The word atom is derived from the Greek word atom which means indivisible.
The Greeks concluded that matter could be broken down into particles to small to be seen. These particles were called atoms.
Atoms are composed of three type of particles: protons, neutrons, and electron.Protons and neutrons are responsible for most of the atomic mass e.g in a 150 person 149 lbs, 15 oz are protons and neutrons while
only 1 oz. is electrons.The mass of an electron is very small (9.108 X
the protons and neutrons reside in the nucleus. Protons have a positive
(+) charge, neutrons have no charge i.e they are neutral. Electrons
reside in orbitals around the nucleus. They have a negative charge (-).
is the number of protons that determines the atomic number, e.g., H =
1. The number of protons in an element is constant (e.g., H=1, Ur=92)
but neutron number may vary, so mass number (protons + neutrons) may
The same element may contain varying numbers of neutrons; these forms of an element are called isotopes. The chemical properties of isotopes are the same, although the physical properties of some isotopes may be different.
isotopes are radioactive-meaning they “radiate” energy as they decay to
a more stable form, perhaps another element half-life: time required
for half of the atoms of an element to decay into stable form. Another
example is oxygen, with atomic number of 8 can have 8, 9, or 10
The Atomic Number, Mass Number and Isotopes of an Element and their Symbols
Explain the atomic number, mass number and isotopes of an element and their symbols
atomic number of a chemical element (also known as its proton number)
is the number of protons found in the nucleus of an atom of that
element.Therefore it is identical to the charge number of the nucleus.
It is conventionally represented by the symbol Z.
atomic number uniquely identifies a chemical element. In an uncharged
atom, the atomic number is also equal to the number of electrons.
The atomic number, Z, should not be confused with the mass number, A.
number is the number of nucleons, i. e the total number of protons and
neutrons in the nucleus of an atom. —The number of neutrons, N, is
known as the neutron number of the atom; thus, A = Z + N (these
quantities are always whole numbers).
protons and neutrons have approximately the same mass (and the mass of
the electrons is negligible for many purposes) and the mass defect of
nucleon binding is always small compared to the nucleon mass, the atomic
mass of any atom, when expressed in unified atomic mass units (making a
quantity called the “relative isotopic mass”), is roughly (to within
1%) equal to the whole number A.
Isotopes are atoms with the same atomic number Z but different neutron numbers N, and hence different atomic masses.
little more than three-quarters of naturally occurring elements exist
as a mixture of isotopes (see monoisotopic elements), and the average
isotopic mass of an isotopic mixture for an element (called the relative
atomic mass) in a defined environment on Earth, determines the
element’s standard atomic weight.
it was these atomic weights of elements (in comparison to hydrogen)
that were the quantities measurable by chemists in the 19th century.The
chemical properties of isotopes are the same, although the physical
properties of some isotopes may be different.
isotopes are radioactive-meaning they “radiate” energy as they decay to
a more stable form, perhaps another element half-life: time required
for half of the atoms of an element to decay into stable form. Another
example is oxygen, with atomic number of 8 can have 8, 9, or 10
Forces Holding the Nucleus
Mention forces holding the nucleus
Stable and unstable atoms
are forces within the atom that account for the behavior of the
protons, neutrons, and electrons. Without these forces, an atom could
not stay together.
that protons have a positive charge, electrons a negative charge, and
neutrons are neutral. According to the laws of physics, like charges
repel each other and unlike charges attract each other. A force called
the strong force opposes and overcomes the force of repulsion between
the protons and holds the nucleus together.
net energy associated with the balance of the strong force and the
force of repulsion is called the binding energy. The electrons are kept
in orbit around the nucleus because there is an electromagnetic field of
attraction between the positive charge of the protons and the negative
charge of the electrons.
some atoms, the binding energy is great enough to hold the nucleus
together. The nucleus of this kind of atom is said to be stable. In some
atoms the binding energy is not strong enough to hold the nucleus
together, and the nuclei of these atoms are said to be unstable.
