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

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.