Converting a reflectron time-of-flight mass spectrometer into a tandem instrument

Adding a simple mass gate at the first time focus of a reflectron-type time-of-flight mass spectrometer, one mass can be selected and its further decay or interaction studied. A new type of mass gate is described that does not have any grids. It is especially suitable for cluster studies. Three processes are identified that lead to an undesirable high background in a reflectron time-of-flight mass spectrometer.