radiographic testing ndt

7/23/2019 radiographic testing NDT

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Radiographic Testing

Compiled for ASNT by

Bahman ZoofanThe Ohio State University


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Level I

Radiographic Testing


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Lesson 1

Introduction to

Radioraphic Testin


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Radioraphy

!" In radioraphy# test ob$ects are

e%posed to &'rays# amma rays

or neutrons# and an imae isproduced"


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Radioraphy

(" Radioraphy is used to test a

variety of products# such as

castins# forins and )eldments" Itis also used heavily in the

aerospace industry for the detection

of crac*s in airframe structures#

detection of )ater in honeycombstructures and detection of forein

ob$ects"


6/293

Advantaes of Radioraphic Testin

!" Radioraphy can be used on most

materials"

(" Radioraphy provides a permanentrecord of the test ob$ect"

+" Radioraphy reveals discontinuities

)ithin a material"

," Radioraphy discloses fabrication errors

and often indicates the need for

corrective action"


7/293

-imitations of Radioraphic Testin

!" The radiorapher must have

access to both sides of the test

ob$ect"(" .lanar discontinuities that are

not parallel to the radiation beam

are difficult to detect"


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-imitations of Radioraphic Testin

+" Radioraphy is an e%pensive

testin method"

," /ilm radioraphy is timeconsumin"

0" Some surface discontinuities or

shallo) discontinuities may bedifficult# if not impossible# to

detect"


9/293

Test Ob$ective

The ob$ective of radioraphic testin

is to ensure product reliability"

.erformin the actual radioraphictest is only part of the procedure"

The test results must then be

interpreted to acceptance standards

by 1ualified personnel# and anevaluation of the results must be

made"


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Safety Considerations

Radiation can cause damae to the

cells of livin tissue# so it is

essential that personnel be a)areand protected" Compliance )ith

state and federal safety reulations

is mandatory"


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2ualification

!" It is important that personnel

responsible for radioraphic

testin have ade1uate trainin#education and e%perience"

(" 3uidelines are for the

1ualification and certification ofnondestructive testin personnel"


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2ualification

+" ASNT has published uidelines

for trainin and 1ualifyin

nondestructive testin 4N5T6personnel" These uidelines are

*no)n as Recommended

Practice No. SNT-TC-1A:

Personnel Qualification andCertification in Nondestructive

Testing.


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2ualification

," Recommended Practice No.

SNT-TC-1Adescribes the

*no)lede and capabilities ofN5T personnel in terms of

certification levels"


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2ualification

0" .er SNT-TC-1A# there are three basic levelsof 1ualification applied to N5T personnel7

a" -evel I"

b" -evel II"

c" -evel III"


15/293

Certification

!" The formal certification of a person

in N5T to a -evel I# -evel II and

-evel III is a )ritten testimony thatthe individual has been properly

1ualified"

(" Certification is meant to document

the actual 1ualification of the

individual in a specific N5T method"


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Certification

+" .roper 1ualification and

certification are e%tremely

important in modernmanufacturin# fabrication and

inservice inspection due to the

impact on the health and safety

of the public"


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Lesson 2

Radioraphic Testin .rinciples


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.enetration and

5ifferential Absorption!" &'rays and amma rays have

the ability to penetrate materials#

includin materials that do nottransmit liht"


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.enetration and

5ifferential Absorption(" 5ependin on the thic*ness and

density of the material# and the

intensity of the source bein used#the amount of radiation that is

transmitted throuh the test ob$ect

)ill vary"

+" The radiation transmitted throuhthe test ob$ect produces the

radioraphic imae"


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.enetration and

5ifferential Absorption," The follo)in fiure illustrates

the partial absorption

characteristics of radiation"Thic*er portions of the test ob$ect

or dense inclusions )ill appear

lihter because of more

absorption of the radiation"


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.enetration and

5ifferential Absorption


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3eometric 8%posure .rinciples

!" A radioraph is a shado) picture of

a test ob$ect placed bet)een the

film9detector and the &'ray oramma radiation source"

(" If the film9detector is placed too far

from the test ob$ect# the imae )illbe enlared"


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+" If the test ob$ect is too close to

the source# the imae )ill be

reatly enlared# resultin in theloss of resolution"

," The deree of enlarement )ill

vary accordin to the relativedistances of the test ob$ect from

the film9detector"


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0" As sho)n in the follo)in fiure#

the imae enlarement Df 9D:is

e1ual to the ratio df 9d:"


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/ilm95etector Imae Sharpness

!" The sharpness of a radioraphic imae isdetermined by7

a" The si;e of the radiationsource"

b" The ratio of the ob$ect'to'film9detector distance"

c" The source'to'ob$ectdistance"


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(" The unsharpness or fu;;iness

around an imae is called

geometric unsharness4enum!ra6# as sho)n in the

follo)in fiure"


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+" To minimi;e the eometric

unsharpness 4"g6 around the

imae# the test ob$ect should beplaced as close to the film9detector

as possible"

,"


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0" 3eometric unsharpness can be

calculated usin the follo)in

formula7"g= #d$D


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a" "grepresents the eometric

unsharpness 4in millimeters or

inches6"b" #is the source si;e 4the

ma%imum pro$ected dimension

of the radiation source# oreffective focal spot si;e6"


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c" Dis the distance from the

source of the radiation to the

ob$ect bein radioraphed"d" dis the distance from the

source side of the test ob$ect

to the film9detector"


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>" Optimum eometric unsharpness of

the imae is obtained )hen7

a" The radiation source is small"b" The distance from the source

to the test ob$ect is relatively

lare"c" The distance from the test

ob$ect to the film9detector plane

is small"


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Imae 5istortion

T)o possible causes of radioraphic imaedistortion are7

!" The test ob$ect and thefilm9detector plane are not

parallel"

(" The radiation beam is not

directed perpendicular to the

film9detector plane"


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&'Radiation and 3amma Radiation

!" &'rays and amma rays are part

of the electromanetic spectrum"

(" These rays have hih eneryand short )avelenths"


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&'Rays

The conditions re1uired to enerate&'rays are7

!" A source of electrons"(" A suitable taret for electrons to

stri*e"

+" A means of speedin theelectrons in the desired direction"


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&'Rays

Characteristic X-rays7 ?hen an

electron from a hiher enery level

interacts )ith an electron in a lo)erenery orbit of an atom# then

characteristic &'rays may be

enerated"


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&'Rays

Continuous radiation:The

enerated &'rays have a

continuous enery spectrum andare not entirely dependent on the

disturbed atom@s characteristics"


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&'Rays

Bremsstrahlung radiation7 This is

a 3erman name for bra*in or

continuous radiation"


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&'Rays

Ke !"ilo-electron volts#7 This unit

corresponds to the amount of

*inetic enery that an electron)ould ain )hen movin bet)een

t)o points that differ in voltae by

! *"


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&'Rays

$e !1 %%% %%% electron volts#7

This unit corresponds to the

amount of *inetic enery anelectron ains )hen movin

bet)een t)o points that differ in

voltae by !


