Abstract
Isochronal annealing, neutron total scattering, and Raman spectroscopy were used to characterize the structural recovery of polycrystalline ThO2 irradiated with 2-GeV Au ions to a fluence of 1 × 1013 ions/cm2. Neutron diffraction patterns show that the Bragg signal-to-noise ratio increases and the unit cell parameter decreases as a function of isochronal annealing temperature, with the latter reaching its pre-irradiation value by 750 °C. Diffuse neutron scattering and Raman spectroscopy measurements indicate that an isochronal annealing event occurs between 275–425 °C. This feature is attributed to the annihilation of oxygen point defects and small oxygen defect clusters.
Original language | English |
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Pages (from-to) | 15-21 |
Number of pages | 7 |
Journal | Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms |
Volume | 405 |
DOIs | |
State | Published - Aug 15 2017 |
Externally published | Yes |
Funding
This research is funded by the Office of Basic Energy Sciences of the U.S. Department of Energy as part of the Materials Science of Actinides Energy Frontier Research Center (DE-SC0001089). The research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy. R.I.P. gratefully acknowledges support from the U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA) through the Carnegie DOE Alliance Center (CDAC) under Grant number DE-NA-0002006. The authors thank Jacob Shamblin, Brandon Perlov, and Jason Behrens for assistance with the neutron scattering measurements.
Keywords
- Annealing
- Defects
- Neutron total scattering
- Raman spectroscopy
- Swift heavy ions
- ThO