Product-Specific Particle Size Analysis with Laser Diffraction | HELOS

The HELOS range of particle distribution sensors offers analysis with laser diffraction for lab applications ranging from less than 0.1 µm – 8,750 µm. With its classical parallel beam laser diffraction set-up, HELOS provides a powerful method means of analyzing the particle size distribution of powders, granulates, solid and droplet aerosols as well as suspensions and emulsions are measured on a product-specific basis. HELOS sets standards in terms of reproducibility, comparability and accuracy of particle size analysis – in combination with extremely short measuring times. The excellent reproducibility of dry dispersion with RODOS makes this system the first choice for all comminution stages and further dry process steps. The instrument design tailored to the needs of pharmaceutical applications and professional system maintenance therefore ensure outstanding system quality and lasting value.

The precondition for convincing and reliable measuring results are based upon product-adapted and reproducible sample analyses. A product adaption will be achieved if particle collectives are dispersed and supplied to the measurement in their original condition: powders and granules - dry, suspensions and emulsions - wet, as well as sprays and inhalants as aerosols – without time-consuming preparations. The modular system displays its true advantage when customized with dosing and dispersing units, guaranteed to adapt to the product sample. A great variety of modular options in our system portfolio provides the best support to the most diverse industrial and research applications.

The complete range of R1 to R8 proved the strong concept of measuring range segmentation. Consistent understanding of all details of the samples to be analysed can be achieved by selecting the optimum measuring range. Typical disperse products rarely span over more than two decades. Even for these products the concept of the multi-range combination holds since the introduction of the innovative R series.

HELOS | Measuring ranges R1 to R8 from 0.1 µm to 8,750 µm with maximum resolution

HELOS | Measuring ranges R1 to R8 from 0.1 µm to 8,750 µm with maximum resolution

The powerful evaluation algorithms of FREE and MIEE provide best possible agreement with absolute values. Very short analysis times, particularly with dry dispersion, are maintained.

Parallel laser beam | Large working distance

Parallel laser beam | Large working distance

The HELOS-R series sets a new benchmark for precision and accuracy, the latest improvements comprising enhanced application of parameter-free Fraunhofer evaluation down to the submicron regime (below 1 µm). The use of more stable inversion procedures in tandem with best optical models and the inclusion of signal statistics brings the laser diffraction even closer to absolute standards. The specifications of ISO 13320 "Particle size analysis - laser diffraction methods" the requirements and limits are considerably outmatched.

Dispersing and Dosing Options

The modular system design together with a great variety of dispersing and dosing units provides a flexible adaptation to the most diverse industrial and research applications:

Dry Applications

  • RODOS | Injection disperser for finest, even cohesive powders | 0.1 µm to 3,500 µm
  • GRADIS | Gravity disperser for coarser, even fragile dry particulate systems | 0.5 µm to 8,750 µm
  • VIBRI | Vibratory feeder for precise dosing and feeding of dry particulate systems (in combination with RODOS or GRADIS)
  • ASPIROS | Micro dosing system for feeding of small amounts of precious or toxic dry substances in encapsulated sample vials (in combination with RODOS)

Wet Applications

  • SUCELL | closed-loop flow-through cell for suspensions and emulsions | 0.1 µm to 1,750 µm | (50) 500 ml cell
  • QUIXEL | Flow-through cuvette with pumping circuit for emulsions and suspensions, even with coarser, high density particles | 0,1 µm to 3.500 µm | heating option
  • CUVETTE | Stationary cuvette for precious or toxic emulsions and suspensions of small sample volume | 0.1 µm to 3,500 µm
  • MULTISAMPLER | Sample handling system for automated feeding of wet samples in 39 ml vials in batch operation (in combination with SUCELL or QUIXEL) | 70 vials per rack


  • OASIS | Combined dry and wet disperser, consisting of RODOS & SUCELL
  • SPRAYER | Actuator for the analysis of droplets released by pump sprays | 0.25 µm to 875 µm
  • SMACTOR | Actuator for the analysis of particles and droplets released by MDIs, pump sprays or sprays with propellants | 0.25 µm to 1,750 µm
  • INHALER | Adapter for the analysis of aerosols released by DPIs, MDIs, nebulizers, pump sprays or sprays with propellants | 0.25 µm to 1,750 µm
  • LIQIBACK | Reprocessing unit for recycling of dispersion liquids (in combination with QUIXEL, SUCELL or OASIS) | 0.45 µm and 1 µm

Feature highlights

  • Highest precision and resolution of the particle size distribution by 8 measuring range modules
  • Automated multi range combination for broad distributions
  • Modular design structure with a great variety of dispersing and dosing units for flexible adaption to the sample
  • 2,000 particle size distributions per second are acquired by using the integrated time resolved mode
  • Unrivalled reproducibility of results and excellent system-to-system comparability
  • Powerful evaluation with parameter-free Fraunhofer or with Mie, if optical properties are known
  • Laser diffraction fully compliant with ISO 13320 for the complete size range from 0.1 µm to 8,750 µm

HELOS-R Series

The HELOS family includes 3 laser particle sizer:

Sensor Measuring range/ Modules Applications
HELOS/BR 0.1 - 875 µm/ 5 powders, suspensions, emulsions, sprays & aerosols
HELOS/KR 0.1 - 8,750 µm/ 8 powders, granules, suspensions, emulsions, sprays & aerosole
HELOS/KR-Vario 0.25 - 8,750 µm/ 8 powders, granules, suspensions, emulsions, sprays & aerosols, special applications


As the pioneer in the field of dry particle sizing technology, we have established ourselves on the international pharmaceutical market with numerous product-specific installations. World market leaders among the pharmaceutical research companies place their trust in our expertise, as do manufacturers of generic drugs and contract manufacturers as well as specialist companies with innovative niche products. Our quality management system has been repeatedly audited over the years and has been consistently tightened so that we do not just meet official directives and international standards but also demanding individual company standards.