屏蔽电缆X射线辐照响应的有限元求解

Finite Element Method for the Response of Shielded Cable Irradiated by X-Ray

分析了X射线辐照电缆的物理过程,建立了基于有限元方法的二维诺顿等效电流源计算模型,将泊松方程、电场强度、电荷守恒方程等求解过程转换为矩阵和向量运算,并利用PETSc程序包编程计算,模拟了辐射感应电导率和间隙效应对屏蔽电缆X射线辐照响应的影响。结果显示,仅考虑辐射感应电导率效应时,随着X射线注量的增加,诺顿等效电流源逐渐趋于饱和,波形宽度变窄,并逐渐变为双极性波形。仅考虑间隙效应时,诺顿等效电流源幅度与间隙宽度近似成正比;间隙效应会大幅抵消辐射感应电导率效应的影响,诺顿等效电流源幅度仍近似正比于间隙宽度。该方法实现了电缆X射线辐照非线性效应的模拟,并将计算对象扩展到屏蔽多导体电缆。

The physical processes of the shielded cable irradiated by X-ray are analyzed,and a two dimensional Norton-equivalent current driver（NCD）calculating model used to simulate the processes is established based on the finite element method.The calculation processes,including the Poisson equation,electric field strength,and electric charge conservation equation are converted to Matrix and vector operations to write codes.The influence of radiation-induced conductivity（RIC）and gap effects on the responses of shielded cable irradiated by X-ray is simulated by portable extensible toolkit for scientific computation（PETSc）program.Considering the effect of radiation induced conductivity,the equivalent current becomes saturated and the wave width becomes narrower with the increase of energy fluence.When the gap effect is considered,the magnitude of Norton equivalent current is approximately proportional to the gap width,and the gap effect will greatly counteract the radiation-induced conductance.The method can be used to simulate the nonlinear effects of cable irradiated by X-ray,and the object is extended to shielded multi-conductor cable.