Determine the composition dependence of grain-boundary enrichment and trap parameters

Determine how the grain-boundary gadolinium enrichment factor and the trap parameter $n_{\rm crit}$ depend on Gd concentration in Gd-doped ceria, beyond the calibration available at 3 mol% Gd, in order to establish the composition dependence of the predicted neutron-induced grain-boundary impedance response.

Background

The model predicts the response as a function of Gd concentration using a calibration of the trap parameter at 3 mol% Gd and a fixed grain-boundary enrichment factor. The paper acknowledges that both quantities may vary with composition: gadolinium enrichment may saturate at high concentration, while the trap parameter may also change with Gd content.

Because these dependencies are not measured, the composition-series predictions are presented under baseline and alternative assumptions. Measurements under gamma irradiation are proposed as a way to test the composition dependence of the framework before conducting neutron experiments.

References

Two further factors are unknown and held fixed: the GB enrichment $f_{\rm enh}$, which probably saturates at high $x$, and the trap parameter $n_{\rm crit}$, calibrated at 3 mol% only.

— Prediction of the thermal neutron response of grain-boundary impedance in Gd-doped ceria based on the radiation-ionic effect  (2610.10191 - Zhang, 7 Oct 2026) in Section 5.3, “Gd content”