To better study biological effects of space radiation using ground-based facilities, the NASA Space Radiation Laboratory (NSRL) at the Brookhaven National Laboratory has been upgraded to rapidly switch ions and energies. This has allowed investigators to design irradiation protocols comprising a mixture of ions and energies more indicative of the galactic cosmic ray (GCR) environment. Despite these advancements, beam selection and delivery schemes should be optimized against facility and experimental constraints and validated to ensure such irradiations are a suitable representation of the space environment. Importantly, since experiments are time consuming and expensive, models capable of predicting biological outcomes over a range of irradiation conditions (single ion, sequential multi ion or mixed fields) are needed to support such efforts. In this work, human fibroblasts were placed behind 20 g/cm² aluminum and 10.345 g/cm² polyethylene and irradiated separately by 344 MeV hydrogen, 344 MeV/n helium, 450 MeV/n oxygen and 950 MeV/n iron ions at various doses. The fluorescence in situ hybridization (FISH) whole chromosome painting technique was then used to assess the cells for chromosome aberrations (CAs), notably simple exchanges. A multi-scale modeling approach was also developed to predict the formation of chromosome aberrations in these experiments. The Geant4 simulation toolkit was used to determine the spectra of particles and energies produced by interactions between the incident beams and shielding. The simulated mixed field generated by shielding was then transferred into the track structure code, RITRACKS (relativistic ion tracks), to generate three-dimensional (3D) voxelized dose maps at the nanometer scale. Finally, these voxel dose maps were input into the new damage and repair model, RITCARD (radiation-induced tracks, chromosome aberrations, repair and damage), to predict the formation of various CAs. The multi-scale model described herein is a significant advancement for the computational tools used to predict biological outcomes in cells exposed to highly complex, mixed ion fields related to the GCR environment. Results show that the simulation and experimental data are in good agreement for the complex radiation fields generated by all ions incident on shielding for most data points. The differences between model predictions and measurements are discussed. Although improvements are needed, the model extends current capabilities for evaluating beam selection and delivery schemes at the NSRL ground-based GCR simulator and for informing NASA risk projection models in the future.

为了更好地研究使用地面设施的空间辐射的生物效应，布鲁克海文国家实验室的NASA空间辐射实验室（NSRL）已升级，可以快速切换离子和能量。这使研究人员能够设计出辐照方案，其中包含离子和能量的混合物，更能指示银河系宇宙射线（GCR）环境。尽管取得了这些进步，但应针对设施和实验约束条件对射束选择和传输方案进行优化，并进行验证，以确保此类辐射能够适当代表空间环境。重要的是，由于实验既费时又昂贵，因此需要能够在一定范围的辐照条件下预测生物结果的模型（单离子，顺序多离子或混合场）来支持这种工作。²铝和10.345 g / cm ²聚乙烯，分别用344 MeV氢，344 MeV / n氦气，450 MeV / n氧和950 MeV / n铁离子分别照射。原位荧光杂交（FISH）全染色体绘画技术随后用于评估细胞的染色体畸变（CA），尤其是简单的交换。还开发了一种多尺度建模方法来预测这些实验中染色体畸变的形成。Geant4仿真工具包用于确定由入射光束和屏蔽层之间的相互作用产生的粒子和能量的光谱。然后将通过屏蔽产生的模拟混合场转移到轨道结构代码RITRACKS（相对论性离子轨道）中，以生成纳米级的三维（3D）体素化剂量图。最后，将这些体素剂量图输入到新的损伤和修复模型RITCARD（辐射诱导的轨迹，染色体畸变，修复和损伤）中，以预测各种CA的形成。本文所述的多尺度模型对于用于预测暴露于与GCR环境相关的高度复杂的混合离子场的细胞中的生物学结果的计算工具具有重大进展。结果表明，对于大多数数据点而言，所有离子入射到屏蔽物上所产生的复杂辐射场的仿真和实验数据都非常吻合。讨论了模型预测和测量之间的差异。尽管需要改进，但该模型扩展了当前的功能，可用于评估基于NSRL地面GCR模拟器的波束选择和传输方案，并在将来通知NASA风险预测模型。与GCR环境有关的混合离子场。结果表明，对于大多数数据点而言，所有离子入射到屏蔽物上所产生的复杂辐射场的仿真和实验数据都非常吻合。讨论了模型预测和测量之间的差异。尽管需要改进，但该模型扩展了当前的功能，可用于评估基于NSRL地面GCR模拟器的波束选择和传输方案，并在将来通知NASA风险预测模型。与GCR环境有关的混合离子场。结果表明，对于大多数数据点而言，所有离子入射到屏蔽物上所产生的复杂辐射场的仿真和实验数据都非常吻合。讨论了模型预测和测量之间的差异。尽管需要改进，但该模型扩展了当前的功能，可用于评估基于NSRL地面GCR模拟器的波束选择和传输方案，并在将来通知NASA风险预测模型。