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8lectron Source

!" ?hen a suitable material is heated#

some of its chared neative

particles 4electrons6 become aitatedand escape the material as free

electrons"

(" Cathode7 In an &'ray tube# a coil of

)ire or filament 4*no)n as thecathode6 serves as the electron

source"


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8lectron Taret

/or industrial radioraphy

applications# a solid material of hih

atomic number# usually tunsten# isused as the taret in the tube

anode"


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8lectron Acceleration

!" By placin a positive chare on

the anode of an &'ray tube and a

neative chare on the cathode#free electrons are accelerated

from the cathode to the anode"

(" The electron path should occur in

a vacuum"


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Radiation Intensity

!" The number of &'rays created by

electrons stri*in the taret is

one measure of the intensity ofthe radiation"

(" Intensity depends on the number

of electrons available at the

cathode of the &'ray tube"


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Radiation Intensity

+" eepin the other factors constant#

an increase in the current throuh

the tube filament )ill increase thecathode temperature# causin

emission of more electrons and

conse1uently increasin the

intensity of the &'ray beam"


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Radiation Intensity

," Similarly# thouh to a lesser

deree# an increase in the

applied tube voltae )illincrease the beam intensity"

0" The output ratin of an &'ray

tube is e%pressed in volts 4* or


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Inverse S1uare -a)

!" The intensity of an &'ray beam varies

inversely )ith the s1uare of the

distance from the radiation source# as

sho)n in the follo)in formula7

I!9I( = 5((95!(

(" This relationship is *no)n as the

inverse s%uare la&')here I!and I(arethe received radiation intensities at

distances 5!and 5("


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&'Ray 2uality Characteristics

!" The spectrum of continuous

&'rays covers a )ide band of

)avelenths# as sho)n in thefollo)in fiure"


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(" An increase in applied voltae in

an &'ray tube increases the

intensity 41uality6 of &'rays" Thisproduces hiher enery rays )ith

reater penetratin po)er"

+" &'rays )ith hiher enery4shorter )avelenths6 are called

hard (-ra)s"


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," &'rays )ith lo)er enery 4loner

)avelenths6 are called soft

(-ra)s"0" ariation in tube current chanes

the intensity of the beam# but the

spectrum of )avelenths

produced remains unchaned#

as seen in the follo)in fiure"


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>" 8ffects of chanes in *ilovoltae

and tube current on the produced

&'rays are summari;ed in thefollo)in table"


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8ffects of ilovoltae and Amperae


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Interaction ?ith


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Interaction ?ith


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.hotoelectric Absorption

!" In photoelectric absorption# )hen

&'rays 4photons6 )ith relatively lo)

enery pass throuh matter# thephoton enery may be transferred

to an orbital electron" 4See the

follo)in fiure"6


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(" .art of the enery is e%pended in

e$ectin the electron from its

orbit# and the remainder ivesvelocity to the electron"


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+" This phenomenon usually ta*es

place )ith lo) enery photons of

:"0


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Compton 8ffect

!" ?hen hiher enery photons 4:"! to

+


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Compton 8ffect


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Compton 8ffect

(" This process is repeated#

proressively )ea*enin the

photon# until the photoelectriceffect completely absorbs the last

photon"


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.air .roduction

.air production occurs only )ith

hiher enery photons of !":(


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.air .roduction


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Scatter Radiation

!" The ma$or components of scatter

radiation are the lo) enery rays

represented by photons )ea*enedin the Compton process"

(" Scatter radiation is lo)'level enery

content of random direction"


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Internal Scatter

!" Internal scatter is the scatterin

that occurs in the ob$ect bein

radioraphed" 4See the follo)infiure"6


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Internal Scatter


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Internal Scatter

(" Internal scatter affects imae

definition by blurrin the imae

outline"+" Buildupoccurs )hen scatter in

the for)ard direction causes an

increase in radiation passin

throuh matter"


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Sidescatter

!" Sidescatter is the scatterin from

)alls of ob$ects in the vicinity of

the test ob$ect or from portions ofthe test ob$ect that causes rays to

enter the sides of the test ob$ect"

(" Sidescatter obscures the imae

outline $ust as internal scatterdoes"


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Bac*scatter

!" Bac*scatter is the scatterin of

rays from surfaces or from

ob$ects beneath or behind thetest ob$ect" 4See the follo)in

fiure"6

(" Bac*scatter also obscures the

test ob$ect imae"


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Bac*scatter


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3amma Rays

!" 3amma rays are produced by

the disinteration of the nuclei of

a radioactive isotope"(" Isotopes are varieties of the

same chemical element havin

different atomic )eihts"


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3amma Rays

+" The )avelenth and intensity of

amma )aves are determined by

the source isotope characteristicsand cannot be controlled or

chaned"


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Natural Isotope Sources

!" Some heavy natural elements

disinterate because of their

inherent instability"(" Radium is the best *no)n and

most used natural radioactive

source"


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+" Natural radioactive sources

release enery in the form of7

a" 3amma rays"b" &lpha particles7 .ositively

chared particles havin

mass and chare e1ual in

manitude of a helium nuclei"


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c"Beta particles7 Neativelychared particles havin thesame chare and mass of theelectron"

," The penetratin po)er of alpha

and beta particles is relatively

neliible"


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Artificial Sources

!" There are t)o )ays of

manufacturin radioactive

isotopes# or so'calledradioisotoes7

a" By usin the by'product of

nuclear fission in atomic

reactors# such as cesium'!+4Cs'!+6"


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Artificial Sources

b" By bombardin certainelements )ith neutrons toma*e them unstable" 8%amples

include7

i" Cobalt'>: 4Co'>:6"

ii" Thulium'!: 4Tm'!:6"

iii" Selenium'0 4Se'06"iv" Iridium'!D( 4Ir'!D(6"


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Artificial Sources

(" These artificial isotopes emit

amma rays# as )ell as alpha

and beta particles"


