OpticalParticleCounter - RAF Instruments

Measurements Made and Methods Used

Measurements Provided: size distribution and concentration of aerosol particles ~0.1 to 5 um diameter in 30 size bins, 10 sps
Manufacturer or Builder of the Instrument: Optics from PCASP (original probe by PMS), electronics and data interface by DMT, flow system by RAF. Instrument is similar to DMT's PCASP-X2

Operational Status:
- requestable, ready for deployment
General Description:
OPC is a rack-mount instrument with internal air pump. Atmospheric sampling needs an inlet and tubing. Particle detection and sizing are based on laser light scattering, with pulse amplitude determined with two gain stages to cover the large dynamic range.
Measurement Characteristics:
- Overall estimate of uncertainty:
- Response time: Measures 10 size distributions per second.
- Precision: 0.05 um typical in smallest size channels
- Other measurement characteristics (comments on signal/noise, bias limits, etc):
  - Time delay and particle loss can occur between inlet and instrument due to sample tubing.

Description of Software, Data Handling, and Data Flow:
- Software Components (data acquisition, display, processing, and analysis):
- Data Processing Chain (from flight to archival): The size distributions are recorded by the NIDAS data system and processed via the nimbus program for incorporation as vector quantities in the netCDF archive. For further information, see the page StandardDataPath.
QA Procedures and Needs:

Lead Contacts

Documentation

Descriptive Publications
Documentation of the Processing Algorithm(s): See the Technical Note on Processing Algorithms at this URL (fix when available)

Internal users: See http://wiki.eol.ucar.edu/rafscience/OpticalParticleCounter (last edited 2012-12-08)