Investigations of Zipping Mechanism in Relativistic Heavy Ion Interactions With Carbon Onions
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Investigations of Zipping Mechanism in Relativistic Heavy Ion Interactions With Carbon Onions RA Al-Duhaileb1, K Xie1, VM Ayres1, RM Ronningen2, AF Zeller2, T Baumann2, A Hirata3 1 College of Engineering, Michigan State University, East Lansing, MI 48824, U.S.A 2 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, U.S.A. 3 Graduate School of Mechanical Sciences, Tokyo Institute of Technology, Tokyo 152-8550, Japan ABSTRACT The interactions of fully stripped Argon-40 heavy ion beams with 140 MeV/nucleon with a series of increasingly polygonal carbon onions are investigated by high-resolution transmission electron microscopy and thermogravimetric analysis. The experimentally observed graphene layer linking is compared with expected results from the displacement and dislocation migration models. The results suggest that dislocation-driven mechanisms may play a significant role in graphene layer linking induced by heavy ion interactions with carbon onions. INTRODUCTION Carbon nanostructures and their composites are under investigation as structural elements1 and/or lubricants2 in environments that involve heavy ion exposure, including space and particle accelerator environments. In the present work, we report the results of an investigation of carbon onion interactions with Argon-40 heavy ion primary beams with an initial kinetic energy of 140 MeV/nucleon. This is comparable to the energy of heavy ions in the solar wind. The investigation was performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University, which enabled well-calibrated energy depositions to be achieved. Irradiation times were based on experimental masses and volumes and selected to result in a 10,000 Gray (Gy: Joule/kg) cumulative total dose for each sample. One observed experimental response was the linking of graphene layers. The actual results were compared expected layer linking results from two different models. The best-studied model for radiation interactions with graphene is interaction through displacement “knock-on” collisions, which produce dangling bonds and interstitial carbon atoms3,4,5,6,7. The dangling bonds and loose carbon atoms then rearrange into energy-lowering configurations. A new model for graphene layer rearrangement by “zipping” driven by dislocation migration mechanisms that are only available in multi-layer radial situations has been proposed recently8. Our results suggest that the newly identified dislocation-driven mechanisms may also play a significant role in graphene layer linking induced by heavy ion interactions with carbon onions. EXPERIMENT An Argon-40 18+ (fully stripped) primary beam with energy of 140 MeV/nucleon (MeV/u) was focused to uniformly irradiate a circular 300 mm2 area measured from known dimensional markings on a beam-viewing scintillator plate prior to the experiments. After passing through a 0.075 mm zirconium (Zr) foil exit window (ΔE = -1.45 MeV/u), a 493.8 mm air gap (ΔE = -2.64
MeV/u), and a 0.2 mm mica coverslip th
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