| 摘要 |
A mass spectrometer is disclosed comprising a RF confinement device 6, a beam expander 7 & 9, and a time of flight mass analyser comprising an orthogonal acceleration extraction region. The beam expander 7 & 9, which preferably comprises a plurality of Einzel lenses, is arranged to expand an ion beam emerging from the RF confinement device 6 so that the ion beam 10 is expanded to a diameter of at least 3 mm in the direction of orthogonal acceleration within the extraction region. The spatial expansion of the ion beam 10 reduces the velocity spread of the ions in the same direction, thereby reducing the turnaround time of ions pulsed into the TOF mass analyser. Also disclosed is a mass spectrometer arranged to analyze positive ions in a first TOF mass analyser and negative ions in a second, adjacent TOF mass analyser (see Figs 11A, 11B & 12). |
