【摘要】 为研究水面瞬发核辐射环境的空间分布特征与规律，建立了中子和γ射线在水面上输运的蒙特卡罗模拟模型，采用全局减方差方法提高计算效率，使典型场景下全局品质因子FOM_G提高约2个量级。开展了不同条件下瞬发中子和γ射线在非均匀大气-海水模型中的输运模拟，得到了中子、中子次级γ和γ的组织剂量及硅剂量等辐射环境参数及其空间分布特征。研究结果表明：目标处瞬发辐射剂量随源心距和水平距离的增加而减小，随高度的增加先增加后减小。距水面一定距离的大型舰艇及其上人员装备等目标总剂量比水面处更大，典型场景下两者差异达约30%。由于源心距和周围介质吸收、散射等的综合作用，当水平距离一定时，目标处瞬发辐射剂量随爆炸高度先增加后减小，因此存在某一个爆炸高度使得目标剂量最大，且该爆炸高度随目标水平距离增加呈逐渐增加的趋势。更多还原

【Abstract】 To investigate the spatial distribution characteristics and patterns of the prompt nuclear radiation environment over water surfaces, a Monte Carlo simulation model for the transport of neutron and γ ray on water surface is established. The global variance reduction method is employed to enhance computational efficiency, resulting in an improvement of approximately two orders of magnitude in the global figure of merit(FOM_G) for typical scenarios. Simulations of the transport of prompt neutron and γ ray in a heterogeneous atmosphere-seawater model under various conditions are conducted, yielding radiation environment parameters such as neutron, neutron secondary γ, and γ tissue doses and silicon doses, as well as their spatial distribution characteristics. The results show that the prompt radiation dose at target decreases with increasing source-to-target distance and horizontal distance, while it first increases and then decreases with increasing height. Targets, such as lighthouses, located a certain distance from the water surface exhibit a greater total dose compared to those at the water surface, with a difference of approximately 30% in the typical scenarios. Due to the combined effects of the source-to-target distance and the absorption and scattering of surrounding media, the prompt radiation dose at target increases initially and then decreases with increasing explosion height when the horizontal distance is fixed. Therefore, there exists an optimal explosion height that maximizes the prompt radiation dose at target, and this height tends to increase with increasing horizontal distance to the target.更多还原