which is attributed to the porous structure and lower density of foams. The results also reveals that by filling foam with water, the mass attenuation coefficients of the samples would be improved and can be higher than that of bulk samples. In terms of the weight-saving advantage, the foams may be better gamma-ray
shielding materials at the present energies. The thermal neutron experiments have shown that filling foam with water or boric acid solution (or borated water) improves the attenuation as compared to bulk material and foam. Foams filled with boric acid solution have the highest attenuation effect. By increasing the boric acid concentration and thickness of the foam, the samples totally stopped the beam.