Novel Insight into Defect Behavior of Irradiated Materials—Combined Neutron Total Scattering and High Temperature Calorimetry Investigation

We present neutron total scattering combined with high-temperature calorimetry as a new strategy for the characterization of radiation effects in materials. Irradiation experiments were performed at the GSI Helmholtz Center with heavy ions of specific energy of 11.4 MeV/u. The use of such ions (penetration depth: ~100 µm) produces the sufficiently large irradiated sample mass (~150 mg) required for bulk structural and thermodynamic analysis. Neutron scattering was performed at the Nanoscale Ordered Materials Diffractometer at the Spallation Neutron Source (Oak Ridge National Laboratory). High temperature oxide melt solution calorimetry and differential scanning calorimetry was utilized to investigate the thermodynamic properties and energetic evolution using the same set of irradiated samples. We studied various ion-induced structural modifications, such as defect formation (CeO₂), disordering (Er₂Sn₂O₇), and amorphization (Dy₂Ti₂O₇). Our analytical approach demonstrated that irradiation-induced modifications are more complex than previously thought with distinct processes occurring over different length scales and temperature regimes.