Radiography Testing

Question 1

Name 5 advantages of RT

Answer 1

a. Can be used with most materials
b. Provides a permanent visual image
c. Reveals the internal nature of the material
d. Discloses the fabrication errors
e. Reveals structure discontinuities

Question 2

Name 5 disadvantages of RT

Answer 2

a. Impractical to use on specimen of complex geometry
b. Specimen must be two side accessible
c. Safety considerations imposed by x and gamma rays should be considered
d. Relatively expensive means of non destructive testing.
e. Laminar type discontinuities often undetected

Question 3

What is a latent image?

Answer 3

A hidden image existing on the film but only is visible after developing as a shadow picture.

Question 4

What is meant by an opaque material?

Answer 4

It is a solid object where light can not penetrate through.

Question 5

What is meant by the term absorption?

Answer 5

The ability of a material to take up all or most of the rays passing through it.
Lead has very good absorption.

Question 6

Describe inherent unsharpness:

Answer 6

Is caused by free electrons as it is passing through the film

Question 7

How does a grain size in a film affect the quality?

Answer 7

It does affect the definition and contrast.
* Fine grain film – good contrast and definition
* Coarse grain – not so good contrast and definition.

Question 8

List 4 isotopes and their half lives:

Answer 8

1. radium 226 1620 years
2. cesium 137 30 years
3. cobalt 60 5.3 years
4. theluim 170 130 days
5. iridium 192 75 days

Question 9

How is energy formed of An isotope and x-ray?

Answer 9

An isotope – artificial isotopes are created by bombarding an element with an excess of neutrons in neuclear reactor factor energy is determined by the type of source.

An x-ray – energy is determined by the voltage applied to the x-ray tube.