Energy in the form of particles or electromagnetic waves emitted from the nuclei of unstable atoms

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RADIATION
Energy in the form of particles or
electro-magnetic waves emitted from the nuclei of
unstable atoms
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RADIATION

• The term really includes all forms of
  electromagnetic radiation
• Commonly used today to describe particulate
  radiation

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NUCLEAR REACTIONS PRODUCE RADIATION

• Protons and neutrons determine nuclear reactions
• One must understand atomic structure to
  understand radiation

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NUCLEAR PARTICLES
Protons and Neutrons are the two basic nuclear
particles. Together they contain practically all
the mass of an atom and are determinants of an
atoms nuclear characteristics.
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RADIOACTIVE DECAY

• Radioactive decay refers to the spontaneous
  emission of radiation from the nucleus of an
  unstable atomic nucleus
• The ratio of neutrons to protons is largely
  determinant of the stability of the nucleus and
  the tendency for radioactive decay
  to occur

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DEFINITION OF RADIOACTIVE DECAY
Radioactive decay is the process of spontaneous
emission of radiation in the form of particles or
photons from the nuclei of unstable atoms
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CHARACTERISTICS OF RADIOACTIVE DECAY

• It is a natural process in our universe
• It is spontaneous we cannot predict when an
  atom will undergo decay

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BASIC TYPES OF RADIOACTIVE DECAY

• Alpha (?) decay
• Occurs when atomic nuclei have too many protons
  and neutrons (i.e., Are heavy)

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ALPHA PARTICLE
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CHACTERISTICS OF ALPHA PARTICLES

• Consist of 2 protons and 2 neutrons
• Mass of an alpha particle is 8000 me or 4 amu
• Charge 2
• Are highly ionizing
• Have low penetrating abilities
  (only cm in air and mm in water)

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MORE ABOUT ALPHA PARTICLES

• Easily shielded common types of shielding are
  paper, cardboard, air, clothing will not
  penetrate skin
• Health hazard when taken internally
• Not commonly used in medicine
• Common sources smoke detectors
  (Am-241) and lantern mantles (thorium nitrate)

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ALPHA PARTICLE DECAY

• Changes both the mass and identity of the nucleus
  of the parent radionuclide
• This means that the decay results in the
  formation of a new element as the daughter
  product

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QUESTIONS?
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NEGATIVE BETA (ß-) DECAY
Occurs when atoms have too many neutrons (i.e.,
Are neutron-rich) and decay by emitting a
negative beta particle (ß-)
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WHAT ARE NEGATIVE BETA PARTICLES?
During negative beta decay, excess neutrons are
converted into protons, electrons, and
antineutrinos. The protons remain in the nucleus
but the new electrons are emitted as negative
beta particles (ß-) or negatrons. You may wish
to think of them as nuclear electrons.
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CHARACTERISTICS OF NEGATIVE BETA DECAY

• Less ionizing than alphas due to decreased mass
  of negatrons
• Changes the identity of the nucleus but not the
  mass
• The z number is increased due to
  conversion of neutrons
  into
  protons

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CHARACTERISTICS OF NEGATIVE BETA PARTICLES
(NEGATRONS)

• Negatrons consist of nuclear electrons
• The mass is the same as electrons
• There is a charge of 1 in negatrons
• More penetrating than alpha particles 12
  meters in air
• They can penetrate skin
  best shielding is wood,
  plastics, thick
  cardboard, etc.

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POSITRON (ß) EMISSION
Occurs when the nucleus of the atom has too many
protons (i.e., is proton-rich). It is also known
as positive beta decay.
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POSTIVE BETA (ß) DECAY
Results in a positive electron emitted from the
nucleus of the proton rich atom. This positive
electron is known as a positron. An additional
particle, a neutrino, is also emitted from the
nucleus. Neutrinos are very small particles with
no electric charge. They have little or no
mass
and participate in
weak interactions.
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CHARACTERISTICS OF POSITRON EMMISION

• Positrons have same mass as electrons
• Positrons have charge 1
• Positrons are less ionizing than alphas
• Positrons are more penetrating than alpha decay
  but less than gamma
• The best shielding is lead
  with thickness of 1 inch
  
  or more

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QUESTIONS?
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GAMMMA (?) EMISSION
Is a form of pure electromagnetic radiation
emitted from nuclei that have excess energy. It
is sometimes called gamma photon radiation.
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GAMMMA RAYS
Are photons emitted from unstable nuclei to rid
themselves of excess energy. Gamma photons are
subatomic packets of pure energy. They are
higher in energy and more penetrating than
thephotons that make up visible light.
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GAMMMA RAYS AND X RAYS
Have the same properties except for their origin
Gammas come from within the nuclei of atoms
X-rays come from outside the nuclei Both are

electromagnetic
energy in the form
of emitted
photons
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PROPERTIES OF GAMMMA (?) AND X RAYS

• Charge is 0 (no charge)
• Mass is 0 (no mass)
• Low ionization
• Penetration abilities can be extremely high
  penetrating power is
  dependent upon the
  energy of the
  emitted photons

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QUESTIONS?
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TERMS TO REVIEW

• Radiation Alpha decay
• Alpha particle Radioactive decay
• Negatron Negative beta decay
• Positron X-ray
• Gamma ray Photon
• Positive beta decay
• Antineutrino

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TEST YOUR KNOWLEDGE

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• Which of the following particles has the most
  mass?
• A. Negatron
• B. Gamma photon
• C. Positron
• D. Alpha

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TEST YOUR KNOWLEDGE

• Which of the following does not penetrate human
  skin?
• A. Alpha radiation
• B. Positron emission
• C. X-rays
• D. Gamma rays
• E. Negatron radiation

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TEST YOUR KNOWLEDGE

• Radioactive decay is a spontaneous process.
• A. True
• B. False

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TEST YOUR KNOWLEDGE

• Which of the following has no mass and no charge?
• A. Alpha particles
• B. Gamma rays
• C. Negative beta particles
• D. Positrons
• E. No correct answer given

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TEST YOUR KNOWLEDGE

• What type of radioactive decay occurs because of
  proton rich nuclei?
• A. Gamma
• B. Positive beta
• C. Alpha
• D. Negative beta
• E. X-ray

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Want to Know More????

• Arrange a visit to a nearby Nuclear Facility or
  search the WWW.
• Farley Nuclear Plant Visitors Center
• near Dothan, AL
• 1-800-344-8295
• http//www.southerncompany.com

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