本文估算了系统级封装(SIP)外壳内,受脉冲X射线辐照产生的电磁干扰(EMI)环境.首先通过蒙特卡罗数值方法计算了可伐合金及印制电路板(PCB)表面受X射线辐照激发电子的产额和能谱,并基于该计算结果开展了电子自洽运动的数值模拟.利用时域有限差分法(FDTD)和粒子模拟技术(PIC)对电子产生电磁场的过程进行了仿真.计算结果表明,电子的运动使得电子发射面附近的EMI环境最强.此外,从频谱可看出,电磁干扰主要集中在低频部分,且频率取决于X射线的时间参数.通过减小SIP外壳的受辐照面积及高度可降低外壳内的EMI环境强度.“,”This article aims to evaluate the electromagnetic interference (EMI) environ-ment in the shell of a system in package (SIP) while irradiated by a pulsed X-ray fluecne.First,the yields and energy spectra of photoelectrons induced by X-ray were calculated using Monte Carlo numerical simulations.These results were used to simulate the self-consistent movement of photoelectrons emitting from the Kovar alloy shell and the die-lectrical material of printed circuit board (PCB).The electromagnetic pulse (EMP) gen-erated by these photoelectrons were calculated using finite difference time-domain(FDTD) method and particle-in-cell (PIC) method.An analysis of the EMI environment in the shell of SIP was performed by numerical results.It is shown that the EMI envi-ronment adjacent to the emission surfaces turns more severe because of the movement of photoelectrons.And most of the radiation energy is located at low-frequency parts,which depends on the characteristic time of X-ray.Also,reducing the area of surfaces illuminated by X-ray and the height of SIP can lessen the threat from EMI.