Radiation Basics

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Radiation Basics

• Mary Lou Dunzik-Gougar, Ph.D.
• Idaho State University /
• Idaho National Laboratory
• Candace C. Davison, M.S.
• Pennsylvania State University
• Radiation Science and Engineering Center

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What do the following things have in common?
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Doctor
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Voyager
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Soda Can
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Bugs
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Each represents an application of nuclear science
and technology.
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What well cover . . .

• Atomic Basics
• What is Radiation?
• Types
• Characteristics
• Sources of Ionizing Radiation
• Concepts
• Radioactivity
• Half-Life
• Contamination vs. Irradiation
• Terms

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100 Years of Nuclear Discovery
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Atomic Structure of Helium
THE HELIUMS subATOMIC
HELIUM ATOM COMPOSITION 2
Protons 2 Neutrons 2 Electrons
e-
p
n
n
p
e-
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More on this helium isotope . . .
MASS NUMBER is the total number of protons and
neutrons
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He
ELEMENT SYMBOL
ATOMIC NUMBER is the number of protons
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What is Radiation?
Transmission of energy via . . . Particles
or Waves
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Types of radiation

• Non-Ionizing
• Radiowaves
• Microwaves
• Infrared
• Ultraviolet
• Visible Light

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Electromagnetic Spectrum
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Types of radiation

• Ionizing
• Alpha
• Beta
• Gamma
• X-Rays
• Neutrons

• Non-Ionizing
• Radiowaves
• Microwaves
• Infrared
• Ultraviolet
• Visible Light

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Why is it called ionizing?
Because it creates ions --atoms with a charge.
Ejected Electron
Ionizing Radiation
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Where does radiation come from?
Atoms . . . from radioactive or unstable atoms
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What part of atoms?
The Nucleus Hence, we have terms such as nuclear
science/medicine/reactors.
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What is radioactivity?
The spontaneous emission of fragments or
bundles of energy from energetic nuclei
creating more stable nuclei.
Radioactive atom
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If radiation comes from atoms and everything is
made of atoms, is there radiation around us right
now?
You Betchya! Its called background radiation.
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Sources of radiation
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Units of Dose and Exposure

• Roentgen (R) - unit of exposure - ionization of
  air by x or gamma rays
• RAD (Radiation Absorbed Dose) - energy deposited
  in material
• rem - (Roengten Equivalent Man)
• unit of dose equivalent

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Perspective
Dose (mrem) Source
1 Dental xray
25 Round trip flight to South Africa
40 Your body
110 Head and body CAT scan
620 Average dose in U.S.
5500 Average dose in Guarapari, Brazil
10,200 Average dose in Ramsar, Iran
0 25,000 No observable effect
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Radiation Types

• Alpha (?)
• 2 protons, 2 neutrons
• Doubly positively charged particle

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PENETRATING ABILITY
-


g
b
a
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SHIELDING
Concrete
alpha
beta
gamma
Lead
Wood
Paper
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Radioactive Decay Equations
Alpha Decay Beta Decay Gamma Decay
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Units of Activity
Activity - a rate the number of emissions (of
radiation) per unit time. dps -
disintegrations per second Bequerel 1 dps
Curie 37,000,000,000 dps Picocurie 0.037 dps
or 2.2 dpm
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Half Life
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Half Life
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Radioactive Contamination
Radioactive Contamination - is radioactive
material in an unwanted place.
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Why are we concerned about Radiation?
Ionizing Radiation
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How do we protect ourselves?
Time
Distance
Shielding
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The End . . .