RT Level I basic

Radiographic TestingRadiographic Testing

Compiled for ASNT byBahman Zoofan

The Ohio State University

Compiled for ASNT byBahman Zoofan

The Ohio State University

Level I

Radiographic Testing

Level I

Radiographic Testing

Lesson 1Lesson 1

Introduction to Radiographic Testing

Introduction to Radiographic Testing

RadiographyRadiography

1. In radiography, test objects are

exposed to X-rays, gamma rays

or neutrons, and an image is

processed.

1. In radiography, test objects are

exposed to X-rays, gamma rays

or neutrons, and an image is

processed.

RadiographyRadiography

2. Radiography is used to test a variety of

products, such as castings, forgings

and weldments. It is also used heavily

in the aerospace industry for the

detection of cracks in airframes

structures, detection of water in

honeycomb structures and for foreign

object detection.

2. Radiography is used to test a variety of

products, such as castings, forgings

and weldments. It is also used heavily

in the aerospace industry for the

detection of cracks in airframes

structures, detection of water in

honeycomb structures and for foreign

object detection.

Advantages of Radiographic TestingAdvantages of Radiographic Testing

1. Radiography can be used on most materials.

2. Radiography provides a permanent record of the test object.

3. Radiography reveals discontinuities within a material.

4. Radiography discloses fabrication errors and often indicates the need for corrective action.

1. Radiography can be used on most materials.

2. Radiography provides a permanent record of the test object.

3. Radiography reveals discontinuities within a material.

4. Radiography discloses fabrication errors and often indicates the need for corrective action.

Limitations of Radiographic TestingLimitations of Radiographic Testing

1. The radiographer must have access to both sides of the test object.

2. Planar discontinuities that are not parallel to the radiation beam are difficult to detect.

1. The radiographer must have access to both sides of the test object.

2. Planar discontinuities that are not parallel to the radiation beam are difficult to detect.

Limitations of Radiographic TestingLimitations of Radiographic Testing

3. Radiography is an expensive testing method.

4. Film radiography is time consuming.

5. Some surface discontinuities or shallow discontinuities may be difficult, if not impossible, to detect.

3. Radiography is an expensive testing method.

4. Film radiography is time consuming.

5. Some surface discontinuities or shallow discontinuities may be difficult, if not impossible, to detect.

Test ObjectiveTest Objective

The objective of radiographic testing is to

ensure product reliability. Performing the

actual radiographic test is only part of the

procedure. The results of the test must

then be interpreted to acceptance

standards by qualified personnel, and an

evaluation of the results must be made.

The objective of radiographic testing is to

ensure product reliability. Performing the

actual radiographic test is only part of the

procedure. The results of the test must

then be interpreted to acceptance

standards by qualified personnel, and an

evaluation of the results must be made.

Safety ConsiderationsSafety Considerations

Radiation can cause damage to the

cells of living tissue, so it is essential

that personnel be aware and

protected. Compliance with state and

federal safety regulations is

mandatory.

Radiation can cause damage to the

cells of living tissue, so it is essential

that personnel be aware and

protected. Compliance with state and

federal safety regulations is

mandatory.

QualificationQualification

1. It is important that personnel

responsible for radiographic testing

have adequate training, education

and experience.

2. Guidelines are for the qualification

and certification of nondestructive

testing personnel.

1. It is important that personnel

responsible for radiographic testing

have adequate training, education

and experience.

2. Guidelines are for the qualification

and certification of nondestructive

testing personnel.


3. ASNT has published guidelines for training and qualifying nondestructive testing (NDT) personnel since 1966. These are known as: Personnel Qualification and Certification in Nondestructive Testing: Recommended Practice No. SNT-TC-1A.

3. ASNT has published guidelines for training and qualifying nondestructive testing (NDT) personnel since 1966. These are known as: Personnel Qualification and Certification in Nondestructive Testing: Recommended Practice No. SNT-TC-1A.


4. Recommended Practice No.

SNT-TC-1A describes the

knowledge and capabilities of

nondestructive testing personnel

in terms of certification levels.

4. Recommended Practice No.

SNT-TC-1A describes the

knowledge and capabilities of

nondestructive testing personnel

in terms of certification levels.


5. Per SNT-TC-1A, there are three

basic levels of qualification applied

to nondestructive testing personnel:

a. Level I.

b. Level II.

c. Level III.

5. Per SNT-TC-1A, there are three

basic levels of qualification applied

to nondestructive testing personnel:

a. Level I.

b. Level II.

c. Level III.

CertificationCertification

1. The formal certification of a person in nondestructive testing to a Level I, Level II and Level III is a written testimony that the individual has been properly qualified.

2. Certification is meant to document the actual qualification of the individual in a specific nondestructive testing method.

1. The formal certification of a person in nondestructive testing to a Level I, Level II and Level III is a written testimony that the individual has been properly qualified.

2. Certification is meant to document the actual qualification of the individual in a specific nondestructive testing method.

CertificationCertification

3. Proper qualification and

certification is extremely

important in modern

manufacturing, fabrication and

inservice inspection due to the

impact on the health and safety

of the public.

3. Proper qualification and

certification is extremely

important in modern

manufacturing, fabrication and

inservice inspection due to the

impact on the health and safety

of the public.

Lesson 2Lesson 2

Radiographic Testing PrinciplesRadiographic Testing Principles

Penetration and Differential Absorption

Penetration and Differential Absorption1. X-rays and gamma rays have the ability

to penetrate materials, including materials that do not transmit light.

2. Depending on the thickness and density of the material, and the intensity of the source being used, the amount of radiation that is transmitted through the test object will vary.

1. X-rays and gamma rays have the ability to penetrate materials, including materials that do not transmit light.

2. Depending on the thickness and density of the material, and the intensity of the source being used, the amount of radiation that is transmitted through the test object will vary.



3. The radiation transmitted through

the test object produces the

radiographic image.

3. The radiation transmitted through

the test object produces the

radiographic image.



The following figure illustrates the

partial absorption characteristics of

radiation. Thicker portions of the test

object or dense inclusions will appear

lighter because of more absorption of

the radiation.

The following figure illustrates the

partial absorption characteristics of

radiation. Thicker portions of the test

object or dense inclusions will appear

lighter because of more absorption of

the radiation.

Geometric Exposure PrinciplesGeometric Exposure Principles

1. A radiograph is a shadow picture of a

test object placed between the

film/detector and the X-ray or gamma

radiation source.

2. If the film/detector is placed too far

from the test object, the image will be

enlarged.

1. A radiograph is a shadow picture of a

test object placed between the

film/detector and the X-ray or gamma

radiation source.

2. If the film/detector is placed too far

from the test object, the image will be

enlarged.


3. If the test object is too close to the

source, the image will be greatly

enlarged, resulting in the loss of

resolution.

4. The degree of enlargement will

vary according to the relative

distances of the test object from the

film/detector.

3. If the test object is too close to the

source, the image will be greatly

enlarged, resulting in the loss of

resolution.

4. The degree of enlargement will

vary according to the relative

distances of the test object from the

film/detector.


5. As shown in the following figure,

the image enlargement: Df/D0 is

equal to the ratio: df/d0.

5. As shown in the following figure,

the image enlargement: Df/D0 is

equal to the ratio: df/d0.

Film/Detector Image SharpnessFilm/Detector Image Sharpness

1. The sharpness of a radiographic

image is determined by:

a. The size of the radiation

source.

b. The ratio of the object-to-film/

detector distance.

c. Source-to-object distance.

1. The sharpness of a radiographic

image is determined by:

a. The size of the radiation

source.

b. The ratio of the object-to-film/

detector distance.

c. Source-to-object distance.


2. The unsharpness or fuzziness

around an image is called geometric

unsharpness (penumbra), as shown

in the following figure.

2. The unsharpness or fuzziness

around an image is called geometric

unsharpness (penumbra), as shown

in the following figure.


3. To minimize the geometric unsharpness (Ug) in the image, the

test object should placed as close to the film/detector as possible.

4. Most radiographic codes recommend the maximum acceptable values for geometric unsharpness.

3. To minimize the geometric unsharpness (Ug) in the image, the

test object should placed as close to the film/detector as possible.

4. Most radiographic codes recommend the maximum acceptable values for geometric unsharpness.


5. Geometric unsharpness can be

calculated using the following

formula:

Ug = Fd/D

5. Geometric unsharpness can be

calculated using the following

formula:

Ug = Fd/D


a. Ug is the geometric unsharpness (in

millimeters or inches).

b. F is the source size (the maximum

projected dimension of the radiation

source, or effective focal spot size).

a. Ug is the geometric unsharpness (in

millimeters or inches).

b. F is the source size (the maximum

projected dimension of the radiation

source, or effective focal spot size).


c. D is the distance from the source

of the radiation to the object

being radiographed.

d. d is the distance from the source

side of the test object to the

film/detector.

c. D is the distance from the source

of the radiation to the object

being radiographed.

d. d is the distance from the source

side of the test object to the

film/detector.


5. Optimum geometric unsharpness of

the image is obtained when:

a. The radiation source is small.

b. The distance from the source to

the test object is relatively large.

c. The distance from the test object

to the film/detector plane is small.

5. Optimum geometric unsharpness of

the image is obtained when:

a. The radiation source is small.

b. The distance from the source to

the test object is relatively large.

c. The distance from the test object

to the film/detector plane is small.

Image DistortionImage Distortion

Two possible causes of radiographic

image distortion are:

1. The test object and the film/

detector plane are not parallel.

2. The radiation beam is not directed

perpendicular to the film/detector

plane.

Two possible causes of radiographic

image distortion are:

1. The test object and the film/

detector plane are not parallel.

2. The radiation beam is not directed

perpendicular to the film/detector

plane.

X-Radiation and Gamma RadiationX-Radiation and Gamma Radiation

1. X-rays and gamma rays are part

of the electromagnetic spectrum.

2. They have high energy and short

wavelengths.

1. X-rays and gamma rays are part

of the electromagnetic spectrum.

2. They have high energy and short

wavelengths.

X-RaysX-Rays

The conditions required to generate

X-rays are:

1. A source of electrons.

2. A suitable target for electrons to

strike.

3. A means of speeding the electrons

in the desired direction.

The conditions required to generate

X-rays are:

1. A source of electrons.

2. A suitable target for electrons to

strike.

3. A means of speeding the electrons

in the desired direction.

X-RaysX-Rays

Characteristic X-rays: When an

electron of sufficient energy

interacts with an orbital electron

of an atom, then characteristic

X-rays may be generated.

Characteristic X-rays: When an

electron of sufficient energy

interacts with an orbital electron

of an atom, then characteristic

X-rays may be generated.

X-RaysX-Rays

Continuous radiation: The

generated X-rays have a continuous

energy spectrum and not entirely

dependent on the disturbed atoms

characteristics.