Unstable atoms will lose neutrons and protons as they attempt to become
energy is the net energy that is the result of the balance with the
strong force and the repulsive force, and this is the amount of energy
that holds the nucleus together.
A stable atom is an atom that has enough binding energy to hold the nucleus together permanently.
An unstable atom does not have enough binding energy to hold the nucleus together permanently and is called a radioactive atom.
The Concept of Radioactivity
Explain the concept of radioactivity
decay, also known as nuclear decay or radioactivity, is the process by
which a nucleus of an unstable atom loses energy by emitting ionising
material that spontaneously emits such radiation — which includes alpha
particles, beta particles, gamma rays and conversion electrons — is
decay is a stochastic (i.e. random) process at the level of single
atoms, in that, according to quantum theory, it is impossible to predict
when a particular atom will decay.
chance that a given atom will decay never changes, that is, it does not
matter how long the atom has existed. For a large collection of atoms
however, the decay rate for that collection can be calculated from their
measured decay constants or half-lives. The half-lives of radioactive
atoms have no known limits for shortness or length of duration, and
range over 55 orders of magnitude in time.
Properties of the Radiations Emitted by Radio-active Substances
Describe properties of the radiations emitted by radio-active substances
are many types of radioactive decay . A decay, or loss of energy,
results when an atom with one type of nucleus, called the parent
radionuclide (or parent radioisotope), transforms into an atom with
anucleus in a different state, or with a nucleus containing a different
number of protons and neutrons. The product is called the daughter
nuclide. In some decays, the parent and the daughter nuclides are
different chemical elements, and thus the decay process results in the
creation of an atom of a different element. This is known as a nuclear
The Nuclear Changes due to the Emission of Alpha (‘8c’b1), Beta (‘8cuc0u8804 ) and Gamma (‘8cu8805 ) Radiations
Explain the nuclear changes due to the emission of Alpha (‘8c’b1), Beta (‘8cuc0u8804 ) and Gamma (‘8cu8805 ) radiations
Properties of Alpha Rays
Alpha rays or alpha particles are the positively charged particles.
particles have the least penetration power. They cannot penetrate the
skin but this does not mean that they are not dangerous.
they have a great ionisation power, so if they get into the body they
can cause serious damage. They have the ability of ionising numerous
atoms a short distance. It is due to this reason that the radioactive
substance that releases alpha particles needs to be handled with rubber
gloves. It should not be inhaled, eaten or allowed near open cuts.
Properties of Beta Rays.
Beta particles are highly energetic electrons which are released from inside of a nucleus.
They are negatively charged and have a negligible mass.
Beta particles have a greater penetration power than the alpha particles and can easily travel through the skin.
beta particles have less ionisation power than the alpha particles but
still they are dangerous and so their contact with the body must be
Properties of Gamma Rays
They have greatest power of penetration.
They are the least ionizing but most penetrating and it is extremely difficult to stop them from entering the body.
These rays carry huge amount of energy and can even travel through thin lead and thick concrete.
The Detection of ‘8c’b1, ‘8cuc0u8804 and ‘8cu8805 Radiations
Explain the detection of ‘8c’b1, ‘8cuc0u8804 and ‘8cu8805 radiations
Geiger Counter, with Geiger-Mueller (GM) Tube or Probe
GM tube is a gas-filled device that, when a high voltage is applied,
creates an electrical pulse when radiation interacts with the wall or
gas in the tube. These pulses are converted to a reading on the
the instrument has a speaker, the pulses also give an audible click.
Common readout units are roentgens per hour (R/ hr), milliroentgens per
hour (mR/hr), rem per hour (rem/hr), millirem per hour (mrem/hr), and
counts per minute (cpm).
probes (e.g., “pancake” type) are most often used with handheld
radiation survey instruments for contamination measurements. However,
energy-compensated GM tubes may be employed for exposure measurements.
often the meters used with a GM probe will also accommodate other
radiation-detection probes. For example, a zinc sulfide (ZnS)
scintillator probe, which is sensitive to just alpha radiation, is often
used for field measurements where alpha-emitting radioactive materials
need to be measured.