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3amma Ray Intensity

!" The activity of a amma ray

source determines the intensity

of its radiation"(" The measure of activity is the

curie# )hich is +" & !:!:

bec1uerel 4B16 or disinterations

per second"


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Specific Activity

!" Specific activity is defined as the

deree of concentration of

radioactive material )ithin aamma ray source"

(" Specific activity is e%pressed in

terms of curies per ram or

curies per cubic centimeter"


84/293

Specific Activity

+" Specific activity is an important

measure of radioisotopes

because the smaller the source#the sharper the radioraphic

imae that can be produced 4as

sho)n in the follo)in fiure6"


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Specific Activity


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Ealf -ife

!" The lenth of time re1uired for

the activity of a radioisotope to

decay to one half of its initialintensity is called its half life"

(" The half life of a radioisotope is a

basic characteristic and depends

on the particular isotope of a

iven element"


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Ealf -ife

+" 5ated decay curves 4similar to

the one sho)n in the ne%t slide6

are supplied by source suppliersfor each particular radioisotope

and should be used by

radioraphers to determine the

e%act source intensity"


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5ated 5ecay Curve


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3amma Ray 2uality Characteristics

!" Radiation from a amma ray

source consists of rays )hose

)avelenths and enery are

determined by the nature of the

source"

(" 8ach of the commonly used

radioisotopes has a specificapplication because of the fi%ed

amma enery characteristics"


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+" The table on the ne%t slide lists the

most common radioisotopes for

radioraphy and their e1uivalentenery"


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Common Radioisotopes


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," 3amma rays and &'rays have

identical propaation

characteristics# and both conform

to the inverse s1uare la)"

0" The mechanism of interaction of

amma rays )ith matter is

identical to those discussed for &'rays"


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Lesson '

81uipment


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&'Ray 81uipment

There are three basic re1uirementsfor the eneration of &'rays7

!" A source of free electrons"(" A means of rapidly acceleratin

the beam of electrons"

+" A suitable taret material to stop

the electrons"


95/293

.ortable &'Ray Units

In field radioraphy 4inspection of

pipelines# brides# vessels and

ships6# portable &'ray units are veryimportant" The characteristics of

these tubes are7

!" -iht)eiht"

(" Compact"

+" Usually air'cooled"


96/293

&'Ray Tube

!" The main components of &'raye1uipment are the follo)in7

a" Tu(e7 8nclosed in a hih'vacuum envelope of heat'

resistant lass or ceramic"

b" Cathode7 To produce free

electrons"

c" &node7 Taret )hich the

electrons stri*e"


97/293

&'Ray Tube

(" Associated )ith the tube are the

follo)in parts7

a" 81uipment that heats thefilament# accelerates and

controls the resultant free

electrons"

b" 81uipment to remove the heat

enerated by the &'rays"

c" Shieldin of the e1uipment"


98/293

&'Ray Tube

+" There are many varieties in the

si;e and shape of &'ray tubes"


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Tube 8nvelope

!" A tube envelope is constructed oflass or ceramic that has7

a" A hih meltin point"

b" Sufficient strenth"

(" /or the follo)in reasons# a

hih'vacuum environment for

the tube element is necessary"


100/293

Tube 8nvelope

a" .revents o%idation of the

electrode material"

b" .ermits ready passae of theelectron beam )ithout ioni;ation

of as )ithin the tube"

c" .rovides electrical insulation

bet)een the electrodes"


101/293

Cathode

The cathode of an &'ray tubeconsists of7

!" )ocusing cup7 /unctions as anelectrostatic lens"

(" )ilament7 A coil of tunsten )irethat produces a cloud of electrons

by flo)in an electrical currentthrouh it"


102/293

/ilament Eeatin

!" A small flo) of current throuh the

filament is enouh to heat it to a

temperature that causes electron

emission"(" A chane in the number of emitted

electrons varies )ith the current flo)

throuh the filament"

+" The tube current# measured inmilliamperes 4mA6# controls the

intensity of &'rays"


103/293

Anode

!" The anode of an &'ray tube is

usually made of copper"

(" Copper and tunsten are themost common anode materials"


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Anode

+" A dense taret material is

re1uired to ensure a ma%imum

number of collisions"

,"


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/ocal Spot

!" The imae sharpness is partly

determined by the si;e of the

focal spot"

(" The electron beam is focused so

that it bombards a rectanular

area of the taret"


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/ocal Spot

+" The pro$ected area of the

electron beam is the effective

focal spot 4as seen in the

follo)in slide6"

," The si;e to )hich the focal spot

can be reduced is limited by the

heat enerated in taretbombardment"


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8ffective /ocal Spot


108/293

-inear Accelerators

There are t)o types of linear

accelerators7

!" Standin )ave linear acceleratorfor enery up to (::


109/293

&'Ray Beam Confiuration

!" Once the &'rays are created#

they cannot be focused or

other)ise directed"

(" The direction of useful

&'radiation is determined by the

positionin of the taret and the

lead shieldin"


110/293

Acceleratin .otential

!" The applied potential bet)een the

cathode and anode determines the

penetratin effect of the produced &'

ray"

(" The hiher the voltae# the reater

the electron velocity alon )ith

shorter )avelenths and morepenetratin po)er for the enerated

&'rays"


111/293

Iron Core Transformers

!" The ma$ority of &'ray e1uipment

for industrial radioraphy 4up to

,:: *6 use iron core

transformers"

(" Their basic limitations are their

si;e and )eiht"


112/293

Eeat 5issipation

!" &'ray eneration is a very

inefficient process as most of the

electron enery is e%pended in

producin heat"

(" Eeat dissipation in the &'ray tube

is accomplished by a flo) of oil#

as or )ater"


113/293

Eeat 5issipation

+" 8fficiency of an &'ray tube

coolin system is the main factor

in determinin the duty cycle of

the tube"


114/293

81uipment Shieldin

!" To prevent un)anted radiation#

lead is used to shield the &'ray

tube"

(" Shieldin desin varies )ith

different &'ray tubes# but in all

cases# it serves to absorb that

portion of the radiation that is nottravelin in the desired direction"


115/293

Control .anel

!" The control panel of an &'ray

system is desined to permit a

radiorapher to set the desired

e%posure parameters"

(" The control panel also provides

critical indications for tube

performance# such as the flo) ofoil or )ater in the coolin system"


116/293

3amma Ray 81uipment

!" Eandlin and storae of amma ray

sources are e%tremely important

since they cannot be shut off"

(" The United States Nuclear

Reulatory Commission 4NRC6 and

various state aencies recommend

safety standards for propertransportation# storae and handlin

of radioisotopes"


