Radiation shielding
Radiation shielding uses materials and structures to reduce exposure to ionizing radiation by absorbing, scattering, or slowing particles and photons.
Attenuation coefficient: A measure of how rapidly radiation intensity decreases as it passes through a material. It quantifies how strongly a shielding material reduces photon intensity per unit thickness.
Ionizing radiation: Radiation with enough energy to remove electrons from atoms or molecules. Shielding is designed around the ionizing particles and photons that can damage tissue.
Lead apron: A protective garment containing lead or another attenuating material, used to reduce X-ray exposure. It illustrates flexible, body-worn shielding in diagnostic radiology.
Lead: A dense, soft metal with atomic number 82, widely used to attenuate X-rays and gamma rays. Its density makes it effective for photons, but it is less suitable for slowing fast neutrons.
Half-value layer: The thickness of a material that reduces a radiation beam’s intensity by half. It turns attenuation into a practical thickness measure for shielding design.
Alpha particle: A helium-4 nucleus consisting of two protons and two neutrons, emitted in some radioactive decays. Alpha particles have short ranges and are usually stopped by thin barriers, but are hazardous if inhaled or swallowed.
Computed tomography: An imaging method that reconstructs cross-sectional images from many X-ray measurements. CT rooms and scanners use structural barriers to protect staff and the public from scattered X-rays.
Polyethylene: A common hydrogen-rich polymer used in products ranging from packaging to radiation barriers. Its hydrogen content makes it useful for neutron moderation, unlike lead’s photon-focused strengths.
Bremsstrahlung: Electromagnetic radiation emitted when charged particles, especially electrons, are decelerated by electric fields. High-energy electrons striking dense shields can produce penetrating X-rays that require additional shielding.
Beta particle: A high-speed electron or positron emitted during radioactive decay. Its greater penetration than alpha radiation calls for a distinct shielding approach.