Coincidence technique to study ion-induced electron emission from atomically thin materials

Abstract

We introduce our multi-coincidence setup used to study the interaction of highly charged ions with atomically thin materials. Ions are transmitted through freestanding two-dimensional materials and detected charge separated on a position sensitive microchannel plate detector with delay line anode. Electrons emitted upon the interaction of the projectile with the target can be detected either using a silicon surface barrier detector or a hemispherical analyser in order to gain information on the number of emitted electrons and their energy distribution, respectively. All data is stored in a listmode file allowing to set filters (e.g., time of flight, charge states) post measurement to identify the origin of correlated ion-electron pairs, i.e. we can determine whether detected ions were transmitted solely through the two-dimensional material layer or through its support structure. Using this coincidence technique we can correlate specific charge exchange and ion stopping channels (i.e. energy deposition) with particular electron emission scenarios (yield and energy distribution).