documentri
TRANSCRIPT
![Page 1: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/1.jpg)
Radiographic FilmsRadiographic Films
![Page 2: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/2.jpg)
Radiographic FilmRadiographic Film
Base
Base must be :-
1. Transparent - To allow white light to go through
2. Chemically inert
3. Must not be susceptible to expansion and contraction
4. High tensile strength
5. Flexibility
![Page 3: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/3.jpg)
Radiographic FilmRadiographic Film
Base
Subbing
Subbing
Subbing layer is the adhesive between the emulsion and base
![Page 4: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/4.jpg)
Radiographic FilmRadiographic Film
Base
Subbing
SubbingEmulsion AgBr
Emulsion AgBr
Supercoat
Supercoat
![Page 5: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/5.jpg)
What are the advantages of Double Coated Film?
•Improve contrast
• Reduce the exposure time
![Page 6: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/6.jpg)
Image formationImage formationWhen radiation passes through an object it is differentially absorbed depending upon the materials thickness and any differing densitiesThe portions of radiographic film that receive sufficient amounts of radiation undergo minute changes to produce the latent image (hidden image)
1. The silver halide crystals are partially converted into metallic silver to produce the latent
image2. The affected crystals are the amplified by the
developer, the developer completely converts the affected crystals into black metallic silver
3. The radiograph attains its final appearance by fixation
![Page 7: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/7.jpg)
Film Types
Grain Size Speed Quality Film factor Coarse Fast Poor 10Medium Medium Medium 35Fine Slow Good 90Ultra Fine V.Slow V.Good 200
Film emulsion produced by mixing solutions of nitrate and salt such as potassium bromide.
• The rate and temperature determine the grain structures
1. Rapid mixing at low temperature - Finest grain structure
2. Slow mixing at high temperature - Large grain structure
![Page 8: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/8.jpg)
Processing FilmProcessing Film
![Page 9: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/9.jpg)
Processing Systems
Dev
elop
er
Stop
bath
Fixe
r Running water
Manual System
![Page 10: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/10.jpg)
DevelopmentDevelopment Metallic Silver converted into Black metallic silver
3-5 min at 20OC 68 F
Main ConstituentsMain ConstituentsDeveloping agent metol-hydroquinoneAccelerator keeps solution alkalineRestrainer ensures only exposed silver halides convertedPreservative prevents oxidation by air
Processing Systems
Replenishment Replenishment
Purpose – to ensure that the activity of the developer and the
developing time required remains constant
Guideline – 1. After 1m2 of film has been developed,
about 400 ml of replenisher needs to be added
![Page 11: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/11.jpg)
Stop BathStop Bath3% Acetic acid - neutralises the developer
Processing Systems
![Page 12: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/12.jpg)
FixerFixer• Sodium thiosulphate or ammonium thiosulphate
• Functions:- 1. Removes all unexposed silver grains 2. Hardens the emulsion gelatin
• Clearing time - The time taken for the radiography to loose its milky appearance.
• Fixing time - Twice the clearing time
Processing Systems
![Page 13: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/13.jpg)
Processing Systems
Running waterRunning water• Films should be washed in a tank with constant running water
for at least 20 minutes.
• Insufficient washing the film can caused the yellow fog appears.
