The Ankersmid Eyetech

Posted in: , on 13. May. 2009 - 14:43

Particle Sizing Takes Shape

Ideally, particles should be characterized by both size and shape.

Particle & Surface Sciences Pty. Limited have introduced a new Particle Characterization Analyzer that also offers Size and Image/Shape Analysis, the Ankersmid Eyetech.

It could be argued that the one drawback of most particle size analyzers is that they only measure particle size. But what else should be expected of an instrument specifically designed to do just that? To answer the question, a distinction has to be made between particle size analysis and particle characterization. Since most particle size analyzers operate on the assumption that the particles being measured are spherical, full particle characterization can only be obtained by considering the actual shape of the particles as well.

This combination of size and shape analysis is now to be found in a new instrument introduced into Australia and New Zealand by Particle & Surface Sciences Pty. Limited. The Ankersmid Eyetech combines a laser based particle size analyzer with advanced image/shape analysis software to provide a complete particle characterization system in a single compact, PC-controlled bench-top unit.

Unlike other laser-based particle size analyzers based on light scattering or diffraction techniques, the Ankersmid Eyetech employs the principle of time of transition analysis to measure particle size directly over the dynamic range of 0.1 to 2000 micron. Enabling measurement of particles in liquids, gases and even on solid surfaces, the mode of operation is based on a focused laser beam scanning circularly in space at a constant high frequency.

Interaction Pulses

This scanning operation sets up a “photo defined zone”, essentially toroidal in shape, in which any particle passing through produces interaction pulses of light detected by a PIN photodiode. The time width of these pulses is directly proportional to particle diameter – the larger the particles scanned, the longer the time of interaction with the laser beam. By rotating the beam in a circle at high frequencies, the instrument minimizes the effect of any motion of the particles relative to the beam.

Laser Obscuration Time (LOT) analysis avoids many of the factors which complicate other optical laser methods. Inconsistencies of light scattering or diffraction theories are eliminated, as well as Brownian motion, refractive index, viscosity and thermal effects.

Having recorded the interaction pulses, the Ankersmid Eyetech system obviously then has to analyze them to convert them directly into particle size data. This they do with very sophisticated software that not only performs the size analysis but also, by pulse-shape analysis, produces the photo-defined measurement zone. By selectively rejecting pulses whose shape is outside of previously defined criteria, the problem of particles interacting with the laser beam outside of the focus point is avoided. (Since the diameter of the laser beam varies along its length, any interaction of a particle outside of the focus point would produce an erroneous pulse width and therefore particle size. Similar problems of resolution occur in other techniques which attempt to control resolution by using narrow orifices or capillaries to physically define the measurement area. The Eyetech defines instead those particles which are precisely in the focus zone of the laser.

It perhaps needs emphasizing here that this electronic pulse-shape analysis has nothing directly to do with particle-shape analysis have nothing directly to do with particle-shape analysis. However, the “open architecture” of the system-made possible by the optically defined measurement zone, without any needs for orifices – has enabled a video monitoring system to be easily added. The Eyetech thus incorporates a CCD (close coupled device) microscopic TV camera, placed at right angles to the laser beam, to produce real-time images of the particles as they pass through the measurement zone.

Shape analysis software (particle shape this time) gives a wide variety of particle information including Ferret’s diameter, martin’s radius, area, perimeter, shape factor, aspect ratio, etc. Since the laser size analysis system, in common with most others, operates on the assumption of spherical particles, this second image analysis channel in the same instrument provides important additional shape information when analyzing aggregates and non-spherical particles. Besides being fed into the system’s computer for the shape, grain and other geometric analyses, the visual image of the particles in the measurement volume is also displayed on a separate video. Essentially there are two totally separate analyzers in the one unit, which use totally different detection principles, allowing a direct cross reference, thus giving confidence in each other’s result.

Sampling Modules

A further advantage of the instrument’s “open architecture” in the variety of cell types that can be employed to introduce particles to the measurement zone. Available modules include mechanically stirred, magnetically stirred, microscope slide, flow-through and Peltier heated/cooled cells and an aerosol generator – a range of sampling devices that illustrate the widespread of applications to which the Eyetech lends itself.


The Ankersmid Eyetech includes its use in

•assessing microbial contamination in drug solutions



•food processing


•industrial areas

•microbiological work such as monitoring membrane filtration.



•particulate contamination in parenteral solutions

•pharmaceutical applications

•plastics production














Particle & Surface Sciences also offer a wide-ranging programme of support solutions, including installation and service of all instruments by factory trained technicians, an Analytical Laboratory and a Sales Department to assist with your enquiries. PsS™ will be running a series of seminars across Australia during 2009. Please visit our website for more information on the locations.

Particle & Surface Sciences are also the sole distributors throughout Australia and New Zealand for Dataphysics, Micromeritics Instruments Corporation, Lighthouse Worldwide Solutions, Clemex, Ankersmid, DOP Solutions, MSP Products, NanoSight Technology, Impact Test equipment, Mipoy and their own products, PsS POLA 2000, POLA 3000 particle counters.

For more information, please visit:


ankersmid_eyetech-model (GIF)

ankersmid_eyetech (GIF)

ankersmid_eye-te12 (GIF)

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