test review Chapter 8 & 9

Question 1

thinner PZT crystal

PZT with higher speeds

Answer 1

high freq pulsed trandsucers

Question 2

thicker PZT crystals

PZT with lower speeds

Answer 2

lower freq pulsed transducers

Question 3

pulses with short duratoin and length

use backing material

reduced sensitivity

wide bandwidth (broadband)

lower Q-factor

improved axial resolution

Answer 3

imaging tranducer characteristics

Question 4

depolarizes

loses the piezoelectric properties

Answer 4

PZt at the curie point

Question 5

piezoelectric effect

Answer 5

when PZT changes shape

Question 6

lead zirconate titanate

ceramic

active element

crystal

Answer 6

names for PZT

Question 7

backing or damping material

Answer 7

reduces ringing in the transducer

Question 8

main frequency/bandwidth=

Answer 8

Q Factor

Question 9

speed of

4-6 mm/µs

Answer 9

propagation speed of PZT material

Question 10

speed is 4 times greater than in soft tissue

Answer 10

prop speed of PZT

Question 11

thinner PZT crystal

Answer 11

higher freq output

Question 12

thicker PZT crystal

Answer 12

lower freq output

Question 13

optimizes pulses created by imaging transducers

Answer 13

backing material improvements

Question 14

greater than the matching layer

20 x that of the skin

Answer 14

impedence of the active element

Question 15

thin barrieir of cork isolates or uncouples the internal components of the transducer from the case

Answer 15

accoustic insulator

Question 16

increases the efficiency of sound energy transfer between the active element and the body

Answer 16

matching layer

Question 17

larger diameter transducer

higher freq

Answer 17

deeper focus

Question 18

smaller diameter transducer

lower freq

Answer 18

shallow focus

Question 19

lower freq transducer

Answer 19

shorter near zone

Question 20

higher freq transducer

Answer 20

longer near zone

Question 21

diameter^2 x freq/6 =

Answer 21

focal depth

Question 22

larger diameter

higher freq

Answer 22

less divergence

Question 23

smaller diameter

lower freq

Answer 23

more divergence

Question 24

how is freq of sound determined?

Answer 24

thickness of pzt

Question 25

how is focal depth determined

Answer 25

transducer diameter

freq of sound

Question 26

how is divergence determined

Answer 26

transducer diameter

freq of sound

Question 27

improved lateral resolution

Answer 27

larger diameter transducer

higher freq

Question 28

depth where sound beam is half the diameter of the beam at the transducer

Answer 28

focal depth

Question 29

frequency does not change, diamter of the transducer increase, what happens to the wavelength?

Answer 29

no change in wavelength

Question 30

frequency does not change, diamter of the transducer increase, what happens to the near zone length?

Answer 30

near zone length increases

Question 31

what determines the spread of the beam in the far field?

Answer 31

transducer diamter

freq of sound

Question 32

less divergence

Answer 32

larger diamter

higher Freq

Question 33

more divergence

Answer 33

smaller diameter

lower freq

Question 34

spherical waves

defracction patterns

Huygens wavelets

Answer 34

created by small pieces of PZT

V shaped

Question 35

Fresnal zone

Answer 35

near zone

Question 36

Fraunhofer zone

Answer 36

far zone

Question 37

sound beam

1

Answer 37

near zone

Fresnal zone

Question 38

sound beam

2

Answer 38

far zone

Fraunhofer zone

Question 39

sound beam

3

Answer 39

focal zone

Question 40

sound beam

4

Answer 40

focus