![Page 14: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/14.jpg)
SENSITOMETRYSENSITOMETRY
![Page 15: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/15.jpg)
Characteristic CurvesCharacteristic Curves• Increasing exposures applied to
successive areas of a film• After development the densities are
measured• The density is then plotted against the
log of the exposure
Characteristic curve
Sensitometric curve
Hunter & Driffield curve
![Page 16: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/16.jpg)
![Page 17: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/17.jpg)
Characteristic CurvesCharacteristic Curves
Log Relative Exposure
Density (Log)
Toe
Shoulder
Straight line section
![Page 18: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/18.jpg)
Characteristic Curves Information which can be obtained from a
films characteristic curve• The position of the curve on the exposure axis
gives information about the films speed• The gradient of the curve gives information on the
films contrast
![Page 19: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/19.jpg)
Characteristic CurvesCharacteristic Curves
Log Relative Exposure
Density (Log)
Density obtained in a photographic emulsion does not vary linearly with applied exposure
The steeper the slope the greater the contrast
![Page 20: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/20.jpg)
Characteristic Curves Information which can be obtained from a
films characteristic curve• The position of the curve on the exposure axis
gives information about the films speed
![Page 21: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/21.jpg)
Characteristic Curves
Log Relative Exposure
Density
A B C D E
Film A is faster than Film B
Film B faster then C
![Page 22: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/22.jpg)
Characteristic Curves Information which can be obtained from a
films characteristic curve• The position of the curve on the exposure axis
gives information about the films speed• The gradient of the curve gives information on the
films contrast• The position of the straight line portion of the curve
against the density axis will show the density range range within which the film is at its optimal
![Page 23: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/23.jpg)
Changing DensityChanging Density
Log Relative Exposure
DensityDensity achieved 1.5
Density required 2.5
Determine interval between logs
1.8 - 1.3 = 0.5
2.5
1.5
1.3 1.8
Antilog of 0.5 = 3.18
Therefore multiply exposure by 3.18(measured density is lower than the required density)(measured density is lower than the required density)
Original exposure 10 mA mins
New exposure 31.8mA mins
![Page 24: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/24.jpg)
Changing FilmChanging Film
Log Relative Exposure
DensityObtain Logs for Films A and B at required density
Interval between logs = 0.15
1.7 1.85
Antilog of 0.15 = 1.42
Multiply exposure by 1.42
Original exposure 10 mA mins
New exposure 14.2 mA mins
2.5
A B
![Page 25: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/25.jpg)
RADIOGRAPHIC DEFINITIONDEFINITION is the sharpness of DEFINITION is the sharpness of the dividing line between areas of the dividing line between areas of different densitydifferent density
![Page 26: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/26.jpg)
Radiographic Definition
Geometric unsharpness Inherent unsharpness• FFD/SFD too short• OFD too large• Source size too large• Vibration/movement• Poor screen contact
• Coarse grain film• Salt screens• Wavelength too short
![Page 27: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/27.jpg)
Geometry Unsharpness ( Ug)Geometry Unsharpness ( Ug)• Controlled by focal spot, focal to film distance ( FFD), object to film distance (OFD)
Inherent unsharpness (Ui) Inherent unsharpness (Ui) • Controlled by the type of films being used (slow or fast), type of screens and amount of backscatter
Radiographic DefinitionRadiographic Definition
![Page 28: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/28.jpg)
Geometry of Image FormationGeometry of Image Formation
![Page 29: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/29.jpg)
Penumbra Ug)
Ug= F x ofd fod
(Ug = 0.25mm)
Focal spot size, F
ofd
fodffd
![Page 30: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/30.jpg)
Source size as small as possible
Source to object distance as large as
possible
Object to film distance as small as
possible
Penumbra (Ug)
![Page 31: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/31.jpg)
Penumbra = S x OFD FFD - OFD
S = 4mmOFD = 25mmFFD = 275
= 4 x 25 275 - 25
Penumbra = 0.4mm
Penumbra CalculationsPenumbra Calculations
![Page 32: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/32.jpg)
Penumbra CalculationsPenumbra Calculations
= 4 x 25 0.25
+ 25
Min FFD = S x OFD Penumbra (0.25)
S = 4mmOFD = 25mmFFD = 275
+ OFD
Min FFD = 425mm
![Page 33: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/33.jpg)
Inherent Unsharpness
Exposed radiographwith crack like indication
Stray electrons fromexposed crystals
Adjacent crystalsaffected by stray electrons