117/293

3amma Ray Sources

!" There are t)o types of amma

ray sources7

a" Natural isotopes"

b" Artificial isotopes"

("


118/293

Radium

!" Radium is a natural radioactive

substance havin a half life of

about !>:: years"

("


119/293

Radium

+" Because of its lo) specific

activity and its lon half life#

radium is rarely used in industrial

radioraphy"

f


120/293

Artificial Radioisotopes

!" The artificial radioisotopes usedin industrial radioraphy forain purposes are7

a" Cobalt'>: 4Co'>:6"b" Iridium'!D( 4Ir'!D(6"

c" Selenium'0 4Se'06"

d" Thulium'!: 4Tm'!:6"e" Cesium'!+ 4Cs'!+6"

A ifi i l R di i


121/293

Artificial Radioisotopes

(" The follo)in table ives a

summary of the main

characteristics of the most used

isotopes"

R di i t Ch t i ti


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Radioisotope Characteristics

I t C


123/293

Isotope Cameras

!" The e1uipment to accomplish

safe handlin and storae of

radioisotopes is called a camera

or e+osure device"

(" These cameras are self'

contained units# meanin no

e%ternal po)er supply isre1uired"

I t C


124/293

Isotope Cameras

+" The e%posure devices contain

self'loc*in mechanisms

ensurin safety in accordance

)ith ANSI and ISO re1uirements#

in addition to NRC and IA8A

re1uirements"


125/293

Lesson *

Radioraphic /ilm

I t d ti


126/293

Introduction

!" Radioraphic film consists of7

a" Base7 A thin# transparent plastic

sheet"

b" +mulsion coat7 A coat of an

emulsion of elatin about

:"::! in" 4:"::+ cm6 thic* on

one or both sides" The emulsioncoat contains very fine rains of

silver bromide 4ABr6"

I t d ti


127/293

Introduction

("Latent !hidden# image7

8%posure of radiation on the film

that cannot be detected until

chemical processin occurs"

+"isi(le image7 Imae on the film

after developed by chemical

processin"

U f l f R di h


128/293

Usefulness of Radioraphs

!" )ilm density7 5eree of

dar*enin on the developed film"

(" Radiographic contrast75ifference bet)een t)o film

areas" The dar*er area 4hiher

density6 has received more

radiation compared to the areaof liht density"

U f l f R di h


129/293

Usefulness of Radioraphs

+" ,einition7 Sharpness of any

chane in film density"

," Contrast and definition areimportant for a successful

interpretation of radioraphs"

R di hi C t t


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Radioraphic Contrast

!" The film density Dis a loarithmic

value defined as7

D= lo!:4,-$,6)here 4,-6 is the intensity of the

incident liht to vie) the film# and ,

is the intensity of the transmitted

liht throuh the film" The hiher

the number# the dar*er the film"

R di hi C t t


131/293


(" If the intensity of liht is !:::

units and the film allo)s only one

unit of that intensity to pass

throuh# the film density based

on the previous e1uation )ill be7

D= lo!:4!:::9!6 = +



132/293


+" Radioraphic contrast 4as sho)n

in the follo)in fiure6 is defined

as the difference in the film

density bet)een t)o selected

areas of the e%posed and

developed film"



133/293




134/293


," Eiher contrast is better for film

interpretation"

0" Radioraphic contrast is acombination of7

a" Sub$ect contrast"

b" /ilm contrast"



135/293


>" Radioraphic contrast depends on7

a" Applied radiation enery

4penetratin 1uality6"b" Contrast characteristics of the

film"

c" Amount of e%posure 4the productof radiation intensity and

e%posure time6"



136/293


d" /ilm screen"

e" /ilm processin"

f" Scattered radiation"

Sub$ect Contrast


137/293

Sub$ect Contrast

!" Sub$ect contrast is the relative

radiation intensities passin

throuh any t)o selected

portions of material" Sub$ect

contrast depends on the

follo)in factors7

Sub$ect Contrast


138/293

Sub$ect Contrast

a" Type and shape of the test

ob$ect"

b" 8nery of the applied eneryradiation 4)avelenth# type of

source6"

c" Scattered radiation"

Sub$ect Contrast


139/293

Sub$ect Contrast

(" Sub$ect contrast decreases as

the )avelenth of the incident

radiation decreases"

Sub$ect Contrast


140/293

Sub$ect Contrast

+" Eiher sub$ect contrast can beachieved by7

a" -arer thic*ness variation"

b" Use of different &'ray oramma ray eneries"

c"


141/293

/ilm Contrast

!" #ilm contrastis the ability of film

to detect and record different

radiation e%posures as

differences in film density"

/ilm Contrast


142/293

/ilm Contrast

(" The relationship bet)een the

amount of e%posure and the

resultin film density is

e%pressed in the form of film

characteristic curves and is

determined by the follo)in

factors7

/ilm Contrast


143/293

/ilm Contrast

a" /ilm rain si;e"

b" Chemistry of the filmprocessin chemical"

c" Concentration of theprocessin chemicals"

d" 5evelopment time"

e" 5evelopment temperature"f" Aitation in the developer

solution"

/ilm Characteristic Curves


144/293


!" The fiure follo)in the ne%t slide

sho)s a film characteristic curve"

a" The vertical a%is is the

resultin film density"

b" The hori;ontal a%is is

e%pressed in a loarithm ofrelative e%posure"



145/293


c" The minimum point of the curve

on the vertical a%is is called fog

densit)"

d" Based on this curve# as the

e%posure increases# film contrast

increases"



146/293




147/293


(" A film characteristic curve hast)o different sections7

a" A tail of lo)er densities"

b" A straihter portion 4)ith a

hiher slope on the curve6"



148/293


+" Eih radioraphic contrast is

achieved )ith densities alon the

straiht portion of a characteristic

curve" This is the reason that films

should al)ays be e%posed for a

density of at least !"0"



149/293


,"


150/293

/ilm Speed

!" /ilm speed is an important

consideration in determinin the

proper e%posure time to obtain the

desired film density"

(" The ne%t fiure illustrates films

)ith hih# medium and lo)

speeds"

/ilm Speed


151/293

/ilm Speed

/ilm Speed


152/293

/ilm Speed

+" no)in film speed is important

)hen selectin film for each

particular radioraphic testin

tas*"

3raininess


153/293

3raininess

!" 3raininess is the visible evidence of

the roupin into clumps of the

silver particles that form the imae

on the radioraphic film"

(" The follo)in fiure sho)s the

effect of rain variation on the

imae definition"

