Patent ID: 8686356

Claim:
An apparatus for fragmenting ions of sample substances, comprising: (a) a first multipole ion guide comprising a set of rods parallel to each other and spaced about an ion guide axis, the first multipole ion guide having an entrance end and an exit end; (b) an electron source arranged downstream of the entrance end of the first multipole ion guide, the electron source configured to produce low-energy electrons; (c) a first enclosure arranged upstream of the entrance end of the first multipole ion guide, the first enclosure enclosing a second multipole ion guide, the second multipole ion guide having an entrance end and an exit end; and (d) one or more lenses configured to direct low-energy electrons from the electron source to a region proximal to the ion guide axis between the exit end of the second multipole ion guide and the exit end of the first multipole ion guide such that the kinetic energies of the low-energy electrons are less than about 10 eV in the region.