and
Radioterrorism
Prof. Radiation Joshua Gray, Ph.D.
ichael P. Shakarjian,
Atomic Structure
Nucleus contains
Atomic
number, Z, of protons
Neutron number, n, of neutrons
Atomic mass number, A , is
A=Z+n
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A=Z+n
Atoms which have the same Z (proton) but
differing A (atomic mass number) and n
(neutron number) are called isotopes.
Note atomic mass number, A, is NOT the
same thing as the chemical atomic weight,
which is the average of all isotopes of an
element weighted according to their relative
abundance.
ichael P. Shakarjian,
Nuclear Stability
Stable atom Non-radioactive Does
not decay.
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A is for Atom
http://video.google.com/videoplay?
docid=-8242415374753728499#
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Radiation
Energy propagated through space.
The energy may be:
Particles
Ionizing
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or waves
or non-ionizing
Non-ionizing Radiation
DOES NOT have sufficient energy to
cause ionization in the substances it
interacts with.
Light
Laser
Heat.
Radio.
Microwaves.
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Ionizing Radiation
Has sufficient energy that its
interaction with matter will produce an
ejected electron and a positively
charged ion.
Ionizing radiation may originate from
the nucleus of an unstable atom
(radionuclide) or from external
stimulation of certain materials (xrays).
ichael P. Shakarjian,
Energy and Injury
Energy transfer to living things is the
key to damage from interactions with
ionizing radiation.
All measurements and calculations
used to evaluate the hazards from
ionizing radiation serve to quantify the
amount of energy that has been
deposited in the region of interest.
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Energy and Injury
The effects depend on:
Type
of radiation
Amount of radiation
Duration of exposure
Area irradiated
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Alpha
An alpha particle is essentially a helium nucleus.
It consists of two protons and two
neutrons, giving it a mass of 4 amu, and
an electric charge of +2.
88 Ra
226
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222
86
Rn + 42 He+ Q ( energy).
Alpha Particle
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Alpha
Alpha particles are the least
penetrating of the four types of
radiation.
They can be absorbed or stopped
by a few centimeters of air or a
sheet of paper.
Alpha particles will not penetrate
dead layer of skin.
ichael P. Shakarjian,
Beta
Beta particles have the same mass and charge as an
electron.
They are spontaneously emitted from the nucleus of an
unstable atom.
Beta particles originate in the nucleus, in contrast with
ordinary electrons, which exist in the orbits around the
nucleus.
15 P
32
32
16
S+
0
-1
+ neutrino + Q.
They travel several hundred times the distance of alpha
particles in air and require a few millimeters of aluminum
to stop them.
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Beta
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Beta Emitters
Carbon 14
Hydrogen 3 ( a.k.a.Tritium)
Sulfur-35
Calcium-45
Strontium-90
P-32
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Gamma Rays
Electromagnetic radiation originating
from the nucleus of an atom.
Often, gamma emission is
accompanied by beta emission.
Gamma rays travel at the speed of
light through a medium until it
interacts.
Unlike
beta, which slows down as it
travels through a medium.
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Gamma Rays
Gamma emitting isotopes have
discrete energy or energies of
emission
Iodine 125
Iodine 131
Cobalt 60
.035
.027
.364
.637
1.17
1.33
.0037 cm Pb
2.3cm water
0.3 cm Pb
5.8cm water
1.1 cm Pb
11 cm water
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X- Rays
Originate from atomic electrons falling
from a higher energy state to a lower
energy state.
Energy released is characteristic of
the isotope.
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Detection of Radiation
Unlike other hazards, radiation cannot
be sensed.
We must use specialized instruments
and perform calculations to determine
the amount of energy deposited.
