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Nuclear Science Merit Badge

Nuclear Science Merit Badge. Howard Matis Lawrence Berkeley National Laboratory. Radiation gives Superhuman Powers to Spiderman. Radiation gives Superhuman Powers to The Hulk. Chernobyl. Radiation is. Plot device for fiction Scary Deadly Life saving Misunderstood Useful. 60°. 60°. R.

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Nuclear Science Merit Badge

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  1. Nuclear Science Merit Badge Howard Matis Lawrence Berkeley National Laboratory Howard Matis - hsmatis@lbl.gov

  2. Radiation gives Superhuman Powers to Spiderman Howard Matis - hsmatis@lbl.gov

  3. Radiation gives Superhuman Powers to The Hulk Howard Matis - hsmatis@lbl.gov

  4. Chernobyl Howard Matis - hsmatis@lbl.gov

  5. Radiation is • Plot device for fiction • Scary • Deadly • Life saving • Misunderstood • Useful Howard Matis - hsmatis@lbl.gov

  6. 60° 60° R 1.5R 5R Radiation Hazard Symbol • The symbol is placed on a placard with the word CAUTION or DANGER or GRAVE DANGER centered about it. Under the symbol is the information addressing the types of hazards. • Examples are: • Radiation Area High Radiation Area Airborne Radioactivity Area Contaminated Area Radioactive Materials Area Howard Matis - hsmatis@lbl.gov

  7. Radiation is Energy • The energy is given off by unstable (radioactive) atoms and some machines. We will be focusing on ionizing radiation and its health effects. Howard Matis - hsmatis@lbl.gov

  8. Atoms Building Blocks of Matter • All matter is made up of atoms • The nucleus is in center • almost all of the mass • Electrons go around • At this scale, electrons are at the edge of town Howard Matis - hsmatis@lbl.gov

  9. What is a Nucleus? • Quarks determine if proton or neutron • Neutrons • Protons • Protons determine chemical properties • Ratio of neutrons to protons make a nucleus stable or unstable Howard Matis - hsmatis@lbl.gov

  10. Isotopes • Many elements have nuclei with the same number of protons • same name • same chemistry • but different numbers of neutrons • different masses Howard Matis - hsmatis@lbl.gov

  11. Examples - Isotopes • Hydrogen (1H) • 1 proton, 0 neutrons, mass 1 • Deuterium (2D) • 1 proton, 1 neutron, mass 2 • Tritium (31T) • 1 proton, 2 neutrons, mass 3 • Helium (4He) (a-particle) • 2 protons, 2 neutrons, mass 4 • Helium-3 (3He) • 2 protons, 1 neutron, mass 3 • Uranium-238 (238U) • 92 protons, 146 neutrons, mass 238 • Uranium-235 (235U) • 92 protons, 143 neutrons, mass 235 Howard Matis - hsmatis@lbl.gov

  12. Types of Radioactivity Six Common Types Alpha Decay Beta Decay Gamma Decay Fission Fusion Cosmic Rays • Each type of radiation is ionizing • But different properties • affect the hazards they pose • the detection mechanism • shielding Howard Matis - hsmatis@lbl.gov

  13. How Does it Decay? • Alpha - lose an alpha particle ( - helium nucleus) • Beta - emit a beta particle ( - electron or anti-electron) • Gamma - emit a gamma ( or photon or light particle) Howard Matis - hsmatis@lbl.gov

  14. Alpha Decay • Alpha particle or helium nucleus emitted • Nucleus changes mass by four units and charge by two units • Common for heavy elements • Changes chemical properties • Alpha particle easily stopped • 4 x nucleon mass • +2 Charge • Big Howard Matis - hsmatis@lbl.gov

  15. Beta Decay • Beta minus - neutron converts to electron and anti-neutrino • Beta plus - proton converts to a anti-electron and neutrino • Nucleus changes charge but not mass number • Changes chemical properties • Radiation moderately penetrating • +1 charge • Small electron Howard Matis - hsmatis@lbl.gov

