Patent ID: 8183524

Claim:
A mass spectrometer comprising: an ion guide comprising a plurality of electrodes; a transient DC voltage source arranged and adapted to apply one or more transient DC voltages or potentials or one or more transient DC voltage or potential waveforms to at least some of the electrodes forming said ion guide in order to urge at least some ions along the axial length of said ion guide wherein, in use, a first pulse or packet of ions is released from said ion guide at a first release time T 1 ; and a Time of Flight mass analyser arranged downstream of said ion guide and comprising an orthogonal acceleration electrode; a drift region and a control device which is arranged and adapted: (i) to energise said orthogonal acceleration electrode a first time after a first delay time Δt 1-1 from said first release time T 1 and prior to the release of a second pulse or packet of ions from said ion guide at a second release time T 2 ; and (ii) to energise said orthogonal acceleration electrode at least a second subsequent time after a second delay time Δt 1-2 from said first release time T 1 and prior to the release of the second pulse or packet of ions at the second release time T 2 .