## 3 Results and Discussion
### Simulation of Multilayer Shield  
Taking the particle environment of the FY-3 satellite's orbit as input, the flux of electrons and protons in the radiation belt and the solar proton fluence can be used as a planar source. The AE-8 MAX and AP-8 MAX models, developed by the NSSDC of the United States, are used to determine the electron and proton beams of the Earth's radiation belt, respectively. Additionally, NSSDC's King model (95% confidence) is used for solar proton fluence. This paper computes the radiation dose received by the satellite's position over an 8-year mission, with orbital parameters provided in Table 3. \begin{table}
\begin{tabular}{c c} \hline \hline
**Index** & **Parameters** \\ \hline Categories & NPSSO \\ Orbital altitude & 836.0 km \\ Orbital inclination & 98.75\({}^{\circ}\) \\ Orbital eccentricity & \(\leq\)0.0025 \\ Orbital period & 101.5 min \\ Longitude of ascending node & 14:00 PM \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Orbital parameters of FY-3 satellite. Figure 8: Omnidirectional protection thickness with PCB. (**a**) \(D_{E}\) = 0 mm; (**b**) \(D_{E}\) = 3 mm; (**c**) \(D_{E}\) = 6 mm. As depicted in Figure 9a, the electron flux distribution in the radiation belt showcases an energy range from 0.04 MeV to 6 MeV, with flux concentration in energies less than 3 MeV. Similarly, Figure 9b illustrates the proton flux distribution within the same zone, where the energy range is mainly between 0.1 MeV and 300 MeV, with flux intensity primarily below 100 MeV. Lastly, Figure 9c elucidates the solar proton fluence distribution, featuring an energy range predominantly between 0.1 MeV and 500 MeV, with high fluence concentration in values lower than 50 MeV. The multi-layer shielding materials have a three-layer planar geometry consisting of Al, Ta, and HDPE arranged in sequence (Al-Ta-HDPE). The distance between the object and the shielding layer is 5 mm, and the object thickness is chosen for typical 0.1 mm semiconductor silicon wafers used in the device. The total equivalent Al thickness for the shielding materials was selected as 3 mm, 5 mm, and 7 mm, and the shielding calculation results for the three materials with different thickness ratios are shown in Figure 10. When the equivalent Al thicknesses of Al, Ta, and HDPE are 0.7 mm, 2.8 mm, and 3.5 mm, respectively, the total equivalent Al thickness is 7 mm, yielding the lowest TID in the object, which is 71% lower than the maximum dose. However, for total equivalent Al thicknesses of 3 mm or 5 mm, even if the three materials reach the best mass ratio, the lowest ionization dose in the object is only 57 % lower than the highest dose. Under the same mass, different combinations of materials can yield different shielding results. Simulation analysis can estimate the better shielding effect of some materials with different thickness components. Even with the same mass ratio of three materials, the ionization dose trends obtained in the object differ. The relative thickness of shielding materials varies dynamically with the energy of incident particles. When the energy is large, the thickness of shielding material will be relatively small, which is not enough to completely attenuate the electron energy. In such cases, Ta has better shielding results than Al and HDPE. When the incident energy is small, the thickness of shielding materials will be comparatively large, which can completely block the incident electrons. However, bremsstrahlung produces X-rays that contribute significantly to the ionizing dose in the object, making the combination of appropriate shielding materials relatively effective. Figure 9: Particle environment in the orbit of the FY-3 satellite. The horizontal axis represents the energy of incident particles, while the main vertical axis shows the integral flux of omnidirectional particles. Additionally, the secondary vertical axis displays the differential flux of particles.