Which of the following is NOT typically a factor in designing shielding for radiation sources?

• A. Source energy
• B. Occupancy
• C. Shielding material density
• D. Color of shielding

Answer: (D)

The design of shielding for radiation sources hinges on reducing exposure by using materials and thicknesses that effectively attenuate the radiation, based on how energetic the source is and how people use the space. Higher source energy requires thicker or more penetrating shielding, since more energetic radiation penetrates more readily. How much time people spend in the area, or the occupancy, matters because it determines how protective the barrier must be to keep dose within safe limits. The density of the shielding material matters because denser materials provide greater attenuation per unit thickness, so lead or concrete choices and thickness are chosen to meet dose goals.

Color of shielding doesn’t influence attenuation or protection; it’s typically cosmetic or used for identification, not a factor in how well the shield blocks radiation.