penetra meter

8/12/2019 Penetra Meter

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PENETRAMETER


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It is a device that is used inradiographictesting to

evaluate the quality of

radiographic images.


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Radiography It is type Non-destructive Testing.

Technique is suitable for the detection

of internal defects.

Rays generated are penetrating

radiation which is differentially

absorbed by the material through

which it passes.


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Radiography

In proportion to the intensity of theradiation reaching the film, and

therefore forming a latent image.

Image developed in a similar way to

normal photographic film.

Usually X-rays or Gamma rays are

used.


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Penetrameter

Image quality indicators (IQIs).

Indicates change in material thicknesswill be detectable in the radiograph.

They come in a wide range of shapes,size

and configurations.

Made from the same type of material as

the specimen being tested.


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Image sharpness

Image contrast Good

IQI

Image Noise

The quality of a radiographic image

can be assessed in terms of three

factors:


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There are four broad patterns of

IQI

1. Wire type

2. Step/hole type

3. Hole-in-plaque type

4. Duplex wire type


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Hole-Type IQIs This consists of a small rectangular

piece of metal with holes.

Notching system is incorporated for if

IQI is the correct material type.

Image quality levels are typically

designated using a two part

expression such as 2-2T.


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Hole-TypeIQIs


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Hole-Type

IQIs


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Wire type It consists of a number of wires of various

diameters are held parallel to one another

in a low density plastic mount.

A typical wire IQI will contain six or sevenwires arranged in order of increasing

diameter.

Diameter of the thinnest discernible wire

is taken as a measure of IQI (wire)

sensitivity


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Wire sizes that correspond to

various hole-type quality levelscan be found


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IQI (wire) sensitivity


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Placement of IQIs


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Placement of IQIs

Place the IQI on the side of thespecimen facing the radiation source.

Most tables of IQI values assume thatthe IQI is in this position.

IQI image is completely insensitive togeometric un-sharpness factors such

as source-to-film distance.


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Conclusions

None of the existing designs of IQIs issufficiently sensitive to image

sharpness parameters .

wire can be drawn suitable for use onthin specimens, are available .

For non-metals, the step/hole type is

the most convenient . used to measure just the quality of the

radiographic image.


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penetra meter

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