Chapter 9 Sound Beams Flashcards
Focus or Focal Point
the location where the beam is the narrowest
Near Zone
Also called near field or fresnel zone
- region from transducer to the focus.
- This is where sound beam gradually narrows or converges
where is the focus located?
at the end of the near zone
Focal Length
also called focal depth or near zone length
- it is the distance from the transducer to the focus
focus
can be described as the focal point, the end of the near zone, the beginning of the far zone or the middle of the focal zone
Far zone
also called far field or fraunhofer zone
- the region that starts at the focus and extends deeper.
- the beam diverges here, or spreads out
Focal Zone
region where the beam is relatively narrow.
- Half is located in the near field and half in the far field
At the transducer what is the beam diameter?
equal to the transducer diameter
At the focus what is the beam diameter?
1/2 transducer diameter
at 2 near zone lengths what is the diameter?
equal to the transducer diameter
deeper than 2 near zone lengths what is the beam diameter?
wider than the transducer diameter
what is another name for focal depth
focal length or near zone length
what 2 things determine focal depth:
transducer diameter and frequency of sound
what is the relationship between transducer diameter and focal depth?
direct
Larger diameter beams create
beams with deeper focus
