- Concrete provides the most effective shielding against neutron radiation because it contains light elements like hydrogen, which are excellent at slowing down (moderating) neutrons through elastic scattering.
- This moderation increases the likelihood of neutron capture, thereby reducing neutron intensity.
- In contrast, heavy metals like lead and steel mainly attenuate gamma rays and are less effective for neutrons.
- Aluminum, while light, is less dense and contains fewer hydrogen atoms than concrete, making it less efficient for neutron shielding.

Reference: Radiation Protection and Dosimetry, Volume 1, Chapter 4/Page 112