- -
-
--
--
- -
-
![Page 34: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/34.jpg)
Inherent Unsharpness
Large film grain size increased inherent Unsharpness
Short wavelength increased inherent Unsharpness
Loose film crystal distribution increased inherent Unsharpness
![Page 35: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/35.jpg)
Intensifying ScreensIntensifying Screens
Radiographic film is usually sandwiched between two intensifying screensThere are three main types of intensifying screens
•Lead screens
•Fluorescent screens
•Fluorometallic screens
![Page 36: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/36.jpg)
Film placed between 2 intensifying screensIntensification action achieved by emitting particulate radiation (electrons)
Generally lead of 0.02mm to 0.15mmFront screen shortens exposure time and improves quality by filtering out scatterBack screen acts as a filter only
Lead Intensifying ScreensLead Intensifying Screens
![Page 37: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/37.jpg)
Film placed between 2 intensifying screens
Intensification action achieved by emitting Light radiation (Visible or UV-A)Intensification action twice that of lead
screensNo filtration action achievedSalt used calcium tungstate
Salt Intensifying ScreensSalt Intensifying Screens
![Page 38: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/38.jpg)
Film placed between 2 intensifying screens
Intensification action achieved by emitting light
radiation (Visible or UV-A) and particulate radiation
electrons)
High cost
Front screen acts as a filter and intensifier
Salt used calcium tungstate
Fluorometallic Intensifying ScreensFluorometallic Intensifying Screens
![Page 39: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/39.jpg)
ScatterScatter
• Radiation emitted from any other source than that giving the primary desired rectilinear propagation
• Scatter will lead to poorer contrast and definition and create spurious indications
• It may also cause radiological protection problems
![Page 40: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/40.jpg)
ScatterScatter• Internal scatter originating within the
specimen• Side scatter walls and nearby
objects in the path of the primary beam
• Back scatter materials located behind the film
![Page 41: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/41.jpg)
ScatterScatter• Internal scatter originating within the
specimen
![Page 42: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/42.jpg)
ScatterScatter• Side scatter walls and nearby objects in the path
of the primary beam
![Page 43: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/43.jpg)
ScatterScatter• Back scatter materials located
behind the film
![Page 44: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/44.jpg)
Control of ScatterControl of Scatter
• Collimation• Protection from back scatter• Beam filtration• Blocking• Grids• Increased beam energy
![Page 45: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/45.jpg)
Sensitivity
IQI sensitivity Defect sensitivity
![Page 46: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/46.jpg)
IQI sensitivityIQI sensitivity
The image on a radiograph which is used to determine the quality level
Defect sensitivity Defect sensitivity
Ability to assist the sensitivity and locate a defect on a radiograph(Depend on the defect orientation)(Depend on the defect orientation)
![Page 47: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/47.jpg)
Image Quality IndicatorImage Quality Indicator
![Page 48: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/48.jpg)
Image Quality Indicators
IQI’s / Penetrameters are used to measure radiographic sensitivity and the quality of the radiographic technique used. They are not used to measure the size of defects detected
Standards for IQI’s include:BS 3971BS EN 462DIN 62
![Page 49: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/49.jpg)
7FE12
Step / Hole type IQI Wire type IQI
Image Quality Indicators
![Page 50: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/50.jpg)
Image Quality Indicators Image Quality Indicators
![Page 51: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/51.jpg)
1 Hole visible = 4T
2 Holes visible = T
3 Holes visible = 2T
IQI Sensitivity
Minimum Penetrmeter Thickness 0.5mm(2% of the weld thickness)Minimum Diameter for 1T Hole 0.5mmMinimum Diameter for 2T Hole 1.0mmMinimum Diameter for 4T Hole 2.00mm
Penetrmeter Design
4T diaT dia
2T dia
17 12mm
38mm T
ASME Image Quality Indicators ASME Image Quality Indicators
![Page 52: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/52.jpg)
Wire Type IQI
Step/Hole Type IQI
Image Quality Indicators
![Page 53: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/53.jpg)
Placement of IQIPlacement of IQI
• IQI must be placed on the maximum thickness of
weld
• Thinnest required step or wire must be placed at the
extreme edge of section under test
• IQI must be placed at the source side
• In case of access problem , IQI has to placed on the film side of the object, letter ‘FS’ should be placed beside the IQI.