Continuous radiation: The

generated X-rays have a continuous

energy spectrum and not entirely

dependent on the disturbed atoms

characteristics.

X-RaysX-Rays

Bremsstrahlung radiation: This is a

German name for braking or

continuous radiation.

Bremsstrahlung radiation: This is a

German name for braking or

continuous radiation.

X-RaysX-Rays

KeV (kilo-electron volts): The

unit corresponds to the amount

of kinetic energy that an electron

would gain when moving

between two points that differ in

voltage by 1 kV.

KeV (kilo-electron volts): The

unit corresponds to the amount

of kinetic energy that an electron

would gain when moving

between two points that differ in

voltage by 1 kV.

X-RaysX-Rays

MeV (1000,000 electron volts): This

unit corresponds to the amount of

kinetic energy of electrons when

moving between two points that

different by 1MV.

MeV (1000,000 electron volts): This

unit corresponds to the amount of

kinetic energy of electrons when

moving between two points that

different by 1MV.

Electron SourceElectron Source

1. When a suitable material is heated,

some of its charged negative particles

(electrons) become agitated and

escape the material as free electrons.

2. Cathode: In an X-ray tube, a coil of

wire (filament) is the source of

electrons (known as the cathode).

1. When a suitable material is heated,

some of its charged negative particles

(electrons) become agitated and

escape the material as free electrons.

2. Cathode: In an X-ray tube, a coil of

wire (filament) is the source of

electrons (known as the cathode).

Electron TargetElectron Target

For industrial radiography

application, a solid material of

high atomic number, usually

tungsten, is used as the target in

the tube anode.

For industrial radiography

application, a solid material of

high atomic number, usually

tungsten, is used as the target in

the tube anode.

Electron AccelerationElectron Acceleration

1. By placing a positive charge on

the anode of an X-ray tube and a

negative charge on the cathode,

free electrons are accelerated

from the cathode to the anode.

2. The electron path should be in a

vacuum.

1. By placing a positive charge on

the anode of an X-ray tube and a

negative charge on the cathode,

free electrons are accelerated

from the cathode to the anode.

2. The electron path should be in a

vacuum.

Radiation IntensityRadiation Intensity

1. The number of X-rays created

by electrons striking the

target is one measure of the

intensity of the X-ray beam.

2. Intensity depends on the

amount of electrons available

at the X-ray tube cathode.

1. The number of X-rays created

by electrons striking the

target is one measure of the

intensity of the X-ray beam.

2. Intensity depends on the

amount of electrons available

at the X-ray tube cathode.


3. Keeping the other factors constant,

an increase in the current through

the tube filament will increase the

cathode temperature, causing

emission of more electrons and

consequently increasing the intensity

of the X-ray beam.

3. Keeping the other factors constant,

an increase in the current through

the tube filament will increase the

cathode temperature, causing

emission of more electrons and

consequently increasing the intensity

of the X-ray beam.


4. Similarly, though to a lesser

degree, an increase in the applied

tube voltage will increase the

beam intensity.

5. The output rating of an X-ray tube

is expressed in volts (kV or MeV).

4. Similarly, though to a lesser

degree, an increase in the applied

tube voltage will increase the

beam intensity.

5. The output rating of an X-ray tube

is expressed in volts (kV or MeV).

Inverse Square LawInverse Square Law

1. The intensity of an X-ray beam varies inversely with the square of the distance from the radiation source.

I1/I2 = D22/D2

1

2. The relationship is known as the inverse square law: where I1 and I2 are the received radiation intensities at distances D1 and D2.

1. The intensity of an X-ray beam varies inversely with the square of the distance from the radiation source.

I1/I2 = D22/D2

1

2. The relationship is known as the inverse square law: where I1 and I2 are the received radiation intensities at distances D1 and D2.

X-Ray Quality CharacteristicsX-Ray Quality Characteristics

1. The spectrum of continuous X-rays

covers a wide band of wavelengths,

as shown in the following figure.

1. The spectrum of continuous X-rays

covers a wide band of wavelengths,

as shown in the following figure.


2. An increase in applied voltage in an X-

ray tube increases the intensity (quality

of X-rays). This produces the generation

of the higher energy rays with greater

penetrating power.

3. X-rays with higher energy (shorter

wavelengths) are called hard

X-rays.

2. An increase in applied voltage in an X-

ray tube increases the intensity (quality

of X-rays). This produces the generation

of the higher energy rays with greater

penetrating power.

3. X-rays with higher energy (shorter

wavelengths) are called hard

X-rays.


4. X-rays with lower energy (longer

wavelengths) are called soft X-rays.

5. Variation in tube current varies the

intensity of the beam, but the

spectrum of wavelengths produced

remains unchanged, as seen in the

following figure.

4. X-rays with lower energy (longer

wavelengths) are called soft X-rays.

5. Variation in tube current varies the

intensity of the beam, but the

spectrum of wavelengths produced

remains unchanged, as seen in the

following figure.


6. Effects of changes in kilovoltage

and tube current on the produced

X-rays are summarized in

the following table.

6. Effects of changes in kilovoltage

and tube current on the produced

X-rays are summarized in

the following table.

Effects of kilovoltage and amperageEffects of kilovoltage and amperage

Interaction With MatterInteraction With Matter

1. Any action that disrupts the

electrical balance of an atom and

produces ions is called

ionization.

2. X-rays passing through matter

cause ionization in their path.

1. Any action that disrupts the

electrical balance of an atom and

produces ions is called

ionization.

2. X-rays passing through matter

cause ionization in their path.

Interaction With MatterInteraction With Matter

3. X-rays are photons (bundles of energy) traveling at the speed of light.

4. In passing through matter, X-rays lose energy to atoms by ionization processes knows as:

a. Photoelectric absorption.

b. Compton effect.

c. Pair production.

3. X-rays are photons (bundles of energy) traveling at the speed of light.

4. In passing through matter, X-rays lose energy to atoms by ionization processes knows as:

a. Photoelectric absorption.

b. Compton effect.

c. Pair production.

Photoelectric AbsorptionPhotoelectric Absorption

1. In photoelectric absorption, when

X-rays (photons) with relatively low

energy pass through matter, the

photon energy may be transferred to

an orbital electron (see the following

figure).

1. In photoelectric absorption, when

X-rays (photons) with relatively low

energy pass through matter, the

photon energy may be transferred to

an orbital electron (see the following

figure).


2. Part of the energy is expended in

ejecting the electron from its orbit,

and the remainder gives velocity to

the electron.

2. Part of the energy is expended in

ejecting the electron from its orbit,

and the remainder gives velocity to

the electron.


3. This phenomenon usually takes

place with low energy photons

of 0.5 MeV or less.

4. It is this absorption effect that

makes radiography possible.

3. This phenomenon usually takes

place with low energy photons

of 0.5 MeV or less.

4. It is this absorption effect that

makes radiography possible.

Compton EffectCompton Effect

1. When higher energy photons (0.1 to 3 MeV) pass through matter, part of the photon energy is expended in ejecting an electron. The remaining slower energy photons travel at different angles compared to the original photon path (see the following figure).

1. When higher energy photons (0.1 to 3 MeV) pass through matter, part of the photon energy is expended in ejecting an electron. The remaining slower energy photons travel at different angles compared to the original photon path (see the following figure).

Compton EffectCompton Effect

2. This process, progressively

weakening the photon, is

repeated until the photoelectric

effect completely absorbs the

last photon.

2. This process, progressively

weakening the photon, is

repeated until the photoelectric

effect completely absorbs the

last photon.

Pair ProductionPair Production

Pair production occurs only with

higher energy photons of 1.02 MeV

or more (see the following figure).

Pair production occurs only with

higher energy photons of 1.02 MeV

or more (see the following figure).

Scatter RadiationScatter Radiation

1. The major components of scatter

radiation are the low energy rays

represented by photons weakened

in the compton process.

2. Scatter radiation is low-level energy

content and of random direction.

1. The major components of scatter

radiation are the low energy rays

represented by photons weakened

in the compton process.

2. Scatter radiation is low-level energy

content and of random direction.

Internal ScatterInternal Scatter

1. Internal scatter is the scattering that

occurs in the object being

radiographed (see the following

figure).

1. Internal scatter is the scattering that

occurs in the object being

radiographed (see the following

figure).

Internal ScatterInternal Scatter

2. It affects image definition by

blurring the image outline.

3. The increase in radiation

passing through matter caused

by scatter in the forward

direction is known as buildup.

2. It affects image definition by

blurring the image outline.

3. The increase in radiation

passing through matter caused

by scatter in the forward

direction is known as buildup.

SidescatterSidescatter

1. Sidescatter is the scattering from

walls and the surrounding of the

object in the vicinity of the test

object that cause rays to enter the

sides of the test object.

2. Sidescatter obscures the image

outline just as internal scatter does.

1. Sidescatter is the scattering from

walls and the surrounding of the

object in the vicinity of the test

object that cause rays to enter the

sides of the test object.

2. Sidescatter obscures the image

outline just as internal scatter does.

Backscatter Backscatter

1. Backscatter is the scattering of

rays from the surface or from

objects beneath or behind the test

object (see the following figure).

2. Backscatter also obscures the

test object.

1. Backscatter is the scattering of

rays from the surface or from

objects beneath or behind the test

object (see the following figure).

2. Backscatter also obscures the

test object.

Gamma RaysGamma Rays

1. Gamma rays are produced by

the disintegration of the nuclei of

a radioactive isotope.

2. Isotopes are varieties of the

same chemical element having

different atomic weights.

1. Gamma rays are produced by

the disintegration of the nuclei of

a radioactive isotope.

2. Isotopes are varieties of the

same chemical element having

different atomic weights.

Gamma RaysGamma Rays

3. The wavelength and intensity of

gamma waves are determined by

the source isotope characteristics

and cannot be controlled or

changed.

3. The wavelength and intensity of

gamma waves are determined by

the source isotope characteristics

and cannot be controlled or

changed.

Natural Isotope SourcesNatural Isotope Sources

1. Some heavy natural elements

disintegrate because of their

inherent instability.

2. Radium is the best known and

most used natural radioactive

source.

1. Some heavy natural elements

disintegrate because of their

inherent instability.

2. Radium is the best known and

most used natural radioactive

source.


3. Natural radioactive sources release energy in the form of:

a. Gamma rays.

b. Alpha particles: Positively charged particles having mass and charge equal in magnitude of a helium nuclei.

c. Beta particles: Negatively charged particles having charge and mass as of the electron.

3. Natural radioactive sources release energy in the form of:

a. Gamma rays.

b. Alpha particles: Positively charged particles having mass and charge equal in magnitude of a helium nuclei.

c. Beta particles: Negatively charged particles having charge and mass as of the electron.


4. The penetrating power of alpha

and beta particles is relatively

negligible.

4. The penetrating power of alpha

and beta particles is relatively

negligible.

