Influence of grain size and porosity on the release of radioactive isotopes from target materials with high open porosity

Characterization of uranium carbide target materials to produce neutron-rich radioactive beams

“…On the one hand, yields of Cs and Fr isotopes were measured higher using high density UC target material with a grain size of 5 lm instead of 20 lm [12]. On the other hand, for elements having short sticking times, the calculated release efficiency presents a maximum when the UC-grain diameter is below 1 lm; for elements with medium and long sticking times, the optimal grain size is found to be in the 1-10 lm range [39,40]. The grain size distributions observed in our study are not sufficiently homogeneous to highlight a correlation between the grain size and the release properties, but behavior differences between elements with long (Sn) or short (Kr) sticking time were identified.…”

Development of radioactive beams at ALTO: Part 1. Physicochemical comparison of different types of UCx targets using a multivariate statistical approach

“…Going to a nanometric structure, where the diffusion paths will be minimized, should all the more improve the release. Some release simulations of different isotopes by UCx targets were carried out with the RIBO code in order to study the release dependence upon grain size and porosity [37], [38]. In the case of isotopes with short sticking time, reducing the size of the grains improves the FPs release.…”

Development of radioactive beams at ALTO: Part 2. Influence of the UCx target microstructure on the release properties of fission products

“…It was recently suggested that the reaction rate velocity during carburization could also be a point to be optimized [33]. In addition to experimental approaches [34]- [36], the release dependence upon grain size and porosity has been studied for various isotopes in UCx targets by simulations carried out with the RIBO code [37], [38]. Finally, recent results on UCx targets have shown that using refractory targets with a nanometric structure enables the production of new and more exotic radioactive isotope beams [22].…”