Bioengineering postdoctoral researcher Elena de Juan Pardo was recently honored with the Otto Hahn Medal for outstanding scientific achievement.
Before coming to Berkeley, de Juan did research for three years in the Materials Research Division of the Max Planck Institute for Plasma Physics. Her work at the institute was done in partnership with the Centro de Estudios e Investigaciones Técnicas and TECNUN, the technological campus of the University of Navarra, where she received her Ph.D. Her research focused on carbon-based materials as plasma-facing materials for the successful operation of fusion devices with magnetically confined plasma, such as the planned International Thermonuclear Experimental Reactor (ITER).
The Otto Hahn Medal is awarded each year to no more than forty promising young researchers from among the thousands who work with the Max Planck Institute. De Juan was the only female researcher chosen in the field of Chemistry and Physics. In addition to the medal, the award provides research funding and up to one year of funding to research in another country.
De Juan has chosen to come to UC Berkeley to work with Assistant Professor Irina Conboy on biomaterials, specifically engineering cell fate through satellite stem cells.
Carbon-based materials are the unique choice as plasma-facing materials (PFMs) for the successful operation of fusion devices with magnetically confined plasma, such as the planned International Thermonuclear Experimental Reactor (ITER), in order to withstand the highest expected power densities (up to 20 MW/m2) without major degradation. Particularly, carbon fibre reinforced carbon materials (CFC) has been suggested as good PFM choice for certain areas of the vessel wall of ITER, due to their improved mechanical properties compared to other carbon materials, in spite of the high costs associated with their manufacture. But carbon-based materials possess a high chemical reactivity with hydrogen ions incident from the plasma as well as the ability to trap hydrogen in co-deposited layers, leading to short lifetime of the components and high tritium inventories, i.e. risk of radioactive contamination. As an alternative to CFCs, new isotropic fine-grain graphites doped with metal carbides have been produced in order to reduce the high chemical erosion yield under hydrogen impact. This reduction would simultaneously diminish the co-deposition and increase the lifetime of the carbon components. With the addition of dopants further beneficial effects are searched, such as an enhancement of the thermal conductivity as well as improved mechanical properties. The chemical erosion behaviour and the deuterium retention of these improved doped graphites under deuterium bombardment are characterised in this work. Due to the expectation of a more pronounced effect of doping with a finer distribution of the dopants, magnetron-sputtered nano-dispersed metal-doped carbon films were additionally investigated in order to elucidate the mechanisms of the mitigation of the chemical erosion. The obtained results are very promising: at low temperatures and deuterium impact energies, dopant enrichment on the surface due to preferential sputtering of carbon strongly contributes to a reduction of the erosion yield; at elevated temperatures, an almost complete suppression of the chemical erosion yield measured by the production of CD4 molecules is observed when dopants are nano-dispersed, which can be explained by a reduction of the activation energy for hydrogen release; and finally, the investigated doped graphites have a similar or even lower deuterium retention by implantation than other graphites.