Room: ePoster Forums
Purpose: In order to eliminate the influence of geometric penumbra, a high transmitted filter and a negative axicon lens are used to obtain a diffraction-free X-ray beam model whose intensity is uniformly distribution during its propagation.
Methods: EGS4 simulation is applied to obtain the wave function of X-ray's getting from the window of linacs, and EGS4 is also used to simulate this novel photom beam model which contains high transmitted filter and negative axicon lens, but do not consider other accessories. BEAMDP is used to analyze its phase space file file after this simulation is executed, and Gaussian curve fitting is executed by matlab, then the wave function of X-rays passing through these optical elements are obtained. We can verify the diffraction-free X-ray beam model is available or not by comparing the wave functions which are obtained by analytic calculation and EGS4 simulation.
Results: After simulating X-rayâ€™s passing through these filters which have the same thickness but with different material by using EGS4 software, it is found that when the material of the selected filer is the same as the target, its filtering effect is best, and also after simulating X-rayâ€™s passing through these filters which are made from tungsten but have different width, it is found that when the width 10.0cm is chosen, a nearly monochromatic X-ray beam can be obtained, but its energy is very small. And with the help of the obtained size of the filter and negative axicon lens, we can get the wave function of the diffraction-free X-ray beam by using EGS4 to simulate this new photon model. At last, it is found that the same wave functions can be obtained by analytic calculation and EGS4 simulation.
Conclusion: We can see that this diffraction-free X-ray beam model is available for generation.