Download presentation
Presentation is loading. Please wait.
1
Background Radiation background radiation is caused by radioactive substances in rocks and soil and by cosmic rays. Some background radiation comes from waste products and man made sources e.g. waste from: • industry; • hospitals.
2
Radioactive sources are used as tracers
• to track the dispersal of waste; • to find leaks/blockages in underground pipes; • to find the route of underground pipes.
3
Using Radioactive sources as tracers
Radioactive sources are used to track the dispersal of waste; • find leaks/blockages in underground pipes; • find the route of underground pipes. This is done by • radioactive material put into pipe; • gamma source used so that it can penetrate to the surface; • progress tracked with detector above ground; • leak/blockage shown by reduction/no radioactivity after this point
4
Using an alpha source in a smoke detector.
Americium-241 emits alpha particles that ionise the air molecules around the alarm. The charged air molecules conduct electricity so a small current flows inside the alarm. When smoke enters the alarm alpha particles are absorbed. This makes the current inside the alarm fall and set off a ringing sound. Alpha emitters must be used for smoke detectors since only alpha particles ionise air and are stopped by smoke. Gamma rays and beta particles easily pass through air without causing ionisation.
Similar presentations