• IQI material chosen should have similar radiation absorption/transmission properties to the test specimen
![Page 54: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/54.jpg)
Ideally IQI should be placed on the source side
IQI sensitivity is calculated from the following formula
Sensitivity % = Thickness of thinnest step/wire visible x 100Object Thickness
IQI Sensitivity
![Page 55: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/55.jpg)
Image Quality IndicatorsThickness BS 3971 DIN 54 109 BS EN 462-2 BS EN 462-1
(mm) STEP WIRE WIRE (DIN 62) STEP/HOLE WIRE1-6 7-12 13-18 4-10 9-15 15-21 1-7 6-12 10-16 H 1 H 5 H 9 H 13 W 1 W 6 W 10 W 13
0.050 70.063 7 60.08 6 50.10 5 7 7 40.125 6 4 6 6 6 30.150.16 5 3 5 5 5 20.20 4 2 7 4 4 4 10.25 3 1 6 7 3 3 7 30.300.32 2 5 6 2 2 6 6 20.350.40 1 4 5 1 1 5 5 10.50 6 3 4 4 40.600.63 5 2 3 3 30.750.80 4 1 7 7 2 2 6 7 20.901.00 3 6 6 1 1 5 6 11.201.25 2 5 5 4 51.50 1 41.60 4 3 41.80 32.00 6 2 3 2 6 32.50 5 1 2 1 5 23.003.20 4 1 4 14.00 3 35.00 2 26.30 1 1
![Page 56: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/56.jpg)
IQI SensitivityA Radiograph of a 16mm thick butt weld is viewed under the correct conditions, 5 wires visible on the radiograph IQI pack 6-12 Din 62, what is the IQI sensitivity?
Sensitivity = Thickness of thinnest wire visible X 100 Total weld thickness
Sensitivity = 0.4 X 100 16
Sensitivity = 2.5 %
![Page 57: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/57.jpg)
IQI SensitivityUsing the same IQI pack 6-12 Din 62, How many IQI wires must be visible to give an IQI sensitivity of 2 %
Thickness of thinnest wire visible = Sensitivity X Total weld thickness 100
= 2.0 X 16 100
= 0.32 6 wires visible
![Page 58: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/58.jpg)
Radiographic Definition
Definition measured by the use of a type III I.Q.I.Alternative terms given
•Duplex type
•Cerl type B
•EN 462 part 5 EN 4
6 2-5
![Page 59: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/59.jpg)
Exposure ControlExposure Control
![Page 60: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/60.jpg)
Exposure control• For FFD/SFD change
T1 D1 2
T2 D2 2=
T1 = New exposure time
T2 = Original exposure time
D1 = New FFD
D2 = Original FFD
![Page 61: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/61.jpg)
Exposure control• For FFD/SFD change
Example:
Calculate new exposure time for FFD = 600 mm
Original exposure at 500mm was 10 min
T1 =(600) 2
(500) 2 X 10 = 14.4 mins
![Page 62: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/62.jpg)
Exposure calculation
E = M X Time (mA.min)
E = exposure (mA.min)M = Tube current (mA)T = Exposure time (min)
![Page 63: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/63.jpg)
Exposure calculationIn one radiographic operation, an-x-ray machine is set at 5mA and the radiographic film is exposed for a period of 15 minutes. What is the total exposure received by the film?Solution:
Given,
Tube current (M) = 5mA
Exposure time (t) = 15 minutes
Exposure ( E) = M X T
= 5 X 15
= 75 mA.min
![Page 64: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/64.jpg)
Radiographic TechniquesRadiographic Techniques
![Page 65: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/65.jpg)
Radiographic Techniques
Single Wall Single Image (SWSI)- film inside, source outside
Single Wall Single Image (SWSI) panoramic- film outside, source inside (internal exposure)
Double Wall Single Image (DWSI)- film outside, source outside (external exposure)
Double Wall Double Image (DWDI)- film outside, source outside (elliptical exposure)
![Page 66: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/66.jpg)
Single wall single image SWSI
IQI’s should be placed source side
Film
Film
![Page 67: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/67.jpg)
Single wall single image SWSI panoramic
• IQI’s are placed on the film side
• Source inside film outside (single exposure)
Film
![Page 68: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/68.jpg)
Film
Double wall single image DWSI
• IQI’s are placed on the film side• Source outside film outside (multiple exposure)• This technique is intended for pipe diameters
over 100mm
![Page 69: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/69.jpg)
Double wall single image DWSI
Radiograph
Identification
ID MR11
• Unique identificationEN W10
• IQI placingA B• Pitch marks
indicating readable film length
![Page 70: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/70.jpg)
Film
Double wall double image DWDI elliptical exposure
• IQI’s are placed on the source side• Source outside film outside (multiple exposure)• A minimum of two exposures• This technique is intended for pipe diameters
less than 100mm
