| 摘要 |
A beam-shaping ion optical system (3) sending ions to an orthogonal acceleration unit is provided with slit plates (31,32) having a plurality of slit openings (31a to 31c, 32a to 32c) whereof the width is narrow in the acceleration direction (Z-axis direction) of the orthogonal acceleration unit, and, disposed in the stage following the slit plate (31), a deflection electrode comprising a separation wall part (33) and an electrode (35), and a deflection electrode comprising a separation wall part (34) and an electrode (36). In a high-sensitivity mode, no voltage is applied to the deflection electrodes, and ions passing through the slit openings (31a, 32a) and the slit openings (31c, 32c) are emitted. While ion-spreading in the Z-axis direction becomes large, decreasing the mass-resolving power, this allows for a high-sensitivity measurement by supplying a large amount of ions for mass spectrometry. In a high-resolution mode, a voltage is applied to the deflection electrodes, and ions passing through the slit openings (31a, 31c) are deflected and blocked. While the sensitivity decreases, this allows a high mass-resolving power to be achieved by limiting ion-spreading in the Z-axis direction. |
