Institute of Nuclear Energy Research, 1000, Wen-Hua Road, Longtan, Taoyuan 325207, Taiwan.
Institute of Nuclear Engineering and Science, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 300044, Taiwan.
Radiat Prot Dosimetry. 2023 Jul 5;199(11):1174-1183. doi: 10.1093/rpd/ncad154.
In this study, an intricate combinatorial geometry model of a Boeing 777-300ER aircraft was constructed for Monte Carlo transport simulations. The aircraft-induced perturbations of the energy spectra and effective doses of secondary cosmic rays at a typical civil aviation altitude (10 km) were investigated on a component-by-component basis, which included neutrons, protons, photons, electrons, positrons, muons and charged pions. Two geomagnetic cutoff rigidities (1.35 and 15.53 GV) and two solar modulation parameters (430 and 1360 MV) were considered in the aforementioned simulations. The characteristics of various cosmic-ray components at six locations along the fuselage were assessed and compared with those of an unperturbed radiation field in the atmosphere. Aircraft structures and contents reduced the effective doses of personnel inside the aircraft to varying degrees, up to an ~32% reduction in the middle section of the passenger cabin. On average, the dose reduction was ~12-16% depending on geomagnetic and solar conditions. Quantifying the aircraft's self-shielding effects can further improve the estimation accuracy of aircrew and passengers' exposure to cosmic radiation. Information regarding the perturbed energy spectra of cosmic rays may be useful for designing onboard experiments or analyzing onboard measurement data.
在这项研究中，为蒙特卡罗输运模拟构建了一个波音 777-300ER 飞机的复杂组合几何模型。基于逐个组件的方式，研究了飞机在典型民航高度（10km）对能量谱和次生宇宙射线有效剂量的扰动，这些组件包括中子、质子、光子、电子、正电子、μ子和带电π介子。在上述模拟中，考虑了两种地磁屏蔽强度（1.35 和 15.53GV）和两种太阳调制参数（430 和 1360MV）。评估了沿机身六个位置的各种宇宙射线组件的特性，并将其与大气中未受扰的辐射场进行了比较。飞机结构和内部物品在不同程度上降低了飞机内部人员的有效剂量，在客舱中段的降低幅度高达约 32%。平均而言，剂量降低取决于地磁和太阳条件，约为 12-16%。量化飞机的自屏蔽效应可以进一步提高对机组人员和乘客暴露于宇宙辐射的估计准确性。关于宇宙射线受扰能谱的信息可能有助于设计机载实验或分析机载测量数据。
