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Radiation Safety SeriesLesson 1

Introduction to Radiation

Discovery of Radioactivity

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History of Discovery

1895 Wilhelm Roentgen; Discovered X-Ray

1895 Henri Becquerel; Rays from Uranium

1898 Marie & Pierre Curie; Work withRadium

1899 Ernest Rutherford; Alpha, Beta &Gamma

1905 Albert Einstein; Theory of Relativity

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Wilhelm Roentgen

8 Nov 1895Discovered X-Rays

Received the NobelPrize in Physics 1901

Brilliant Scientist

Never sought Honorsor profit from his work

www.accessexcellence.org/AE/AEC/CC/radioactivity.html

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Henri Becquerel

Third GenerationScientist

DiscoveredRadioactivity

Discovered chargedpartials.

Received the NobelPrize in Physics 1903

www.accessexcellence.org/AE/AEC/CC/radioactivity.html

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Marie & Pierre Curie

Marie coined the termRadioactivity

Both discoveredPolonium & Radium Both shared the Nobel

Prize in Physics of

1903 1910 Curie is basicunit of radioactivity

www.accessexcellence.org/AE/AEC/CC/radioactivity.html

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Ernest Rutherford

The father of nuclearphysics

Particles- Alpha, Beta& Neutron Radioactive decay

equation

Concept of half life Elements transmuted 1908 Nobel Price

www.accessexcellence.org/AE/AEC/CC/radioactivity.html

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Albert Einstein

General physicist Most well-known

physicist of our time E = mc2 Theoretical indication

that the Atomic Bombis possible

www.bartleby.com/173/

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Milestones in Radiation and

Radiography1922 Memorial to scientists in Hamburg Germany

1922 Industrial X-Ray; Watertown Laboratory

1929 Gamma Radiography; Naval Research Lab.1945 1st Atomic Bomb; White Sands Missile

Range

1946 Atomic Energy Commission EstablishedRadiation Safety Training Series Part 1: Radiation, Rudarmel Enterprises, inc. Lake Oswego, Oregon

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Atoms are Elements

Elements are made of Electrons

ProtonsNeutrons +, positive charge -, negative charge

0, neutral charge

Radiation Safety Training Series Part 1: Radiation, Rudarmel Enterprises, inc. Lake Oswego, Oregon

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SHELLS ONLY HOLD SOME

ELECTRONS The first 18 elements k-shell only holds two

l-shell only holds eight m-shell only holds eight m-shell can actually hold

up to 18 electrons as you

move further along theperiodic table.Radiation Safety Training Series Part 1: Radiation, Rudarmel Enterprises, inc. Lake Oswego, Oregon

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ORBITAL BASICS

A shell is sometimescalled an orbital orenergy level.

Shells are areas thatsurround the center of anatom.

The center of the atom is

called the nucleus. Electrons live in

something called shells.Radiation Safety Training Series Part 1: Radiation, Rudarmel Enterprises, inc. Lake Oswego, Oregon

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Mathematical Probability

Orbitals are describedby probability

An orbital exists as acloud Each atom has a

different orbital cloudstructure

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch6/quantum.html

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www.mii.org

http://www.smartdraw.com/resources/examples/science/images/periodic_table_full.gifhttp://www.smartdraw.com/resources/examples/science/images/periodic_table_full.gifhttp://www.smartdraw.com/resources/examples/science/images/periodic_table_full.gifhttp://www.smartdraw.com/resources/examples/science/images/periodic_table_full.gif

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Element Description

Atomic number 6 Atomic mass 12.01

Electron configuration Oxidation state Symbol

Melting/boiling point Density/electronegativ

ity

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Isotopes

Hydrogen is thecommon stable form

Deuterium is rare butstable form Tritium (radioactive)

is an unstable form

Atoms of the sameelement have differentcharacteristics

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Origin and Types of Radiation

Bremsstrahlung braking ray

-high energy electron impacting a target

Nuclear decay Manmade radioactivity

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Simple X-Ray Generator

Electrons boiled offthe cathode

Electrons impact theAnode -dense material A continuous

spectrum of X-Raysare emitted in alldirections

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Radiation from Nuclear Decay

Collimated radiation One spot would glow

Magnetic field wouldmake three spots glow

- Alpha

- Beta- Gamma

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Types of Radiation

Alpha partial is two protons and twoneutrons having a positive charge and mass

Beta particle is a high energy electron witha negative charge and little mass Gamma ray is electromagnetic energy

possessing no mass and no charge Neutron particle has no charge but it doeshave mass

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Electromagnetic Spectra

www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

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Differences in Gamma and X-ray

X-Ray wavelengths ranges 10-8 to 10-13 Gamma wavelength ranges 10-11 to 10-13

X-Ray is electronically generated and stopswhen you turn off the power

Gamma is naturally occurring andcontinuous

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Human Exposure to Radiation

Exposure from Manmade Sources

Medical (mostly diagnostic x-ray) 45%

Fallout from atomic bombs 2.5%Nuclear power 0.15%

Consumer products (mostly color TVs) 0.5%

Approx. % annual exposure 50%

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Human Exposure to Radiation

Occupational Radiation exposures

Workers at Gamma Radiography

Companys 3XGamma radiographers 5X

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Time, Distance and Shielding

How do we reduce our exposure toradiation?

We can calculate stay times, dose rates anddistance from sources.

We can calculate shielding requirements

and or effects Our first step, Inverse Square Law

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Inverse Square Law, General

Continued Being strictly geometric in its origin, the

inverse square law applies to diverse

phenomena. Point sources of gravitationalforce, electric field, light, sound or radiationobey the inverse square law.

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Inverse Square Law, Radiation

http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html

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Inverse Square Law, Radiation

S/4r2 = I

S = 4r2 I

S = 4r12 I1S = 4r2

2 I24r1

2 I1 = S = 4r22 I2

4r12 I1 = 4r22 I2

r12 I

1= r

22 I

2

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Example

If the intensity of the Andrex is 1040 R/hr atone foot from the tube head then what is the

distance to the 2mR line.I1 = 1040 R/hr r 1 = 1

I2 = 2 mR/hr r 2 = ?

r12 I1 = r2

2 I2 r2 = (r12 I1/ I2)

r2 = (r12 I1/ I2)

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Example

r2 = (r12 I1/ I2)

r2 = (1040 R/hr 1 / 0.002 R/hr)

r2 = 721

r2 = 721 feet

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Works SitedPartial List:

http://www.accessexcellence.org/AE/AEC/CC/radioactivity.html

http://www.accessexcellence.org/AE/AEC/CC/historical_background.html

Radiation Safety Training Series Part 1: Radiation, Rudarmel Enterprises, inc.Lake Oswego, Oregon

http://www.chem4kids.com/files/atom_structure.html

http://orbitals.com/orb/

http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch6/quantum.html

www.bartleby.com/173/

www.mii.org

http://hyperphysics.phy-astr.gsu.edu/hbase/forces/isq.html