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The Telescope Array experiment studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated when a primary cosmic ray particle interacts with the atmosphere. Meanwhile, scintillator detectors measure the lateral distribution of secondary shower particles that hit the ground. The Middle Drum (MD) fluorescence telescope station consists of 14 telescopes from the High Resolution Fly’s Eye (HiRes) experiment, providing a direct link back to the HiRes measurements. Using the scintillator detector data in conjunction with the telescope data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum is presented and compared to that measured by the Middle Drum station in monocular mode. Further, the hybrid data establishes a link between the Middle Drum data and the surface array. A comparison between the Middle Drum hybrid energy spectrum and scintillator Surface Detector (SD) spectrum is also shown.

Fe(C5H5)2+ and FeC5H5+ ions undergo ligand dissociation upon collision with an Si(100) surface at hyperthermal energy (5–120 eV). The dissociation starts at a collision energy of 5 eV for the both ions, in agreement with the reaction energetics. However, the dissociation yield for FeC5H5+ is much lower than for Fe(C5H5)2+ at the energies above the dissociation threshold. This result suggests that the molecular shape has a strong influence on the short-time dynamics of polyatomic ion dissociation at a surface.