1. By the end of this presentation you should be able to…… List the three types of nuclear radiation Describe the nature of each type.

2. There are three types of radiation. 1.Alpha radiation (  It is a clump of two protons and two neutrons. Essentially, it is the same as a helium nucleus This is the way it is represented in equations: 4 He 2 It is positively charged, since it has 2 protons and no electrons. It is the largest of all the three types of radiation with a mass number of 4.

3. This is an unstable atom of radium. It has 88 protons and (226 - 88) 138 neutrons. When it “throws out” a particle of radiation, it is said to have “decayed”. Since nucleus of this atom is now different from the original nucleus, 86 protons and 136 neutrons, this means a new element has been formed, radon. The alpha particle that is thrown out has a lot of energy and can damage human cells. 226 Ra 222 Rn + 4 He 88 86 2

4. BETA DECAY: There are 2 types of beta decay beta-plus (b + ) decay beta–minus (b - ) decay the “weak interaction” between “quarks” is responsible for beta decay Beta-minus decay: a neutron in the nucleus decays into a proton (stays in the nucleus) and an electron and an electron antineutrino. The electron is detected as the beta particle. Beta-plus decay: a proton in the nucleus decays into a neutron (stays in the nucleus) and a positron and an electron neutrino. The electron is detected as the beta particle.

5. 3. Gamma radiation (  It is a high energy photon (a particle of energy) You can also describe it as a high frequency electromagnetic wave (so travels at the speed of light) It has no significant mass. It has no charge It is the smallest of all the types of radiation. It has the greatest amount of kinetic energy.

6. Gamma ray This type of radiation is usually emitted along with alpha or beta particles. It is the smallest and most energetic of all three. For this reason it can be the most dangerous (if the source of radiation is outside of the body). Barium-137 is unstable and decays by gamma emission. The gamma ray takes some of the energy of the nucleus away with it so the remaining barium atom is more stable. The mass does not change.

7. The effects of radiation on cells Useful website Useful website All three types are dangerous because they carry high amounts of energy. If they came into contact with another atom, it could knock electrons off it. This is called ionisation. (i.e an ion or charged atom is formed). If an atom of a living cell is ionised, the newly created ion may do things it shouldn’t, like cause reactions that could produce poisons that could damage the cell. Radiation will have the same effect on cancer cells, so can be used as treatment if cancer cells can be destroyed. The problem is that if healthy cells receive high doses of radiation, they can become cancerous. proton (+) KEY electron (-) neutron