Shielding is an engineering control that is:

• A. An Engineering Control That Is the Same for All Radiation Types
• B. Not an Engineering Control
• C. An Engineering Control That Is Different for Different Types of Radiation
• D. An Action That Increases Exposure

Answer: (C)

Shielding as an engineering control must be tailored to the specific type of radiation because different radiations interact with matter in different ways and have different penetrating abilities. Alpha particles are large and carry a positive charge, so they’re easily stopped by a sheet of paper or even outer skin; beta particles are more penetrating and require plastics or light metals to attenuate them. Gamma rays and x-rays are highly penetrating and require dense, thick shielding such as lead or concrete to reduce their intensity effectively. Neutrons behave differently still and need hydrogen-rich materials or boron-containing substances to slow and capture them.

Because the amount and type of shielding needed varies with the radiation type, shielding is best described as an engineering control that is different for different types of radiation. It is not the same for all radiation types, and it is not an action that increases exposure.