用传输线和时域有限差分法计算电缆X射线响应

 介绍了时域传输线和时域有限差分两种计算电缆X射线瞬态响应的方法，并利用电缆芯线总电荷以及介质层的电荷分布，结合实验结果，分别给出了时域传输线模型中的电流源和时域有限差分模型中电流密度的计算方法。作为例子，在60 keV单能X射线垂直于电缆轴向辐照的条件下，采用两种方法计算了电缆两端接匹配负载时负载上的电流响应；采用传输线方法计算了不同能量X射线辐照电缆时的芯线负载电流响应。计算结果表明，两种方法计算的电缆X射线瞬态响应是一致的；电缆介质层中存在静电场；X射线能量不同时，电缆芯线负载电流存在最大值。计算中，电缆与X射线的作用采用蒙特卡罗方法计算。

Calculation of coaxial line X-ray responses by transmission line method and finite difference time domain method

For calculating the coaxial line responses in X rays environment,transmission line(TL) method and finite difference time domain(FDTD) method are presented up respectively.Using charges of the central wire,distributed charge in insulation and the result of test,the current source of TL equations and the current density of Maxwell equations are presented.As an example,the central wire currents of the load under the condition of the matching load of cable ends are calculated using the two methods for energy of 60 keV,and the central wire currents of different energies are calculated with TL method.Numerical results indicate that the responses currents of the two methods are consistent,electrostatic field exists in the insulator,and the central wire currents have a maximum value for different energies.Photoelectric parameters are calculated using Monte-Carlo method.