Medium energy ion irradiation capability for studies of radiation damage effects over a wide temperature range

In this report, we present preliminary ion irradiation experiments performed using a new medium energy (up to ∼20 MeV), high temperature ion irradiation capability that we developed at Los Alamos National Laboratory. Details of ion fluence and irradiation temperature (including ion beam heating) control, measurements procedure and accuracy are described. In particular, we investigated irradiation-induced atomic intermixing in a layered structure composed of MgO and HfO₂ thin films deposited on a sapphire substrate. This multi-layered structure represents a dispersion nuclear fuel form surrogate. To simulate a nuclear reactor environment, we performed ion irradiation using 10 MeV Au ions to a fluence of 5 × 10¹⁵ cm^-2 at a substrate temperature of 1000 °C. The degree of atomic intermixing was assessed from depth profiles of Mg, Hf, and Al atoms, which were obtained using Rutherford backscattering spectrometry. We found considerable interlayer mixing for sample regions in close proximity to the sapphire substrate.