Analysis and instrument control is via simple, intuitive browser-style software. These deliver precise, high resolution wet and dry measurements with better than 1% accuracy and reproducibility. These include the Mastersizer 30E from Malvern Panalytical. This technique is capable of measuring particles from 10nm to 3500 microns.ĪTA Scientific supplies a range of particle sizing instruments that employ laser diffraction technology. These scattering patterns are measured by the detectors and particle size distribution is determined from the resulting data. Larger particles bring about a high intensity of scattering at low angles to the beam, smaller particles create a low intensity signal at much wider angles. The laser light is scattered in a variety of angles. The particles are dispersed in a liquid (often water) or air and illuminated by a collimated laser beam. This means it provides a result for the whole sample rather than for individual particles. Laser diffraction is an ensemble technique of particle sizing. It is a rapid, highly reproducible measuring technique which provides particle size distribution over a wide particle diameter range. The "raw" scattered light data is then passed to the calculation algorithm where it will be transformed into a particle size distribution.įor more information about acquiring an instrument, click here.Laser diffraction, also known as Low Angle Laser Light Scattering (LALLS), is widely used for particle size analysis and is the standard method in many industries. Ultra long-life solid-state light sources and detectorsĪcquiring the best possible scattered light data is the basis of any reliable size measurement.Tilted measurement cell to reduce stray light noise.Maximum stability and alignment with post-less, cast aluminum mountings.Maintenance-free, dust-free sealed optical bench.Hundreds of refinements to the basic design have been included to improve performance and usability. The LA-960V2 particle size analyzer represents the tenth generation laser diffraction instrument designed by HORIBA. Very high quality lenses, mirrors, and glass measurement cell.80+ photodetectors covering an approximate angular range of 0-170 degrees.Two light sources at different wavelengths.A typical laser diffraction optical system will include:
The core technologies are all mature, but as with many things higher quality leads to superior performance. Measurement quality is all about the analyzer itself: quality of components, engineering refinement, and a fundamental design which reflects basic principles. Transform that scattering data into a particle size distribution.Measure scattered light angle and intensity.The basic workflow of a laser diffraction particle size analysis breaks down into two parts: 1: Red wavelength laser diode for larger particles, 2: Blue LED for smaller particles, 3: Low angle detectors for larger particles, 4: Side and back angle detector arrays and smaller particles. All HORIBA laser diffraction analyzers use the Mie scattering solution by default and allow the user to input custom refractive index values.Ī simplified layout of the LA-960 optical bench. The use of a refractive index and the Mie scattering theory directly affects accuracy in this size range. The scattered light is at relatively low intensity and wide angle for these smaller particles. This means the measurement will not benefit from the use of a refractive index to accurately interpret refracted light.įor particles smaller than 20 microns refracted light becomes increasingly important to calculate an accurate particle size. Particles larger than this size communicate useful size information through diffraction and not refraction. The "certain size" is determined as a multiple of the wavelength of light used for the measurement and typically approximated at 20 microns. The scattered light is at relatively high intensity and low angle for these larger particles. Diffracted and refracted light is useful for this purpose absorbed and reflected light works against this purpose and must be taken into account during measurement and size calculation.įor particles larger than a certain size the vast majority of light is scattered by diffraction. We can obtain information about the size of a particle using the angle and intensity of scattered light. Refraction occurs as light changes angle traveling throught the particle. Diffraction is also known as "edge diffraction" as that is where it occurs.
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