consists of a fine metal gauze mounted about a millimetre away from a
thin wire.A voltage is applied between the two so that sparking takes
place between them – this usually requires some 4000 – 5000 V. The
voltage is then reduced until sparking just stops.
an alpha-source is brought up close to the gauze it will ionise the
air, and sparks will occur between the gauze and wire. With beta and
gamma sources insufficient ions are usually produced for sparking to
take place.The spark counter can be used to measure the range of
The cloud chamber, also known as the Wilson chamber, is a particle detector used for detecting ionising radiation.
picture shows in a single shot the 4 particles that we can detect in a
cloud chamber: proton, electron, muon (probably) and alpha. In its most
basic form, a cloud chamber is a sealed environment containing a
supersaturated vapor of water or alcohol.
a charged particle (for example, an alpha or beta particle) interacts
with the mixture, the fluid is ionized. The resulting ions act as
condensation nuclei, around which a mist will form (because the mixture
is on the point of condensation).
high energies of alpha and beta particles mean that a trail is left,
due to many ions being produced along the path of the charged particle.
These tracks have distinctive shapes (for example, an alpha particle’s
track is broad and shows more evidence of deflection by collisions,
while an electron’s is thinner and straight).
any uniform magnetic field is applied across the cloud chamber,
positively and negatively charged particles will curve in opposite
directions, according to the Lorentz force law with two particles of
Other devices used to detect radiation include:
Half-Life as Applied to a Radioactive Substance
Describe half-life as applied to a radioactive substance
life can be defined as the time taken for the number of nuclei in a
radioactive material to halve. It can also be defined as the time taken
for the count rate of a sample of radioactive material to fall to half
of its starting level.
count rate is measured by using an instrument called a Geiger-Muller
tube over a period of time. A Geiger-Muller tube detects radiations by
absorbing the radiation and converting it into an electrical pulse which
triggers a counter and is displayed as a count rate.
release of radiation by unstable nuclei is called radioactive decay.
This process occurs naturally and cannot be influenced by chemical or
release of radiation is also a random event and overtime the activity
of the radioactive material decreases. It is not possible to predict
when an individual nucleus in a radioactive material will decay.
it is possible to measure the time taken for half of the nuclei in a
radioactive material to decay. This is called the half life of
radioactive material or radioisotope.
The Half-Life of a Radioactive Element
Determine the half-life of a radioactive element
An exponential decay process can be described by any of the following three equivalent formulas:
N0 is the initial quantity of the substance that will decay (this quantity may be measured in grams, moles, number of atoms, etc).
N(t) is the quantity that still remains and has not yet decayed after a time t.
t1⁄2 is the half-life of the decaying quantity.
τis a positive number called the mean lifetime of the decaying quantity.
λis a positive number called the decay constant of the decaying quantity.
Where ln (2) is the natural logarithm of 2 (approximately 0.693).
plugging in and manipulating these relationships, we get all of the
following equivalent descriptions of exponential decay, in terms of the
The Application of a Natural Radioactive Substances
Identify the applications of a natural radioactive Substances
doctors, and dentists use a variety of nuclear materials and procedures
to diagnose, monitor, and treat a wide assortment of metabolic
processes and medical conditions in humans. In fact, diagnostic x-rays
or radiation therapy have been administered to about 7 out of every 10
Americans. As a result, medical procedures using radiation have saved
thousands of lives through the detection and treatment of conditions
ranging from hyperthyroidism to bone cancer.
most common of these medical procedures involves the use of x-rays — a
type of radiation that can pass through our skin. When x-rayed, our
bones and other structures cast shadows because they are denser than our
skin, and those shadows can be detected on photographic film. The
effect is similar to placing a pencil behind a piece of paper and
holding the pencil and paper in front of a light. The shadow of the
pencil is revealed because most light has enough energy to pass through
the paper, but the denser pencil stops all the light. The difference is
that x-rays are invisible, so we need photographic film to “see” them
for us. This allows doctors and dentists to spot broken bones and dental
and other forms of radiation also have a variety of therapeutic uses.
