| 摘要 |
<p>A multipole ion guide is configured to improve the transmission efficiency of ions which traverse the length of one guide (7) and enter either another multipole ion guide such as a quadrupole mass analyser (14) or a three-dimensional ion trap (64). The ion transfer multipole ion guide radial dimensions are reduced such that the pole assembly (30) and an appropriately shaped exit lens (31) can be positioned within a portion of the internal space defined by the larger radius second multipole ion guide poles (43). Ions exiting the first ion guide of reduced size find themselves inside the second ion guide close to the centerline (41). In this manner, ions can be efficiently transferred from one ion guide to another, even for those ions with low kinetic energies. In a second embodiment of the invention, the exit region of a multipole ion guide (50) is configured such that the multipole ion guide poles can be extended into a counterbore (65) of a three-dimensional ion trap end cap electrode (64). With this configuration, ions (including those with low kinetic energies) can be transferred into a three-dimensional ion trap with increased trapping efficiency.</p> |
