Analysis of cross-section data used in the Monte Carlo track structure simulation

1)本研究的目的是对电子径迹结构规范中使用的水截面进行比较和评价。本研究的目的是阐明什么程度的输入数据和物理和化学假设之间的差异影响的结果在生物物理模拟的辐射效应。2）电离截面和光谱的二次电子计算的各种理论。分析是针对水蒸气截面进行的，因为这些截面更丰富，更容易获得。所有适当发表的实验总电离截面由一个适当的函数拟合，并用于产生电子轨道。三组汇编数据用于总激发截面和平均激发能的比较。3）使用各种截面组合，根据相互作用和点核的径向分布，比较由Monte Carlo径迹代码生成的径迹。电离过程中发射的二次电子的光谱被认为是这些数量的最有影响力的因素。一组不同的激发和弹性散射的横截面没有影响电子轨道结构尽可能多的电离截面。结果表明，目前用于生物物理模拟的不同截面和不同相位的程序在大尺寸目标上表现出相似性，而在DNA目标上表现出明显的差异。4）我们推荐了适用于总电离截面和弹性截面实验数据的拟合函数。我们的结论是，大多数代码产生的轨道在合理的协议与宏观量，如总阻止能力和总产量的链断裂。然而，我们预测在轨道上的聚类频率的差异。

1) The purpose of this study is to make an intercomparison and assessment of cross sections for water used in electron track structure codes. This study is intended to shed light on to what extend the differences between the input data and physical and chemical assumptions influence the outcome in biophysical modelling of radiation effects.2) lonisation cross sections and spectra of secondary electrons were calculated by various theories. The analyses were carried out for water vapor cross sections as these are more abundant and readily available. All suitably published experimental total ionization cross sections were fitted by an appropriate function and used for generation of electron tracks. Three sets of compiled data were used for comparison of total excitation cross sections and mean excitation energy.3) The tracks generated by a Monte Carlo track code, using various combinations of cross sections, were compared in terms of radial distributions of interactions and point kernels. The spectrum of secondary electrons emitted by the ionization process was found to be the most influential factor on these quantities. A different set of cross sections for excitation and elastic scattering did not affect the electron track structure as much as did ionization cross sections. It is concluded that all codes, using different cross sections and in different phase, currently used for biophysical modelling exhibit close similarities in larger size targets while appreciable differences are observed at DNA size targets.4) We recommend fitted functions to all available suitable experimental data for the total ionization and elastic cross sections. We conclude that most codes produce tracks in reasonable agreement with the macroscopic quantities such as total stopping power and total yield of strand breaks. However, we predict differences in frequencies of clustering in track.