When used in this way, they are most often intended to kill cancerous
tissue, reduce the size of a tumor, or reduce pain. For example,
radioactive iodine (specifically iodine-131) is frequently used to treat
thyroid cancer, a disease that strikes about 11,000 Americans every
machines have also been connected to computers in machines called
computerized axial tomography (CAT) or computed tomography (CT)
scanners. These instruments provide doctors with color images that show
the shapes and details of internal organs. This helps physicians locate
and identify tumors, size anomalies, or other physiological or
functional organ problems.
addition, hospitals and radiology centers perform approximately 10
million nuclear medicine procedures in the United States each year. In
such procedures, doctors administer slightly radioactive substances to
patients, which are attracted to certain internal organs such as the
pancreas, kidney, thyroid, liver, or brain, to diagnose clinical
Academic and Scientific Applications
colleges, high schools, and other academic and scientific institutions
use nuclear materials in course work, laboratory demonstrations,
experimental research, and a variety of health physics applications. For
example, just as doctors can label substances inside people’s bodies,
scientists can label substances that pass through plants, animals, or
our world. This allows researchers to study such things as the paths
that different types of air and water pollution take through the
environment. Similarly, radiation has helped us learn more about the
types of soil that different plants need to grow, the sizes of newly
discovered oil fields, and the tracks of ocean currents.
addition, researchers use low-energy radioactive sources in gas
chromatography to identify the components of petroleum products, smog
and cigarette smoke, and even complex proteins and enzymes used in
also use radioactive substances to determine the ages of fossils and
other objects through a process called carbon dating. For example, in
the upper levels of our atmosphere, cosmic rays strike nitrogen atoms
and form a naturally radioactive isotope called carbon-14. Carbon is
found in all living things, and a small percentage of this is carbon-14.
When a plant or animal dies, it no longer takes in new carbon and the
carbon-14 that it accumulated throughout its life begins the process of
radioactive decay. As a result, after a few years, an old object has a
lower percent of radioactivity than a newer object. By measuring this
difference, archaeologists are able to determine the object’s
could talk all day about the many and varied uses of radiation in
industry and not complete the list, but a few examples illustrate the
point. In irradiation, for instance, foods, medical equipment, and other
substances are exposed to certain types of radiation (such as x-rays)
to kill germs without harming the substance that is being disinfected —
and without making it radioactive. When treated in this manner, foods
take much longer to spoil, and medical equipment (such as bandages,
hypodermic syringes, and surgical instruments) are sterilized without
being exposed to toxic chemicals or extreme heat. As a result, where we
now use chlorine — a chemical that is toxic and difficult-to-handle — we
may someday use radiation to disinfect our drinking water and kill the
germs in our sewage. In fact, ultraviolet light (a form of radiation) is
already used to disinfect drinking water in some homes.
radiation is used to help remove toxic pollutants, such as exhaust
gases from coal-fired power stations and industry. For example, electron
beam radiation can remove dangerous sulphur dioxides and nitrogen
oxides from our environment. Closer to home, many of the fabrics used to
make our clothing have been irradiated (treated with radiation) before
being exposed to a soil-releasing or wrinkle-resistant chemical. This
treatment makes the chemicals bind to the fabric, to keep our clothing
fresh and wrinkle-free all day, yet our clothing does not become
radioactive. Similarly, nonstick cookware is treated with gamma rays to
keep food from sticking to the metal surface.
agricultural industry makes use of radiation to improve food production
and packaging. Plant seeds, for example, have been exposed to radiation
to bring about new and better types of plants. Besides making plants
stronger, radiation can be used to control insect populations, thereby
decreasing the use of dangerous pesticides. Radioactive material is also
used in gauges that measure the thickness of eggshells to screen out
thin, breakable eggs before they are packaged in egg cartons. In
addition, many of our foods are packaged in polyethylene shrink-wrap
that has been irradiated so that it can be heated above its usual
melting point and wrapped around the foods to provide an airtight
around us, we see reflective signs that have been treated with
radioactive tritium and phosphorescent paint. Ionizing smoke detectors,
using a tiny bit of americium-241, keep watch while we sleep. Gauges
containing radioisotopes measure the amount of air whipped into our ice
cream, while others prevent spillover as our soda bottles are carefully
filled at the factory.
also use gauges containing radioactive substances to measure the
thickness of paper products, fluid levels in oil and chemical tanks, and
the moisture and density of soils and material at construction sites.
