The Joint Institute for Nuclear Research awarded the JINR Prize for 2020 to the team whose member is Dr. Nikita Medvedev, deputy head of the theory group in the Department of Radiation and Chemical Physics (Institute of Physics) and head of the theory group in the Laser Plasma Department (Institute of Plasma Physics).
The team won the first prize in the category of the Applied Physics Research for an article entitled “Experimental study and multiscale modeling of latent tracks structure in radiation resistant dielectrics” .
It is based on the series of papers devoted to understanding the ultrafast response of insulators to fast heavy ion irradiation [1,2]. In a collaborative work between Institute of Physics and Institute of Plasma Physics of the CAS, JINR and Kurchatov Institute in Russia, and Nelson Mandela University in South Africa, a comprehensive simulation of the ion impacts was developed and validated against experiments. Combining state-of-the-art experimental observation of nanostructure of tracks induced by an ion impact with the advanced modelling, various effects and stages of electronic and atomic kinetics were investigated.
It was found that despite the fact that non-equilibrium stage of electron kinetics defines initial conditions for the further atomic dynamics, the ultimate observable tracks are mainly defined by the ability of the material to recrystallize. Recrystallization, in turn, is connected to the complexity of atomic structure. The transient atomic disorder in non-amorphizable materials may be significantly larger than the final observable tracks. Moreover, a mismatch was observed between the energy deposition profile of charged particle and the size of the created track (see Figure below). In particular, the maximum damage does not coincide with the Bragg peak - the region of maximum energy deposition by a fast heavy ion - which has important implications for practical applications of ion irradiation including nanotechnology and radiation therapy of cancer.
 R. A. Rymzhanov, J. H. O’Connell, A. Janse van Vuuren, V. A. Skuratov, N. Medvedev, and A. E. Volkov: J. Appl. Phys.127, 015901 (2020).
 R. A. Rymzhanov, N. Medvedev, J. H. O’Connell, V. A. Skuratov, A. Janse van Vuuren, S. A. Gorbunov, and A. E. Volkov: Nucl. Instrum. Met. Phys. Res. B473, 27 (2020).