Based on the physical model and the calculating method developed by the authors, the calculation software of the spatial distribution of density of x-ray photons in solid is made. The scattering of electron beam with energy in KeV in solid and the excitement of x-ray photons can be simulated by using this program. The quantitative results-of the distributionof density of x-ray photons and the spatial range including various proportion of the photons are also obtained. It is significant for quantitative research of electron microscopy.

This paper presents a model of a magnetic field in cylindrical coordinates. When B_Z is measured on the boundary of the magnetic field, the magnetic field inside the cylinder can be computed to high precision by Fourier fit. The results obtained from the computing program based on this model agree with expe-remental measurements well.