Since 2019, i am now Emeritus Senior Researcher and part of the Health Project of the pole Physics for Health and Environment at Laboratoire de Physique Corpusculaire in Clermont.Now i don't have any administrative tasks that yesterday took a lot of time and energy.I also change my field of interest in concentrating my work in radiobiology. Together with biologists, i work of biological dose effect enhancement in radio and proton therapy using Gold Nanoparticle targeting mitochondria of Prostatic cell (PC3). The main objectives are: 1°) understanding loacalization of the uptaked GNP in the cell, especially to demonstrate by microbeam imaging if they can go into the mitochondria. With the help of chemists of the group, we plan to get Gold Nanoparticle with TPP ligand to help GNP to penetrate mitochondria. 2°) simulating effect of these GNP under irradiation. Some experiments show that GNP are clusterized and this bulk matter could perhaps change physical inelastic cross section of produced secondaries electrons under irradiation. That is why i am investigating collective effects in bulk gold using dielectric frame work. 3°) effet of enhancement should be only quantified at nanometric scale, using microdosimetric theory.Science is beautifful and moreover increasing your personnal knowledge make you more happy !!