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Detection of Radiation
and radiation is
detected using a Geiger
Counter
A tube with inert gas
(helium, neon, or argon)
that conducts electricity
when a particle or photon
makes the gas conductive
Radiation can only be
detected using a
scintillation counter
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Half Life
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Half-life
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Half Life
Describes the rate at which a radioactive
substance decays
Carbon
14
Hydrogen 3
Calcium-45
Strontium-90
Technetium 99m
Iodine-131
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5730y
12.3y
163d
28.1y
6h
8d
Protection From Photons
Time
Distance - Intensity decreases as 1/d2
Shielding
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Particles and protection
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The Absorbed Dose
Energy deposited is key in
determining damage
Absorbed dose describes the amount
of energy imparted to matter
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Dose Equivalent
Biologically weighted absorbed dose
Rem or Sievert where
100
Rem = 1 Sievert
1 Rem = 100 ergs/gm
Rem = Absorbed Dose (Rad) x Quality
Factor
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Dose Equivalent (SI Units)
Biologically weighted absorbed dose
Sievert where
1 Sievert = 1 Joule/kg (=100 Rem)
Sv
= Absorbed Dose(Gray) x radiation
weighting factor
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Activity
The rate of radioactive decay of a sample
Represents the number of atoms decaying
per unit time
Curie = 3.7 x 1010 disintegrations/s
2.2 x 1012 disintegrations/minute
Ci =
2.2 x 106 disintegrations/minute
SI Unit of Activity - Becquerel
1 Bq =
1 d/s
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Biological Effects of
Radiation
Activity alone is NOT a measure of
hazard.
Early Somatic Effects
Late Somatic Effects
Heredity Effects
Stochastic and Non-Stochastic
Effects-Risk
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Cellular Effects
Radiation passing through living cells
will directly ionize or excite atoms and
molecules in the cell structure
If this results in the molecules
breaking up (dissociation), some of
the parts will be charged
Fragments are called free radicals
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Free Radicals
Free radicals are VERY
CHEMICALLY REACTIVE
Water free radicals can combine into
peroxides H2O2
Chemical Poison
Or the HO radical which is more
damaging than peroxide
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.
Total Cellular Effect
Dependant on the dose of radiation
Cell
Death
Cell Repair Intracellular or through
mitotic with replacement healthy cells
If damage to organ is too large, the
organ may not be able to repair itself
Confused
growth or uncontrolled
growth may result from damage to the
growth mechanism
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Radiosensitivity
Cells that make up the body differ in both appearance
and function, therefore, its response to radiation
damage can be expected to be different
Law of Bergonie and Tribondeau - ~1902
Radiosensitivity is:
Directly proportional to the
reproductive capacity
Inversely proportional to the degree of
differentiation
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Radiosensitivity
High Sensitivity
Bone
marrow
Lymphoid tissues
Sperm and ova
Low sensitivity
Muscle
Bone
Nerve
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Radiation Damage
Somatic damage Damage limited to
the exposed individual
Germ cell Damage Damage to
genetic material in the germ cells
results in possible damage to
offspring
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Factors Influencing
Radiation Effects
1.
2.
3.
4.
5.
6.
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Sensitivity of the individual for a
select group, the effects may differ
more greatly than for a
heterogeneous group
Nature or Type of Radiation
Absorbed Dose
Time distribution or Fractionation
Dose Distribution in the Body
Age at irradiation
Uranium and critical mass
A critical mass is the smallest amount of fissile
material needed for a sustained nuclear chain reaction.
Uranium 235 radiation can produce a sustained
reaction, used in nuclear reactions
ichael P. Shakarjian,
Dirty Bombs
An explosive device designed to disperse
nuclear fallout
Radiation exposure could be fairly high, but
not fatal
Create psychological harm through
ignorance, mass panic, and terror.