They also use an x-ray process, called radiography, to find otherwise
imperceptible defects in metallic castings and welds. Radiography is
also used to check the flow of oil in sealed engines and the rate and
way that various materials wear out. Well-logging devices use a
radioactive source and detection equipment to identify and record
formations deep within a bore hole (or well) for oil, gas, mineral,
groundwater, or geological exploration. Radioactive materials also power
our dreams of outer space, as they fuel our spacecraft and supply
electricity to satellites that are sent on missions to the outermost
regions of our solar system.
Nuclear Power Plants
produced by nuclear fission — splitting the atom — is one of the
greatest uses of radiation. As our country becomes a nation of
electricity users, we need a reliable, abundant, clean, and affordable
source of electricity. We depend on it to give us light, to help us
groom and feed ourselves, to keep our homes and businesses running, and
to power the many machines we use. As a result, we use about one-third
of our energy resources to produce electricity.
can be produced in many ways — using generators powered by the sun,
wind, water, coal, oil, gas, or nuclear fission. In America, nuclear
power plants are the second largest source of electricity (after
coal-fired plants) — producing approximately 21 percent of our Nation’s
The purpose of a nuclear power plant is to boil water to produce steam to power a generator to produce electricity.
While nuclear power plants have many similarities to other types of
plants that generate electricity, there are some significant
differences. With the exception of solar, wind, and hydroelectric
plants, power plants (including those that use nuclear fission) boil
water to produce steam that spins the propeller-like blades of a turbine
that turns the shaft of a generator. Inside the generator, coils of
wire and magnetic fields interact to create electricity. In these
plants, the energy needed to boil water into steam is produced either by
burning coal, oil, or gas (fossil fuels) in a furnace, or by splitting
atoms of uranium in a nuclear power plant. Nothing is burned or exploded
in a nuclear power plant. Rather, the uranium fuel generates heat
through a process called fission.
power plants are fueled by uranium, which emits radioactive substances.
Most of these substances are trapped in uranium fuel pellets or in
sealed metal fuel rods. However, small amounts of these radioactive
substances (mostly gases) become mixed with the water that is used to
cool the reactor. Other impurities in the water are also made
radioactive as they pass through the reactor. The water that passes
through a reactor is processed and filtered to remove these radioactive
impurities before being returned to the environment. Nonetheless, minute
quantities of radioactive gases and liquids are ultimately released to
the environment under controlled and monitored conditions
U.S. Nuclear Regulatory Commission (NRC) has established limits for the
release of radioactivity from nuclear power plants. Although the
effects of very low levels of radiation are difficult to detect, the
NRC’s limits are based on the assumption that the public’s exposure to
man-made sources of radiation should be only a small fraction of the
exposure that people receive from natural background sources.
has shown that, during normal operations, nuclear power plants
typically release only a small fraction of the radiation allowed by the
NRC’s established limits. In fact, a person who spends a full
year at the boundary of a nuclear power plant site would receive an
additional radiation exposure of less than 1 percent of the radiation
that everyone receives from natural background sources. This
additional exposure, totaling about 1 millirem (a unit used in measuring
radiation absorption and its effects), has not been shown to cause any
harm to human beings.
are used to induce mutations in plants in order to develop superior
varieties that are harder and more resistant to diseases.