Artificial SourcesArtificial Sources

1. There are two ways of manufacturing

radioactive isotopes, or so-called

radioisotopes:

a. By using the by product of

nuclear fission in atomic

reactors, like cesium-137 (Cs-137).

1. There are two ways of manufacturing

radioactive isotopes, or so-called

radioisotopes:

a. By using the by product of

nuclear fission in atomic

reactors, like cesium-137 (Cs-137).

Artificial SourcesArtificial Sources

b. By bombarding certain elements

with neutrons to make them

unstable. Examples are:

cobalt-60 (Co-60), thulium-170

(Tm-170), selenium-75 (Se-75)

and iridium-192 (Ir-192).

2. These artificial isotopes emit gamma

rays, and alpha and beta particles.

b. By bombarding certain elements

with neutrons to make them

unstable. Examples are:

cobalt-60 (Co-60), thulium-170

(Tm-170), selenium-75 (Se-75)

and iridium-192 (Ir-192).

2. These artificial isotopes emit gamma

rays, and alpha and beta particles.

Gamma Ray IntensityGamma Ray Intensity

1. The activity of a gamma ray

source determines the intensity

of its radiation.

2. The measure of activity is the

curie (Becquerel) which is

3.7 X 1010 disintegrations per

second.

1. The activity of a gamma ray

source determines the intensity

of its radiation.

2. The measure of activity is the

curie (Becquerel) which is


second.

Specific ActivitySpecific Activity

1. Specific activity is defined as the

degree of concentration of

radioactive material within a

gamma ray source.

2. Specific activity is expressed in

terms of curies per gram or curies

per cubic centimeter.

1. Specific activity is defined as the

degree of concentration of

radioactive material within a

gamma ray source.

2. Specific activity is expressed in

terms of curies per gram or curies

per cubic centimeter.

Specific ActivitySpecific Activity

3. Specific activity is an important

measure of radioisotopes

because the smaller the source,

the sharper the radiographic

image that can be produced (as

shown in the following figure).

3. Specific activity is an important

measure of radioisotopes

because the smaller the source,

the sharper the radiographic

image that can be produced (as

shown in the following figure).

Half LifeHalf Life

1. The length of time required for the

activity of a radioisotope to decay to

one half of its initial intensity is

called its half life.

2. The half life of a radioisotope is a

basic characteristic, and depends

on the particular isotope of a given

element.

1. The length of time required for the

activity of a radioisotope to decay to

one half of its initial intensity is

called its half life.

2. The half life of a radioisotope is a

basic characteristic, and depends

on the particular isotope of a given

element.

Half LifeHalf Life

3. Dated decay curves (similar to one

shown in the next slide) are supplied

by source suppliers for each

particular radioisotope and should be

used by radiographers to determine

the exact source intensity.

3. Dated decay curves (similar to one

shown in the next slide) are supplied

by source suppliers for each

particular radioisotope and should be

used by radiographers to determine

the exact source intensity.

Gamma Ray Quality CharacteristicsGamma Ray Quality Characteristics

1. Radiation from a gamma ray source

consists of rays whose wavelengths and

energy are determined by the nature of

the source.

2. Each of the commonly used

radioisotopes has a specific application

because of the fixed gamma energy

characteristics.

1. Radiation from a gamma ray source

consists of rays whose wavelengths and

energy are determined by the nature of

the source.

2. Each of the commonly used

radioisotopes has a specific application

because of the fixed gamma energy

characteristics.


3. The table on the next slide lists the most common radioisotopes for radiography and their equivalent energy.

3. The table on the next slide lists the most common radioisotopes for radiography and their equivalent energy.


4. Gamma rays and X-rays have identical propagation characteristics, and both conform to the inverse square law.

5. The mechanism of interaction of gamma rays with matter is identical to those discussed for X-rays.

4. Gamma rays and X-rays have identical propagation characteristics, and both conform to the inverse square law.

5. The mechanism of interaction of gamma rays with matter is identical to those discussed for X-rays.

Lesson 3Lesson 3

EquipmentEquipment

X-Ray EquipmentX-Ray Equipment

There are three basic requirements

for the generation of X-rays:

1. A source of free electrons.

1. A means of rapidly accelerating

the beam of electrons.

2. A suitable target material to stop

the electrons.

There are three basic requirements

for the generation of X-rays:

1. A source of free electrons.

1. A means of rapidly accelerating

the beam of electrons.

2. A suitable target material to stop

the electrons.

Portable X-Ray UnitsPortable X-Ray Units

In field radiography (inspection of

pipelines, bridges, vessels, and

ships), portable X-ray units are very

important. The characteristic of these

tubes are:

1. Light weight.

2. Compact.

3. Usually air cooled.

In field radiography (inspection of

pipelines, bridges, vessels, and

ships), portable X-ray units are very

important. The characteristic of these

tubes are:

1. Light weight.

2. Compact.

3. Usually air cooled.

X-Ray TubeX-Ray Tube

The main components of any X-ray equipment are:

1. Tube: Enclosed in a high vacuum envelope of heat resistant glass or ceramic.

2. Cathode: To produce free electros.

3. Anode: Target which the electrodes strike.

The main components of any X-ray equipment are:

1. Tube: Enclosed in a high vacuum envelope of heat resistant glass or ceramic.

2. Cathode: To produce free electros.

3. Anode: Target which the electrodes strike.


Associated with the tube are the following parts:

1. Equipment that heats the filament, accelerates, and controls the resultant free electrons.

2. Equipment to remove the heat generated by the X-rays.

3. Shielding of the equipment.

Associated with the tube are the following parts:

1. Equipment that heats the filament, accelerates, and controls the resultant free electrons.

2. Equipment to remove the heat generated by the X-rays.

3. Shielding of the equipment.


There are many varieties in the

size and shape of X-ray tubes.

There are many varieties in the

size and shape of X-ray tubes.

Tube EnvelopeTube Envelope

1. Tube envelope is constructed of

glass or ceramic that has:

a. A high melting point.

b. Sufficient strength.

2. For the following reasons, a high

vacuum environment for the tube

element is necessary.

1. Tube envelope is constructed of

glass or ceramic that has:

a. A high melting point.

b. Sufficient strength.

2. For the following reasons, a high

vacuum environment for the tube

element is necessary.

Tube EnvelopeTube Envelope

a. Preventing oxidation of the

electrode material.

b. Permits ready passage of the

electron beam without ionization of

gas within the tube.

c. Provides electrical insulation

between the electrodes.

a. Preventing oxidation of the

electrode material.

b. Permits ready passage of the

electron beam without ionization of

gas within the tube.

c. Provides electrical insulation

between the electrodes.

CathodeCathode

Cathode of X-ray tubes consists of:

1. Focusing cup: Functions

as an electrostatic lens.

2. Filament: A coil of tungsten

wire that produces a cloud

of electrons by flowing an

electrical current through it.

Cathode of X-ray tubes consists of:

1. Focusing cup: Functions

as an electrostatic lens.

2. Filament: A coil of tungsten

wire that produces a cloud

of electrons by flowing an

electrical current through it.

Filament HeatingFilament Heating

1. A small flow of current through the filament is enough to heat it to a temperature that causes electron emission.

2. A change in the number of emitted electrons varies with the current flow through the filament.

3. The tube current is measured in milliamperes (mA), and it controls the intensity of X-rays.

1. A small flow of current through the filament is enough to heat it to a temperature that causes electron emission.

2. A change in the number of emitted electrons varies with the current flow through the filament.

3. The tube current is measured in milliamperes (mA), and it controls the intensity of X-rays.

Anode and CathodeAnode and Cathode

1. The anode of X-ray tube is

usually made of copper.

2. Copper and tungsten are the

most common anode materials.

1. The anode of X-ray tube is

usually made of copper.

2. Copper and tungsten are the

most common anode materials.

AnodeAnode

3. A dense target material is

required to ensure a maximum

number of collisions.

4. Material with a high melting point

is necessary for a target to

withstand the excessive heat.

3. A dense target material is

required to ensure a maximum

number of collisions.

4. Material with a high melting point

is necessary for a target to

withstand the excessive heat.

Focal SpotFocal Spot

1. The image sharpness is partly determined by the size of the focal spot.

2. The electron beam is focused so that a rectangular area of the target is bombarded by the beam.

1. The image sharpness is partly determined by the size of the focal spot.

2. The electron beam is focused so that a rectangular area of the target is bombarded by the beam.

Focal SpotFocal Spot

3. The projected area of the electron beam is the effective focal spot (as seen in the following slide).

4. The size to which the focal spot can be reduced is limited by the heat generated in target bombardment.

3. The projected area of the electron beam is the effective focal spot (as seen in the following slide).

4. The size to which the focal spot can be reduced is limited by the heat generated in target bombardment.

Linear AcceleratorsLinear Accelerators

There are two types of linear

accelerators:

1. Standing wave linear accelerator for energy up to 200 MeV.

2. Traveling wave linear accelerator for energy up to 30 GeV (giga-electron volts, or billion electron volts).

There are two types of linear

accelerators:

1. Standing wave linear accelerator for energy up to 200 MeV.

2. Traveling wave linear accelerator for energy up to 30 GeV (giga-electron volts, or billion electron volts).

X-Ray Beam ConfigurationX-Ray Beam Configuration

1. Once the X-rays are created, they

cannot be focused or otherwise

directed.

2. The direction of useful X-radiation

is determined by the positioning of

the target and the lead shielding.

1. Once the X-rays are created, they

cannot be focused or otherwise

directed.

2. The direction of useful X-radiation

is determined by the positioning of

the target and the lead shielding.

Accelerating PotentialAccelerating Potential

1. The applied potential between the

cathode and anode determines the

penetrating effect of the produced X-

ray.

2. The higher the voltage, the greater the

electron velocity and the shorter

wavelengths and more penetrating

power for the generated X-rays.

1. The applied potential between the

cathode and anode determines the

penetrating effect of the produced X-

ray.

2. The higher the voltage, the greater the

electron velocity and the shorter

wavelengths and more penetrating

power for the generated X-rays.

Iron Core TransformersIron Core Transformers

1. The majority of X-ray equipment

for industrial radiography (up to

400 kV) use iron core

transformers.

2. Their basic limitations are their

size and weight.

1. The majority of X-ray equipment

for industrial radiography (up to

400 kV) use iron core

transformers.

2. Their basic limitations are their

size and weight.

Heat DissipationHeat Dissipation

1. X-ray generation is a very

inefficient process; most of the

electron energy is expended in

producing heat.

2. Heat dissipation in the X-ray tube is

done by a flow of oil, gas or water.

1. X-ray generation is a very

inefficient process; most of the

electron energy is expended in

producing heat.

2. Heat dissipation in the X-ray tube is

done by a flow of oil, gas or water.

Heat DissipationHeat Dissipation

3. Efficiency of an X-ray tube

cooling system is the main factor

in determining the duty cycle of

the tube.

