The collision of a hypervelocity massive projectile with free-standing graphene: Investigation of secondary ion emission and projectile fragmentation

International audience; We present here the study of the individual hypervelocity massive projectiles (440-540 keV, 33-36 km/s Au-400(4+) cluster) impact on 1-layer free-standing graphene. The secondary ions were detected and recorded separately from each individual impact in the transmission direction using a time-of-flight mass spectrometer. We observed C-1-10(+/-) ions emitted from graphene, the projectiles which penetrated the graphene, and the Au-1-3(+/-) fragment ions in mass spectra. During the projectile-graphene interaction, the projectile loses similar to 15% of its initial kinetic energy (similar to 0.18 keV/atom, 72 keV/projectile). The Au projectiles are neutralized when approaching the graphene and then partially ionized again via electron tunneling from the hot rims of the holes on graphene, obtaining positive and negative charges. The projectile reaches an internal energy of similar to 450-500 eV (similar to 4400-4900 K) after the impact and then undergoes a similar to 90-100 step fragmentation with the ejection of Au-1 atoms in the experimental time range of similar to 0.1 mu s.