Fig. 2.

The radiation dose rate was attenuated depending on the thickness of various materials. The materials included newspaper, corrugated cardboard, a magazine, cork, and a board of Betula (birch), all made from wood. The apparent attenuation coefficient for wood was estimated using the equation I = I₀exp(−μt), where I is the intensity of the radiation dose rate with shielding, I₀ is the intensity of the radiation dose rate without shielding, μ is the apparent attenuation coefficient for wood, and t is the material thickness