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Hydrogen Ion Beams from Nanostructured Gas Field Ion Sources

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div class="title">Hydrogen Ion Beams from Nanostructured Gas Field Ion Sources - Volume 22 Issue S3 - Hironori Moritani, Radovan Urban, Mark Salomons, Robert Wolkow, Jason Pitters

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  • J L Pitters
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  • M Rezeq
  • J Pitters
  • R Wolkow
Rezeq, M., J. Pitters, and R. Wolkow, Journal of Chemical Physics, 2006. 124(20).