  16. Gamma Decay • Nucleus changes energy level • Emits gamma ray or photon • Nucleus stays the same • No change in chemical properties • Very penetrating • Almost no size • Neutral Howard Matis - hsmatis@lbl.gov

  17. Paper Plastic Lead Concrete a++ Alpha 0b- Beta 0g Gamma and X-rays 1n Neutron Absorption of Radiation Howard Matis - hsmatis@lbl.gov

  18. Fission Sometimes a very heavy nucleus will fall apart before it can emit an alpha particle. The heavy parent nucleus fissions … … into two lighter (radioactive) fission fragment nuclei plus some left over neutrons Fission can release an enormous amount of energy and is utilized in power plants and fission bombs (A-bomb). Howard Matis - hsmatis@lbl.gov

  19. Fusion • When two nuclei collide and stick together • Process that powers the sun and stars • All life arises from it • Not usually found in every day experience on Earth • Component of the H-bomb Howard Matis - hsmatis@lbl.gov

  20. How Unstable Is It? • The “Half-life” describes how quickly Radioactive Material decays away with time.It is the time required for half of the unstable atoms to decay. • Some Examples: • Some natural isotopes (like uranium and thorium) have half-lives that are billions of years • Since Earth is about 5 billion years old, short lived naturally produced isotopes gone • Most medical isotopes (like 99mTc) last only a few days Howard Matis - hsmatis@lbl.gov

  21. Half-Life Experiment Guess the number I am thinking from 1 to 4 Howard Matis - hsmatis@lbl.gov

  22. Some Isotopes & Their Half Lives Howard Matis - hsmatis@lbl.gov

  23. How do we Measure the Amount of Radiation? Howard Matis - hsmatis@lbl.gov

  24. Radiation Absorbed Dose Qty: Dose Unit: rad (Gray) 1 rad = 1000 mrad 1 rad = 100 erg/gram 1 Gy =100 rad Radioactivity Qty: Activity Unit: Curie (Bequerel) 1 Ci = 1000 mCi 1 Bq = 1 disintegration/sec 1 Ci = 3.7  1010 Bq Roentgen equivalent man Radiation Risk Qty: Dose Equivalent Unit: rem (Sievert) 1 rem = 1000 mrem 1 Sv=100 rem Radiation Quantities and Units Howard Matis - hsmatis@lbl.gov

  25. Convert from Curies to Rad • Curie is the number of decays/s • 1 Curie = 3.7  1010 decays/s (exactly) • Rad is the absorbed dose or physical dose • Amount of energy deposited in unit mass • human tissue or other media • 1 Rad = 100 erg/g • Often use gray • 1 J/kg • 1 gray = 100 rad Howard Matis - hsmatis@lbl.gov

  26. Need Biological Dose – REM • To convert from rad to rem multiply by appropriate value of Q • Q is the Quality Factor • Q reflects the damage rad  Q = rem Howard Matis - hsmatis@lbl.gov

  27. Radiation and Health Does radiation affect you? Howard Matis - hsmatis@lbl.gov

  28. Ionizing Radiation can Damage DNA Ionizing radiation has the ability to ionize* atoms and molecules, possibly altering structure and function. * ionize = produce positive and negative electrical charge Howard Matis - hsmatis@lbl.gov

  29. Alpha Radiation Is Only a Hazard When Inside Your Body (Internal Hazard) Your skin will stop it can’t penetrate skin internal hazard stopped by paper found in soil, radon and other radioactive materials Howard Matis - hsmatis@lbl.gov

  30. Beta Radiation Is a Skin, Eye and Internal Hazard skin, eye and internal hazard stopped by plastic found in natural food, air and water Howard Matis - hsmatis@lbl.gov

  31. found in medical uses stopped by lead naturally present in soil and cosmic radiation X-ray and Gamma Radiation Are Penetrating Radiation and an External Hazard Howard Matis - hsmatis@lbl.gov

  32. - + How does Radiation Injure Cells? • High energy radiation breaks chemical bonds. • This creates free radicals, like those produced by other insults as well as by normal cellular processes in the body. • The free radicals can change chemicals in the body. • These changes can disrupt cell function and may killcells. Howard Matis - hsmatis@lbl.gov

