Radiographic Testing Flashcards
How does radiography work?
Penetrating radiation is directed towards an object. The object absorbs the radiation depending on its density and thickness. The absorption is recorded on film or electronically.
What are the 2 sources of EMR used in radiographic inspection?
1) X-ray
2) Gamma ray
What is the estimated annual and quarterly dose of radiation for atomic workers?
50 mSv/year
30 mSv/quarter
What is a critical variable when using radiography when it comes to flaw orientation?
The orientation of the beam in respect to the defect is very critical so in order to conduct a radiography test the orientation of the defect must be known
The darker parts of the X-ray film absorb ______ radiation than the lighter parts.
Less
What are the three most common uses of radiography?
1) Inspection of assembled parts/internals
2) Corrosion detection
3) Surface and subsurface defect detection
What are the 3 means of protecting yourself from radiation?
1) Time
2) Distance
3) Shielding
What are some devices that can be used to track personnel radiation absorption?
1) Survey meter
2) Pocket dosimeter
3) Radiation badge
4) Radiation alarm
The thinner or less dense the area, the _________ radiation passes through the object causing it to be _________ in color.
More, dark
Denser or thicker regions of a sample absorb _________ radiation and appear __________ in color on the film.
More, light
What are the 2 most common radiation sources?
1) Iridium 192
2) Cobalt 60
What are some factors that affect the quality of a radiography image?
1) Source size
2) Source to film distance
3) Specimen to film distance
4) Orientation of specimen
5) Type of film
6) Screen
What is a penetrameter?
A device used to establish quality of a radiograph
What are the 2 most common types of penetrameters?
1) Plaque-type
2) Wire-type
What is half-value layer?
Half-value layer is a shielding term that describes the amount of material required to reduce the level of radiation to half its original value.
What is a tenth-value layer?
The amount of material required to reduce the radiation to a tenth of its original value
As the density of a material reduces, a ____________ thickness of that shielding material will be required
Larger
What are some common shielding materials?
1) Depleted Uranium
2) Steel
3) Lead
4) Concrete
What are the advantages of radiography?
1) Technique is not limited by material type or density
2) Can inspect assembled components
3) Minimal surface preparation required
4) Sensitive to changes in thickness, corrosion, voids, cracks, and material density changes
5) Can detect surface and subsurface defects
6) Provides a permanent record of the inspection
What are the disadvantages of radiography?
1) Many safety precautions
2) Many hours of technician training prior to use
3) Access to both sides of a sample is required
4) Expensive equipment cost
5) Orientation is critical to defect detection
What is the radiography film material made of?
Silver Bromide
How is radiography different from any other NDT methods?
Radiography can detect planar flaws like corrosion, internal compound, and internal flaw detection.
How can you ensure that the image produced would have a good radiographic definition?
1) The source is as small as possible
2) Keep the source to film distance as large as possible
3) Minimize sample to film distance
