Computational study of alpha-ray induced electron excitation in diamonds for radiation detection

Abstract

To investigate the mechanism of radiation detection in diamonds, we developed a real time time dependent density functional theory based calculation scheme to evaluate changes in the density of states induced by alpha ray irradiation. A bulk diamond structural model was constructed, with impurities optionally introduced to assess their effect on electronic excitation. Simulations revealed that the passage of high speed helium ions, representing alpha particles, produced significant electronic excitation in the diamond model. Subsequent calculations of the excited state dynamics after ion removal indicated that excitation can persist for several hundred femtoseconds without triggering nonradiative relaxation. These findings demonstrate that the proposed approach offers a robust theoretical framework for evaluating the performance of diamond-based radiation detectors.