Considerable time and expense to clean
victims and the physical area
Some areas rendered unusable
Economic damage
Deployed, but never detonated
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Dirty Bombs - Examples
1995, Moscow
Chechen
rebels bury nuclear material in
Ismailovsky Park. Partially buried container
of Cs
1998, Greensboro, NC
19
Small tubes of Cs used for radiation
therapy taken from hospital safe
1998, 1999
Chechen
rebels try to blow up train with dirty
bomb; try to steal radioactive materials from
factory in Grozny
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Dirty Bombs - Examples
2002, Chicago
Jose
Padilla arrested on suspicion of
planning a dirty bomb attack
2002, Moscow
Yuri
Vishnyevsky, Nuclear Regulatory
Agency, says that small amounts of reactorgrade materials are unaccounted for
2003, Afghanistan
Evidence
that Taliban is helping Al Qaeda
construct a dirty bomb
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Aum Shinrikyo
Tried to:
Hire Russian nuclear experts
Purchase Russian nuclear technology
Mine uranium
Steal sensitive nuclear power plant
information.
Shoko
Asahara
Thwarted by Russian refusal to cooperate
Lack of technical expertise within the group
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Accidents with Radioactives
1956 - Lakenheath Airbase, Suffolk, England
1966 Palomares Spain
1987 Goiania, Brazil
2001 - Georgia
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1956 - Lakenheath Airbase,
Suffolk, England
Bomber crashes at air base
Hits a concrete nuclear weapons
bunker
3 U.S. Mark VI nuclear bombs
Same
as Nagasaki
One Mark VI with exposed detonators
sheared
Near miss (!).
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1966, Palomares Spain
B-52 Bomber collides with fueling boom of a KC-135
tanker; planes explode
Four unarmed B28 hydrogen bombs released.
1
Off shore later retrieved intact
3 On land
Two explode, scattering plutonium
650 acres (>1 sq mile) of village, crops, and farms
contaminated.
1700 U.S. and Spanish workers decontaminate area 1400
tons of radioactive soil and vegetation
Similar accident in Greenland, 1968
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1987 Goiania, Brazil
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1987 Goiania, Brazil
Scrap Merchant steals radiation therapy source from
hospital
Contains small amount of 137CsCl powder
Powder dispersed and tracked throughout Goiania.
200 people exposed, 4 died.
4
yr old girl who ate a sandwich after playing with blue
radioactive powder.
Decontamination took 6 months
500 cubic meters of waste created
>100,000 people demanded screening
Economic disaster for city
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2001, Georgia
Two woodcutters found a two small, warm, metal
cylinders in the forest
Slept
next to them for warmth.
Admitted to hospital the next day with terrible
radiation burns.
Cylinder was a generator that contained
concentrated 90Sr.
Russians
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built thousands of these
Misplaced thermoelectric nuclear
generators from the USSR
Electrical generator which obtains its power from radioactive decay.
Heat released by the decay of radioactive material is converted into electricity
ichael P. Shakarjian,
Broken Arrows to Faded Giants
Pentagon Terminology for Nuclear Weapon
Accidents
Broken Arrow Accident involving a nuclear
weapon, warhead or nuclear component
Bent Spear Significant incident involving a
nuclear weapon, warhead, nuclear components, or
vehicle with nuclear loaded
Empty Quiver Seizure, theft, or loss of a U.S.
nuclear weapon.
Faded Giant An event involving a nuclear reactor
or radiological accident.
Ex:
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Nuclear submarine, Kursk, Aug 14, 2000
Radioactive materials
Strontium 90
Useful
as a contaminant
Some nuclear power plants in Russia
were robbed of their uranium sources
Sources for material thousands
worldwide
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Fiestaware
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Radiation detection at ports of
entry into the US
Personal radiation detector
Radiation portal Monitor
Radiation Isotope Identifiers
Large-scale gamma-ray/x-ray imaging
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Radiation detection
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Effects of Radiation
Chernobyl
http://www.kiddofspeed.com/
http://www.kiddofspeed.com/chapter1.html
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Future of biological and
chemical weapons
Nanotechnology
Personalized medicine
More biological threats
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Course Conclusions
In this class, we covered:
Potential
agents of terrorism
Political, environmental and health
issues associated with the use of
chemical, biological, or nuclear
weapons
Countermeasure development
First response
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