Most of Monte Carlo Simulation (MCS) toolkits used to estimate the biological damage induced by radiations in cells consider these latter as composed of single water molecule. In this work, we used the Geant4-DNA MCS toolkit to evaluate the biological damage in cells modeled as clusters of water molecules instead of single water molecule. Increasing the number of molecules in water clusters enable to approximate liquid phase. Total cross sections for the ionization of small water clusters by electron impact are calculated. The first Born approximation is used to describe the collision dynamics where the incident and the scattered electrons are described by plane waves while the ejected electron is described by a Coulomb wave. Electrons belonging to the target molecule are described by a single-center molecular wave function. Using calculated cross sections, a scaling law and a universal curve are extracted to predict cross sections for the ionization of water clusters by single electron impact. These cross sections are implemented in Geant4-DNA to simulate the number of ionizations, mean-free path, range, stopping power, and the number of double and single strand breaks.

中文翻译：

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水簇的电离截面作为液相水的替代品：Geant4-DNA 模拟研究

大多数用于估计细胞中辐射引起的生物损伤的蒙特卡罗模拟 (MCS) 工具包都认为细胞由单个水分子组成。在这项工作中，我们使用 Geant4-DNA MCS 工具包来评估以水分子簇而不是单个水分子为模型的细胞中的生物损伤。增加水簇中的分子数量可以接近液相。计算了通过电子撞击电离小水簇的总横截面。第一玻恩近似用于描述碰撞动力学，其中入射电子和散射电子由平面波描述，而弹出电子由库仑波描述。属于目标分子的电子由单中心分子波函数描述。使用计算的横截面，提取比例定律和通用曲线来预测单电子撞击水簇电离的横截面。这些横截面在 Geant4-DNA 中实现，以模拟电离次数、平均自由程、范围、阻止能力以及双链和单链断裂的数量。