Which shielding material is most commonly used against neutron decay?

The most commonly used shielding material against neutron radiation is concrete. This is due to concrete's composition, which includes hydrogen-rich materials that are effective in slowing down neutrons through elastic scattering. When neutrons collide with hydrogen atoms, they lose energy, effectively reducing their intensity and harm.

Concrete's properties also contribute to its effectiveness as a shielding material; it is dense enough to provide structural integrity, is relatively inexpensive, and can be molded into various shapes for specific applications. Additionally, its ability to absorb both fast and thermal neutrons makes it a preferred choice in facilities where neutron radiation is prevalent, such as nuclear power plants or research laboratories.

Other materials such as plastic can also offer neutron shielding, but they are typically less effective unless specifically designed with additives that enhance their neutron absorption capabilities. Glass, due to its lower hydrogen content, is not suitable for effective neutron shielding. Lead, while excellent for shielding against gamma radiation due to its high atomic number, is not effective against neutrons, as it does not interact favorably with neutron particles. Thus, concrete stands out as the best option for neutron shielding.