3. Efficiency of an X-ray tube

cooling system is the main factor

in determining the duty cycle of

the tube.

Equipment ShieldingEquipment Shielding

1. To prevent unwanted radiation, lead is used to shield the X-ray tube.

2. The design of this shielding varies with different X-ray tubes, but in all cases, it serves to absorb that portion of the radiation that is not traveling in the desired direction.

1. To prevent unwanted radiation, lead is used to shield the X-ray tube.

2. The design of this shielding varies with different X-ray tubes, but in all cases, it serves to absorb that portion of the radiation that is not traveling in the desired direction.

Control PanelControl Panel

1. The control panel of an X-ray system is designed to permit a radiographer to set the desired exposure parameters.

2. The control panel also provides critical indications for tube performance, such as cooling system, flow of cooling oil, or water.

1. The control panel of an X-ray system is designed to permit a radiographer to set the desired exposure parameters.

2. The control panel also provides critical indications for tube performance, such as cooling system, flow of cooling oil, or water.

Gamma Ray EquipmentGamma Ray Equipment

1. Handling and storage of gamma ray sources are extremely important due to the fact they cannot be shut off.

2. The United State Nuclear Regulatory Commission (NRC) and various state agencies recommend safety standards for proper transportation, storage and handling of radioisotopes.

1. Handling and storage of gamma ray sources are extremely important due to the fact they cannot be shut off.

2. The United State Nuclear Regulatory Commission (NRC) and various state agencies recommend safety standards for proper transportation, storage and handling of radioisotopes.

Gamma Ray SourcesGamma Ray Sources

1. There are two types of gamma ray sources:

a. Natural isotopes.

b. Artificial isotopes.

2. Most isotopes used in industrial radiography are round wafers encapsulated in a stainless steel cylinder.

1. There are two types of gamma ray sources:

a. Natural isotopes.

b. Artificial isotopes.

2. Most isotopes used in industrial radiography are round wafers encapsulated in a stainless steel cylinder.

RadiumRadium

1. Radium is a natural radioactive

substance having a half life of

about 1600 years.

2. Most radium sources consist of

radium sulfate packaged in

either spherical or cylindrical

capsules.

1. Radium is a natural radioactive

substance having a half life of

about 1600 years.

2. Most radium sources consist of

radium sulfate packaged in

either spherical or cylindrical

capsules.

RadiumRadium

3. Because of its low specific

activity and its long half life,

radium is rarely used in industrial

radiography.

3. Because of its low specific

activity and its long half life,

radium is rarely used in industrial

radiography.

Artificial RadioisotopesArtificial Radioisotopes

1. The artificial radioisotopes used in industrial radiography or gauging purposes are:

1. Cobalt-60 (Co-60).

2. Iridium-192 (Ir-192).

3. Selenium-75 (Se-75).

4. Thulium-170 (Tm-170).

5. Cesium-137 (Cs-137).

1. The artificial radioisotopes used in industrial radiography or gauging purposes are:

1. Cobalt-60 (Co-60).

2. Iridium-192 (Ir-192).

3. Selenium-75 (Se-75).

4. Thulium-170 (Tm-170).

5. Cesium-137 (Cs-137).

Artificial RadioisotopesArtificial Radioisotopes

2. The following table gives a

summary of the main

characteristics of the most used

isotopes.

2. The following table gives a

summary of the main

characteristics of the most used

isotopes.

Radioisotope characteristicsRadioisotope characteristics

Isotope CamerasIsotope Cameras

1. The equipment to accomplish safe handling and storage of radioisotopes is called a camera or exposure device.

2. These cameras are self contained units, meaning no external power supply is required.

1. The equipment to accomplish safe handling and storage of radioisotopes is called a camera or exposure device.

2. These cameras are self contained units, meaning no external power supply is required.

Isotope CamerasIsotope Cameras

3. The exposure devices contain

self locking mechanisms

ensuring safety in accordance

with ANSI and ISO requirements,

in addition to NRC and IAEA

requirements.

3. The exposure devices contain

self locking mechanisms

ensuring safety in accordance

with ANSI and ISO requirements,

in addition to NRC and IAEA

requirements.

Lesson 4Lesson 4

Radiographic FilmRadiographic Film

IntroductionIntroduction

1. Radiographic film consists of:

a. Base: A thin, transparent plastic sheet.

b. Emulsion coat: Coat of an emulsion of gelatin on one or both sides about 0.001 in. (0.003 cm) thick. The emulsion coat contains very fine grains of silver bromide (AgBr).



b. Emulsion coat: Coat of an emulsion of gelatin on one or both sides about 0.001 in. (0.003 cm) thick. The emulsion coat contains very fine grains of silver bromide (AgBr).


2. Latent (hidden) image:

Exposure of radiation on the film

that cannot be detected until

chemical processing occurs.

3. Visible image: Image on the

film after developed by chemical

processing.

2. Latent (hidden) image:

Exposure of radiation on the film

that cannot be detected until

chemical processing occurs.

3. Visible image: Image on the

film after developed by chemical

processing.

Usefulness of RadiographsUsefulness of Radiographs

1. Film density: Degree of darkening

on the developed film.

2. Radiographic contrast:

Difference between two film areas.

Darker area (higher density) has

received more radiation compared

to the area of light density.

1. Film density: Degree of darkening

on the developed film.

2. Radiographic contrast:

Difference between two film areas.

Darker area (higher density) has

received more radiation compared

to the area of light density.

Usefulness of RadiographsUsefulness of Radiographs

3. Definition: Sharpness of any

change in film density.

4. Contrast and definition are

important for a successful

interpretation of radiographs.

3. Definition: Sharpness of any

change in film density.

4. Contrast and definition are

important for a successful

interpretation of radiographs.

Radiographic ContrastRadiographic Contrast

1. The film density D is logarithmic value

defined as:

D = log10 (I0/I)

where (I0) is the intensity of the incident

light to view the film, and I is the intensity

of the transmitted light through the film.

The higher the number, the darker the

film.

1. The film density D is logarithmic value

defined as:

D = log10 (I0/I)

where (I0) is the intensity of the incident

light to view the film, and I is the intensity

of the transmitted light through the film.

The higher the number, the darker the

film.


2. If the intensity of light is 1000

units and the film allows only

one unit of that intensity to pass

through, the film density based

on the previous equation will be:

D = log10 (1000/1) = 3

2. If the intensity of light is 1000

units and the film allows only

one unit of that intensity to pass

through, the film density based

on the previous equation will be:

D = log10 (1000/1) = 3


3. Radiographic contrast (as shown

in the following figure) is defined

as the difference in the film

density between two selected

areas of the exposed and

developed film.

3. Radiographic contrast (as shown

in the following figure) is defined

as the difference in the film

density between two selected

areas of the exposed and

developed film.


4. Higher contrast is better for film

interpretation.

5. Radiographic contrast is a

combination of:

a. Subject contrast.

b. Film contrast.

4. Higher contrast is better for film

interpretation.

5. Radiographic contrast is a

combination of:

a. Subject contrast.

b. Film contrast.


6. Radiographic contrast depends on:

a. Applied radiation energy (penetrating quality).

b. Contrast characteristics of the film.

c. Amount of exposure (the product of radiation intensity and exposure time).

6. Radiographic contrast depends on:

a. Applied radiation energy (penetrating quality).

b. Contrast characteristics of the film.

c. Amount of exposure (the product of radiation intensity and exposure time).


d. Film screen.

e. Film processing.

f. Scattered radiation.

d. Film screen.

e. Film processing.

f. Scattered radiation.

Subject ContrastSubject Contrast

1. Subject contrast is the relative

radiation intensities passing

through any two selected

portions of material. Subject

contrast depends on the

following factors:

1. Subject contrast is the relative

radiation intensities passing

through any two selected

portions of material. Subject

contrast depends on the

following factors:


a. Type and shape of the test object.

b. Energy of the applied energy

radiation wavelength, type of

source.

c. Scattered radiation.

a. Type and shape of the test object.

b. Energy of the applied energy

radiation wavelength, type of

source.

c. Scattered radiation.


2. Subject contrast decreases as

the wavelength of the incident

radiation decreases.

2. Subject contrast decreases as

the wavelength of the incident

radiation decreases.


3. Higher subject contrast can be achieved by:

a. Larger thickness variation.

b. Use of different X-ray or gamma ray energies.

c. Masks.

d. Diaphragms.

e. Filters or screens.

3. Higher subject contrast can be achieved by:

a. Larger thickness variation.

b. Use of different X-ray or gamma ray energies.

c. Masks.

d. Diaphragms.

e. Filters or screens.

Film ContrastFilm Contrast

1. The ability of film to detect and

record different radiation

exposures as differences in film

density is called film contrast.

1. The ability of film to detect and

record different radiation

exposures as differences in film

density is called film contrast.


2. The relationship between the

amount of exposure and the

resulting film density is

expressed in the form of film

characteristic curves and is

determined by the following

factors:

2. The relationship between the

amount of exposure and the

resulting film density is

expressed in the form of film

characteristic curves and is

determined by the following

factors:


a. Film grain size.

b. Chemistry of the film processing chemical.

c. Concentration of the processing chemicals.

d. Development time.

e. Development temperature.

f. Agitation in the developer solution.

a. Film grain size.

b. Chemistry of the film processing chemical.

c. Concentration of the processing chemicals.

d. Development time.

e. Development temperature.

f. Agitation in the developer solution.

Film Characteristic CurvesFilm Characteristic Curves

1. The following figure shows a film characteristic curve.

a. The vertical axis is the resulting film density.

b. The horizontal axis is expressed in a logarithm of relative exposure.

1. The following figure shows a film characteristic curve.

a. The vertical axis is the resulting film density.

b. The horizontal axis is expressed in a logarithm of relative exposure.


c. The minimum point of the curve

on the vertical axis is called fog

density.

d. Based on this curve, as the

exposure increases, film contrast

increases.

c. The minimum point of the curve

on the vertical axis is called fog

density.

d. Based on this curve, as the

exposure increases, film contrast

increases.


2. A film characteristic curve has

two different sections:

a. A tail of lower densities.

b. A straighter portion (with

a higher slope on the

curve).

2. A film characteristic curve has

two different sections:

a. A tail of lower densities.

b. A straighter portion (with

a higher slope on the

curve).


3. High radiographic contrast is

achieved with densities at the

straight portion of a characteristic

curve. This is the reason that

films should always be exposed

for a density of at least 1.5.

3. High radiographic contrast is

achieved with densities at the

straight portion of a characteristic

curve. This is the reason that

films should always be exposed

for a density of at least 1.5.


4. Most radiographic codes,

standards and specifications

usually give upper and lower

density limits within a range of

1.8 to 4.0.

4. Most radiographic codes,

standards and specifications

usually give upper and lower

density limits within a range of

1.8 to 4.0.

