| 摘要 |
<p>A plasma source for a spectrometer includes a plasma torch (10) located with in a waveguide or resonant cavity (40) for both the electric and the magnetic field comoponents of a microwave electromagnetic field to excite a plasma (54). This produces a plasma (54) having a generally elliptical cross sectio n into which sample is relatively easily injected but which still provides goo d thermal coupling between the plasma and the sample. The invention gives significantly improved limits of detection compared to prior art microwave induced plasma systems. The torch is preferably axially aligned with the direction of the magnetic field component and may be located within a resona nt iris (32) within the waveguide or cavity (40).</p> |
