Which particles are particularly concerning because they can release energy when stopped by a sheet of paper?

Alpha particles are a type of radiation emitted during radioactive decay, consisting of two protons and two neutrons (essentially a helium nucleus). They are particularly concerning because, when they collide with matter, they can deliver a significant amount of energy but have very limited penetration ability.

Alpha particles can be stopped by a sheet of paper or even the outer layer of human skin. When they interact with matter, they can ionize the atoms in that material and release energy. This ionization can lead to biological damage if alpha-emitting materials are ingested or inhaled, as they then have direct access to living tissues.

Understanding the nature of alpha particles is crucial for assessing radiation exposure and implementing appropriate safety measures in environments where radioactive materials are present.