Film SpeedFilm Speed

1. Film speed is an important

consideration in determining the

proper exposure time to obtain the

desired film density.

2. The next figure illustrates films with

high, medium and low speeds.

1. Film speed is an important

consideration in determining the

proper exposure time to obtain the

desired film density.

2. The next figure illustrates films with

high, medium and low speeds.

Film SpeedFilm Speed

3. Knowing film speed is important

in film selection for each

particular radiographic testing

task.

3. Knowing film speed is important

in film selection for each

particular radiographic testing

task.

GraininessGraininess

1. Graininess is the visible evidence of

the grouping into clumps of the silver

particles that form the image on the

radiographic film.

2. The following figure shows the effect

of grain variation on the image

definition.

1. Graininess is the visible evidence of

the grouping into clumps of the silver

particles that form the image on the

radiographic film.

2. The following figure shows the effect

of grain variation on the image

definition.

GraininessGraininess

3. The degree of graininess of an

exposed film depends on the

following factors:

a. Grain size.

b. The quality of the radiation.

c. Film process conditions.

d. Type of film screens.

3. The degree of graininess of an

exposed film depends on the

following factors:

a. Grain size.

b. The quality of the radiation.

c. Film process conditions.

d. Type of film screens.

Film Selection FactorsFilm Selection Factors

1. When not otherwise specified by the

customer or governing standards, the

selection of film is made by the

radiographer. Most of the time, the

selection of film is based on the

following factors:

a. Need for certain contrast and

definition quality.

1. When not otherwise specified by the

customer or governing standards, the

selection of film is made by the

radiographer. Most of the time, the

selection of film is based on the

following factors:

a. Need for certain contrast and

definition quality.


b. Thickness and density of the test

object.

c. The type of indication or

discontinuity normally associated

with the object.

d. Size of an acceptable indication.

b. Thickness and density of the test

object.

c. The type of indication or

discontinuity normally associated

with the object.

d. Size of an acceptable indication.


e. Accessibility, location and

configuration of the test object.

f. Customer requirements.

e. Accessibility, location and

configuration of the test object.

f. Customer requirements.


2. In film selection, remember that:

a. Film contrast, film speed and

graininess are interrelated.

b. Faster films need shorter

exposure time, but usually

have larger grains and poor

resolution/sensitivity.

2. In film selection, remember that:

a. Film contrast, film speed and

graininess are interrelated.

b. Faster films need shorter

exposure time, but usually

have larger grains and poor

resolution/sensitivity.


c. Slower films need longer

exposure time, but have finer

grain and good resolution/

sensitivity.

c. Slower films need longer

exposure time, but have finer

grain and good resolution/

sensitivity.


d. Film manufacturers’

recommendations for film

selection are a useful tool in

selecting the proper film for a

given application.

d. Film manufacturers’

recommendations for film

selection are a useful tool in

selecting the proper film for a

given application.

Film ProcessingFilm Processing

1. Film processing makes the latent

image visible.

2. The following general

precautions must be observed

during film processing:

1. Film processing makes the latent

image visible.

2. The following general

precautions must be observed

during film processing:


a. Follow manufacturer recommendations

for chemical concentrations, temperature

and processing time.

b. Use equipment, tanks, trays and holders

that can withstand the chemical action.

a. Follow manufacturer recommendations

for chemical concentrations, temperature

and processing time.

b. Use equipment, tanks, trays and holders

that can withstand the chemical action.


c. Ensure tanks are clean.

d. Recommended safelights should

be used and should be checked

regularly.

c. Ensure tanks are clean.

d. Recommended safelights should

be used and should be checked

regularly.


e. Maintain cleanliness in the

darkroom to avoid any artifacts

on developed radiographs.

f. Avoid any contamination of

different solutions.

e. Maintain cleanliness in the

darkroom to avoid any artifacts

on developed radiographs.

f. Avoid any contamination of

different solutions.

Tank ProcessingTank Processing

The arrangement of tank processing

(manual processing) unit is shown in

the next slide.

The arrangement of tank processing

(manual processing) unit is shown in

the next slide.


1. The tanks for processing solutions and

wash water should be deep enough for

the film to be submerged.

2. The chemicals in the tanks must be

stirred and the temperature must be

checked with calibrated thermometer

before turning off the ambient light.

1. The tanks for processing solutions and

wash water should be deep enough for

the film to be submerged.

2. The chemicals in the tanks must be

stirred and the temperature must be

checked with calibrated thermometer

before turning off the ambient light.


3. All required equipment should be

arranged before turning off the

ambient light.

4. All unnecessary materials should

be kept away from the

processing area.

3. All required equipment should be

arranged before turning off the

ambient light.

4. All unnecessary materials should

be kept away from the

processing area.


5. Test the safe lights and arrangement

them for easy viewing. Follow the

standard recommendations for

regular checking.

6. The door to the darkroom should be

locked to prevent accidental

exposure to ambient light.

5. Test the safe lights and arrangement

them for easy viewing. Follow the

standard recommendations for

regular checking.

6. The door to the darkroom should be

locked to prevent accidental

exposure to ambient light.


7. To load the film inside the hangers, it

should grasped by its edges or corner

to avoid finger prints, bending,

wrinkling or crimping during handling.

8. Keep the loading area completely dry.

9. Follow the tank processing

procedures.

7. To load the film inside the hangers, it

should grasped by its edges or corner

to avoid finger prints, bending,

wrinkling or crimping during handling.

8. Keep the loading area completely dry.

9. Follow the tank processing

procedures.

Tank Processing FeaturesTank Processing Features

There are five separate steps in tank processing:

1. Developing.

2. Stop bath.

3. Fixing.

4. Washing.

5. Drying.

There are five separate steps in tank processing:

1. Developing.

2. Stop bath.

3. Fixing.

4. Washing.

5. Drying.

DevelopingDeveloping

Developing is the chemical

process of reducing silver

bromide particles in the exposed

area of the film emulsion to

metallic silver.

Developing is the chemical

process of reducing silver

bromide particles in the exposed

area of the film emulsion to

metallic silver.


1. Follow the manufacturers’

recommendations for developing

temperature and time.

2. Film should be agitated during

developing to obtain a uniform

development and to avoid any air

bubbles from attaching to the film.


recommendations for developing

temperature and time.

2. Film should be agitated during

developing to obtain a uniform

development and to avoid any air

bubbles from attaching to the film.


3. Use strips of exposed radiographs

to control the developer activity as

regular quality control checking.


recommendations to replenish the

solution.

3. Use strips of exposed radiographs

to control the developer activity as

regular quality control checking.


recommendations to replenish the

solution.

Stop BathStop Bath

The stop bath, a solution of acetic acid

and water, serves to remove the residual

developer solution from the film.

1. Uncontaminated running water for at

least 2 min can be used as an

alternative to stop bath.

The stop bath, a solution of acetic acid

and water, serves to remove the residual

developer solution from the film.

1. Uncontaminated running water for at

least 2 min can be used as an

alternative to stop bath.

Stop BathStop Bath

2. Manufacturers’ directions should

be used to make the stop bath

solution.

3. A fresh stop bath solution is

yellow in color and clear under

safelight.

2. Manufacturers’ directions should

be used to make the stop bath

solution.

3. A fresh stop bath solution is

yellow in color and clear under

safelight.

FixingFixing

1. Fixer, an acidic solution, has two

functions on the film:

a. It dissolves and removes the

silver bromide from the

undeveloped portions of the film

without affecting the

developed portion.

b. It hardens the emulsion gelatin.

1. Fixer, an acidic solution, has two

functions on the film:

a. It dissolves and removes the

silver bromide from the

undeveloped portions of the film

without affecting the

developed portion.

b. It hardens the emulsion gelatin.

FixingFixing

2. The minimum time required for

fixing is twice the amount of time

necessary to clean the film.

3. Fixing time should not exceed 15

min.

4. Improper fixing shortens the

archival length of the film.

2. The minimum time required for

fixing is twice the amount of time

necessary to clean the film.

3. Fixing time should not exceed 15

min.

4. Improper fixing shortens the

archival length of the film.

FixingFixing

5. Film should be agitated in fixing

solution at 2 min intervals.

6. The replacement of fixing

solution should be determined by

checking the acidity of the

solution.

5. Film should be agitated in fixing

solution at 2 min intervals.

6. The replacement of fixing

solution should be determined by

checking the acidity of the

solution.

WashingWashing

After fixing, washing is necessary to

remove the fixer from the emulsion.

1. Each film is washed for a period

of time equal to twice the fixing.

2. Hypo clearing agent may be

used to speed up film washing.

After fixing, washing is necessary to

remove the fixer from the emulsion.

1. Each film is washed for a period

of time equal to twice the fixing.

2. Hypo clearing agent may be

used to speed up film washing.

WashingWashing

3. Best results for washing are

obtained with a water temperature

between 65 and 70° F (18.3 and

21.1° C).

4. To avoid any water marks, film is

immersed in a wetting agent that

also aids in reducing the drying

time.

3. Best results for washing are

obtained with a water temperature

between 65 and 70° F (18.3 and

21.1° C).

4. To avoid any water marks, film is

immersed in a wetting agent that

also aids in reducing the drying

time.

DryingDrying

The final stage of the film

processing is drying.

The final stage of the film

processing is drying.

Automatic Film ProcessingAutomatic Film Processing

Automatic film processing

systems are used whenever the

volume of work makes them

economical.

Automatic film processing

systems are used whenever the

volume of work makes them

economical.


1. The entire processing cycles is

completed in less than 15 min.

2. Automatic film processing units

consistently produce radiographs

of much higher quality than a

manual one.

1. The entire processing cycles is

completed in less than 15 min.

2. Automatic film processing units

consistently produce radiographs

of much higher quality than a

manual one.


3. Loading the film inside the unit

should be done in a dark

environment.

4. Properly maintaining the system

is the key for high performance

of an automatic system.

3. Loading the film inside the unit

should be done in a dark

environment.

4. Properly maintaining the system

is the key for high performance

of an automatic system.

Darkroom Facilities and EquipmentDarkroom Facilities and Equipment

Some requirements that must be satisfied in the design and construction of a darkroom:

1. It must be lighted with suitable and tested safelights.

2. It must be protected against ambient light from outside sources.

3. The walls and ceiling must be painted with lightly-colored, semi- gloss paint.

Some requirements that must be satisfied in the design and construction of a darkroom:

1. It must be lighted with suitable and tested safelights.

2. It must be protected against ambient light from outside sources.

3. The walls and ceiling must be painted with lightly-colored, semi- gloss paint.

Darkroom Facilities and EquipmentDarkroom Facilities and Equipment

4. Darkroom floors are usually covered with chemical resistant, water-proof and slip-proof materials.

5. Cleanliness is of great importance during the entire film processing procedure.

4. Darkroom floors are usually covered with chemical resistant, water-proof and slip-proof materials.

5. Cleanliness is of great importance during the entire film processing procedure.




b. Emulsion coat: Coat of an emulsion of gelatin on one or both sides about 0.001 in.