Difference between Natural and Artificial Radioactivity
Distinguish between natural and artificial radioactivity
Artificial radioactivity is the phenomenon by which even light elements are made radioactive by artificial or induced methods.
occurs when a previously stable material has been made radioactive by
exposure to specific radiation. Most radioactivity does not induce other
material to become radioactive. This Induced radioactivity was
discovered by Irène Curie and F. Joliot in 1934. This is also known as
man-made radioactivity. The phenomenon by which even light elements are
made radioactive by artificial or induced methods is called artificial
and Joliot showed that when lighter elements such as boron and
aluminium were bombarded with α-particles, there was a continuous
emission of radioactive radiations, even after the α−source had been
removed. They showed that the radiation was due to the emission of a
particle carrying one unit positive charge with mass equal to that of an
activation is the main form of induced radioactivity, which happens
when free neutrons are captured by nuclei. This new heavier isotope can
be stable or unstable (radioactive) depending on the chemical element
free neutrons disintegrate within minutes outside of an atomic nucleus,
neutron radiation can be obtained only from nuclear disintegrations,
nuclear reactions, and high-energy reactions (such as in cosmic
radiation showers or particle accelerator collisions). Neutrons that
have been slowed down through a neutron moderator (thermal neutrons) are
more likely to be captured by nuclei than fast neutrons.
Methods of Producing Artificial Radioactive Isotopes
Describe methods of producing artificial radioactive isotopes
Methods of inducing radioactivity
Nuclear activation:Neutron activation
is the process in which neutron radiation induces radioactivity in
materials, and occurs when atomic nuclei capture free neutrons, becoming
heavier and entering excited states. The excited nucleus often decays
immediately by emitting gamma rays, or particles such as beta particles,
alpha particles, fission products and neutrons (in nuclear fission).
Thus, the process of neutron capture, even after any intermediate decay,
often results in the formation of an unstable activation product. Such
radioactive nuclei can exhibit half-lives ranging from small fractions
of a second to many years.
Photonuclear reactions: A
photonuclear reaction is a reaction resulting from an interaction
between a photon and a nucleus.-During a photonuclear reaction energy of
a gamma-ray photon is fully or partially absorbed by the nucleus
forcing it into and excited state. From this excited state the nucleus
can emit any particle, provided it has enough energy for such a process
to occur. Most commonly it will emit a photon, but also a neutron (n), a
proton (p) or an alpha (α) particle can be emitted.
Applications of Artificial Radioactivity
Mention the applications of artificial radioactivity
Application of artificial radioactivity include:
physicians and radiation safety officers, activation of sodium in the
human body to sodium-24, and phosphorus to phosphorus-32, can give a
good immediate estimate of acute accidental neutron exposure.
way to demonstrate that nuclear fusion has occurred inside a fusor
device is to use a Geiger counter to measure the gamma ray radioactivity
that is produced from a sheet of aluminum foil.In the ICF fusion
approach, the fusion yield of the experiment (directly proportional to
neutron production) is usually determined by measuring the gamma-ray
emissions of aluminum or copper neutron activation targets.Aluminum can
capture a neutron and generate radioactive sodium-24, which has a
half-life of 15 hours and a beta decay
energy of 5.514 MeV.The activation of a number of test target elements
such as sulfur, copper, tantalum and gold have been used to determine
the yield of both pure fissionand thermonuclearweapons.
article: neutron activation analysis. Neutron activation analysis is
one of the most sensitive and accurate methods of trace element
analysis. It requires no sample preparation or solubilization and can
therefore be applied to objects that need to be kept intact such as a
valuable piece of art. Although the activation induces radioactivity in
the object, its level is typically low and its lifetime may be short, so
that its effects soon disappear. In this sense, neutron activation is a
non-destructive analysis method.
The potential use of
photonuclear reactions for a range of applications is described. These
are: photonuclear transmutation doping of semiconductors, neutron
production from electron linacs, quality checking of radioactive waste,
fission product incineration, photoexcitation of isomers for dosimetry,
and nuclear resonance fluorescence for materials analysis. Initial brief
descriptions of atomic and nuclear interactions of photons and of
bremsstrahlung are given.
