@article{oai:repo.qst.go.jp:00080895,
 author = {Murase, Ryu and Tsuchida, Hidetsugu and Tomita, Shigeo and Chiba, Atsuya and Nakajima, Kaoru and Majima, Takuya and Saito, Manabu and Atsuya, Chiba},
 journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms},
 month = {Nov},
 note = {We report first experimental results on the orientation effect of fast diatomic molecular projectiles on secondary ion emission processes for 3.6-MeV C2+ traversing a self-supporting target of phenylalanine (Phe) film evaporated on a carbon foil. Coincidence measurements were performed on the image of fragments resulting from the Coulomb explosion of C2+ projectiles and the time-of-flight mass spectrometry of secondary ions emitted from the Phe film. We compared the secondary ion yield for C2+ projectiles with parallel and perpendicular orientations to the beam direction. The parallel orientation was found to enhance the secondary ion yield by a factor of approximately 1.1 compared with that for the perpendicular orientation. This enhancement corresponds to an increase in the average charge of Coulomb-exploded fragments. This finding implies that there is a linear correlation between the electronic energy deposition causing secondary ion production and the effective charge number of the incident molecular ions which interact with biomolecular targets.},
 pages = {284--289},
 title = {Effects of molecular axis orientation of MeV diatomic projectiles on secondary ion emission from biomolecular targets},
 volume = {478},
 year = {2020}
}