(0.003 cm) thick. The emulsion coat contains very fine grains of silver bromide (AgBr).



b. Emulsion coat: Coat of an emulsion of gelatin on one or both sides about 0.001 in.

(0.003 cm) thick. The emulsion coat contains very fine grains of silver bromide (AgBr).


2. Latent (hidden) image: Trace of

exposure of radiation on the exposed

film, cannot be detected by ordinary

physical methods.

3. Visible image: Image on the film after

developed by chemical processing.

2. Latent (hidden) image: Trace of

exposure of radiation on the exposed

film, cannot be detected by ordinary

physical methods.

3. Visible image: Image on the film after

developed by chemical processing.

Lesson 5Lesson 5

SafetySafety


1. Radiographers are cautioned to

be aware of the latest effective

safety regulations.

2. Radiation safety practices are

based on the effects of radiation

on the human body, and

characteristics of radiation.

1. Radiographers are cautioned to

be aware of the latest effective

safety regulations.

2. Radiation safety practices are

based on the effects of radiation

on the human body, and

characteristics of radiation.


3. Personnel protection is

dependant upon detection

devices, and through the proper

use of time, distance and

shielding.

3. Personnel protection is

dependant upon detection

devices, and through the proper

use of time, distance and

shielding.


4. Agreement States are the

regulations covering use, handling

and transportation of radioactive

materials approved by the Nuclear

Regulatory Commission (NRC).

4. Agreement States are the

regulations covering use, handling

and transportation of radioactive

materials approved by the Nuclear

Regulatory Commission (NRC).


5. All of the safety regulations are

designed to limit exposure to the

radiographer and to provide

protection to the general public.

5. All of the safety regulations are

designed to limit exposure to the

radiographer and to provide

protection to the general public.


6. The radiographer, who is

employed by a licensee of NRC

or who is employed by a

licensee of an agreement state,

must have knowledge of, and

comply with, all applicable

regulations.

6. The radiographer, who is

employed by a licensee of NRC

or who is employed by a

licensee of an agreement state,

must have knowledge of, and

comply with, all applicable

regulations.

Units of Radiation Dose MeasurementUnits of Radiation Dose Measurement

1. The damaging effects of

radiation are dependent on both

the type and the level of energy

of the radiation.

2. For different types of radiation, a

relative biological effectiveness

is applied.

1. The damaging effects of

radiation are dependent on both

the type and the level of energy

of the radiation.

2. For different types of radiation, a

relative biological effectiveness

is applied.

Units of Radiation Dose MeasurementUnits of Radiation Dose Measurement

3. For radiation safety purposes,

the cumulative effect of radiation

on the human body is of primary

concerns.

3. For radiation safety purposes,

the cumulative effect of radiation

on the human body is of primary

concerns.

Roentgen (R)Roentgen (R)

1. The roentgen (R) or sievert (Sv) is

the physical unit measure of the

ionization of air by X-radiation or

gamma radiation.

1. The roentgen (R) or sievert (Sv) is

the physical unit measure of the

ionization of air by X-radiation or

gamma radiation.


2. It is defined as the quantity of

radiation that will produce one

electrostatic unit (esu) of charge

in one cubic centimeter of air at

standard pressure and

temperature (STP).

2. It is defined as the quantity of

radiation that will produce one

electrostatic unit (esu) of charge

in one cubic centimeter of air at

standard pressure and

temperature (STP).


3. 1 R of radiation = absorption by

ionization of about 83 erg (unit of

work or energy in physics) of

radiation energy per gram of air.

4. For practical purpose, mR is often

used, which is:

1 mR = 1/1000 R.

3. 1 R of radiation = absorption by

ionization of about 83 erg (unit of

work or energy in physics) of

radiation energy per gram of air.

4. For practical purpose, mR is often

used, which is:

1 mR = 1/1000 R.

Radiation Absorbed Dose (rad)Radiation Absorbed Dose (rad)

1. Radiation absorbed dose (rad) is

the unit of measurement of

radiation absorption by humans.

2. It represents an absorption of

100 erg of energy per gram of

irradiated tissue.

1. Radiation absorbed dose (rad) is

the unit of measurement of

radiation absorption by humans.

2. It represents an absorption of

100 erg of energy per gram of

irradiated tissue.


3. Whereas the roentgen applies only

to X-rays and gamma rays, radiation

absorbed dose applies to any type of

radiations

4. For X-ray and gamma radiation,

exposure to 1 R results in 1 rad.

3. Whereas the roentgen applies only

to X-rays and gamma rays, radiation

absorbed dose applies to any type of

radiations

4. For X-ray and gamma radiation,

exposure to 1 R results in 1 rad.


5. The unit gray (Gy) has been

introduced as: 100 rad = 1 Gy.

5. The unit gray (Gy) has been

introduced as: 100 rad = 1 Gy.

Quality FactorQuality Factor

1. Quality factor takes into account the

biological effect of different

radiations on human body.

1. Quality factor takes into account the

biological effect of different

radiations on human body.

Quality FactorQuality Factor

2. Quality factor values are

determined by National

Committee on Radiation

Protection. They are summarized

in the following table.

2. Quality factor values are

determined by National

Committee on Radiation

Protection. They are summarized

in the following table.

Roentgen Equivalent Man (rem)Roentgen Equivalent Man (rem)

1. Roentgen equivalent man (rem)

represents the absorbed dose in

radiation absorbed dose (rad),

multiplied by the quality factor of the

type of radiation.

2. Radiation safety levels are

established in terms of roentgen

equivalent man (rem).

1. Roentgen equivalent man (rem)

represents the absorbed dose in

radiation absorbed dose (rad),

multiplied by the quality factor of the

type of radiation.

2. Radiation safety levels are

established in terms of roentgen

equivalent man (rem).

Roentgen Equivalent Man (rem)Roentgen Equivalent Man (rem)

3. Since the quality factor of

X-radiation and gamma radiation

is one, then:

1 rad = 1 rem.

3. Since the quality factor of

X-radiation and gamma radiation

is one, then:

1 rad = 1 rem.

International System of Units (SI) Measurements


1. The Nuclear Regulatory

Commission, state regulations

and radiographers in the US

often still use the old English

units: curie, roentgen, rem and

rad.

1. The Nuclear Regulatory

Commission, state regulations

and radiographers in the US

often still use the old English

units: curie, roentgen, rem and

rad.



2. Different organizations like The National

Institute of Standards & Technology

(NIST), The American National

Standards Institute (ANSI), The

American Society for Testing and

Materials (ASTM), The Institute of

Electrical and Electronics Engineers

(IEEE), …

2. Different organizations like The National

Institute of Standards & Technology

(NIST), The American National

Standards Institute (ANSI), The

American Society for Testing and

Materials (ASTM), The Institute of

Electrical and Electronics Engineers

(IEEE), …



… the International Organization for

Standardization (ISO) and The

American Society for

Nondestructive Testing (ASNT)

all support the replacement of

older units with SI units.

… the International Organization for

Standardization (ISO) and The

American Society for

Nondestructive Testing (ASNT)

all support the replacement of

older units with SI units.

Becquerel Replaces CurieBecquerel Replaces Curie

1. Curie (Ci) is the original unit for

radioactivity, which is defined as:


second.

2. In SI, the replace unit for

radioactivity is the becquerel (Bq),

which is one disintegration per

second.

1. Curie (Ci) is the original unit for

radioactivity, which is defined as:


second.

2. In SI, the replace unit for

radioactivity is the becquerel (Bq),

which is one disintegration per

second.

Becquerel Replaces CurieBecquerel Replaces Curie

3. 1 Ci = 37 GBq (gigabecquerel),

where giga = 109.

3. 1 Ci = 37 GBq (gigabecquerel),

where giga = 109.

Coulomb per Kilogram Replaces Roentgen

Coulomb per Kilogram Replaces Roentgen

1. Coulomb (C) is the unit of

electrical change, where:

1 C = 1 ampere X 1 second.

2. 1 R = 258 microcoulombs per

kilogram of air (258 µC·kg–1 of

air).

1. Coulomb (C) is the unit of

electrical change, where:

1 C = 1 ampere X 1 second.

2. 1 R = 258 microcoulombs per

kilogram of air (258 µC·kg–1 of

air).

Gray (Gy) Replaces RadGray (Gy) Replaces Rad

In the SI system, the unit of

radiation dose is the gray (Gy),

and 1 Gy =100 rad.


radiation dose is the gray (Gy),

and 1 Gy =100 rad.

Sievert (Sv) Replaces RemSievert (Sv) Replaces Rem


radiation absorbed by the human

body is Sievert (Sv), and

1 Sv = 100 rem.


radiation absorbed by the human

body is Sievert (Sv), and

1 Sv = 100 rem.

Maximum Permissible DoseMaximum Permissible Dose

1. Permissible dose is defined by

the NIST as the dose of radiation

that is not expected to cause

appreciable bodily injury to a

person.

1. Permissible dose is defined by

the NIST as the dose of radiation

that is not expected to cause

appreciable bodily injury to a

person.


2. The following restrictions for the

maximum annual permissible

dose limits for classified workers

should be observed:

a. Total effective dose

equivalent being equal to

5 rem (0.05 Sv).

2. The following restrictions for the

maximum annual permissible

dose limits for classified workers

should be observed:

a. Total effective dose

equivalent being equal to

5 rem (0.05 Sv).


Or

b. The sum of the absorbed dose

to any individual organ or tissue

other than the lens of the eye

being maximum equal to

50 rem (0.5 Sv).

Or

b. The sum of the absorbed dose

to any individual organ or tissue

other than the lens of the eye

being maximum equal to

50 rem (0.5 Sv).


c. The dose absorbed by lens of the

eye be maximum of 15 rem (0.15

Sv).

d. A shallow dose equivalent of

50 rem (0.5 Sv) to the skin of the

whole body or to the skin of any

extremity.

c. The dose absorbed by lens of the

eye be maximum of 15 rem (0.15

Sv).

d. A shallow dose equivalent of

50 rem (0.5 Sv) to the skin of the

whole body or to the skin of any

extremity.


3. The maximum annual radiation

dose is limited to 5 rem (0.05 Sv).

4. The absorbed dose shouldn’t

exceed 0.5 rem (5 mSv) during an

entire pregnancy.

3. The maximum annual radiation

dose is limited to 5 rem (0.05 Sv).

4. The absorbed dose shouldn’t

exceed 0.5 rem (5 mSv) during an

entire pregnancy.


5. Dose limits to the general public

shall not exceed 0.002 rem or

2 mrem (0.02 mSv) per hour or

exceed 0.5 rem or 500 mrem

(5 mSv) annually.

