Passive Cavity Aerosol Spectrometer Probe

The PCASP-100X is an airborne optical spectrometer that measures aerosol particles in the 0.1 µm to 3 µm range.


Get unmatched sensitivity and specificity in real-time measurements of aerosols.

Enable direct measurement of the air stream with the leading cannister-based aircraft instrument.

Power your research with elimination of dead-time losses, plus continuous monitoring of multiple housekeeping variables.

Get user-programmable sample rates, number of channels, and channel size thresholds.

Particle light-scattering

  • Optical bench collects light that is scattered by individual particles passing through a HeNe, 0.6328 µm laser beam.
  • An amplification system with three gain stages covers the full range of particle sizes.
Measured Parameters Particle size (determined from particle light-scattering) Ambient temperature Standard and volumetric flows for sample and sheath air
Derived Parameters Particle Concentration Median Volume Diameter (MVD) Effective Diameter (ED
Particle Size Range 0.1 – 3.0 µm
Maximum Count Rate 3,000 particles/cm3
Counting Efficiency 50% at minimum threshold, increasing to 100% by the fourth size channel
Sampling Frequency 0.1 to 25 Hz, selectable
Flow Rate Sample flow: 1 cc/sec Sheath flow: 15 cc/sec
Air Speed Range 0 - 250 m/sec
Number of Size Bins Standard is 30
Laser HeNe multi-mode classical passive cavity, wavelength 0.6328 µm
Light Collection Angle Nominally 35° - 120°
Data System Interface RS-422, 34800 baud rate; USB
Power requirements Probe: 115VAC or 230VAC, 50-60Hz, less than 120W; specify voltage when ordering Anti-ice: 28 VDC, 215 W
Weight 40 lbs (18.2 kg)
Dimensions 40” long x 7” diameter (102 cm long x 18 cm diameter)
Operating Conditions Temperature: -30 to +40 °C Altitude: 0 to 30,000 ft (9.1 km) Relative Humidity: 0 - 90% RH (non-condensing)

PADS software and laptop
Data Acquisition System
Aerosol Generator

The Lifecycle Care Program ensures PCASP integrity and performance vital to your research mission for 3 years or 3 calls (whichever comes first). When conducting complex and time intensive laboratory or field measurements it is critical to avoid down time, and ensure data collection accuracy. The program consists of 3 key deliverables for each year or call:

  • Instrument Logistics
  • Instrument Integrity
  • Instrument Performance

Lifecycle Care Program Includes:


  • Shipping to and from Droplet Measurement Technologies facility
  • Customs handling, including CARNET ATA if required


  • Incoming instrument evaluation and health check


  • Software and firmware validation
  • 100%-unit functionality test
  • Calibration data
  • Calibration report
  • Certificate of calibration

At times, our technician might discover an instrument issue, which might not be covered by the Lifecycle Care Program or by our product warranty. In such case we will reach out to you with a service & repair estimate to allow you to provide us with the next steps of action.