| 摘要 |
The invention relates to a method and a device which reduces the phase space volume of ions in an ion beam in such a way that their injection into a downstream time-of-flight mass spectrometer optimizes the performance of that spectrometer. The performance of the time-of-flight mass spectrometer, i.e. the sensitivity of the spectrometer, the temporal resolution for fast concentration changes of the examined substances, and particularly the mass resolving power, relates critically to the transmission of the ions. The invention consists of completely decelerating the ions by means of collisions with a damping gas in an RF ion guide system, guiding them to the end of the ion guide system by active forward thrust, extracting them by a drawing lens system, and forming an ion beam with a low phase space volume. In particular, the ion guide system can take the form of a pair of wires coiled in a double helix and be surrounded by an envelope which is filled with the damping gas.
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