• These microspheres show a size distribution which is appropriate for methods that need particle size uniformity between monodisperse (highly uniform, <5% CV**) and polydisperse (widely distributed, <12% CV). These include instruments for light blockage, light diffraction, acoustical imaging, electrolyte displacement or other methods used for analysing wide size range materials. The material is composed of polystyrene cross-linked with divinylbenzene. This gives the particle good durability and chemical stability. They can be washed in water-alcohol mixtures and resuspended in water, air or similar media. The density of polystyrene is 1.05 g/cm3, and the index of refraction is 1.59 at 589nm (25C). Microspheres in this series are packaged as an aqueous suspension in 15 mL dropper-tipped vials.
  • This series of NIST traceable size standards provides an accurate and convenient method for calibrating or checking the performance of laser particle counters used in cleanrooms and other contamination monitoring applications. The products are suspensions of monodisperse polystyrene spheres (PSL) for use in airborne or liquid particle dispersion systems. They are available in a range of sizes from 0.1 to 100µm in diameter. The particles are prepared as low residue aqueous suspensions for minimal background interference, packaged in 15mL dropper-tipped vials. The particle diameters are calibrated by electron or optical microscopy. Each package includes a Certificate of Calibration and Traceability to the National Institute of Standards and Technology (NIST). In comparison with the well established 3000 and 4000 Series products described elsewhere, these product lines are precisely diluted for immediate use in laser particle counters with minimal time-consuming adjustments of concentration.
  • These uniform microspheres are NIST-traceable by calibration methods such as optical microscopy. Products from 1 to 160µm in diameter are packaged as aqueous suspensions of polystyrene spheres in dropper-tipped bottles. Diameters of 200µm and larger are packaged as dry spheres in screw-capped bottles. These larger particles are composed of polystyrene DVB (divinylbenzene). The spheres have a density of 1.05g/cm3 and an index of refraction of 1.59 @ 589nm.
  • Small borosilicate glass microspheres have fewer spherical imperfections and inclusions than other glass microspheres. They also have better mechanical and thermal stability. This series has been calibrated with NIST traceable methods of optical microscopy. They are packaged as dry powders in 1 gram bottles. They have a density of 2.50-2.55g/cm 3 and an index of refraction of 1.56 @ 589nm (23°C). Brands: Thermo Scientific
  • Duke Scientific Corporation's new COUNT-CAL™ is a cost effective and convenient product for validating particle counters. Packaged in single-use bottles, and intended to be sampled directly from the bottle, it eliminates the need for serial dilutions and extensive sample handling, thereby minimizing contamination. The particles are suspended in an ultraclean diluent and the concentration is optimized for use in light obscuration particle counters and other low concentration counting applications. The particle diameters are traceable to the Standard Meter through the National Institute of Standards and Technology (NIST).
  • Thermo Scientific provides these products for calibrating particle counters which require dry particles, from 5 to 100 µm. They are conveniently packaged in dropper-tipped vials in 1 gram quantities, enabling the user to dispense the microspheres directly into the sampling chamber. They are not suitable for dispersion in liquid media. The mean diameters are traceable to the National Institute of Standards and Technology (NIST). DRI-CAL™ Particle Size Standards are composed of polystyrene DVB (divinylbenzene) and have a density of 1.05g/cm3. The refractive index is 1.59 @ 589nm. The certified mean diameter was determined by optical microscopy using a NIST calibrated stage micrometer. Size distribution was determined by electrical resistance analysis.
  • Ezy-Cal™

    This product line offers a series of ready-to-use standards for validating optical particle counters with no dilution and handling. The products are suspensions of monodisperse polymer microspheres in water with a concentration of 2000 particles per mL. A magnetic stir bar is included in each bottle for clean, convenient and direct sampling by instruments. This series of size standards is provided for setting or checking the calibration of channel thresholds or for checking the count precision of liquid-borne particle counters. Their certified diameters are traceable to NIST. They are packaged as 100mL screw-cap bottles, sufficient for four or five calibration procedures on most counters. The microspheres are composed of polystyrene, which has an index of refraction of 1.59 @ 589nm and a density of 1.05 g/cm3. The aqueous suspension medium contains a combination of dispersing agents, which help to keep the particles from clumping or sticking to flow surfaces in the particle counter. The EZY-CAL™ product line meets all of the unique and demanding requirements of the contamination control laboratory in modern industries.
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