5. Dose limits to the general public

shall not exceed 0.002 rem or

2 mrem (0.02 mSv) per hour or

exceed 0.5 rem or 500 mrem

(5 mSv) annually.

Protection Against RadiationProtection Against Radiation

Safe radiographic techniques and

radiographic installation design

are achievable by applying these

principles:

1. Time: Keep the time close

to a radiation source as low as

possible.

Safe radiographic techniques and

radiographic installation design

are achievable by applying these

principles:

1. Time: Keep the time close

to a radiation source as low as

possible.

Protection Against RadiationProtection Against Radiation

2. Distance: Keep the distance

from a radiation source a high as

possible.

3. Shielding: Keep adequate

shielding for radiation source.

2. Distance: Keep the distance

from a radiation source a high as

possible.

3. Shielding: Keep adequate

shielding for radiation source.

Allowable Working TimeAllowable Working Time

1. The amount of absorbed radiation

by the human body is directly

proportional to the time that the

body is exposed to radiation.

Example: 2 rem (0.2 mSv) in

60 s = 10 mrem (1 mSv) in 5 min.

1. The amount of absorbed radiation

by the human body is directly

proportional to the time that the

body is exposed to radiation.

Example: 2 rem (0.2 mSv) in

60 s = 10 mrem (1 mSv) in 5 min.

Allowable Working TimeAllowable Working Time

2. Allowable working time for working with

gamma sources is calculated by

measuring radiation intensity and

substituting it in the following equation:

allowable working time in hr/week =

permissible exposure in Ci/wk /

exposure rate in Ci/h

2. Allowable working time for working with

gamma sources is calculated by

measuring radiation intensity and

substituting it in the following equation:

allowable working time in hr/week =

permissible exposure in Ci/wk /

exposure rate in Ci/h

Working DistanceWorking Distance

1. The greater the distance from a

radiation source, the lower the

radiation intensity.

2. The inverse square law is used

is used to calculate radiation

intensities at various distances

from a radiation source.

1. The greater the distance from a

radiation source, the lower the

radiation intensity.

2. The inverse square law is used

is used to calculate radiation

intensities at various distances

from a radiation source.


I1/I2 = D22/D2

1

where I1 and I2 are intensities at

distances D1 and aD2,

respectively.

I1/I2 = D22/D2

1

where I1 and I2 are intensities at

distances D1 and aD2,

respectively.


3. The same principles hold for X-radiation. The intensity at a known distance with predetermined current and voltage setting (usually given by the X-ray tubes manufacturers) can be determined by applying the inverse square law.

3. The same principles hold for X-radiation. The intensity at a known distance with predetermined current and voltage setting (usually given by the X-ray tubes manufacturers) can be determined by applying the inverse square law.


4. Radiation intensity at any point is

the sum of the primary radiation

and the secondary (scattered)

radiation at that point.

4. Radiation intensity at any point is

the sum of the primary radiation

and the secondary (scattered)

radiation at that point.

ShieldingShielding

1. Materials commonly used for

shielding to reduce personnel

exposures are lead, steel, water and

concrete.

1. Materials commonly used for

shielding to reduce personnel

exposures are lead, steel, water and

concrete.

ShieldingShielding

2. Shielding cannot stop all of the

energy of X-radiation or gamma

radiation; therefore, it is practical to

measure shielding efficiency in

terms of half value layers.

2. Shielding cannot stop all of the

energy of X-radiation or gamma

radiation; therefore, it is practical to

measure shielding efficiency in

terms of half value layers.

ShieldingShielding

3. Half value layer (HVL) is that

amount of shielding that will stop

half of the radiation of a given

intensity.

3. Half value layer (HVL) is that

amount of shielding that will stop

half of the radiation of a given

intensity.

ShieldingShielding

4. Similarly, shielding efficiency is often measured in tenth value layers. A tenth value layer is that amount of shielding that will stop nine tenth of the radiation of a given intensity. (See the following tables.)

4. Similarly, shielding efficiency is often measured in tenth value layers. A tenth value layer is that amount of shielding that will stop nine tenth of the radiation of a given intensity. (See the following tables.)

X-ray half value layersX-ray half value layers

Gamma ray half and tenth value layers

Gamma ray half and tenth value layers

Exposure AreaExposure Area

1. Exposure areas should consist of a

room with concrete or block walls,

lined with lead or other suitable

shielding materials.

2. Exposure area can be an enclosed

shielding cabinet large enough for

the test objects and with reliable

safety features.

1. Exposure areas should consist of a

room with concrete or block walls,

lined with lead or other suitable

shielding materials.

2. Exposure area can be an enclosed

shielding cabinet large enough for

the test objects and with reliable

safety features.


3. Controls should be located outside the exposure area.

4. In field radiography or temporary job sites, safe distance in relation to exposure must be determined and be secured by:

a. Guard rails or ropes.

b. Legible radiation warning signs.

c. Sufficient shielding.

3. Controls should be located outside the exposure area.

4. In field radiography or temporary job sites, safe distance in relation to exposure must be determined and be secured by:

a. Guard rails or ropes.

b. Legible radiation warning signs.

c. Sufficient shielding.


5. Only monitored radiographers are

permitted in the radiation area.

6. Keeping a safe distance from the

radiation source is the simplest and

most effective safety consideration

in field radiography.

5. Only monitored radiographers are

permitted in the radiation area.

6. Keeping a safe distance from the

radiation source is the simplest and

most effective safety consideration

in field radiography.

Radiation Protective ConstructionRadiation Protective Construction

1. Lead and concrete are the most

common materials used to protect

against radiation.

2. Shielding measurements are

usually expressed in terms of

thickness.

1. Lead and concrete are the most

common materials used to protect

against radiation.

2. Shielding measurements are

usually expressed in terms of

thickness.


3. Ensuring a leak-proof shielding is

very important.

4. Sheets of lead must be overlapped,

and nails and screws in the walls

must be covered with adequate

leads.

3. Ensuring a leak-proof shielding is

very important.

4. Sheets of lead must be overlapped,

and nails and screws in the walls

must be covered with adequate

leads.


5. Pipes, conduits and air ducts

passing through the walls of the

shielding must be completely

shielded (see the following

figure).

5. Pipes, conduits and air ducts

passing through the walls of the

shielding must be completely

shielded (see the following

figure).


6. The thickness of lead is dependent on two factors:

a. Energy of the radiation source.

b. Occupancy of the surrounding areas.

7. Other than lead, structural materials such as concrete and brick are often used as shielding materials.

6. The thickness of lead is dependent on two factors:

a. Energy of the radiation source.

b. Occupancy of the surrounding areas.

7. Other than lead, structural materials such as concrete and brick are often used as shielding materials.


8. At voltages greater than 400 kV,

concrete is used as shielding

because:

a. Difficulty installing very thick lead.

b. Thick sheets of lead are cost-

prohibitive.

8. At voltages greater than 400 kV,

concrete is used as shielding

because:

a. Difficulty installing very thick lead.

b. Thick sheets of lead are cost-

prohibitive.


c. Concrete is the best alternative

material because of its radiation

protection property and its

construction simplicity.

c. Concrete is the best alternative

material because of its radiation

protection property and its

construction simplicity.

Gamma Ray RequirementsGamma Ray Requirements

1. Special radiation protection is required for gamma radiation based on two factors:

a. Gamma radiation cannot be shot off.

b. Gamma radiation has considerable penetrating ability.

1. Special radiation protection is required for gamma radiation based on two factors:

a. Gamma radiation cannot be shot off.

b. Gamma radiation has considerable penetrating ability.


2. A combination of shielding and

distance is usually used during

gamma radiography.

3. Specially labeled storage

containers are necessary to

store gamma sources when not

in use.

2. A combination of shielding and

distance is usually used during

gamma radiography.

3. Specially labeled storage

containers are necessary to

store gamma sources when not

in use.


4. After every use, readings with survey

meters are taken to ensure the source is

safely stored.

5. Special projectors (called pigs) or

isotope cameras containing heavy

shielding made of lead or depleted

uranium should be used for using

radioisotope sources.

4. After every use, readings with survey

meters are taken to ensure the source is

safely stored.

5. Special projectors (called pigs) or

isotope cameras containing heavy

shielding made of lead or depleted

uranium should be used for using

radioisotope sources.

United States Nuclear Regulatory CommissionUnited States Nuclear

Regulatory Commission

1. The NRC regulates handling, storage and use of radioisotopes.

2. Figures 5.2 and 5.3 in the Radiographic Testing Classroom Training Book show NRC Form-4 and NRC Form-5, used to monitor the occupational dose history.

1. The NRC regulates handling, storage and use of radioisotopes.

2. Figures 5.2 and 5.3 in the Radiographic Testing Classroom Training Book show NRC Form-4 and NRC Form-5, used to monitor the occupational dose history.

Occupational Radiation Exposure Limits


1. Limitations on individual dosage

greater than those listed in the

following table may be permitted with

the following conditions:

a. The dose for the whole body

does not exceed 5 rem (0.05

Sv) during any calendar year.

1. Limitations on individual dosage

greater than those listed in the

following table may be permitted with

the following conditions:

a. The dose for the whole body

does not exceed 5 rem (0.05

Sv) during any calendar year.



b. The individual’s accumulated

occupational dose has been

recoded on NRC Form-4 and the

individual has signed the form.

b. The individual’s accumulated

occupational dose has been

recoded on NRC Form-4 and the

individual has signed the form.

Maximum permissible doseMaximum permissible dose

Levels of Radiation in Unrestricted Areas

Levels of Radiation in Unrestricted Areas

The following image shows the

exposure limits in an unrestricted

area.

The following image shows the

exposure limits in an unrestricted

area.

Personnel MonitoringPersonnel Monitoring

There are different personnel

monitoring devices required for use

by radiographers and their assistants

during radiographic operations:

There are different personnel

monitoring devices required for use

by radiographers and their assistants

during radiographic operations:


1. Film badges.

2. Thermoluminescent dosimeters

(TLDs).

3. Optically stimulated

luminescence badges (OSL).

1. Film badges.

2. Thermoluminescent dosimeters

(TLDs).

3. Optically stimulated

luminescence badges (OSL).


4. Direct reading dosimeters.

5. Pocket dosimeters.

6. Electronic personal dosimeters.

The last two types should be

capable of measuring exposures

from 0 to 200 mR (0 to 2 mSv).

4. Direct reading dosimeters.

5. Pocket dosimeters.

6. Electronic personal dosimeters.

The last two types should be

capable of measuring exposures

from 0 to 200 mR (0 to 2 mSv).

Caution Signs, Labels and SignalsCaution Signs, Labels and Signals

1. The radiation symbol should be placed in:

a. Exposure areas.

b. Containers for transporting and storing radioactive

materials.

