Which radiation requires shielding such as water, lead, steel, or concrete?

Which radiation requires shielding such as water, lead, steel, or concrete?

• A. Alpha
• B. Beta
• C. Gamma
• D. Neutron

Answer: (D)

Neutron protection relies on slowing and absorbing the neutrons using hydrogen-rich materials. Neutrons don’t have an electric charge, so they pass through many substances easily. To reduce exposure, we use materials with lots of light nuclei, especially hydrogen, because collisions with hydrogen atoms efficiently slow fast neutrons in a process called moderation. Once neutrons are slowed to thermal energies, they’re more likely to be captured by certain nuclei, effectively removing them from the beam. Water and concrete are classic neutron shields precisely because they contain a lot of hydrogen. This hydrogen-rich shielding slows the neutrons and helps absorb them. Metals like lead or dense steel aren’t as good for moderating neutrons and can even result in gamma production when neutrons interact with them, so they’re not the best primary neutron shields. Gamma rays, by contrast, are best attenuated with dense materials like lead or concrete, but for neutron protection the emphasis is on hydrogen-containing shielding. So the type of radiation that specifically requires shielding like water or concrete is neutron radiation, due to the need to slow and capture neutrons with hydrogen-rich materials.

Neutron protection relies on slowing and absorbing the neutrons using hydrogen-rich materials. Neutrons don’t have an electric charge, so they pass through many substances easily. To reduce exposure, we use materials with lots of light nuclei, especially hydrogen, because collisions with hydrogen atoms efficiently slow fast neutrons in a process called moderation. Once neutrons are slowed to thermal energies, they’re more likely to be captured by certain nuclei, effectively removing them from the beam.

Water and concrete are classic neutron shields precisely because they contain a lot of hydrogen. This hydrogen-rich shielding slows the neutrons and helps absorb them. Metals like lead or dense steel aren’t as good for moderating neutrons and can even result in gamma production when neutrons interact with them, so they’re not the best primary neutron shields. Gamma rays, by contrast, are best attenuated with dense materials like lead or concrete, but for neutron protection the emphasis is on hydrogen-containing shielding.

So the type of radiation that specifically requires shielding like water or concrete is neutron radiation, due to the need to slow and capture neutrons with hydrogen-rich materials.