Atomic Structure
Alpha, Beta and Gamma Radiation
To compare alpha, beta and gamma radiation, including how far they penetrate materials and the hazards they present.
What you will learn
The differences between alpha, beta and gamma radiation
How far each type travels through materials
Which types are the most strongly ionising
What materials can absorb or reduce each type
Why radiation inside the body can be especially harmful
Explanation
Alpha is a helium nucleus, beta-minus is an emitted electron and gamma is electromagnetic radiation from the nucleus. Alpha is strongly ionising with low penetration; beta has intermediate penetration; gamma is weakly ionising but highly penetrating. Paper stops alpha, thin aluminium reduces beta strongly, and thick lead or concrete reduces gamma intensity. Example: Select shielding for a beta source. Suitable aluminium shielding; thickness depends on the source energy. Avoid unjustified claims.