Fig. 1. Changes of elemental mass attenuation coefficients with photon energy (color online) (a) Lanthanide, (b) Non-lanthanide

Fig. 2. Changes of mass attenuation coefficients of the combination of W, Bi and Gd with photon energy (color online)

Fig. 3. Diagram of X-ray shielding model^[24]

Fig. 4. Snapshots of typical X-ray shielding samples prepared in experiment

Fig. 5. X-ray energy spectra of no filter / 2.7 mm Al filter (color online)

Fig. 6. Monte Carlo simulation of the shielded spectra of samples at 100 kV X-ray tube with 2.7 mm Al filter (color online)(a) #1~#4 samples, (b) #5 superimposed #a~#d, #4 samples

Fig. 7. Z_eff for 0~150 keV photons when #5 superimposed #a~#d, #4 samples (color online)