization of SF6 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 SF5+, SF4+, SF3+, SF2+, (SF+ + SF42+), S+, F+, SF32+, SF22+ and SF2+ and for the total cross section, which is obtained as the sum of the partial cross sections. The overall uncertainty in the absolute cross sections for singly charged ions, except S+, is +/-5%; that for S+ is +/-8%. The uncertainty in the cross sections for doubly charged ions is +/- 12 to 15%. Data are also presented for formation of (SFn+, F+) ion pairs. Comparison is made With prior experiments and calculations.