Multireflection planar time-of-flight mass analyzer. I: An analyzer for a parallel tandem spectrometer

To increase the speed and selectivity of tandem mass-spectrometric analysis, a tandem of two time-of-flight analyzers that operate in a radically new “nested time” mode is proposed. Such an approach makes it possible to perform parallel analysis of the fragment spectra for all parent ions within a single separation cycle using the first (“slow”) analyzer. The method suggested can be implemented with a new “slow” time-of-flight analyzer, which combines lateral confinement of a low-energy ion beam in periodic lenses and multiple reflection of the ions from planar gridless mirrors. Also, the new approach opens the way to considerably extending the effective length of the ion trajectory, while retaining the possibility of operating in the entire mass range and providing high-order time-of-flight ion focusing in energy. As follows from the analytical data and the experimental data obtained on a prototype of the analyzer, the instrument offers a high transmission (no less than 6 mm×1.5° in either direction transverse to the beam), good resolving power (more than 5000), and wide (six orders of magnitude) dynamic range.