An apparatus to investigate the fragmentation of molecular dications by electron impact

An experimental setup to study the fragmentation of molecular dications formed via inner shell ionization by electron impact is described. The main components of the setup are a cylindrical mirror analyzer, CMA, used to detect the Auger electrons, which mark the molecular site where the ionization occurred and select the state of the dication, and a time of flight mass spectrometer, TOF-MS, used to detect the parent doubly charged ion or its fragments. The fragmentation is studied via Auger electron-ion and Auger electron-ion-ion coincidence experiments. The results of the measurements used to characterize the spectrometer are presented and discussed. Then the potentialities of the setup are described via selected examples of its applications.