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AMI Glossary
3D Time of Flight

An imaging mode in which the gray scale or color value of the image pixel represents the depth of the feature within the part.

3V™ (Virtual Volumetric View)

An imaging display used in combination with the Zip-SliceTM imaging mode that provides a 3D representation of a sample.


An oscilloscope (external or digital C-SAM®) display in which the signal received by the transducer is shown as a vertical excursion from the horizontal time trace. Ultrasonic echoes detected earlier in time are shown at the beginning of the trace and those occurring later in time are shown farther to the right.

Acoustic Impedance

A material property defined as the product of the density and velocity of ultrasound for a specific material.

AIPD™ (Acoustic Impedance Polarity Detector)

A capability of the C-SAM® that allows for the detection and simultaneous display of positive and negative polarity reflections.

Anisotropic material

A material in which the physical properties (e.g., velocity of sound) are different depending on the direction.

Applications Setup Wizard™

A software function that aids in the setup of a scan by determining imaging parameters such as focus and gate position based on the part composition and construction.


The loss in acoustic energy that occurs between any two points of travel.

Back surface reflection

The signal received from the far boundary or back surface of a test object.


Having a relatively wide frequency content. Used to describe pulses that contain a wide range of frequencies.


An imaging mode that produces a cross-sectional view of a sample while maintaining a fixed focus.

Bulk Scan
An imaging mode in which continuous, or bulk, material is displayed. This mode provides information on a volume of material.

Critical angle
The incident angle of the ultrasound above which a specific mode of refracted ultrasonic wave does not propagate past the interface.

Critical flaw size
The smallest defect that must be detected.

C-SAM®(C-mode Scanning Acoustic Microscope)
An acoustic microscope that operates in both reflection and transmission modes using high frequency ultrasound for the inspection of components and materials.

C-SAM® Interactive
An interactive, multimedia enhanced, training tool built into our software. This tool guides the user in the operation and principles of the instrument.

C-scan (C-mode)
A 2D data representation applied to pulse-echo techniques that yield a plane view of the specimen. Each C-scan image represents information at a pre-selected depth.

A unit for expressing relative strength of a voltage signal. (dB)

Delay line
A material (usually a low attenuation solid) placed in front of a transducer to cause a time delay between the initial pulse and the curved lens portion.

A signal (voltage) indicating reflected acoustic energy.

FACTS2™ (Fast Automated C-mode Tray Scanning System)
An acoustic microscope that takes the C-SAM® technology and automates the process for production screening of parts on JEDEC trays.

FDI™ (Frequency Domain Imaging)
An imaging mode that uses the frequency component of a reflection.

Focal zone (also depth of field)
The distance before and after the focal plane in which the intensity differs by a specified amount (usually 6dB) from the focal intensity.

Focused beam
A sound beam that converges to a cross section smaller than the diameter of the transducer.

The number of oscillations per second (unit in Hz).

Front interface echo (FIE)
The signal received from the first boundary (front surface) of a test object.

An electronic “window” for monitoring signals in a selected segment on an A-scan display.

Interface Scan
An imaging mode that inspects the bond between materials (e.g., mold compound to die surface or wafer to wafer). This mode falls under the broader classification of a C-scan.

Isotropic Material
A material in which the physical properties (e.g., velocity of sound) are the same in all directions.

Main bang
The pulse applied to the piezoelectric element to generate ultrasound.

Multiple reflections
Repetitive echoes from an interface.

An imaging mode displaying multiple levels within the same image (e.g., die surface and lead frame).

Pixel intensity level
The numerical value of a pixel based on echo polarity and amplitude.

A transient signal having a short time width and possessing ultrasound energy over a broad frequency range.

Q-BAM™ (Quantitative B-scan Analysis Mode)
An imaging mode that produces a cross-sectional view of a sample while maintaining the correct focus throughout the entire thickness of the sample.

Deflection from a straight path undergone by an energy wave in passing obliquely from one medium into another in which the velocity is different.

An imaging mode that evaluates cylinders. This mode incorporates a rotational mechanism that nondestructively “unwraps” the cylinder. Other imaging modes, such as the Interface Scan, can be used in combination with this mode.

SLAM (Scanning Laser Acoustic Microscope)
A real-time acoustic microscope that operates in transmission mode.

The amplitude distribution of frequencies in a pulse.

An inspection mode that evaluates spheres such as bearing balls. This mode incorporates a multi-axis rotational mechanism that nondestructively inspects the sphere surface and/or bulk material. This mode operates by use of an alarm to indicate the presence of a flaw rather than producing an image of the sphere.

STaR™ (Simultaneous Transmission and Reflection)
An imaging mode with the ability to generate a transmission mode image at the same time as the reflection mode image.

Surface Scan
An imaging mode in which the surface of a sample is displayed. Oftentimes, additional information will be revealed due to the unique interaction of ultrasound and solids.

An imaging mode in which the ultrasonic energy passes through the entire thickness of the sample (i.e., transmission mode).

Time of Flight (TOF)
The time taken for an acoustic pulse to travel between two points. In the C-SAM®, it usually signifies the time taken by a pulse to travel from the lens to the sample and back. This quantity is used to estimate the distance of the lens from the sample front surface.

Tray Scan
A function within the C-SAM® that allows for automated inspection of parts on JEDEC trays.

An imaging mode in which multiple locations (such as various components on a PCB) are defined for repeat imaging on multiple boards. This mode accommodates multiple parts types per board.

Ultrasonic Spectroscopy
Analysis of the frequency content of an acoustic wave generally performed using a Fast Fourier Transform.

VHR™ (Very High Resolution)
A capability of the C-SAM® and FACTS2™ that allows for the collection of more pixels per image (i.e., higher pixel density imaging).

VRM™ (Virtual Rescanning Mode)
An imaging mode that saves the A-scan at every pixel location in an image. With the saved data virtually infinite imaging is possible without the need for the physical part.

Waterfall™ transducer
A method of fluid coupling that employs a column of water between the part and the ultrasonic transducer thereby limiting the water exposure a part receives.


An imaging mode that collects multiple planes of information, all typically in focus, for the creation of a 3D image of a part.

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