Software control of beam angle, focal distance, and spot size
Multiple-angle inspection with a single, small, electronically controlled, multielement probe
Greater flexibility for the inspection of complex geometry
High-speed scans with no moving parts

Phased-array technology allows the generation of an ultrasonic beam with the possibility of setting the beam parameters such as angle, focal distance, and focal point size through software; furthermore, this beam can be multiplexed over a large array. These capabilities open a series of new possibilities; for instance, it is possible to quickly vary the angle of the beam to scan a part without moving the probe itself; phased arrays also allow the replacement of multiple probes and even mechanical components. Inspecting a part with a variable-angle beam also ensures detection regardless of the defect orientation while optimizing signal-to-noise ratio.

A phased-array probe is typically a one- or two-dimensional array of small transducer elements. A few different probe types are illustrated here: rho-theta, circular, 2D matrix, and linear.

Software Control of Beam Angle, Focal Distance, and Focal Spot Size.
To generate a beam, the various probe elements are pulsed at slightly different times. By precisely controlling the delays between the probe elements, beams of various angles, focal distances, and focal spot sizes can be produced. The echo from the desired focal point hits the various transducer elements with a computable time shift. The signals received at each transducer element are time-shifted before being summed up together. The resulting sum is an A-scan that emphasizes the response from the desired focal point and attenuates various other echoes from other points in the material.

Multiple-Angle Inspection with a Single, Small, Electronically Controlled, Multielement Probe
A conventional UT inspection would require a number of different transducers. A single phased-array probe can be made to sequentially produce the various angles and focal points required by the application.

Advanced Options
Dynamic Depth Focusing
Another outstanding feature of R/D Tech's FOCUS phased-array system is the ability to dynamically focus the beam within a part, at the reception.
The image on the left shows the inspection of a standard calibration block with a normal transducer with a fixed focus set at around half depth. Compare this with the inspection of the same block but with dynamic focusing (right). Dynamic focusing allows inspections of thick components with a single probe, with flaws in perfect focus regardless of the depth.

System Configuration

FOCUS May Be Used with Any UT System
The FOCUS system may be used as the front end to any existing ultrasonic system. Once the probe's firing and reception delays (focal laws) are programmed into FOCUS, a simple trigger to the system produces an amplified analog A-scan, which is fed directly into the input of a conventional UT system.
When using FOCUS as the front end with a non-R/D Tech UT system, phased-array parameters must be entered from a standard PC (laptop or tabletop) or any other computer equipped with either Ethernet® or a serial link.
FOCUS Is Expandable
FOCUS may be delivered in versions ranging from 8 to 128 channels. Expansion to a greater number of channels requires the simple installation of plug-in boards. Also note that multiple FOCUS systems can be used in parallel to increase the effective number of active elements.

System Specifications

General
System bandwidth (-3dB)	650 kHz-20 MHz
Maximum pulsing rate	20 kHz, with or without change of the focal laws
Inspection modes	Pulse echo or transmit/receive (dynamically selectable). Note that twice the quoted number of channels are available in transmit/receive mode.
Multiple probe capability	The system supports up to 4 probes of 32 elements in pulse-echo configuration or any combination of probes up to 128 elements.
Dynamic range	56 dB/channel
Computer interface	Both RS232 and Ethernet standard.
	Windows NT®-based software available for setup from computer. Custom interfaces may be designed using standard remote procedure call (RPC) functions or dynamic link libraries (DLL).
Focal law storage	Up to 1024 different focal laws can be stored for high-speed multiplexing. Independent focal laws may be used for transmission and reception.
Power requirements	85-265 VAC, 47-63 Hz
Temperature range	0°C-50°C

Pulser/Receiver
Number of pulsers	Configurations available with 8,16, 64, or 128 pulsers
Pulser delays	Adjustable from 0 µs to 25 µs in 2-ns increments
Output impedance	6 Ω
Pulse output	Amplitude adjustable from 50 V to 200 V; pulse width adjustable from 20 ns to 500 ns; fall time < 6 ns
Pulse type	Negative square pulse
Number of receivers	Configurations available with 8, 16, or 32 receivers (more in custom configurations)
Receiver delays	Adjustable from 0 µs to 25 µs in 2-ns increments
Receiver DAC curves	Up to 30 dB/µs on each element slope before summing
Receiver gain range	0-80 dB. Independent gain for each receiver and focal law.
Maximum input signal	+10 dBm (2 Vpp) for each element
Input filters	4 user-selectable filter ranges: none, 500 kHz-5 MHz, 2 MHz-10 MHz, 5 MHz-15 MHz
Input impedance	50 Ω
RF output	+10 dBm in 50 Ω

Available Configurations
FOCUS may be tailored for specific applications. The various configurations are identified with a two-number suffix as follows:

The 1st number is the maximum number of simultaneously active drivers (8, 16, or 32 drivers).
The 2nd number is the total number of available connections for transducer elements (8, 16, 32, 64, or 128 elements).
Example: A FOCUS 32:64 connects to up to 64 elements out of which up to 32 may be active at any time.

Benchtop version
48 cm x 39 cm x 18 cm, 22 kg
32:128 max. configuration

The QuickScan PA
A 19 in. rack mount version is also available.

Please note that the systems may be expanded at any time up to the limit supported by the chosen housing with the simple addition of plug-in boards. Also note that while the maximum available configuration is FOCUS 32:128, custom configurations are also available with more channels. Multiple FOCUS systems can also be used in parallel to increase the number of active elements.

Questions ?

Joindre un spécialiste d’Olympus NDT