Cloud Droplet Probe

This miniature, lightweight, low-power cloud particle spectrometer measures droplets in the range of 2 µm to 50 µm in concentrations as high as 2,000 particles/cm3.


Gather data across a wide range of platforms, including aircraft, towers, UAVs, and spray rigs.

Avoid particle fragmentation that can lead to overestimating particles thanks to anti-shatter tips and wetless windows.

Rely on the dynamic baseline feature to automatically adjust both sizer and qualifier signals to accommodate temperature drifts and ensure accurate particle sizing.

Get precise information on particle scattering intensity and inter-arrival times that are accurate to within a microsecond with the optional Particle-by-Particle Feature (PBP).

Particle light-scattering

  • CDP is a forward-scattering optical spectrometer that accepts and sizes only particles that pass through a region of the laser beam with uniform power.
  • Forward-scattered light is collected, directed through a 50/50 optical beam splitter, then measured by photodetectors to determine size and depth of field.
Measured Parameters Single-particle light scattering
Derived Parameters Particle diameter Particle number concentration Liquid water content (LWC) Effective diameter (ED) Median volume diameter (MVD)
Particle Size Range 2 – 50 µm
Number Conc. Range 0 – 2,000 particles/cm3
Typical Sample Area 0.24 mm2
Number of Size Bins 30
Air Speed Range 10 – 250 m/sec
Sampling Frequency Selectable, 0.04 to 20 seconds
Refractive Index Non-absorbing, 1.33 (the industry standard for water)
Light Collection Angles Optical design: 4° – 12° Optical performance: 1.7° – 14°
Laser 658 nm, up to 50 mW
Data System Interface RS-422; USB
Power Requirements System Power: 28 VDC at 2A Anti-ice Power: 28 VDC at 12A
Environmental Operating Conditions Temperature: -40 to 40 °C Relative Humidity: 0 – 100%, non-condensing Altitude: 0 – 50,000 feet (0 – 15,000 meters)
Weight Probe: 1.37 kg / 3.0 pounds (standard version); a lightweight UAV version is also available Electronics box and header cable: 0.82 kg / 1.8 lb
Probe Dimensions 26.7 cm L x 17.5 cm W x 21.6 cm H (10.5” L x 6.9” W x 8.5” H)
Electronics Box Dimensions 17.8 cm L x 8.9 cm W x 5.1 cm H (7.0” L x 3.5” W x 2.0” H
  • PADS software and laptop
  • Spinning pinhole for alignment and calibration check
  • Canister adapter – allows the CDP-2 to be used with conventional cloud probe mounting canisters

The Lifecycle Care Program ensures CDP 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.