GRIDLESS ION-ACCELERATION SYSTEMS FOR TIME-OF-FLIGHT MASS-SPECTROMETRY

Pointlike ion sources allow the application of gridless acceleration s ystems in time-of-flight mass spectrometry (TOF/MS). When ions are ext racted from large sample areas according to the applied ionization met hod and sample geometry, the application of electrostatic lenses for a cceleration seems to be difficult. Inhomogeneous extraction fields are likely to induce acceleration time variations for ions emerging from different locations on the sample. We investigated gridless accelerati on systems with the help of computer simulations. An appropriate solut ion for TOF/MS was found and experimentally tested, combining the feat ures of compactness and a wide-acceptance aperture with simple princip les of construction.