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

2. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov2 Radiation gives Superhuman Powers to Spiderman

3. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov3 Radiation gives Superhuman Powers to The Hulk

4. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov4 Chernobyl

5. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov5 Radiation is Plot device for fiction Plot device for fiction Scary Scary Deadly Deadly Life saving Life saving Misunderstood Misunderstood Useful Useful

6. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov6 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 R 1.5R 5R 60°

7. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov7 Radiation is Energy The energy is given off by unstable (radioactive) atoms and some machines. The energy is given off by unstable (radioactive) atoms and some machines. We will be focusing on ionizing radiation and its health effects.

8. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov8 Atoms Building Blocks of Matter All matter is made up of atoms All matter is made up of atoms The nucleus is in center The nucleus is in center almost all of the mass almost all of the mass Electrons go around Electrons go around At this scale, electrons are at the edge of town At this scale, electrons are at the edge of town

9. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov9 What is a Nucleus? Quarks determine if proton or neutron Quarks determine if proton or neutron Neutrons Neutrons Protons Protons Protons determine chemical properties Protons determine chemical properties Ratio of neutrons to protons make a nucleus stable or unstable Ratio of neutrons to protons make a nucleus stable or unstable

10. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov10 Isotopes Many elements have nuclei with the same number of protonsMany elements have nuclei with the same number of protons same namesame name same chemistrysame chemistry but different numbers of neutronsbut different numbers of neutrons different massesdifferent masses

11. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov11 Examples - Isotopes Uranium-238 ( 238 U) 92 protons, 146 neutrons, mass 238 Uranium-235 ( 235 U) 92 protons, 143 neutrons, mass 235 Hydrogen ( 1 H) 1 proton, 0 neutrons, mass 1 Deuterium ( 2 D) 1 proton, 1 neutron, mass 2 Tritium ( 3 1 T) 1 proton, 2 neutrons, mass 3 Helium ( 4 He) (  -particle) 2 protons, 2 neutrons, mass 4 Helium-3 ( 3 He) 2 protons, 1 neutron, mass 3

12. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov12 Types of Radioactivity Each type of radiation is ionizingEach type of radiation is ionizing But different propertiesBut different properties affect the hazards they poseaffect the hazards they pose the detection mechanismthe detection mechanism shieldingshielding Six Common Types Alpha Decay Beta Decay Gamma Decay FissionFusion Cosmic Rays

13. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov13 How Does it Decay? Alpha - lose an alpha particle (  - helium nucleus) Alpha - lose an alpha particle (  - helium nucleus) Beta - emit a beta particle (  - electron or anti-electron) Beta - emit a beta particle (  - electron or anti-electron) Gamma - emit a gamma (  or photon or light particle) Gamma - emit a gamma (  or photon or light particle)

14. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov14 Alpha Decay Alpha particle or helium nucleus emitted Alpha particle or helium nucleus emitted Nucleus changes mass by four units and charge by two units Nucleus changes mass by four units and charge by two units Common for heavy elements Common for heavy elements Changes chemical properties Changes chemical properties Alpha particle easily stopped Alpha particle easily stopped 4 x nucleon mass 4 x nucleon mass +2 Charge +2 Charge Big Big

15. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov15 Beta Decay Beta minus - neutron converts to electron and anti-neutrino Beta minus - neutron converts to electron and anti-neutrino Beta plus - proton converts to a anti-electron and neutrino Beta plus - proton converts to a anti-electron and neutrino Nucleus changes charge but not mass number Nucleus changes charge but not mass number Changes chemical properties Changes chemical properties Radiation moderately penetrating Radiation moderately penetrating +1 charge +1 charge Small electron Small electron

16. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov16 Gamma Decay Nucleus changes energy level Nucleus changes energy level Emits gamma ray or photon Emits gamma ray or photon Nucleus stays the same Nucleus stays the same No change in chemical properties No change in chemical properties Very penetrating Very penetrating Almost no size Almost no size Neutral Neutral

17. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov17 Absorption of Radiation   ++ 0-0- 00 1n1n Alpha Beta Gamma and X-rays Neutron PaperPlasticLeadConcrete

18. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov18 Fission The heavy parent nucleus fissions … … into two lighter (radioactive) fission fragment nuclei plus some left over neutrons Sometimes a very heavy nucleus will fall apart before it can emit an alpha particle. Fission can release an enormous amount of energy and is utilized in power plants and fission bombs (A-bomb).

19. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov19 Fusion When two nuclei collide and stick together When two nuclei collide and stick together Process that powers the sun and stars Process that powers the sun and stars All life arises from it All life arises from it Not usually found in every day experience on Earth Not usually found in every day experience on Earth Component of the H-bomb Component of the H-bomb

20. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov20 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. 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 Examples: Some natural isotopes (like uranium and thorium) have half-lives that are billions of years 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 Since Earth is about 5 billion years old, short lived naturally produced isotopes gone Most medical isotopes (like 99m Tc) last only a few days Most medical isotopes (like 99m Tc) last only a few days

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

22. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov22 Some Isotopes & Their Half Lives ISOTOPE HALF- LIFE APPLICATIONS 238 U – Uranium billions of years Natural uranium is comprised of several different isotopes. When enriched in the isotope of 235 U, it’s used to power nuclear reactor or nuclear weapons. 14 C – Carbon 5730 y 5730 y Found in nature from cosmic interactions, used to “carbon date” items and as radiolabel for detection of tumors. 137 Ce – Cesium 30.2 y 30.2 y Blood irradiators, tumor treatment through external exposure. Also used for industrial radiography. 3 H – Tritium 12.3 y 12.3 y Labeling biological tracers. 192 Ir – Iridium 74 d Implants or "seeds" for treatment of cancer. Also used for industrial radiography. 99 Mo – 99 Mo – Molybdenum 66 h Parent for 99m Tc generator. 99m Tc – Technetium 6 h 6 h Brain, heart, liver (gastroenterology), lungs, bones, thyroid, and kidney imaging, regional cerebral blood flow, etc.

23. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov23 How do we Measure the Amount of Radiation?

24. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov24 Radiation Quantities and Units Radioactivity Qty: Activity Unit: Curie (Bequerel) 1 Ci = 1000 mCi 1 Ci = 1000 mCi 1 Bq = 1 disintegration/sec 1 Bq = 1 disintegration/sec 1 Ci = 3.7  10 10 Bq 1 Ci = 3.7  10 10 Bq Radiation Risk Qty: Dose Equivalent Unit: rem (Sievert) 1 rem = 1000 mrem 1 rem = 1000 mrem 1 Sv=100 rem 1 Sv=100 rem Radiation Absorbed Dose Qty: Dose Unit: rad (Gray) 1 rad = 1000 mrad 1 rad = 1000 mrad 1 rad = 100 erg/gram 1 rad = 100 erg/gram 1 Gy =100 rad 1 Gy =100 rad Roentgen equivalent man

25. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov25 Convert from Curies to Rad Curie is the number of decays/s Curie is the number of decays/s 1 Curie = 3.7  10 10 decays/s (exactly) 1 Curie = 3.7  10 10 decays/s (exactly) Rad is the absorbed dose or physical dose Rad is the absorbed dose or physical dose Amount of energy deposited in unit mass Amount of energy deposited in unit mass human tissue or other media human tissue or other media 1 Rad = 100 erg/g 1 Rad = 100 erg/g Often use gray Often use gray 1 J/kg 1 J/kg 1 gray = 100 rad 1 gray = 100 rad

26. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov26 Need Biological Dose – REM rad  Q = rem Q Gamma x-ray 1 Beta1 Neutron3-20 Alpha20 To convert from rad to rem multiply by appropriate value of Q Q is the Quality Factor Q reflects the damage

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

28. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov28 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 positive and negative electrical charge electrical charge

29. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov29 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

30. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov30 Beta Radiation Is a Skin, Eye and Internal Hazard skin, eye and internal hazard stopped by plastic found in natural food, air and water

31. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov31 X-ray and Gamma Radiation Are Penetrating Radiation and an External Hazard stopped by lead naturally present in soil and cosmic radiation found in medical uses

32. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov32 How does Radiation Injure Cells? 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 kill cells. + -

33. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov33 Types of Exposure & Health Effects Acute Dose - Deterministic Acute Dose - Deterministic Large radiation dose in a short period of time Large radiation dose in a short period of time Large doses may result in observable health effects Large doses may result in observable health effects Early: Nausea & vomiting Early: Nausea & vomiting Hair loss, fatigue, & medical complications Hair loss, fatigue, & medical complications Burns and wounds heal slowly Burns and wounds heal slowly Examples: medical exposures and accidental exposure to sealed sources Examples: medical exposures and accidental exposure to sealed sources Chronic Dose - Stochastic Chronic Dose - Stochastic Radiation dose received over a long period of time Radiation dose received over a long period of time Body more easily repairs damage from chronic doses Body more easily repairs damage from chronic doses Does not usually result in observable effects Does not usually result in observable effects Examples: Background Radiation and Internal Deposition Examples: Background Radiation and Internal Deposition Inhalation

34. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov34 At HIGH Doses, We KNOW Radiation Causes Harm High Dose effects seen in High Dose effects seen in Radium dial painters Radium dial painters Early radiologists Early radiologists Atomic bomb survivors Atomic bomb survivors Populations near Chernobyl Populations near Chernobyl Medical treatments Medical treatments Criticality Accidents Criticality Accidents Cancer Cancer Leukemia (A-bomb data) Leukemia (A-bomb data) Thyroid (Chernobyl data) Thyroid (Chernobyl data) Bone and other solid cancers (A-bomb data) Bone and other solid cancers (A-bomb data) Birth defects (A-bomb data) Birth defects (A-bomb data) Genetic effects (only animal data) Genetic effects (only animal data).

35. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov35 Effects of ACUTE (Deterministic) Exposures Dose (rads*) Effects 25-50 First sign of physical effects (drop in white blood cell count) (drop in white blood cell count) 100 Threshold for vomiting (within a few hours of exposure) 320 - 360 ~ 50% die within 60 days (with minimal supportive care) 480 - 540 ~50 % die within 60 days (with supportive medical care) 1,000 ~ 100% die within 30 days For common external exposures 1 rad ~ 1 rem = 1,000 mrem * For common external exposures 1 rad ~ 1 rem = 1,000 mrem

36. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov36 At LOW Doses, We PRESUME Radiation Causes Harm No physical effects have been observed 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

37. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov37 Sources of Radiation Average radiation exposure in the United States Average radiation exposure in the United States 360 mrem or 360 mrem or 0.360 rem 0.360 rem Very location dependent Very location dependent

38. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov38 Manufactured Sources of Radiation Contribute an Average of 60 mrem/year cigarette smoking - 1300 mrem lung dose lung dose building materials - 3.6 mrem smoke detectors - 0.0001 mrem medical - 53 mrem

39. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov39 Risks in Perspective 1 in 1 million chance of fatality 40 tablespoon peanut butter (aflotoxin) 40 tablespoon peanut butter (aflotoxin) 2 days in New York City (air quality) 2 days in New York City (air quality) 3 mrem radiation (cancer) 3 mrem radiation (cancer) 1 mile on motorcycle (collision) 1 mile on motorcycle (collision) 300 miles in car (collision) 300 miles in car (collision) 10 charbroiled steaks 10 charbroiled steaks Smoking 1 cigarette Smoking 1 cigarette

40. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov40 ALARA Reduce radiation dose by using: Time Time Distance Distance Shielding Shielding ALARA stands for As Low As Reasonably Achievable

41. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov41 Reduce Time Spend as short as time as necessary to complete the task

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

43. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov43 Increase Distance Twice the distance = ¼ of the dose

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

45. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov45 Use Shielding

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

47. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov47 Reactors Glow in the Dark Reactor core emits electrons Reactor core emits electrons Electrons move faster than the speed of light in water Electrons move faster than the speed of light in water At that speed they emit blue light At that speed they emit blue light Cherenkov Radiation Cherenkov Radiation Similar to sonic boom or wake of a boat Similar to sonic boom or wake of a boat

48. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov48 Can You Glow in the Dark? Ingest a very hot radiation source Ingest a very hot radiation source Beta needed Beta needed Short half life Short half life Do not swallow Do not swallow Unless your midriff is exposed Unless your midriff is exposed Or inject source into your blood Or inject source into your blood Don’t be in direct light Don’t be in direct light Usually too faint for sunlight Usually too faint for sunlight Try it for Halloween? Try it for Halloween?

49. Nuclear Science Merit BadgeHoward Matis - hsmatis@lbl.gov49 Summary Radiation is part Radiation is part Our natural environment Our natural environment Technology Technology Health effects Health effects Known for high doses Known for high doses Unknown for low Unknown for low You deal with it regularly You deal with it regularly

50. Nuclear Science Merit Badge Howard Matis - hsmatis@lbl.gov 50 The End