| 摘要 |
<p>The invention provides a mass spectrometer capable of detecting both positive and negative ions. Positive ions emerging from the mass analyzer (2,3,4) strike a conversion electrode (8) to release secondary electrons which pass through an annular electrode (10) to strike a phosphor (12), releasing photons. Negative ions strike the surface of the annular electrode (10) to release secondary electrons which also strike the phosphor (12), releasing photons. The photons are detected with a conventional photomultiplier (14). The electrodes (8,10,12) are biased and disposed so that both positive ions and negative ions may be detected without changing the potentials applied to them.</p> |
