Penetrating Powers of Ionizing Radiation Image ALPHA Particles Stopped by a sheet of paper and cannot penetrate the outer dead layer of skin BETA Particles Stopped by a layer of clothing or a thin sheet of a substance, such as aluminum GAMMA Rays and X-Rays Stopped by several feet of concrete or a few inches of lead ^pCMV Environmental Protection RadTown Radiation Exposure Activity Set EPA 402-B-19-038 ' * Agency https://www.EPA.gov/RadTown/Activitv-3-Penetrating -Powers-lonizing-Radiation ------- |