Aerosol Spectrometer / Particle Counter / Photometer
ISO 21501
VDI 3867
VDI 3926

LAP 322 - Aerosol Particle Size Spectrometer

The Aerosol Particle Size Spectrometer LAP 322 provides the determination of aerosol particle size distributions (0.2-40µm) and particle concentrations. It  is based on optical single-particle measurements by means of 90° scattered light measurement.
By dint of high number of provided particle size classes a high particle sizing resolution can be realised, as well as a very good classification accuracy (VDI 3867, Part 4 and ISO 21501-1).
The aerosol spectrometer LAP 322 combines sensor, controlled volume flow supply, and signal acquisition in one rugged, handy housing. The included Data Acquisition and Control Software PASWin for standard Windows PCs provides for an easy operability.


  • Measuring range of particle size: 200 nm … 40 µm (with just one sensor), various measuring ranges selectable
  • Wide concentration range: from 1 to max. 104 particles/cm3) – ideal for filter testing
  • Easy and defined extension of concentration measuring range by use of Aerosol Dilution Systems
  • Optimized measuring zone:
  1. no border zone –> no border zone error
  2. vertical flow guiding ensures the transportation of large particles to the measuring zone
  • High counting efficiency of >50% already at 200nm
  • Light source with long life time (20,000 h) by use of approved laser diode
  • Very good size resolution by means of multi channel analysis with typically >90 size channels
  • Mobile and flexible –  both sensor and signal acquisition combined in a compact housing
  • Incl. ease of use and comprehensive Windows based Control and Analysis Software PASWin
  • Easy control of Sample Switching Unit SYS 520 for measurement of fractional efficiencies
  • Measurement of particle size distributions (spray, dust, powder)
  • Analysis of test and calibration aerosols
  • Filter testing and characterization
  • Determination of fractional efficiency
  • Indoor air quality
  • Atmospheric research and environmental monitoring
  • Characterization of pharmaceutical aerosols
  • Aerosol research
  • Device carrying case
  • Sample Switching Unit SYS 520, directly connectable to Aerosol Spectrometer and controllable via software PASWin, enables switching between 2 different sampling points, e.g. for efficiency measurements at filter test rigs
  • Aerosol Dilution System DIL 555, for aerosol dilution in case of high aerosol concentration

The aerosol spectrometer underlies the principle of light scattering. According to size of a particle passing the measuring volume scattered light occurs that is mapped on photo detector situated in 90° direction. Change of collected light at the photo detector is a measure of particle size and is subject to multi channel analysis.

The counting results that are sorted into several channels according to their impulse height represent the basis for determining of number based particle size distribution by means of calculation base and calibration function.

The entire measuring range covers particle sizes from 0.2 µm to 40 µm. It has been proved that only at number concentrations higher than 104 particle/cm3 noticeable losses in the counting rate are caused by coincidence. By using Topas dilution systems of series DIL the concentration range can reliably be enhanced and coincidence can be reduced to an insignificant scale.
The compact design and easy operation allow flexible utilization of aerosol spectrometers of series LAP for measuring particle size distribution as well as particle concentration in aerosols.

Measuring size range 0.2 – 40 µm
(0.2-5 µm, 0.24-10 µm, 0.7-40 µm)
Concentration range <10particle/cm³
Size classes max. 128 (64) or user-defined
Volume flow 3 l/min
Light source 30 mW laser diode
660 nm
Interface RS232 Interface
Power supply 110..230 VAC  12 VDC 4.2 A
Dimensions 220 mm x 380 mm x 200 mm
Weight 9.4 kg