3raininess


154/293

3raininess

3raininess


155/293

3raininess

+" The deree of raininess of an

e%posed film depends on the

follo)in factors7

a" 3rain si;e"

b" The 1uality of the radiation"

c" /ilm processin conditions"

d" Type of film screens"

/ilm Selection /actors


156/293


!" ?hen not other)ise specified by

the customer or overnin

standards# the selection of film is

made by the radiorapher"


157/293


a" Need for certain contrast anddefinition 1uality"

b" Thic*ness and density of the

test ob$ect"c" The type of indication or

discontinuity normallyassociated )ith the ob$ect"

d" Si;e of an acceptableindication"



158/293


e" Accessibility# location and

confiuration of the test ob$ect"

f" Customer re1uirements"



159/293


(" In film selection# remember that7

a" /ilm contrast# film speed and

raininess are interrelated"

b" /aster films need shorter

e%posure time but usually

have larer rains and poor

resolution9sensitivity"



160/293


c" Slo)er films need loner

e%posure time but have finer

rain and ood

resolution9sensitivity"



161/293


d" /ilm manufacturers@

recommendations for film

selection are a useful tool in

selectin the proper film for aiven application"

/ilm .rocessin


162/293

/ilm .rocessin

!" /ilm processin ma*es the latent

imae visible"

(" The follo)in eneral

precautions must be observed

durin film processin7



163/293

Se ec o ac o s

a" /ollo) manufacturer

recommendations for

chemical concentrations#

temperature and processintime"

b" Use e1uipment# tan*s# trays

and holders that can)ithstand the chemical action"



164/293

c" 8nsure tan*s are clean"

d" Use recommended safelihts#

and chec* them reularly"

e"


165/293

The arranement of a tan*

processin 4manual processin6 unit

is sho)n in the ne%t slide"

Tan* .rocessin


166/293

Tan* .rocessin


167/293

!" The tan*s for processin solutions

and )ash )ater should be deep

enouh for the film to be

submered"(" The chemicals in the tan*s must

be stirred and the temperature

must be chec*ed )ith a calibratedthermometer before turnin off the

ambient liht"

Tan* .rocessin


168/293

+" All re1uired e1uipment should be

arraned before turnin off the

ambient liht"

," All unnecessary materials shouldbe *ept a)ay from the

processin area"

Tan* .rocessin


169/293

0" Test the safelihts and arrane

them for easy vie)in" /ollo)

the standard recommendations

for reular chec*in"

>" -oc* the door to the dar*room to

prevent accidental e%posure to

ambient liht"

Tan* .rocessin


170/293

" To load the film inside the haners#

rasp it by its edes or corner to

avoid finerprints# bendin#

)rin*lin or crimpin durinhandlin"

F" eep the loadin area completely

dry"

D" /ollo) the tan* processin

procedures"

Tan* .rocessin .rocedures


171/293

There are five separate steps in

tan* processin7

!" 5evelopin"

(" Stop bath"

+" /i%in"

," ?ashin"0" 5ryin"

5evelopin


172/293

p

5evelopin is the chemical process

of reducin silver bromide particles

in the e%posed area of the film

emulsion to metallic silver"

5evelopin


173/293

p

!" /ollo) the manufacturers@

recommendations for developin

temperature and time"

(" Aitate the film durin developin

to obtain a uniform development

and to avoid any air bubbles from

attachin to the film"

5evelopin


174/293

p

+" Use strips of e%posed radioraphs

to control the developer activity as

a method of reular 1uality control

chec*in"," /ollo) the manufacturers@

recommendations to replenish the

solution"

Stop Bath


175/293

The stop bath# a solution of acetic

acid and )ater# serves to remove

the residual developer solution from

the film"

!" Runnin uncontaminated )ater

for at least ( min" can be used

as an alternative to the stopbath"

Stop Bath


176/293

("


177/293

!" /i%er# an acidic solution# has t)o functions on thefilm7

a" It dissolves and removes the

silver bromide from theundeveloped portions of the film

)ithout affectin the developed

portion"b" It hardens the emulsion elatin"

/i%in


178/293

(" The minimum time re1uired for

fi%in is t)ice the amount of time

necessary to clean the film"

+" /i%in time should not e%ceed

!0 min"

," Improper fi%in shortens the

archival lenth of the film"

/i%in


179/293

0" /ilm should be aitated in fi%in

solution at ('min" intervals"

>" The replacement of fi%in

solution should be determined by

chec*in the acidity of the

solution"

?ashin


180/293

After fi%in# )ashin is necessary to

remove the fi%er from the emulsion"

!" 8ach film is )ashed for a period of

time e1ual to t)ice the fi%in"

(" Eypo clearin aent may be used

to speed up film )ashin"

?ashin


181/293

+" Best results for )ashin are

obtained )ith a )ater temperature

bet)een >0 and : G/ 4!F"+ and

(!"! GC6"

," To avoid any )atermar*s# film is

immersed in a )ettin aent that

also aids in reducin the dryintime"

5ryin


182/293

The final stae of film processin is

dryin"

Automatic /ilm .rocessin


183/293

Automatic film processin systems

are used )henever the volume of

)or* ma*es them economical"



184/293

!" The entire processin cycle is

completed in less than !0 min"

(" Automatic film processin units

consistently produce radioraphs

of much hiher 1uality than those

obtained usin a manual process"



185/293

+" -oadin the film inside the unit

should be done in a dar*

environment"

," .roperly maintainin the system

is the *ey for hih performance

of an automatic system"

5ar*room /acilities and 81uipment


186/293

Some re1uirements that must besatisfied in the desin and

construction of a dar*room7

!" It must be lihted )ith suitable andtested safelihts"

(" It must be protected aainst

ambient liht from outside sources"

+" The )alls and ceilin must be

painted )ith lihtly colored#

semiloss paint"

5ar*room /acilities and 81uipment


187/293

," 5ar*room floors are usually

covered )ith chemical resistant#

)aterproof and slip'proof

materials"

0" Cleanliness is of reat

importance durin the entire film

processin procedure"


188/293

Lesson .

