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P4: Radiation for Life. Lesson 11: Uses of Radioisotopes (part 1). Lesson Objectives. Identify sources of background radiation . Understand the use of alpha sources in smoke detectors . Understand how radioisotopes are used as industrial tracers. Success Criteria. Key Words :
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P4: Radiation for Life Lesson 11: Uses of Radioisotopes (part 1)
Lesson Objectives • Identify sources of background radiation. • Understand the use of alpha sources in smoke detectors. • Understand how radioisotopes are used as industrial tracers
Success Criteria Key Words: background radiation • cosmic rays • radioisotope • alpha • decay • tracer • gamma
Background radiation: Granite rocks contain small amounts of radioactive uranium. When uranium decays it emits radon gas which is also radioactive. Wales, Devon, Cornwall. Lots of granite!!
Demo! ‘Radioactive Penetration’!
Tracers Radioisotopes are used as tracers in industry, research and medicine. Tracers are used to: • Detect leaks or blockages in underground pipes • Find the routes of underground pipes • Track dispersal of waste • Monitor the uptake of fertilisers in plants • Check for a blockage in a patient’s blood vessel
Locating a leak/blockage • A very small amount of a suitable radioisotope is put into the pipe • A detector is passed along the ground above the path of the pipe to track the progress of the radioisotope • An increase in the activity is detected in the region of the leak or blockage and little or no activity is detected after this point.
How can radiation detect a fire? smoke particle α α Smoke alarms contain a weak source of alpha radiation. The alpha particles ionize the air. If there is smoke present, it interacts with the ions produced by the alpha particles and ionization is reduced. This means that less current is flowing through the air, which causes the alarm to sound.
Success Criteria Key Words: background radiation • cosmic rays • radioisotope • alpha • decay • tracer • gamma