Phased array ultrasonics
Phased Array (PA) ultrasonics is an advanced method of
ultrasonic testingthat has applications in medical imaging and industrial nondestructive testing, originally pioneered by Albert Macovskiof Stanford University. [cite web |url= http://web.mit.edu/invent/iow/macovski.html|title= Inventor of the Week: Albert Macovski, Medical Imaging Systems|publisher= web.mit.edu/invent|date= 2000-08|accessdate=2007-03-11] In medicine a common application of phased array is the imaging of the heart (images of the fetusin the womb are usually made by curvilinear array, a multi-element probe that does not actually phase the signals). When applied to steel the PA image shows a slice that may reveal defects hidden inside a structure or weld.
Principle of operation
The PA probe consists of many small ultrasonic elements, each of which can be pulsed individually. By varying the timing, for instance by pulsing the elements one by one in sequence along a row, a pattern of interference is set up that results in a beam at a set angle. In other words, the beam can be steered electronically. The beam is swept like a search-light through the tissue or object being examined, and the data from multiple beams are put together to make a visual image showing a slice through the object.
Features of phased array
* The method most commonly used for
* Multiple probe elements produce a steerable, tightly focused, high-resolution beam.
* Produces an image that shows a slice through the object.
* Compared to conventional, single-element
ultrasonic inspectionsystems, PA instruments and probes are more complex and expensive.
* In industry, PA technicians require more experience and training than conventional technicians.
weld for defects using an ultrasonic phased array instrument. The scanner, which consists of a frame with magnetic wheels, holds the probe in contact with the pipe by a spring. The wet area is the ultrasonic couplant that allows the sound to pass into the pipe wall.]
* [http://www.olympusndt.com/data/File/intro_pa/Intro_PA_Chap1.en.pdf Chapter One] of "Introduction to Phased Array Ultrasonic Technology Applications" [industrial PA] (PDF 1.42 MB)
* [http://www.olympusndt.com/data/File/advances_book/Applications_Cha1.en.pdf Chapter One] of "Advances in Phased Array Ultrasonic Technology Applications" [industrial PA] (PDF 4.6 MB)
* [http://www.olympusndt.com/data/File/pa-booklet/PA_Technical_Guidelines_Extract.en.pdf Chapter One] of "Phased Array Technical Booklet" [industrial PA] (PDF 1.6 MB)
* [http://www.asnt.org/publications/materialseval/basics/apr05basics/apr05basics.htm "Industrial applications of portable phased array"] [technical paper]
* [http://www.asnt.org/publications/Materialseval/solution/jan05solution/jan05sol.htm "Construction Weld Testing Procedures Using Phased Array] " [technical paper; based on computer modelling]
* [http://dukemil.egr.duke.edu/Ultrasound/k-space/node2.html "Introduction to theory for medical phased array"] , Martin E. Anderson, Duke University
* [http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=37 Phased array animated simulator] [registration required after 5 minutes' use]
* [http://www.harfangmicro.com/FAQ.html Phased Array definition and lexicon]
* [http://www.olympusndt.com/en/ndt-tutorials/phased-array/ Phased Array Tutorial]
* [http://www.olympusndt.com/en/books/ "Introduction to Phased Array Ultrasonic Technology Applications"] , R/DTech Inc. (now Olympus NDT), 2004.
* [http://www.olympusndt.com/en/books/ "Automated Ultrasonic Testing for Pipeline Girth Welds"] , R/DTech Inc. (now Olympus NDT).
* " [http://www.asme.org/Codes/Publications/BPVC/Boiler_Pressure_Vessels_Code.cfm ASME Boiler and Pressure Vessel Code] ". American Society Of Mechanical Engineers, 2004. Section V — "Nondestructive Examination". [See Article 4 — "Ultrasonic Examination Methods for Welds". Para E-474 "UT-Phased Array Technique"]
* ASME Code Case 2235-9, "Use of Ultrasonic Examination in Lieu of Radiography — Section I and Section VIII, Divisions 1 and 2". American Society Of Mechanical Engineers, Approval Date: October 11, 2005. [See page 1, footnote 1 on phased array] (PDF [http://cstools.asme.org/csconnect/PDF/CodeCases/966.pdf here] )
Phased array(general theory and electromagnetic telecommunications).
Phased array optics
Wikimedia Foundation. 2010.
Look at other dictionaries:
Phased array — This article is about general theory and electromagnetic phased array. For the ultrasonic and medical imaging application, see phased array ultrasonics. In wave theory, a phased array is a group of antennas in which the relative phases of the… … Wikipedia
Ultrasonic testing — Step 1 : The UT probe is placed on the root of the blades to be inspected with the help of a special borescope tool (video probe). Step 2 : Instrument settings are input. Step 3 : The probe is scanned over the blade root. In this case, an… … Wikipedia
Nondestructive testing — or Non destructive testing (NDT) is a wide group of analysis techniques used in science and industry to evaluate the properties of a material, component or system without causing damage. The terms Nondestructive examination (NDE),… … Wikipedia
High intensity focused ultrasound — HIFU (high intensity focused ultrasound) (sometimes FUS or HIFUS) is a highly precise medical procedure using high intensity focused ultrasound to heat and destroy pathogenic tissue rapidly. It is one modality of therapeutic ultrasound, and… … Wikipedia
High-intensity focused ultrasound — Contents 1 Theory 2 Aiming 3 How HIFU works 4 Method of use … Wikipedia
Sonografie — (Sonographie), auch Echografie oder umgangssprachlich Ultraschall genannt, ist die Anwendung von Ultraschall als bildgebendes Verfahren zur Untersuchung von organischem Gewebe in der Medizin und Veterinärmedizin sowie von technischen Strukturen.… … Deutsch Wikipedia