Safety

Introduction


189/293

!" Radioraphers are cautioned to

be a)are of the latest effective

safety reulations"

(" Radiation safety practices are

based on the effects of radiation

on the human body and

characteristics of radiation"

Introduction


190/293

+" .ersonnel protection is

dependent upon detection

devices# as )ell as the proper

use of time# distance andshieldin"

Introduction


191/293

," Areement States are states that

observe the reulations coverin

use# handlin and transportation of

radioactive materials approved bythe Nuclear Reulatory

Commission 4NRC6"

Introduction


192/293

0" All of the safety reulations are

desined to limit e%posure to the

radiorapher and to provide

protection to the eneral public"

Introduction


193/293

>" The radiorapher# )ho is

employed by a licensee of NRC

or )ho is employed by a

licensee of an areement state#must have *no)lede of# and

comply )ith# all applicable

reulations"

Units of Radiation

5ose


194/293

5ose


195/293

5ose


196/293

!" The roenten 4R6 or sievert 4Sv6 is

the physical unit of measure of the

ioni;ation of air by &'radiation or

amma radiation"

Roenten 4R6


197/293

(" Roenten 4R6 is defined as the

1uantity of radiation that )ill

produce one electrostatic unit

4esu6 of chare in one cubiccentimeter of air at standard

temperature and pressure 4ST.6"

Roenten 4R6


198/293

+" ! R of radiation e1uals absorption

by ioni;ation of about F+ er 4unit

of )or* or enery in physics6 of

radiation enery per ram of air"

," /or practical purposes# mR is

often used# )hich is7

! mR = !9!::: R"

Radiation Absorbed 5ose 4rad6


199/293

!" Radiation absorbed dose 4rad6 is

the unit of measurement of

radiation absorption by humans"

(" It represents an absorption of

!:: er of enery per ram of

irradiated tissue"



200/293

+" ?hereas the roenten applies

only to &'rays and amma rays#

rad applies to any type of

radiation"

," /or &'ray and amma radiation#

e%posure to ! R results in ! rad"



201/293

0" The unit gra)43y6 has been

introduced as7 !:: rad = ! 3y"

2uality /actor


202/293

!" 2uality factor ta*es into account

the bioloical effect of different

radiations on the human body"

2uality /actor


203/293

(" 2uality factor values are

determined by the National

Committee on Radiation

.rotection" They are summari;edin the follo)in table"

2uality /actor


204/293

Roenten 81uivalent


205/293

!" Roenten e1uivalent mammal

4rem6 represents the radiation

absorbed dose 4rad6 multiplied

by the 1uality factor of the type ofradiation"

(" Radiation safety levels are

established in terms of roentene1uivalent mammal 4rem6"

Roenten 81uivalent


206/293

+" Since the 1uality factor of

&'radiation and amma radiation

is !# then7

! rad = ! rem"

International System of Units

4SI6


207/293

4 6

!" The Nuclear Reulatory

Commission# state reulations

and radioraphers in the U"S"

often still use the old 8nlishunits7 curie# roenten# rem and

rad"

International System of Units

4SI6


208/293

4 6

(" 5ifferent orani;ations# such as thefollo)in# support the replacementof older units )ith SI units7

a" The National Institute of

Standards H Technoloy 4NIST6"

b" The American National

Standards Institute 4ANSI6"

c" The American Society for Testin

and


209/293

4 6

d" The Institute of 8lectrical and

8lectronics 8nineers 4I8886"

e" The International Orani;ation for

Standardi;ation 4ISO6"

f" The American Society for

Nondestructive Testin 4ASNT6"

Bec1uerel Replaces Curie


210/293

!" Curie 4Ci6 is the oriinal unit for

radioactivity# )hich is defined as7

+" & !:!:disinterations per

second"(" In SI# the unit for radioactivity is

the bec1uerel 4B16# )hich is !

disinteration per second"

Bec1uerel Replaces Curie


211/293

+" ! Ci = + 3B1 4iabec1uerel6#

)here ia = !:D"

Coulomb per iloram

Replaces Roenten


212/293

!" Coulomb 4C6 is the unit of

electrical chare# )here7

! C = ! ampere & ! s

(" ! R = (0F microcoulombs per

*iloram of air 4(0F CJ*K!of

air6"

3ray 43y6 Replaces Rad


213/293

In the SI system# the unit of

radiation dose is the ray 43y6# and

! 3y = !:: rad"

Sievert 4Sv6 Replaces Rem


214/293

In the SI system# the unit of

radiation absorbed by the human

body is the Sievert 4Sv6# and

! Sv = !:: rem"


215/293

!" .ermissible dose is defined by

NIST as the dose of radiation that

is not e%pected to cause

appreciable bodily in$ury to aperson"


216/293

(" The follo)in restrictions for the

ma%imum annual permissible

dose limits for classified )or*ers

should be observed7a" Total effective dose e1uivalent

bein e1ual to 0 rem 4:":0 Sv6"


217/293

Or

b" The sum of the deep dose and

the committed dose

e1uivalent to any individualoran or tissue other than the

lens of the eye bein e1ual to

0: rem 4:"0 Sv6"


218/293

c" The ma%imum dose absorbed

by the lens of the eye bein

!0 rem 4:"!0 Sv6"

d" A shallo) dose e1uivalent of0: rem 4:"0 Sv6 to the s*in of

the )hole body or to the s*in

of any e%tremity"


219/293

+" The ma%imum annual radiation

dose is limited to 0 rem 4:":0 Sv6"

," The absorbed dose shouldn@t

e%ceed :"0 rem 40 mSv6 durin anentire prenancy"


220/293

0" 5ose limits to the eneral public

shall not e%ceed :"::( rem or

( mrem 4:":( mSv6 per hour or

e%ceed :"0 rem or 0:: mrem40 mSv6 annually"

.rotection Aainst Radiation


221/293

Safe radioraphic techni1ues and

radioraphic installation desin are

achievable by applyin these

principles7!" Time7 eep the time close to a

radiation source as lo) as

possible"

.rotection Aainst Radiation


222/293

(" ,istance7 eep the distance

from a radiation source as hih

as possible"

+" /hielding7 eep ade1uateshieldin for the radiation source"

Allo)able ?or*in Time


223/293

!" The amount of absorbed radiation

by the human body is directly

proportional to the time that the

body is e%posed to radiation"8%ample7 ( rem 4:"( mSv6 in

>: s = !: mrem 4! mSv6 in 0 min"

Allo)able ?or*in Time


224/293

(" Allo)able )or*in time for )or*in

)ith amma sources is calculated

by measurin radiation intensity

and substitutin it in the follo)ine1uation7

allo&a!le &oring time in hr$&ee

/ermissi!le e+osure in Ci$&9

e+osure rate in Ci$h

?or*in 5istance


225/293

!" The reater the distance from a

radiation source# the lo)er the

radiation intensity"

?or*in 5istance


226/293

(" The inverse s1uare la) is used

to calculate radiation intensities

at various distances from a

radiation source7,1$,0= D00$D10

)here ,1and ,0are intensities at

distances D1and D0#respectively"

?or*in 5istance


227/293

+" The same principles hold for

&'radiation" The intensity at a

*no)n distance )ith

predetermined current andvoltae settin 4usually iven by

the &'ray tube@s manufacturer6

can be determined by applyin

the inverse s1uare la)"

?or*in 5istance


228/293

," Radiation intensity at any point is

the sum of the primary radiation

and the secondary 4scattered6

radiation at that point"

Shieldin


229/293

!"


