Physics Test 4
Terms
undefined, object
copy deck
- In a transducer, electrical voltage coverted a acoustic sound is called ______
- transmission
- In a transducer, acoustic to electrical is called _____
- reception
- define transducer.
- devie that converts one form of energy into another
- What are the ranges for diagnostic imaging.
- 2-15 MHz
- Define axial resolution.
- ability to see 2 structures separately when they are parallel to the sound beams main axis
- helps reduce impedances mismatch between probe/skin
- matching layer
- When discussing the thickness of the element. A thicker PZT has a _____frequency.
- higher
- A continous pulse has a ____matching layer
- thin
- What is the principle in which we operate US.
- pizoelectric or ferroelectric
- What is the purpose for gel.
-
coupling agent
PZT>matching layer>gel>skin - When there is reflection, the the matching layer is _____-
- decreased
- What two things determine frequency for a pulse?
-
for pulsed, it is speed and thickness.
Higher speed means _____frequency. ( Higher)
Thicker PZT means _____frequency. (Lower) -
Formula for quality factor:
- main frequency/bandwidth
- wide bandwidths _____q factor
- low
- What is the pneumonic for axial resolution?
-
Longitudnal
Axial
Range
Radial
Depth - What is the best axial resolution?
- __high__frequency, __low___cycles
- What is the most common PZT material?
- lead zicarnate titanate
- PZT stands for
- piezoelectric
- PRP and PRF are ____
- inversely
- When discussing depth, when depth is decreased PRP is ____
- shallow
-
WHat does damping material do to bandwidth?
to Q factor? -
causes wide bandwith
low Q factor - range of frequencies from highest to lowest in a pulse.
- bandwith
- which part of the transducer reduces ringing?
- backing
- 1/4 wavelenth thick
- matching layer
- active element is _____wavelength thick
- 1/2
- what are other names for transducer.
-
ceramic, active element, crystal
- what is the formula for Q factor
- main fre
-
exposed to a strong magnetic field
heated to a substantial temp - polarized
- depolarized
- if heated above Curie
- the temp for losing polarization is
- Curie point
- Does damping affect pulse lenth?
- no
-
Relationship beween PD and bandwith
Bandwidth
Thinner_____frequency
Frequency and increased frequency and PRF not related - decreases