| 摘要 |
<p>The invention typically provides a double focusing mass spectrometer comprising an ion source (55), an ion momentum analyzer (56), a multichannel detector (58) and a multielectrode electrostatic ion-energy analyzer (57), wherein the energy dispersing field is generated by arrays of electrodes disposed in groups above and below the ion beam. By appropriate selection of the potentials applied to the electrodes, the focusing properties of the analyzer can be changed, allowing different extents of the mass spectrum to be accurately focused on the face of the detector (58) as it is tilted by the actuator (61) at different angles to the ion beam (64) emerging from the analyzer (57). This enables the spectrometer to simultaneously record either a small part of a mass spectrum at high resolution or a larger part at a lower resolution. Alternative arrangements of the detector which allow a similar result to be obtained are also disclosed.</p> |
