Abstract：The initial energy spectrum of X-rays tube was studied.On the basis of the theoretical analysis, Monte-carlo simulation program (EGSnrc) is adopted to simulate the low-X rays energy spectrum, which is affected by the focus size of X-ray, anode materials, angle, thickness and radius of the target.The results show that the influence of focus size on energy spectrum will be stabilized within 1% along with the increase of energy; the atomic number of target material is higher, the greater the strength of the spectral lines; the average energy of spectrum will be reduced along with the increase of anode target angle. When target thick is greater than electronic range the influence of target thick can be ignored and the larger target area will cause the photon loss.
2011, Vol. 32 
