Kreamkau Chapter 3 - Key Terms Flashcards
Aperature
size of a transducer element (for a single-element transducer) or group of elements.
Apodization
nonuniform driving of elements in an array to reduce grating lobes
Array
A transducer assembly containing serval piezoelectric elements
Axial
In the direction of the transdcuer axis
Axial resoltion
the minimum reflector separation along the sound path that is required to produce sseparate echoes
Beam
region containing continuous sound wave
Composite
Combo of a piezoelectric ceramic and nonpiezoelectric polymer
Convex Array
curved linear array
Crystal
element
Curie point
temp at which an element material loses its piezoelectric property
Damping
material attached to the rear race of a transducer element to reduce PD
Detail resolution
the ability to image fine detail and to distingush closely space reflectors
Disk
a thin, falt, circular object
Dynamic aperature
aperture that increases with increasing focal
Dynamic focusing
continuously variable reception focusing that follows increasing depth of the trasmited pulse as it travels
Element
the piezoelectric component of a transducer assembly
Elevational resolution
the detail resolution in the direction perpendicular in the scan plane.
Far zone
the region of a sound beam in which the beam diameter increases as the distance form the transducer increases.
Focal length
distance from a focused transducer to the center of a focal region or to the location of the spatial peak intensity
Focal region
Region of minimum beam diameter and area
Focal zone
length of the focal region
Focus
the concentration of the sound beam into a smaller beam area than would exist otherwise
Gating lobes
additional weaker beams of sound traveling out in directions different from the primary beam as a result of multi-element structure of transducer arrays.
Lateral
perpendicular to the direction of sound travel
Lateral resolution
minimum reflector separation perpendicular to the sound path that is required to produce separate echoes
Lead zirconate titanate
a ceramic piezoelectric material
Lens
a curved material that focuses a sound or light beam
Linear
adjectival form of line
Linear array
array made of rectangular elements arranged in a straight line
Linear phased array
linear array operated by applying voltage pulses to all elements
Linear sequenced array
linear array operated by applying voltage pulses to groups of elements
Matching layer
material attached to the front face of transducer element to reduce the reflection at the transducer surface.
Natural focus
the narrowing of a sound beam that occurs with an unfocused flat transducer element.
Near zone
region of sound beam in which the beam diameter decreases as the distance from the transducer increases
Operating frequencies
preferred frequency of operation of a transducer
Phased array
an array that steers and focuses the beam electronically
Phased linear array
linear sequenced array with phased focusing added
Piezoelectricity
conversion of pressure to electric voltage
Probe
transducer assembly
Resolution
the ability to distinguish echoes in terms of space, time, or strength
Resonance frequency
operating requency
Scanhead
transducer assembly
Sector
a geometirc figure bounded by two radii and the arc of the circle included between them
Sensitivity
ability of an imaging system to detect weak echoes
Side lobes
weaker beams of sound traveling out from a single element in direction different from those of the primary beam
Sound beams
the region of a medium that contains virtually all of the sound produced by a transducer
Source
an emitter of ultrasound - transducer
Transducer
a device that converts energy from one form to another
Transducer assembly
transducer elements with damping and matching materials in case
Ultrasound transducer
a device that converts electric energy to ultrasound energy, and vice versa
Vector array
linear sequenced array that emits pulses from different starting points and in different directions