Radiation Hazards and Safety
The Effects of Nuclear Radiation on Human Body
Explain the effects of nuclear radiation on human body
body parts are more specifically affected by exposure to different
types of radiation sources. Several factors are involved in determining
the potential health effects of exposure to radiation. These include:
The size of the dose (amount of energy deposited in the body)
The ability of the radiation to harm human tissue
Which organs are affected
most important factor is the amount of the dose – the amount of energy
actually deposited in your body. The more energy absorbed by cells, the
greater the biological damage. Health physicists refer to the amount of
energy absorbed by the body as the radiation dose. The absorbed dose,
the amount of energy absorbed per gram of body tissue, is usually
measured in units called rads. Another unit of radation is the rem, or
roentgen equivalent in man. To convert rads to rems, the number of rads
is multiplied by a number that reflects the potential for damage caused
by a type of radiation. For beta, gamma and X-ray radiation, this number
is generally one. For some neutrons, protons, or alpha particles, the
number is twenty.
Hair:The losing of hair quickly and in clumps occurs with radiation exposure at 200 rems or higher.
brain cells do not reproduce, they won’t be damaged directly unless the
exposure is 5,000 rems or greater. Like the heart, radiation kills
nerve cells and small blood vessels, and can cause seizures and
Thyroid:The certain body parts
are more specifically affected by exposure to different types of
radiation sources. The thyroid gland is susceptible to radioactive
iodine. In sufficient amounts, radioactive iodine can destroy all or
part of the thyroid. By taking potassium iodide can reduce the effects
Blood System:When a person is
exposed to around 100 rems, the blood’s lymphocyte cell count will be
reduced, leaving the victim more susceptible to infection. This is often
refered to as mild radiation sickness. Early symptoms of radiation
sickness mimic those of flu and may go unnoticed unless a blood count is
done. According to data from Hiroshima and Nagaski, show that symptoms
may persist for up to 10 years and may also have an increased long-term
risk for leukemia and lymphoma. For more information, visit Radiation
Effects Research Foundation.
exposure to radioactive material at 1,000 to 5,000 rems would do
immediate damage to small blood vessels and probably cause heart failure
and death directly.
damage to the intestinal tract lining will cause nausea, bloody
vomiting and diarrhea. This is occurs when the victim’s exposure is 200
rems or more. The radiation will begin to destroy the cells in the body
that divide rapidly. These including blood, GI tract, reproductive and
hair cells, and harms their DNA and RNA of surviving cells.
reproductive tract cells divide rapidly, these areas of the body can be
damaged at rem levels as low as 200. Long-term, some radiation sickness
victims will become sterile.
sickness results when humans (or other animals) are exposed to very
large doses of ionizing radiation. Radiation exposure can occur as a
single large exposure (acute), or a series of small exposures spread
over time (chronic). Exposure may be accidental or intentional (as in
Accidental exposure to high doses of radiation such as a nuclear power plant accidents.
Exposure to excessive radiation for medical treatments.
Bleeding from the nose, mouth, gums, and rectum
Inflammation of exposed areas (redness, tenderness, swelling, bleeding)
Nausea and vomiting
Open sores on the skin
Skin burns (redness, blistering)
Sloughing of skin
Ulcers in the esophagus, stomach or intestines
Check the person’s breathing and pulse.
Start CPR, if necessary.
Remove the person’s clothing and place the items in a sealed container. This stops ongoing contamination.
Vigorously wash body with soap and water.
Dry the body and wrap with soft, clean blanket.
Call for emergency medical help or take the person to nearest emergency medical facility if you can do so safely.
How to Protect yourself from Nuclear Radiation Hazards
Protect himself/herself from nuclear radiation hazards
average the procedure time for a diagnostic coronary angiogram is
approximately 30 minutes and an interventional procedure PCI or
EPS/pacing would take between 90 to 120 minutes. However the
fluoroscopic and the cine screening time are highly variable depending
on the nature of the procedure and the experience of the operator. The
lower the amount of time spent in a radiation area, the lower the
exposure will be. Significant reductions can be achieved when an
activity is delayed until after cine imaging is completed. Every effort
should be made by the operating cardiologist in the cath lab to minimise
fluoroscopy and cine screening time.
the distance from the radiation beam decreases the risk of exposure.
doubling the distance between the primary beam and operator, reduces the
exposure by a factor of four. In addition, the radiation exposure
varies according to the angle at which the camera is projected Oblique
views (left and right anterior oblique) and steep angulations increase
radiation exposure but are often employed to improve visualisation.
