Fig. 2

Approach used for studying ultra-high dose rate irradiation using the general-purpose Geant4 toolkit and its Geant4-DNA extension. Geant4: modeling of the irradiation facility in full-scale conditions, including the eRT6 linac and the irradiated sample housed within the water tank. The sample acts as a computational volume for characterizing electron distributions. Geant4-DNA: geometry of the simulated water system, with the sphere surface serving as a source for the eRT6-specific electrons. For illustrative purposes, the colored dots indicate the positions of excited/ionized water molecules and solvated electrons arising from various primary electrons during a 1 µs pulse of 5 mGy. The emission time points associated with each primary electron are also displayed, illustrating the temporal structure of the irradiation. Δt denotes the time interval between successive electrons or bunches of electrons within the simulated pulse.