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Radiation: What it is and what it does

Radiation: What it is and what it does. Mary Lou Dunzik-Gougar, Ph.D. Associate Chair of Nuclear Engineering at Idaho State University with joint appointment at Idaho National Laboratory Candace C. Davison, M.Engr . Research & Education Specialist Pennsylvania State University

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Radiation: What it is and what it does

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  1. Radiation: What it is and what it does Mary Lou Dunzik-Gougar, Ph.D. Associate Chair of Nuclear Engineering at Idaho State University with joint appointment at Idaho National Laboratory Candace C. Davison, M.Engr. Research & Education Specialist Pennsylvania State University Radiation Science and Engineering Center

  2. What do the following things have in common?

  3. Voyager

  4. Soda Can

  5. Bugs

  6. Each represents an application of nuclear science and technology.

  7. Questions we’ll answer. . . • What is radiation? • Where does it come from? • What is radioactivity? • What’s the difference betweencontamination and irradiation? • What are some applications? • Is it safe?

  8. What is Radiation? Transmission of energy via . . . Particles or Waves

  9. Types of radiation Non-Ionizing Radiowaves Microwaves Infrared Ultraviolet Visible Light Ionizing

  10. Electromagnetic Spectrumhttp://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

  11. Types of radiation Ionizing Alpha Beta Gamma (rays) X-Rays Neutrons Non-Ionizing Radiowaves Microwaves Infrared Ultraviolet Visible Light

  12. p+ n n p+ • Beta () • like an electron • negatively charged particle - • Gamma () • Wave energy (not a particle) Nature of Radiation Alpha () 2 protons, 2 neutrons positively charged particle

  13. PENETRATING ABILITY - + + g b a

  14. SHIELDING Concrete alpha beta gamma Lead Wood Paper

  15. Which type of radiation is emanating from these every day objects?

  16. Where does radiation come from? Atoms . . . from radioactive or unstable atoms

  17. What part of atoms? The Nucleus! Hence, we have terms such as nuclear science/medicine/reactors.

  18. Remember atomic structure? THE HELIUM’S subATOMIC HELIUM ATOMCOMPOSITION 2 Protons 2 Neutrons 2 Electrons e- p+ n n p+ e-

  19. Protons have a large mass and a positive charge. p+ Electrons have a very small mass and a negative charge. Electrons travel outside the nucleus. e- More on this helium isotope . . . MASS NUMBER is total number of protons and neutrons 4 2 Neutrons have large mass, approximately equal to proton mass, but no charge. He n ATOMIC NUMBER is number of protons & identifies the element ELEMENT SYMBOL

  20. Why is it called ionizing? Because it creates ions . . . atoms with a charge. Ejected Electron Ionizing Radiation

  21. If radiation comes from atoms and everything is made of atoms, is there radiation around us right now? But, of course! It’s called background radiation.

  22. “Listen” to the background radiation with a Geiger counter.

  23. Sources of average radiation dose in the US Consumer Products (2%) Cosmic (5%) Nuclear Power (<0.1%) Human Body (5%) The average American receives a radiation dose of 620 millirem per year. Source: National Council on Radiation Protection and Measurement Report 160 (2006)

  24. What’s radioactivity?

  25. Energy and radiation released Different atom formed What is radioactivity? The spontaneous emission of “fragments” or “bundles” of energy from energetic nuclei creating more stable nuclei. Radioactive atom

  26. Radioactive atoms emit radiation.

  27. Half Life

  28. Half Life

  29. If I’m exposed to radiation, do I become (more) radioactive?

  30. No!You’ve been irradiated, exposed to radiation.Which is not to be confused with . . .

  31. Radioactive Contamination Radioactive Contamination is radioactive material in an unwanted place.

  32. What are some applications of irradiation?

  33. Alpha radiation is used to • Power space probes • Beta radiation is used for gauging • Thickness of aluminum during production • Gamma radiation is used for • Preserving food, protecting from insects

  34. Question... How do we make a stable atom radioactive?

  35. Answer... • How do we make a stable atom radioactive? • By adding energy to the nucleus • This is done by adding a particle such as a neutron from a reactor or a high energy charged particle from an accelerator such as an electron or proton

  36. Question... OK, so I don’t become radioactive from being irradiated, but are there other effects of radiation exposure?

  37. Human Cells Atoms in Cells Form Ions No/Neutral Change in Cell Change in Cell Cell Dies Reproduces Replaced Not Replaced Malignant Growth Benign Growth What happens when you’re exposed to radiation? Ionizing Radiation

  38. Time Distance Shielding How do we protect ourselves?

  39. How much is too much dose?

  40. Perspective

  41. Effects of AcuteWhole-Body Radiation Doses

  42. Dose Limits in US Regulations 5000 (radiation workers) & 100 (members of the public) per year in milli-rem (or 50 and 1 in milli-Sievert)

  43. Some things to remember We live in a radioactive world Radiation (or things that generate radiation) are used to our benefit Nuclear power and other nuclear technologies are tightly regulated – very conservative limits are applied to limit doses

  44. The End . . .

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