Selected Topics Flashcards
What describes the differences between density of a radiograph?
Contrast
Would a long or short wavelength produce a sharper contrast radiograph
long
___ occurs when incident x-ray photon is deflected from its original path by an interaction with an electron
compton scattering
___ refers to the scattering of electrons and reduces contrast and definition
scatter
__ refers to scatter radiation that bounces off an object behind the film then back into the film
backscatter radiation
__ describes the fraction of radiation absorbed or scattered per unit thickness of the absorber
linear attenuation coefficient
What is the partially shaded outer region of a shadow cast by an opaque object?
Penumbra
This type of X-ray produces radiation of composed of a continuous spectrum of energies over some range.
Bremmstrahlung
As wavelengths become shorter/longer, penetrating power increases
shorter
What 2 factors determine film contrast?
type of film used, process used to develop film
Who discovered radioactive materials?
Henri Becquerel
The thickness of a material where 50% of incident energy has been attenuated is known as __
half value layer
Who discovered the x-ray?
Wilheim Roentgen
__ and __ is a form of particle radiation and electomagnetic radiation.
x-rays and gamma rays
What happens to penetrating power as radiaion energy increases?
increases
A specific radioactive source always produces gamma rays at the same A) Intensity, B) Activity, C) Energy level
C) Energy level
Through what two processes is radiation produced in x-ray generators?
Bremsstrahlung, K-Shell
__ indicates the amount of attenuation per centimeter.
Linear attenuation coefficient
__ is the rate an radioactive isotope becomes stable
Decay Rate
What two types of interactions account for the majority of attenuation in industrial radiography?
commpton scattering and photoelectric absorption
What is the purpose of using lead foil sheets in radiography?
to increase film density because incident radiation liberates electrons to help expose the film
Higher energy radiation has more A) Speed, B) Incident Energy, C)Penetrating Power
C) Penetrating Power
What causes undercut?
scattering within the film
What is undercut?
loss of resolution at a sharp thickness transition area
Why are radiation beam filters used?
to remove low energy radiation to increase definition
Where are Image Quality Indicators placed?
on front side of test component, in area of similar thickness to primary area of interest
What are the four types of radiation-matter interactions that contribute to total attenuation?
compton scattering, pair production, photoelectric absorption, rayleigh scattering
__ x-ray technique allows test component to be viewed in various cross-sectional slices
computed tomography
Why is target of x-ray tube often made of tungsten?
It’s high atomic mass results in more x-rays generated due to atomic particle interactions.
List 3 strengths of radiographic inspection.
not limited to material type, can be used to inspect assembled components, can detect surface and subsurface features
What causes attenuation of radiation (2)?
absorbtion, scattering
What type of defects are radiography best suited?
volumetric defects such as porosity
When should radiography be used for crack detection?
the orientation of the crack is known
