Quasi-planar gridless ion mirrors in multi-reflection time-of-flight mass analyzers

In the paper a method of periodic focusing of ions in the drift direction in a multi-reflection time-of-flight analyzer with zig-zag ion trajectories is considered. The method is based on a periodic modulation of spatial electrostatic field distribution in gridless ion mirrors in this direction. The considered way is alternative to conventionally used periodic lenses in planar multi-reflection time-of-flight analyzers. It allows confining ion packet sizes in the drift direction along the whole ion path. Besides, in combination with periodic lenses the described method enables forming spatial isochronosity of ion packets in the drift direction in the second aberration order and thus increasing the mass resolving power of the analyzer up to 1 000 000.