230/293

(" Shieldin cannot stop all of the

enery of &'radiation or amma

radiationL therefore# it is practical

to measure shieldin efficiency interms of half value layers"

Shieldin


231/293

+" Ealf value layer 4E-6 is that

amount of shieldin that )ill stop

half of the radiation of a iven

intensity"

Shieldin


232/293

," Similarly# shieldin efficiency is

often measured in tenth value

layers" A tenth value layer is that

amount of shieldin that )ill stopnine tenths of the radiation of a

iven intensity" 4See the

follo)in tables"6

&'Ray Ealf alue -ayers


233/293

3amma Ray Ealf andTenth alue -ayers

8%posure Area


234/293

!" The e%posure area should consist

of a room )ith concrete or bloc*

)alls# lined )ith lead or other

suitable shieldin materials"(" An e%posure area can be an

enclosed shieldin cabinet lare

enouh for the test ob$ects and

)ith reliable safety features"

8%posure Area


235/293

+" Controls should be located

outside the e%posure area"

," In field radioraphy# a safe

distance in relation to e%posuremust be secured by7

a" 3uard rails or ropes"

b" -eible radiation )arnin sins"c" Sufficient shieldin"

8%posure Area


236/293

0" Only monitored radioraphers arepermitted in the radiation area"

>" eepin a safe distance from the

radiation source is the simplest andmost effective safety consideration

in field radioraphy"

Radiation .rotective Construction


237/293

!" -ead and concrete are the most

common materials used to protect

aainst radiation"

(" Shieldin measurements areusually e%pressed in terms of

thic*ness"



238/293

+" 8nsurin a lea*'proof shieldin is

very important"

," Sheets of lead must be

overlapped# and nails and scre)s

in the )alls must be covered )ith

ade1uate lead"



239/293

0" .ipes# conduits and air ducts

passin throuh the )alls of the

shieldin must be completely

shielded" 4See the follo)infiure"6



240/293



241/293

>" The thic*ness of lead is dependent on t)o factors7

a" 8nery of the radiation source"

b" Occupancy of the surroundinareas"

" Other than lead# structural

materials such as concrete andbric* are often used as shieldin

materials"



242/293

F" At voltaes reater than ,:: *#concrete is used as shieldin because7

a" Installin very thic* lead can bedifficult"

b" Thic* sheets of lead are cost'

prohibitive"



243/293

c" Concrete is the best

alternative material because of

its property of radiation

protection and its simplicity ofconstruction"

3amma Ray Re1uirements


244/293

!" Special radiation protection is

re1uired for amma radiation

based on t)o factors7

a" 3amma radiation cannot beshut off"

b" 3amma radiation has

considerable penetratin ability"



245/293

(" A combination of shieldin and

distance is usually used durin

amma radioraphy"

+" Specially labeled storaecontainers are necessary to

store amma sources )hen not

in use"



246/293

," After every use# readins )ith

survey meters are ta*en to ensure

the source is safely stored"

0" Special pro$ectors 4calledigs6 orisotope cameras containin heavy

shieldin made of lead or depleted

uranium should be used forhandlin radioisotope sources"

Nuclear Reulatory Commission


247/293

!" The NRC reulates handlin#

storae and use of radioisotopes"

(" The ne%t t)o slides sho) NRC

/orm', and NRC /orm'0# used tomonitor the occupational dose

history"



248/293



249/293

Occupational Radiation

8%posure -imits

-i it ti i di id l d


250/293

-imitations on individual dosae

reater than those listed in the table

after the ne%t slide may be permitted

)ith the follo)in conditions7!" The dose for the )hole body does

not e%ceed 0 rem 4:":0 Sv6 durin

any calendar year"

Occupational Radiation

8%posure -imits

( Th i di id l@ l t d


251/293

(" The individual@s accumulated

occupational dose has been

recorded on NRC /orm', and

the individual has sined theform"


252/293

-evels of Radiation in

Unrestricted Areas

Th f ll i t bl h th


253/293

The follo)in table sho)s the

e%posure limits in an unrestricted

area"

8%posure -imits in Unrestricted

Areas

8 ti 8 li it illi


254/293

8%posure time 8%posure limit millirem4millisievert6

! hour

! calendar year

( 4:":(6

!:: 4!6

.ersonnel


255/293

There are different personnel

monitorin devices re1uired for use

by radioraphers and their assistants

durin radioraphic operations7

.ersonnel


256/293

!" /ilm bades"

(" Thermoluminescent dosimeters

4T-5s6"

+" Optically stimulatedluminescence bades 4OS-6"

.ersonnel


257/293

," 5irect readin dosimeters"

0" .oc*et dosimeters"

>" 8lectronic personal dosimeters"

The last t)o types should be

capable of measurin e%posures

from : to (:: mR 4: to ( mSv6"

Caution Sins# -abels and Sinals

! The radiation symbol 4as


258/293

!" The radiation symbol 4asillustrated on the ne%t slide6 should

be placed7

a" In e%posure areas"b" On containers for transportin

and storin radioactive

materials"



259/293


( The )ords caution or danger also


260/293

(" The )ords cautionor dangeralsomust appear"

+" The )ords radioactive material

should be mar*ed on containers ofradioactive materials and in the

areas housin such containers"


, 8%posure devices should be


261/293

," 8%posure devices should belabeled )ith a radiation symbol

and the phrase Danger

radioactive material do nothandle" Company information

and a (,'hr" phone number must

be mentioned on the sin"

8%posure 5evices and

Storae Containers

Based on the radiation reulations7


262/293

Based on the radiation reulations7

!" 8%posure devices must have the

name of the company or

laboratory and the location of theoffice placed in a noticeable site

on the device"

(" All of the labels# sins# etc"# shallbe leible"

Radiation Survey

Instrumentation Re1uirements


263/293

!" Radioraphers should have

operable and calibrated radiation

survey meters"

(" 8ach e%posure device shall be

accompanied by a survey meter"

