I have an x-ray tube. When I see the spectrum, I notice the characteristic lines of the anode. What do I have to do if I want to absorb a characteristic line? I have thought that I can add a filter. But.. which filter? Should it be an element such that the bound energy for the K-shell electrons is minor of the energy of the characteristic line that I want to absorb? ________________________________________ In this specific case: I have an x-rays tube with a anod in molybdenum. In the spectrum, I see the caracteristic lines k_alpha=63 pm and k_beta=71 pm. I want to filter the k_alpha line much more than the k_beta line. Which filter do I have to use? Zr, E_k=18 kev Nb, E_k=18.99 kev Mo, E_k=20 kev According to what I previously said, I'd choose Zr and Nb. Do you agree with me? Thanks a lot!