Chapter 9 key terms Flashcards
narrows to a focal point and then diverges once again
shape of a sound beam
focus
near zone (Fresnal zone)
focal length (near zone length)
far zone (Fraunhofer zone)
focal zone
anatomy of a sound beam
diameter of the beam as it travels throught the phases
beam width
location where the beam is the narrowest point
focus
focal zone
distance from the transducer to the focus
focal depth
region of the beam from the transducer to the focal point
near zone
fresnal Zone
region of the beam from the focal point and extends
far zone
Fraunhofer zone
expanding of the beam as it travels into the far zone
divergence
larger diameter crystals create__________of the beam
Higher Freq
less divergence
smaller diameter crystals create ___________of the beam
lower Freq
more divergence
transducer diameter
freq of sound
factors that affect focal depth
produced by very small sources
diverge in the shape of a V
V shaped wave when the source is about the size of the sounds wavelength
spherical waves
large active element may be thought of as millions of tiny distinct sources
each of these tiny particles is a __________and creates a _________wavelet with a V shape
Huygen’s Principle
Huygen’s Wavelet
ability to distinctly identify two structures that are very close together
side by side perpendicular to the beam
lateral resolution
ability to distinctly identify two structures that are very close together
fron to back parallel to the beam
axial resolution
angular
transverse
azimuthal resolution
lateral resolution synonyms
axial gives distance between object in depth
Lateral gives distance side to side
axial vs lateral
concentration of asound energy into a narrow beam and thus improving lateral resolution
focusing
external
internal
phased array
methods of focusing
beam diameter in near field and focal zone narrows
focus is moved closer to the transducer
beam diameter beyond the focal zone widens
size of the focal zone is reduced
effects of focusing