![Page 71: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/71.jpg)
Double wall double image DWDI
Shot A Radiograph
Identification
ID MR12
• Unique identification EN W10
• IQI placing
1 2• Pitch marks indicating readable film length
4 3
![Page 72: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/72.jpg)
Double wall double image (DWDI) perpendicular exposure
Film
• IQI’s are placed on the source side• Source outside film outside (multiple exposure)• A minimum of three exposures• Source side weld is superimposed on film side weld• This technique is intended for small pipe diameters
![Page 73: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/73.jpg)
Density requirement 2.0 to 3.0Density unacceptable
Density1.2
Density1.2
Density3.0
Density3.0
Sandwich Technique
![Page 74: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/74.jpg)
LEAD SCREENS
FILM AFILM B
FILM A: Fast film - Thicker sectionFILM B: Slow film - Thinner section
FILM AFILM B
Density2.0
Density2.0
Density3.0
Density3.0
Sandwich Technique
Density 2.0 to 3.0 acceptable
![Page 75: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/75.jpg)
Interpretation conditionsInterpretation conditions
![Page 76: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/76.jpg)
Viewing conditionsViewing conditions
• Darkened room
• Clean viewer
• Minimum adequate illumination from the viewer is 3000cd/m2
• Eyesight must be adjusted to the darkened conditions
• Comfortable viewing position and environment
• Avoid fatigue
![Page 77: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/77.jpg)
Radiographic QualityRadiographic Quality Density - relates to the degree of darkness
Contrast - relates to the degree of difference in density between adjacent areas on a radiograph
Definition - relates to the degree of sharpness
Sensitivity - relates to the overall quality of the radiograph
![Page 78: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/78.jpg)
Factors Influencing Sensitivity
Sensitivity
Contrast Definition
![Page 79: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/79.jpg)
ContrastContrastSubject contrastSubject contrast :- Contrast arising from variation in
opacity within an irradiated area
Radiographic contrastRadiographic contrast :- The density difference on a radiography
between two areas- usually subject and
the background (overall)
Film contrastFilm contrast :- The slope of characteristic curve of the film at
specified density. ( Type of film being used, fine
grain or large grain)
![Page 80: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/80.jpg)
Factors Influencing Sensitivity
Density
Sensitivity
Contrast Definition
Film Energy Subject contrast
Processing
![Page 81: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/81.jpg)
Factors Influencing SensitivitySensitivity
Definition
Density Film Energy Object contrast
Processing
Time Temperature Type Strength Agitation
Contrast
![Page 82: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/82.jpg)
Radiographic Contrast
Film Contrast Subject Contrast
Film type Density Processing Scatter Wavelength Screens
![Page 83: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/83.jpg)
Radiographic Contrast
Poor contrast
Poor contrast
High contrast
![Page 84: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/84.jpg)
Radiographic DensityRadiographic Density
Density = Log10
Incident lightTransmitted
light
* Greater contrast is achieved at higher density
![Page 85: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/85.jpg)
Radiographic DensityRadiographic Density
Lack of Density
Under exposure
Developer temp too low
Exhausted developer
Developer too weak
Excessive Density
Over exposure
Excessive development
Developer temp too high
Too strong a solution
![Page 86: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/86.jpg)
Measuring Radiographic DensityMeasuring Radiographic Density Density is measured by a densitometer A densitometer should be calibrated
using a density strip
4.0 3.5 3.0 2.5 2.0 1.5 1.0
![Page 87: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/87.jpg)
Factors Influencing SensitivitySensitivity
Definition
Film speed
Screens Energy Vibration ProcessingGeometry
Contrast
![Page 88: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/88.jpg)
Factors Influencing SensitivitySensitivity
Contrast Definition
Film speed
Screens Energy Vibration Processing
Time Temperature Type Strength Agitation
Geometry
![Page 89: DocumentRi](https://reader031.vdocuments.mx/reader031/viewer/2022030317/577ccef81a28ab9e788e8b09/html5/thumbnails/89.jpg)
What is a good radiograph? A good radiograph satisfies A good radiograph satisfies the inspection requirementthe inspection requirement