IONIZING RADIATION
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Non-Ionizing Radiation
Does not have enough energy to remove
electrons from surrounding atoms
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There Are Lots Of Types Of Radiation
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Atomic Structure
 All matter is made up of atoms
 Protons
 Neutrons
 Electrons
 Not all atoms are stable
 Unstable atoms are known as radioactive
atoms
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Our Bodies Are Resilient
_
DNA damage is most important and
can lead to cell malfunction or death.
_
Our body has ~ 60 trillion cells
» Each cell takes “a hit” about every 10
seconds, resulting in tens of millions of
DNA breaks per cell each year.
» BACKGROUND RADIATION causes only a
very small fraction of these breaks
(~ 5 DNA breaks per cell each year).
_
Our bodies have a highly efficient
DNA repair mechanisms
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Unstable Atoms Emit Radiation
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Alpha Particle
An alpha particle contains two
protons and two neutrons. An
alpha particle is essentially the
nucleus of a helium nucleus (but
with a great deal more energy).
It has a charge of positive two.
It is represented by the
following chemical symbol.
4
2
He
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Alpha Radiation is only a hazard when inside
your body (internal hazard)
skin will
can’t Your
penetrate
skinstop it
internal hazard
stopped by paper
found in soil,
radon and other
radioactive
materials
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Beta Particle
The beta particle is a high
energy electron. It has a
charge of negative one. It
has the following symbol.

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Beta Radiation is a Skin, Eye and Internal
Hazard
skin, eye and internal hazard
stopped by plastic
found in natural food, air and water
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Gamma Radiation
Gamma rays (and Xrays
and Cosmic rays ) are
electromagnetic
radiation. They are
pure energy with no
no charge or mass.
The gamma ray has
the following symbol.

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X and gamma radiation are penetrating
radiation and an EXTERNAL HAZARD.
stopped by lead
found in
medical uses
naturally present in soil
and cosmic radiation
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Background and Manufactured Radiation
In the U.S. Contributes
360 mrem per Year
radon - 200
cosmic - 28
diet - 40
terrestrial - 28
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Uses of Radiation
Nuclear Power
Food sterilization
Industrial and
Medical Uses
Consumer products
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Manufactured sources of radiation
contribute an average of 60 mrem/year
cigarette smoking - 1300 mrem
medical - 53 mrem
round trip US by air
5 mrem per trip
building materials - 3.6 mrem
smoke detectors - 0.0001 mrem
fallout < 1 mrem
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Radiation Versus Radioactive
Contamination
 Radiation
is particles or waves of energy
emitted from unstable atoms.
 Radioactive
Contamination is radioactive
material usually in any location you do not
want it.
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Biological Effects of Radiation
 Early
scientists determined that
radiation was a useful tool but it
could hurt you.
 Radiation
can cause burns and
cellular damage.
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Biological Effects of Radiation
 The principle hazard from radiation exposure is an
increase in the risk of cancer induction.
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SIGNS ARE REQUIRED TO NOTIFY EVERYONE OF
THE PRESENCE OF RADIATION
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MONITORING RADIATION
EXPOSURE
Radiation dosimeters measures radiation
dose to people.
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Minimize Dose By Good
Practices
 TIME
- reduce time of exposure
 DISTANCE - increase distance
 SHIELDING - use shielding
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Radiation is detected with survey meters
Alpha Survey Meter
Beta, Gamma & X-ray
Survey Meter
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