2. The words caution or danger must appear.

1. The radiation symbol should be placed in:

a. Exposure areas.

b. Containers for transporting and storing radioactive

materials.

2. The words caution or danger must appear.


3. The words radioactive material

should be marked on containers of

radioactive materials and the areas

housing such containers.

3. The words radioactive material

should be marked on containers of

radioactive materials and the areas

housing such containers.


4. Exposure devices should have a radiation symbol and the phrase, Danger radioactive material – do not handle. Company information and a 24 h phone number must be mentioned on the sign.

4. Exposure devices should have a radiation symbol and the phrase, Danger radioactive material – do not handle. Company information and a 24 h phone number must be mentioned on the sign.

Exposure Devices and Storage Containers

Exposure Devices and Storage Containers

Based on the radiation regulations:

1. Exposure devices must have the name

of the company or laboratory and the

location of the office placed in a

noticeable site on the device.

2. All of the labels, signs, etc. shall be

legible.

Based on the radiation regulations:

1. Exposure devices must have the name

of the company or laboratory and the

location of the office placed in a

noticeable site on the device.

2. All of the labels, signs, etc. shall be

legible.

Radiation Survey Instrumentation Requirements

Radiation Survey Instrumentation Requirements

1. Radiographers should have operable

and calibrated radiation survey meters.

2. Each exposure device shall be

accompanied by a survey meter.

3. The meters shall have a range of

2 mR (0.02 mSv) per hour through

1 R (0.1 Sv) per hour.

1. Radiographers should have operable

and calibrated radiation survey meters.

2. Each exposure device shall be

accompanied by a survey meter.

3. The meters shall have a range of

2 mR (0.02 mSv) per hour through

1 R (0.1 Sv) per hour.

Radiation Surveys Radiation Surveys

1. An operable and calibrated radiation

survey instrumentation should be

available at an exposure area.

1. An operable and calibrated radiation

survey instrumentation should be

available at an exposure area.

Radiation SurveysRadiation Surveys

2. When working with radioisotopes, a

radioactive survey shall be made

around the camera to ensure the

source has been returned to its

shielded condition. This is known

as 360º sweep.

2. When working with radioisotopes, a

radioactive survey shall be made

around the camera to ensure the

source has been returned to its

shielded condition. This is known

as 360º sweep.

Radiation Surveys Radiation Surveys

3. Before storing each sealed source,

a radiation survey shall be made to

be sure that the source is in its

shielded position.

4. All these readings shall be recorded

on a radiation report survey.

3. Before storing each sealed source,

a radiation survey shall be made to

be sure that the source is in its

shielded position.

4. All these readings shall be recorded

on a radiation report survey.

Detection and Measurement Instruments

Detection and Measurement Instruments

There are different instruments that

measure the radiation based on the

ionization produced in a gas. These

instruments fall into two categories:

1. Instruments that measure total dose

exposure.

2. Instruments that measure dose rate (radiation intensity).

There are different instruments that

measure the radiation based on the

ionization produced in a gas. These

instruments fall into two categories:

1. Instruments that measure total dose

exposure.

2. Instruments that measure dose rate (radiation intensity).

Instruments that Measure Total Dose Exposure

Instruments that Measure Total Dose Exposure

a. Pocket dosimeter.

b. Electronic personnel dosimeters.

c. Thermoluminescent dosimeters

(TLDs).

d. Optically stimulated

luminescence (OSL) badges.

a. Pocket dosimeter.

b. Electronic personnel dosimeters.

c. Thermoluminescent dosimeters

(TLDs).

d. Optically stimulated

luminescence (OSL) badges.

Instruments that Measure Dose Rate

Instruments that Measure Dose Rate

Instruments that measure dose rate are called survey meters.

a. Ionization chambers.

b. Geiger-mueller counters.

Instruments that measure dose rate are called survey meters.

a. Ionization chambers.

b. Geiger-mueller counters.

Pocket DosimetersPocket Dosimeters

1. The pocket dosimeter is a small

device, about the size of a

fountain pen, as shown in the

following picture.

1. The pocket dosimeter is a small

device, about the size of a

fountain pen, as shown in the

following picture.


1. Its operation is based on two

main principles:

a. Radiation causes

ionization

in a gas.

b. Similar electrical changes

repel each other.

1. Its operation is based on two

main principles:

a. Radiation causes

ionization

in a gas.

b. Similar electrical changes

repel each other.


2. The dosimeter should be

properly charged (the indicator

on zero scale) before using.

2. The dosimeter should be

properly charged (the indicator

on zero scale) before using.


3. Pocket dosimeters are designed

with a sensitivity that permits them

to be scaled in doses from 0 to 200

mR (0 to 2 mSv).

4. Pocket dosimeters must be

calibrated annually, per NRC

regulation, and the date should be

labeled on them.

3. Pocket dosimeters are designed

with a sensitivity that permits them

to be scaled in doses from 0 to 200

mR (0 to 2 mSv).

4. Pocket dosimeters must be

calibrated annually, per NRC

regulation, and the date should be

labeled on them.

Personal Electronic DosimetersPersonal Electronic Dosimeters

1. Personal electronic dosimeters (or electronic dosimeters) have different features:

a. Easy to use.

b. Sensitive.

c. Different dosimeter functions can be enabled or disabled.

1. Personal electronic dosimeters (or electronic dosimeters) have different features:

a. Easy to use.

b. Sensitive.

c. Different dosimeter functions can be enabled or disabled.


2. The electronic dosimeter provides dose, dose rate and set point check, and usually operates with an AA battery.

3. The set points can be present to definitive alarm points.

4. The pocket size monitors provide three-digit digital display.

2. The electronic dosimeter provides dose, dose rate and set point check, and usually operates with an AA battery.

3. The set points can be present to definitive alarm points.

4. The pocket size monitors provide three-digit digital display.


5. The energy response of the pocket sized monitor for gamma and X-ray is 40 keV to 1.2 MeV.

6. They should be calibrated annually.

5. The energy response of the pocket sized monitor for gamma and X-ray is 40 keV to 1.2 MeV.


Film Badges and Thermoluminescent Dosimeters

Film Badges and Thermoluminescent Dosimeters

1. The film badge (shown on the

next slide), consists of a small

film holder equipped with thin

lead on cadmium filters.

2. The badge is designed only to

be worn by an individual when

working in a radiation area.

1. The film badge (shown on the

next slide), consists of a small

film holder equipped with thin

lead on cadmium filters.

2. The badge is designed only to

be worn by an individual when

working in a radiation area.

Optically Stimulated Luminescence (OSL) Badge


1. OSL badges measure beta (b),

gamma, neutron and

X-radiation exposures.

2. The OSL is a thin strip of

specially formulated aluminum

oxide crystalline material.

1. OSL badges measure beta (b),

gamma, neutron and

X-radiation exposures.

2. The OSL is a thin strip of

specially formulated aluminum

oxide crystalline material.



3. It detects energies from 5 keV to

40 MeV for photons, 150 keV to

10 MeV for beta particles, and 40

keV to 35 MeV for neutrons.

4. The dose measurements range

from 1 mrem to 1000 rem.

3. It detects energies from 5 keV to

40 MeV for photons, 150 keV to

10 MeV for beta particles, and 40

keV to 35 MeV for neutrons.

4. The dose measurements range

from 1 mrem to 1000 rem.

Ionization Chamber InstrumentsIonization Chamber Instruments

1. Ionization chamber instruments

measure the radiation intensity

(dose rate) in milliroentgen per hour

or millisievert per hour.


typically attain an accuracy of

±15%, except in low intensity

radiation areas.


measure the radiation intensity

(dose rate) in milliroentgen per hour

or millisievert per hour.


typically attain an accuracy of

±15%, except in low intensity

radiation areas.

Ionization Chamber InstrumentsIonization Chamber Instruments

3. Radiation intensity measurements

in areas of low intensity radiation

are usually made with geiger-

mueller counters.


should be calibrated annually.

3. Radiation intensity measurements

in areas of low intensity radiation

are usually made with geiger-

mueller counters.


should be calibrated annually.

Geiger-Mueller CountersGeiger-Mueller Counters

1. A geiger-mueller counter is a high sensitive radiation detection device.

2. Geiger-mueller counters are typically accurate to ±20% for the quantity of radiation to which they are calibrated.


1. A geiger-mueller counter is a high sensitive radiation detection device.

2. Geiger-mueller counters are typically accurate to ±20% for the quantity of radiation to which they are calibrated.


Area Alarm SystemsArea Alarm Systems

2. These systems consist of one or

more sensing elements usually

ionization chambers whose

output is fed a central alarm

meter.

2. These systems consist of one or

more sensing elements usually

ionization chambers whose

output is fed a central alarm

meter.

Area Alarm SystemsArea Alarm Systems

3. The meter can be present so that

an audible alarm is sounded,

and a visual indication is given

where permissible radiation

levels are exceeded.

3. The meter can be present so that

an audible alarm is sounded,

and a visual indication is given

where permissible radiation

levels are exceeded.

Electrical SafetyElectrical Safety

1. Because X-ray machines use high

voltage circuits, the radiographer

must comply with safe electrical

procedures.

2. This is more serious specifically for

portable X-ray equipment, which

requires certain electrical

precautions.

1. Because X-ray machines use high

voltage circuits, the radiographer

must comply with safe electrical

procedures.

2. This is more serious specifically for

portable X-ray equipment, which

requires certain electrical

precautions.


3. During operation or service of

X-ray equipment, the following

precautions, applicable to both

permanent and portable

installations, should be observed

carefully.

3. During operation or service of

X-ray equipment, the following

precautions, applicable to both

permanent and portable

installations, should be observed

carefully.


a. Do not turn power on until set up

for exposure is completed.

b. Ensure that grounding

instructions are complied with.

a. Do not turn power on until set up

for exposure is completed.

b. Ensure that grounding

instructions are complied with.


c. Regularly check power cables for signs of

wear, and replace them where

necessary.

d. Avoid handling power cables when

the power is on. The machine’s

operational key should be removed when

not in use.

c. Regularly check power cables for signs of

wear, and replace them where

necessary.

d. Avoid handling power cables when

the power is on. The machine’s

operational key should be removed when

not in use.


e. If power cables must be handled

with the power on, use safety

equipment such as rubber gloves,

rubber mats and insulated high

voltage sticks.

f. Be sure that water and moisture is not

in close contact with power cables.

e. If power cables must be handled

with the power on, use safety

equipment such as rubber gloves,

rubber mats and insulated high

voltage sticks.

f. Be sure that water and moisture is not

in close contact with power cables.


g. Ensure that capacitors are

completely discharged before

checking an electronic circuit.

g. Ensure that capacitors are

completely discharged before

checking an electronic circuit.

RT Level I basic

Documents

personnel qualification

actual radiographic

radiographic testingcompiled

qualified personnel

expensive testing method

personnel responsible

film radiography

test objects