Lesson aims By the end of this lesson you should –Know where radiation comes from –Be able to name the three types of radiation –Be able to state how each radiation can be stopped

Where does radioactivity come from? Radioactivity comes from the nuclei of atoms. Not all substances are radioactive.

- Nuclear model of atom Electron (-) Proton (+) Neutron (no charge)

Substances that are not radioactive have stable nuclei. Radioactive substances have unstable nuclei. Unstable nuclei have many more neutrons than protons.

There are 3 types of ionising radiation α (alpha particle) Helium nuclei 2 protons and 2 neutrons β (beta particle) fast moving electron γ (gamma rays) electro magnetic waves All 3 types come from the nucleus of the atom!!

   Sheet of paper 3 mm or more of aluminium Few cm of lead  Alpha particles cannot pass through paper  Beta particles cannot pass through aluminium  Intensity of gamma waves is reduced by lead

Nuclear Radiations RadiationParticle or Wave? ChargeStopped by… Alpha Beta Gamma

Ionisation Powers of Radiation Prolonged exposure to ionising radiation is dangerous to humans. Ionisation is the ability of radiation to remove electrons from atoms which will then change their structure

Try and answer the following questions with a partner… Which radiation would be most dangerous if it was outside the body? Which radiation would be most dangerous if it was inside the body?

Dangers of radioactivity – OUTSIDE BODY OUTSIDE the body  and  are more dangerous as they can penetrate the skin into your body to your organs. Alpha Radiation will ionise atoms in living cells – this can damage them and cause cancer or leukaemia. Gamma Beta

Dangers of radioactivity (INSIDE BODY) INSIDE the body an  radiation is the most dangerous because it is the most ionising and so it is the least penetrating of all three. β is less dangerous to cells and gamma (γ) is the least dangerous because they are more penterating. Gamma Beta Alpha Dangers of radioactivity – INSIDE BODY

PROTECTION OF MEDICAL STAFF PROTECTIVE SUITSTONGS SCREEN / BARRIERARM’S LENGTH

PROTECTION OF PATIENT SMALL DOSES FOCUS EXACTLY WHERE NEEDED PROTECTIVE BIB/GARMENT