Dangers of Radiation & Safety

Ionising radiation (alpha, beta, gamma) has enough energy to knock electrons off atoms. This can damage cells and DNA.

How Radiation Harms Living Things

• Cell death: too much damage kills cells. In the body this can cause burns or radiation sickness at very high doses.
• Mutations: small changes to DNA. Most are repaired, but some are permanent.
• Cancer: mutated cells can grow out of control years later.

Irradiation means being exposed to radiation. It does not make you radioactive. Contamination means getting radioactive material on or inside you; it keeps emitting radiation until removed or it decays.

Penetration and Shielding

• Alpha (α): very ionising, stopped by paper or skin; dangerous if breathed in or swallowed.
• Beta (β): more penetrating; stopped by a few mm of aluminium or thick plastic.
• Gamma (γ): very penetrating; needs thick lead or concrete to reduce it.

Safety Rules: Time, Distance, Shielding

• Reduce time: work quickly and plan ahead to spend less time near a source.
• Increase distance: use tongs or remote handlers. Radiation intensity falls rapidly with distance; roughly, doubling distance quarters intensity: $I \propto \frac{1}{d^2}$.
• Use shielding: wear lab coats and gloves; place lead or concrete between you and the source.

Safe Handling, Moving, and Storage

• Keep sources sealed, clearly labelled with the radiation trefoil symbol.
• Store in a locked, lead-lined container, away from people.
• Move sources in shielded boxes; never in pockets. Use tongs to increase distance.
• Do not eat or drink when using sources; wash hands afterwards.
• Use a detector (e.g. Geiger counter) to check for contamination and to monitor exposure.
• Record who uses the source, when, and for how long.

Background Radiation (Context)

Everyone is exposed to low levels all the time from radon gas, rocks and buildings, food and drink, cosmic rays, and medical scans. Safety rules keep extra exposure as low as reasonably possible.

Common Misconceptions

• “Alpha is harmless.” False: outside the body it is blocked, but inside it can cause severe damage.
• “Sterilised food or tools become radioactive.” False: irradiation kills germs but does not make objects radioactive.