Chapter 9 key terms

Question 1

narrows to a focal point and then diverges once again

Answer 1

shape of a sound beam

Question 2

focus

near zone (Fresnal zone)

focal length (near zone length)

far zone (Fraunhofer zone)

focal zone

Answer 2

anatomy of a sound beam

Question 3

diameter of the beam as it travels throught the phases

Answer 3

beam width

Question 4

location where the beam is the narrowest point

Answer 4

focus

focal zone

Question 5

distance from the transducer to the focus

Answer 5

focal depth

Question 6

region of the beam from the transducer to the focal point

Answer 6

near zone

fresnal Zone

Question 7

region of the beam from the focal point and extends

Answer 7

far zone

Fraunhofer zone

Question 8

expanding of the beam as it travels into the far zone

Answer 8

divergence

Question 9

larger diameter crystals create__________of the beam

Higher Freq

Answer 9

less divergence

Question 10

smaller diameter crystals create ___________of the beam

lower Freq

Answer 10

more divergence

Question 11

transducer diameter

freq of sound

Answer 11

factors that affect focal depth

Question 12

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

Answer 12

spherical waves

Question 13

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

Answer 13

Huygen’s Principle

Huygen’s Wavelet

Question 14

ability to distinctly identify two structures that are very close together

side by side perpendicular to the beam

Answer 14

lateral resolution

Question 15

ability to distinctly identify two structures that are very close together

fron to back parallel to the beam

Answer 15

axial resolution

Question 16

angular

transverse

azimuthal resolution

Answer 16

lateral resolution synonyms

Question 17

axial gives distance between object in depth

Lateral gives distance side to side

Answer 17

axial vs lateral

Question 18

concentration of asound energy into a narrow beam and thus improving lateral resolution

Answer 18

focusing

Question 19

external

internal

phased array

Answer 19

methods of focusing

Question 20

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

Answer 20

effects of focusing