Evaluation Of Radiation-induced Damage Research Articles

Proton and gamma irradiation of novel tungsten boride and carbide candidate shielding materials

Low-activation cWC and RSBs show considerable promise as broad-spectrum radiation-dense materials suitable for use in compact spherical tokamaks (cSTs). The radiation response of novel radiation dense materials cemented tungsten carbide (cWC) and reactive sintered borides (RSBs) at ambient and non-ambient temperatures is investigated for the first time in this work.Sample irradiation consisted of 1.5 MeV protons at 408 K and at 873 K and 60Co gamma irradiation at 293 K and 77 K. Evaluation of radiation-induced damage via electron backscatter diffraction (EBSD) and TEM observed that cWCs have greater radiation attenuation than RSBs but RSBs have more diffuse dislocation distributions. Temperature at irradiation was observed to have a significant impact on dislocation presence with more diffuse dislocation presence in RSBs at 873K but with a well-defined damage front in cWCs as determined by changes in band contrast and indexing in EBSD and by dislocation presence in TEM. Dislocation presence observed to be significantly phase-dependant, particularly for cWC where the WC phase acts to absorb the bulk of radiation-induced dislocations. Both cWC and RSBs demonstrated significant γ-ray attenuation at 77 K with most radiation-induced changes confined to the top 25 µm from the incident face.

Evaluation of Radiation-Induced Damage in Membrane Ion Channels and Synaptic Receptors

The study of irradiation of brain cells with exposure to accelerated charged particles is essential topic in modern radiobiological research. Using Geant4-DNA based Monte-Carlo simulation of particle tracks we studied initial energy deposition and radiolytic species production within critical targets on neural cells: voltage-gated membrane channels and synaptic receptors. According to the modeling results the most probable targets for radiation damage can be attributed to synaptic receptors of GABA and NMDA type rather than ion channels. Indirect damage caused by chemical interaction with free radicals dominates over direct ionization events. We also provide an estimation for damage induction efficiency after the exposure with particles of different dose and linear energy transfer.