| 摘要 |
The invention provides a mass spectrometer having a quadrupole mass analyzer having an entrance aperture, an ion source disposed on the axis of said analyzer, particle intercepting means blocking the line-of-sight path between said ion source and said entrance aperture, and field generating means for directing ions from said source into said entrance aperture, said field generating means comprising first field generating means for deflecting ions from said source away from said axis to avoid said particle intercepting means and second field generating means for directing into said entrance ions so deflected by said first means. Using this arrangement, substantial improvement in signal:noise ratio is achieved, corresponding in some instances to a reduction in noise by a factor of over 100. |