60-degree angulations give up to three times the operator dose than
30-degree angulations (11). The second operator or assistant is
generally less exposed to radiation compared to the first operator but
certainly more at risk than the other staff in the room.
shields and shielding will significantly reduce the risk of exposure
but only if appropriately used and in proper working order. Protective
equipment includes lead aprons, thyroid collars and leaded glasses. With
the newly designed frames and ultra light lenses, protective leaded
eyewear is now used by more of the cardiologists and staff in cardiac
cath lab. Some cath labs also use overhanging lead screens to prevent
radiation exposure to brain. The staff should wear a protective apron of
at least 0.25 mm lead equivalent. Protective gloves should be of at
least 0.35 mm lead equivalent. All such protective clothing should bear
an identifying mark and should be examined at yearly intervals.
Defective items should be withdrawn from use.
Adhering to guideline and protocols:Every
unit or work place that deals with ionising radiation should have their
own local guidelines and rules for radiation safety. These must be
read, understood and strictly adhered to in daily practice. Staff must
comply with these local rules in order to insure that the Trust and all
their employees do not contravene statutory requirements of the ionising
radiation regulations and other relevant legislation.
Minimising risk of exposure to staff and patients: The
occupational limit of radiation exposure in the UK currently is
estimated at 20 mSv per year averaged over five consecutive years (5).
Every operator who undertakes a cardiovascular procedure in the cath lab
is responsible for the amount of radiation exposure to the patient, his
or her co-staff and to themselves. In the event of an incident where
the patient might have been exposed to inadvertent excess radiation
either due to clinical circumstances, malfunctioning of the equipment or
operation errors, the radiation protection adviser should be informed
of the incident. It is their duty to estimate the radiation dose
received by the patient and also advise whether the incident is to be
reported.Only essential staff shall be in the cath lab during radiation
exposure. All persons not required in the room should leave the room
during serial radiographic exposure. The operator shall stand behind a
barrier if possible. People who must move around the room during the
procedure should wear a wraparound protective garment. When possible,
the cardiologist and all other personnel required in the room should
step back from the table and behind portable shields during cine and
serial radiography procedures. This action can decrease the exposure of
the cardiologist and the other nearby personnel by a factor of three or
Nuclear Fission and Fusion
The Nuclear Fission and Fusion
Explain the nuclear fission and fusion
fission is either a nuclear reaction or a radioactive decay process in
which the nucleus of an atom splits into smaller parts (lighter nuclei).
fission process often produces free neutrons and photons (in the form
of gamma rays), and releases a very large amount of energy even by the
energetic standards of radioactive decay. It is an exothermic reaction
which can release large amounts of energy both as electromagnetic
radiation and as kinetic energy of the fragments (heating the bulk
material where fission takes place).
order for fission to produce energy, the total binding energy of the
resulting elements must be less negative (higher energy) than that of
the starting element.
fusion is a nuclear reaction in which two or more atomic nuclei come
very close and then collide at a very high speed and join to form a new
type of atomic nucleus.
During this process, matter is not conserved because some of the matter of the fusing nuclei is converted to photons (energy).
fusion of two nuclei with lower masses than iron (which, along with
nickel, has the largest binding energy per nucleon) generally releases
energy, while the fusion of nuclei heavier than iron absorbs energy.
opposite is true for the reverse process, nuclear fission. This means
that fusion generally occurs for lighter elements only, and likewise,
that fission normally occurs only for heavier elements.
Application of Nuclear Fission and Fusion
Mention the applications of nuclear fission and fusion
Nuclear fission is used in:
Nuclear power plants to generate electricity for domestic and industrial use.
In making nuclear bombs.
Nuclear fusion is used in:
In fussion power plants to make electricity.
To make nuclear weapons such as the hydrogen bombs.
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