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William Sawyer1 Ellen Farmer1

1, West Chester University, West Chester, Pennsylvania, United States

In an effort to identify suitable materials for storing high level radioactive waste, recent research suggests that pure and doped ZrO2 nanocrystals could be suitable candidates. It has been suggested that when placed in an intense high level radiation environment these nanocrystals exhibit enhanced resistance to structural disintegration compared to their bulk counter parts. The mechanisms through which radiation loses energy results in a very large flux of low energy electrons. To date, radiation damage in ZrO2 nanocrystals by electrons with energies below 200 keV has not been reported. We have found direct evidence of extensive radiation damage in ZrO2 nanocrystals due to intense bombardment (2 x 102 electrons/nm2 sec) by electrons with beam energies between 60 keV and 120 keV. Intense electron irradiation in this energy range produces a significant loss of Zr and O from the nanocrystal resulting in TEM images of hollow or “ghost” like structures which retain the stoichiometry of the nanocrystal. We present an explanation based on the Knotek-Feibelman process.

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