An apparatus (100, 300, 700) is described, comprising: a linear
ion trap (102) comprising two pairs of pole electrodes and a radiofrequency, RF, electrical potential supply (117) configured to apply respective RF waveforms to the pairs of pole electrodes, thereby forming a RF
trapping field component to trap
analyte ions (116) radially in a
trapping region (115) of the linear
ion trap for
processing of the
analyte ions (116) therein; a
charged particle source (101) comprising a pulse valve (103), a conduit (106, 107), having an entrance in fluid communication therewith and an exit, wherein the conduit (106, 107) extends in the direction of the
trapping region (115), and a
discharge device (108) electrically coupled to an electrical potential supply (109) and disposed between the entrance and the exit of the conduit (106, 107), wherein the pulse valve (103) is configured to release a gas pulse from a
gas supply into the entrance of the conduit (106, 107) and wherein the electrical potential supply (109) is configured to apply a
high voltage to the
discharge device (108) to generate a
discharge (110) in the gas pulse in the conduit (106, 107), thereby generating charged particles (114) from the gas and accelerating the generated charged particles in the direction of the
trapping region (115). A method is also described.