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Nuclear Science Merit Badge Class. Nuclear Science Merit Badge Class. Nuclear Science Merit Badge Class. Nuclear Science Merit Badge.
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Nuclear Science Merit Badge Class Nuclear Science Merit Badge Class
Nuclear Science Merit Badge “Nuclear science gives us a simple explanation of the natural world. The ultimate goal of nuclear science is to find out if there is one fundamental rule that explains how matter and forces interact. Earning the Nuclear Science Merit badge is a chance for Scouts to learn about this exciting field at the cutting edge of science today.”
Part 1 Radiation and it’s effects.
Do the following: • Tell what radiation is. • Describe the hazards of radiation to humans, the environment, and wildlife. Explain the difference between radiation exposure and contamination. In your explanation, discuss the nature and magnitude of radiation risks to humans from nuclear power, medical radiation, and background radiation including radon. Explain the ALARA principle and measures required by law to minimize these risks. • c. Describe the radiation hazard symbol and explain where it should be used. Tell why and how people must use radiation or radioactive materials carefully.
Radiation is • Plot device for fiction • Scary • Deadly • Life saving • Misunderstood • Useful
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.
Nuclear Science Merit Badge Radiation Naturally
ALARA Principle and what is it? • ALARA" is an acronym for "As Low As Reasonably Achievable".
How is ALARA used in the practice of radiation protection? • ALARA is a basic radiation protection concept or philosophy. • It is an application of the "Linear No Threshold Hypothesis," which assumes that there is no "safe" dose of radiation. • Under this assumption, the probability for harmful biological effects increases with increased radiation dose, no matter how small. • Therefore, it is important to keep radiation doses to affected populations (for example, radiation workers, minors, visitors, students, members of the general public, etc.) as low as is reasonably achievable.
Where are ALARA principles utilized? • ALARA principles can be utilized in an infinite number of situations. • For example, the proper design of a nuclear facility depends on ALARA considerations (e.g., can the addition of more shielding to an area be justified in terms of the lower doses it will achieve?). • In addition, designing an x-ray facility for medical applications requires consideration of the amount of shielding needed to ensure that individuals located near the facility (e.g., on the other side of the wall from the x-ray unit) do not receive any more dose than is really necessary during operation of the x-ray device.
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
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
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)
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
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
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
Beta Radiation Is a Skin, Eye and Internal Hazard skin, eye and internal hazard stopped by plastic found in natural food, air and water
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
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
Deterministic (Acute) Effects All of these effects results from acute high doses of radiation to either a part of the body or the whole body. For whole body exposure it is generally thought that an absorbed dose of between 3-5 Gy will cause 50% of those exposed to die within 30 days if medical intervention is not given. This is known as the LD-50 dose. • Examples will include: • radiation burns (skin reddening), • hair loss • cataracts and radiation sickness (nausea, vomiting and diarrhea).
Stochastic (Chronic) Effects • Cancer • Leukemia • Genetic effects • Cataracts
Biological effects of radiation to humans. • Type of radiation involved. -All kinds of ionizing radiation can produce health effects. 2. Size of dose received. -The higher the dose of radiation received, the higher the likelihood of health effects. 3. Rate the dose is received. • Part of the body exposed. • The age of the individual. • Biological differences
Examples of Medical radiation • Radiology • Barium Enema • Chest X Ray • Mammogram • CT Exam • Nuclear Medicine • Used to fight cancer and is usually administered intravenously or by mouth. • Cardiology • Angiogram (contrast materials are injected into the heart so the arteries can be seen. • Radiation Oncology • Brachytherapy • Linear Accelerators • Gamma Stereotactic Radiosurgery.
Background radiation • This radiation is constantly present in the environment and comes from a variety of sources. • Food and water • Space • Radon gas • Self-luminous dials and signs • Global radioactive contamination due to historical nuclear weapons testing.
Background radiation cont. • Global radioactive contamination due to historical nuclear weapons testing • Nuclear power station or nuclear fuel reprocessing accidents • Normal operation of facilities used for nuclear power and scientific research • Emissions from burning fossil fuels, such as coal fired power plants • Emissions from nuclear medicine facilities and patients
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
Other examples of Radiation symbols United Nations Symbol
Do the following: a. Tell the meaning of the following: atom, nucleus, proton, neutron, electron, quark, isotope; alpha particle, beta particle, gamma ray, X-ray; ionization, radioactivity, and radioisotope. b. Choose an element from the periodic table. Construct 3-D models for the atoms of three isotopes of this element, showing neutrons, protons, and electrons. • Use the three models to explain the difference between atomic number and mass number and the difference between the quark structure of a neutron and a proton.