  33. Types of Exposure & Health Effects • Acute Dose - Deterministic • Large radiation dose in a short period of time • Large doses may result in observable health effects • Early: Nausea & vomiting • Hair loss, fatigue, & medical complications • Burns and wounds heal slowly • Examples: medical exposures andaccidental exposure to sealed sources • Chronic Dose - Stochastic • Radiation dose received over a long period of time • Body more easily repairs damage from chronic doses • Does not usually result in observable effects • Examples: Background Radiation andInternal Deposition Inhalation Howard Matis - hsmatis@lbl.gov

  34. At HIGH Doses, We KNOW Radiation Causes Harm • High Dose effects seen in • Radium dial painters • Early radiologists • Atomic bomb survivors • Populations near Chernobyl • Medical treatments • Criticality Accidents • Cancer • Leukemia (A-bomb data) • Thyroid (Chernobyl data) • Bone and other solid cancers (A-bomb data) • Birth defects (A-bomb data) • Genetic effects (only animal data) . Howard Matis - hsmatis@lbl.gov

  35. Effects of ACUTE (Deterministic) Exposures * For common external exposures 1 rad ~ 1 rem = 1,000 mrem Howard Matis - hsmatis@lbl.gov

  36. At LOW Doses, We PRESUME Radiation Causes Harm • No physical effects have been observed The Bad News: Radiation is a carcinogen and a mutagen The Good News: Radiation is a very weak carcinogen and mutagen! Very Small DOSE = Very Small RISK Howard Matis - hsmatis@lbl.gov

  37. Sources of Radiation • Average radiation exposure in the United States • 360 mrem or • 0.360 rem • Very location dependent Howard Matis - hsmatis@lbl.gov

  38. Manufactured Sources of Radiation Contribute an Average of 60 mrem/year cigarette smoking - 1300 mrem lung dose medical - 53 mrem building materials - 3.6 mrem smoke detectors - 0.0001 mrem Howard Matis - hsmatis@lbl.gov

  39. Risks in Perspective 1 in 1 million chance of fatality • 40 tablespoon peanut butter (aflotoxin) • 2 days in New York City (air quality) • 3 mrem radiation (cancer) • 1 mile on motorcycle (collision) • 300 miles in car (collision) • 10 charbroiled steaks • Smoking 1 cigarette Howard Matis - hsmatis@lbl.gov

  40. ALARA ALARA stands for As Low As Reasonably Achievable Reduce radiation dose by using: • Time • Distance • Shielding Howard Matis - hsmatis@lbl.gov

  41. Reduce Time Spend as short as time as necessary to complete the task Howard Matis - hsmatis@lbl.gov

  42. Activity Demonstrate Time – (t) Howard Matis - hsmatis@lbl.gov

  43. Increase Distance Twice the distance = ¼ of the dose Howard Matis - hsmatis@lbl.gov

  44. Activity Demonstrate Distance – (d) Howard Matis - hsmatis@lbl.gov

  45. Use Shielding Howard Matis - hsmatis@lbl.gov

  46. Activity Demonstrate Shielding – (s) Howard Matis - hsmatis@lbl.gov

  47. Reactors Glow in the Dark • Reactor core emits electrons • Electrons move faster than the speed of light in water • At that speed they emit blue light • Cherenkov Radiation • Similar to sonic boom or wake of a boat Howard Matis - hsmatis@lbl.gov

  48. Can You Glow in the Dark? • Ingest a very hot radiation source • Beta needed • Short half life • Do not swallow • Unless your midriff is exposed • Or inject source into your blood • Don’t be in direct light • Usually too faint for sunlight • Try it for Halloween? Howard Matis - hsmatis@lbl.gov

  49. Summary • Radiation is part • Our natural environment • Technology • Health effects • Known for high doses • Unknown for low • You deal with it regularly Howard Matis - hsmatis@lbl.gov

  50. The End Howard Matis - hsmatis@lbl.gov

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