1. What is Radiation? Health Physics Society - Power Reactor Section Radiation Science Education

2. Outline Ionizing & Non-Ionizing Photons & Particles Stable & Unstable Atoms Half -Life Radiation Detectors

3. Ionizing & Non-Ionizing Radiation  Ionizing Radiation: Radiation is energy transmitted as particles or waves. Ionizing radiation has sufficient energy to dislodge orbital electrons, thereby producing ions.  Examples: alpha, beta, gamma, neutron, and x-rays  Non-Ionizing Radiation: Radiation that does not have sufficient energy to dislodge orbital electrons.  Examples: visible light, infra-red, micro-waves, radio-waves, and radar

4. Ionizing Radiation Hits An Atom Incomin g Photon Ejected Electron

5. Particles and Photons Radiation can be in the form of particles or waves (photons). The most common types of ionizing radiation are alpha, beta, gamma, neutron, and x-rays. –Gamma and x-ray radiation are photons. They are part of the electromagnetic spectrum and considered packets of pure energy. –Alpha, beta, and neutron radiation are particles having mass. Betas are electrons and alphas are helium nuclei.

6. Electromagnetic Spectrum

7. Radioactive Decay: The process of unstable atoms spontaneously emitting radiation. Half-Life = 1.3 billion years Parent Nucleus Potassium-40 Unstable atom Daughter Nucleus Calcium-40 Stable atom    

8. What is Half-Life? Radioactive decay is the process where an unstable atom emits radiation. Radioactive decay changes unstable atoms into more stable atoms. Half-life is the time it takes for 1/2 the atoms of a particular radioactive element to transform itself by decay.

9. Gas-Filled Detectors Incident Ionizing Radiation + + + Anode + Voltage Source Electrical Current Measuring Device Cathode - - - -

10. Key Concepts  Radioactive Decay: The process where an unstable atom transforms itself into a more stable atom by spontaneous emission of radiation.  Ionizing Radiation: Any radiation which is capable of dislodging electrons from atoms thereby producing ions.  Half Life: The time it takes for one-half of the atoms of a particular radioactive element to transform itself by radioactive decay.