Terms and Definitions • AtomBasic component of matter. An atom is the smallest part of an element having all the chemical properties of that element. An atom consists of a nucleus (that contains protons and neutrons) and surrounding electrons. • NucleusThe central part of an atom that contains protons and neutrons. The number of protons uniquely defines the chemical element. • ProtonOne of three basic particles in an atom. Protons are located in the atom nucleus, have a positive electrical charge, and each has mass about equal to a neutron.
Terms and Definitions • NeutronOne of three basic particles in all atoms except hydrogen. Neutrons are located in the atom nucleus, are electrically neutral, and each has mass about equal to a proton. • ElectronOne of three basic particles in an atom. The electron has a negative electrical charge, orbits the atom nucleus, and has very little mass compared to the nucleus. • Quark basic building block of protons, neutrons, other baryons, and mesons.
Terms and Definitions • Isotope: atomic nuclei having same number of protons but different numbers of neutrons. • Alpha particle: positively- charged particles consisting of two protons and two neutrons emitted by radioactive materials. • Beta particle: high speed electron emitted by a radioactive nucleus in beta decay. • Gamma particle: high energy photon emitted by a radioactive nucleus.
Terms and Definitions • X ray: high- energy photons; high- frequency, short-wavelength electromagnetic waves. • Ionizing radiation particles or waves that can remove electrons from atoms, molecules, or atoms in a solid. • Radioactivity Spontaneous emission of radiation from the unstable nucleus of an atom. • Radioactive isotope Element that emits ionizing radiation when it decays. Radioactive isotopes are commonly used in science, industry, and medicine.
Definitions • Background radiation: Radiation arising from natural sources always present in the environment, including solar and cosmic radiation from outer space and naturally radioactive elements in the atmosphere, the ground, building materials, and the human body. • Contamination: Act of making a substance impure, radioactive, or unclean.
Definitions • Becquerel (Bq): Measure of the rate of decay of a radioactive substance. One Bq is 1 disintegration per second. The human body has thousands of disintegrations from the presence of potassium-40. • Curie (Ci): Unit of measure of the rate of decay of a radioactive material. One Curie is the radioactive intensity of one gram of radium--37 billion disintegrations per second. • Half-life: Time for a radioactive substance to lose half of its activity due to radioactive decay. At the end of one half-life, 50% of the original radioactive material has decayed.
Definitions • Nuclear energy : Energy, usually in the form of heat or electricity, produced by the process of nuclear fission within a nuclear reactor. The coolant that removes the heat from the nuclear reactor is normally used to boil water, and the resultant steam drives steam turbines that rotate electrical generators. Nuclear energy is also produced when two nuclei fuse. • Nuclear Reactor: Any of several devices in which a chain reaction is initiated and controlled, with the resulting heat typically used for power generation and the neutrons and fission products used for military, experimental, and medical purposes. Also called atomic reactor.
Definitions • Particle accelerator: A device, such as a cyclotron or linear accelerator, that accelerates charged subatomic particles or nuclei to high energies. Also called atom smasher. • Rad: Basic unit of absorbed dose of ionizing radiation. • Gray: unit of absorbed dose of ionizing radiation. • Radiation: Particles and electromagnetic rays (waves) emitted from the center of an atom during radioactive disintegration.
Definitions • Radon: Heavy, natural, radioactive gas formed by the radioactive decay of radium, a decay product of uranium. Its atomic number is 86 and its atomic weight is 222. It’s symbol is Rn. • rem: (Roentgen equivalent man), a unit used in radiation protection to measure the amount of damage to human tissue from a dose of ionizing radiation. An average American receives about 0.360 rems of radiation per year. • Sievert : Unit that measures the effect of radiation on the body. "Sievert" replaces the old unit "REM" (Radiation Equivalent Man), a calculated number based on dose and the body organ (e.g. a dose on your eye would give a different number from the same dose on the liver). 1 REM = 10 milliSieverts (mSv).
Computer Lab • Construct a 3-D model for atoms. • Choose 3 elements and explain the difference between them.
Computer Lab Using the following website, you will be constructing a model of the atom.
Discuss modern particle physics with your counselor: a. Name three particle accelerators and describe several experiments that each accelerator performs. b. then discuss modern particle physics with your counselor:
Types of particle accelerators • Cyclotrons • These all used single beams with fixed targets. They tended to have very briefly-run, inexpensive, and unnamed experiments • Fixed-target accelerators • More modern accelerators that were also run in fixed target mode • Synchrotrons • a type of particle accelerator similar to a betatron but having an electric field of fixed frequency with electrons but not with protons as well as a changing magnetic field.