+" The meters shall have a rane of

( mR 4:":( mSv6 per hour throuh! R 4:"! Sv6 per hour"

Radiation Surveys

! Operable and calibrated radiation


264/293

!" Operable and calibrated radiation

survey instrumentation should be

available at an e%posure area"

Radiation Surveys

( ?hen )or*in )ith radioisotopes


265/293

(" ?hen )or*in )ith radioisotopes#

a radioactive survey shall be made

around the camera to ensure the

source has been returned to itsshielded condition" This is *no)n

as a 234 s&ee"

Radiation Surveys

+ Before storin each sealed


266/293

+" Before storin each sealed

source# a radiation survey shall

be made to ensure that the

source is in its shielded position"," All these readins shall be

recorded on a radiation report

survey"

5etection and


267/293

There are different instruments that

measure radiation based on the

ioni;ation produced in a as" These

instruments fall into t)o cateories7!" Instruments that measure total

dose e%posure"

(" Instruments that measure doserate 4radiation intensity6"

Instruments that


268/293

a" .oc*et dosimeters"

b" .ersonal electronic

dosimeters"

c" /ilm bades andthermoluminescent dosimeters

4T-5s6"

d" Optically stimulatedluminescence 4OS-6 bades"

Instruments that


269/293

Instruments that measure dose rateare called surve) meters" Theseinclude7

!" Ioni;ation chambers"(" 3eier'mueller counters"

.oc*et 5osimeters

The poc*et dosimeter is a small


270/293

The poc*et dosimeter is a smalldevice# about the si;e of a fountain

pen" 4See the follo)in fiure"6

.oc*et 5osimeters


271/293

.oc*et 5osimeters

! The operation is based on t)o


272/293

!" The operation is based on t)omain principles7

a" Radiation causes ioni;ation in a

as"b" Similar electrical chares repel

each other"(" The dosimeter should be properly

chared 4the indicator on ;eroscale6 before usin"

.oc*et 5osimeters

+ .oc*et dosimeters are desined


273/293

+" .oc*et dosimeters are desined)ith a sensitivity that permits

them to be scaled in doses from

: to (:: mR 4: to ( mSv6"," .oc*et dosimeters must be

calibrated annually# per NRC

reulation# and the date should

be labeled on them"

.ersonal 8lectronic 5osimeters

! .ersonal electronic dosimeters


274/293

!" .ersonal electronic dosimeters4or electron dosimeters67

a" Are easy to use"

b" Are sensitive"

c" Eave numerous functions that

can be enabled or disabled"


( 8lectronic dosimeters provide


275/293

(" 8lectronic dosimeters providedose# dose rate and set point

chec*s# and usually operate )ith

an AA battery"+" The set points can be preset to

definitive alarm points"

," The poc*et'si;ed monitorsprovide three'diit diital display"


0 The enery response of the


276/293

0" The enery response of thepoc*et'si;ed monitor for amma

rays and &'rays is ,: *e to

!"(


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!" /ilm bades 4sho)n on the ne%tslide6 consist of a small film

holder e1uipped )ith thin lead or

cadmium filters"(" Bades are desined to be )orn

by individuals only )hen )or*in

in a radiation area"

/ilm Bades and

Thermoluminescent 5osimeters


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/ilm Bades and


+" After a period of time# the film is


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+" After a period of time# the film isremoved and developed by standard

techni1ues"

," Both devices record total radiation

received and serve to chec* each

other"

0" Thermoluminescent dosimeters

4T-5s6 contain a special crystal oflithium fluoride that stores the enery"

/ilm Bades and


> The T-5 is sent to a lab )here


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>" The T-5 is sent to a lab )herethe crystals are processed to

e%tract the amount of absorbed

enery"" Compared to film bades# T-5s

are not as sensitive to heat#

moisture or rouh handlin# but

they are more e%pensive"

Optically Stimulated

-uminescence 4OS-6 Bades

!" OS- bades measure beta 4b6#


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!" OS- bades measure beta 4b6#amma# neutron and

&'radiation e%posures"

(" The OS- is a thin strip ofspecially formulated aluminum

o%ide crystalline material"

Optically Stimulated

-uminescence 4OS-6 Bades

+" OS- bades detect eneries


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+" OS- bades detect eneriesfrom 0 *e to ,:


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!" Ioni;ation chambers measurethe radiation intensity 4dose rate6

in milliroenten per hour or

millisievert per hour"(" Ioni;ation chambers typically

attain an accuracy of M!0#

e%cept in lo)'intensity radiation

areas"

Ioni;ation Chambers

+" In areas of lo)'intensity


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+" In areas of lo) intensityradiation# radiation intensity

measurements are usually made

)ith eier'mueller counters"," Ioni;ation chambers should be

calibrated annually"

3eier'


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ysensitive radiation detection

devices"

(" 3eier'mueller counters aretypically accurate to M(: for the

1uantity of radiation to )hich they

are calibrated"

+" They should be calibrated annually"

Area Alarm Systems

!" These systems consist of one or


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ese syste s co s st o o e omore sensin elements# usually

ioni;ation chambers# )hose

output is fed to a central alarmmeter"

Area Alarm Systems

(" The meter can be preset so that


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pan audible alarm is sounded and

a visual indication is displayed

)hen permissible radiation levelsare e%ceeded"

8lectrical Safety

!" Because &'ray machines use


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yhih'voltae circuits# the

radiorapher must comply )ith

safe electrical procedures"(" This is more serious specifically

for portable &'ray e1uipment#

)hich re1uires certain electrical

precautions"

8lectrical Safety

+" 5urin operation or service of


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p&'ray e1uipment# the follo)in

precautions# applicable to both

permanent and portableinstallations# should be observed

carefully"

8lectrical Safety

a" 5o not turn po)er on until


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psetup for e%posure is

completed"

b" 8nsure that roundininstructions are complied )ith"

8lectrical Safety

c" Reularly chec* po)er cables


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y pfor sins of )ear# and replace

them )hen necessary"

d" Avoid handlin po)er cables)hen the po)er is on" The

machine@s operational *ey

should be removed )hen not in

use"

8lectrical Safety

e" If po)er cables must be handled


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p)ith the po)er on# use safety

e1uipment such as rubber

loves# rubber mats andinsulated hih'voltae stic*s"

f" Be sure that )ater and moisture

are not in close contact )ith

po)er cables"

8lectrical Safety

" 8nsure that capacitors are


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pcompletely dischared before

chec*in an electronic circuit"

radiographic testing ndt

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