General Introduction to Properties of Nuclear Sysytems And Radiation

8/6/2019 General Introduction to Properties of Nuclear Sysytems And Radiation

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INTRODUCTION TO PROPERTIES OF

NUCLEAR SYSYTEMS AND RADIATIONS

PRESENTED BY:

SHIREEN QURESHI


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RADIATIONS

Radiations is really nothing more than the emission of

energy waves through the space, as well as through

physical objects.

Usually these energy waves are classified into:

Ionizing waves

Non ionizing waves


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NON IONIZING WAVES Electromagnetic radiations

Visible light

Infra red radiations

Micro waves Radio waves

Very low frequency

Extremely low frequency

Thermal radiations Black body radiations


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VISIBLE LIGHT: Light or visible light is a very narrowrange of all possible electromagnetic radiations ofwavelength about 400-700 nm.

INFRARED: It has wavelength between 0.7 to 300micrometer. They are longer than visible light butshorter than microwaves.

MICROWAVES: It has wavelenght ranging from aslong as 1m to as short as 1mm with frequencybetween 300MHz to 300GHz.


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RADIO WAVES: They have wavelength longer than

infrared light.

VLF: VLF refers to radio frequencies in the range of 3

to 30KHz.

ELF: ELF refers to radio frequencies from 3 to 30Hz


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THERMAL RADIATIONS: A common synonym of

infrared radiations , the process by which the surface

of an object radiates its thermal energy in the form

EMW. They are generated when heat from movementof charged particle within atom is converted to

electromagnetic radiations.


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IONIZING RADIATIONS Alpha radiations

Beta radiations

Gamma radiations

X-rays


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ISOTOPE: An isotope of an element is comprised ofatoms containing the same number of protons as allother isotopes of that element, but each isotope has a

different number of neutrons eg carbon-12 carbon-13. ISOTONE: Two nuclides are isotones if they have

equal number of neutron but different number ofproton.

RADIOACTIVITY: Its a natural and spontaneousprocess by which the unstable atoms of an isotope ofan element transform or decay to a different state andemit or radiate excess energy in the form of particle orwave.


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ALPHA RADIATION Alpha radiation is the emission of alpha particles from

atoms nucleus. An alpha particle contains 2 protonsand 2 neutrons and is similar to He nucleus i.e 2He

4 .

They are commonly emitted during decay of largenuclei.

An example of alpha transmutation takes place whenuranium decays into the element (Th) by emitting analpha particle

92u238 2He4 + 90Th234


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BETA RADIATIONS Beta radiation is the transmutation of a neutron into a

proton and an electron. when an atom emits a beta

particle the atoms mass will not change, however the

atomic number will increase by 1.

6C14 -1e

0 + 7N14

Beta radiations are of two types:

Beta(-)Beta(+)


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GAMMA RADIATIONS Gamma radiation is composed of photons (1019 Hz)

and photons have neither mass nor electric charge.

They penetrate much further through matter than

alpha and beta.

X-rays emitted during the beta decay of cobolt-60 are

a common example of gamma radiation.

Wavelength smaller than 10nm.


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NUCLEAR REACTIONS While many elements undergo radioactive decay

naturally, nuclear reactions can also be stimulated

artificially.

There are two such types of reactions

NUCLEAR FISSION: reactions in which atoms

nucleus splits into smaller parts, releasing a large

amount of energy in the process. Most commonly thisis done by firing a neutron at the nucleus of an atom.


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FISSION REACTION OF URANIUM-235


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NUCLEAR FUSION: reactions in which two or more

elements fuse together to form one large element,

releasing energy in the process.

In this tremendous amount of energy is released andis known as thermonuclear reactions.


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NUCLEAR FUSION OF TWO HYDROGEN

ISOTOPES


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RADIATIONS TYPEOF

RADIAT

ION

MASS CHARGE SHIELDINGMATERIAL

ALPHA particles 4 +2 Paper, skin,clothes

BETA particles 1/1836 +1 Plastic, glass,light metals

GAMMA Electromagneticwave

0 0 Dense metal,concrete, Earth

NEUTRONS particles1 0

Water, concrete,polythene, oil

PROPERTIES OF RADIATIONS


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PROPERTIES Alpha particles are heavy and doubly charged which

cause them to loose their energy very quickly in

matter.

They are considered hazardous to a persons health ifan alpha emitting material is ingested or inhaled.

Beta particles are much smaller and have one charge.

They are effectively shielded by thin layers of metal orplastic and are again only considered hazardous if a

beta emitter is ingested or inhaled.


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Gamma radiations are highly energetic photons.

They penetrate deeply into the matter

They are difficult to stop.

X-rays are EMW with wavelength smaller than 10nm

X-rays and gamma rays are best shielded by thick

layers of lead and are hazardous to people when are

external to body..


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Neutrons are categorized according to their speeds

High speed neutrons have ability to ionize atoms

Neutrons are best shielded with concrete


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BENEFICIAL EFFECTS OF NUCLEAR

RADIATION Medicinal such as radiotherapy for cancer and X-rays

Level indicators and thickness gauges

In smoke detectors

In tracing locations of gas and liquid leaks In tracing location of malfunctioning in the body such

as blocked kidney.

in communications like variation in intensity ofradiation represents changes in information beingtransmitted.

Researchers use radioactive atoms to determine ageof radioactive materials that were once part of livingorganism.


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NUCLEAR RADIATION DAMAGES CELLS Radiation can damage cells and DNA inside them

through its ionizing effect .If enough ionization occurs

DNA ,cell & tissue damage results.

A common example is sunburn caused by ultravioletlight.

Mutation can result melanoma & other cancers.


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Thank you!!!

General Introduction to Properties of Nuclear Sysytems And Radiation

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