Passive Cavity Aerosol Spectrometer Probe

Full Name:

Passive Cavity Aerosol Spectrometer Probe with Signal Processing Package-200

Short Name or Variable Name:

PCASP, S200

HAIS Instrument:

TABS

Description

Model:

PCASP-100X

Measurements Provided:

Size distribution and concentration of aerosol particles ~0.1 to 3.0 micrometer diameter in 30 size bins.

*Note: due to its flow system design, the PCASP is not suitable for operation above about 8 km altitude.*

Typical Sampling Rates:

10 Hz

General Description:

PCASP is a wing-mounted aerosol probe that uses a standard PMS canister. Sample air enters the forward-facing inlet and decelerates by ~10x. Side-facing skarf tube provides suction for continuous flushing of the air to provide fast time response.
During cloud penetrations, the splash-breakup of cloud particles can produce large concentrations of spurious particles, and some of these can enter the PCASP air sample as a contamination. Internal diaphragm pump drives air flow through the optical cavity. Sample rate is ~1 cc/sec within a particle-free sheath flow of 15 cc/sec.

Measurement Characteristics:

Sample air throughput: 1 cc/sec
Overall estimate of uncertainty:
Response time: 10 sps
Precision: 30 ch, progressive bin width; 0.02 um resolution in smallest channels
Other measurement characteristics: splash artifact contamination in clouds

Calibration Methods:

Size calibrations use monodisperse aerosols, including PSL (polystyrene latex) spheres or ammonium sulfate passed through DMA

History of Significant Changes:

Addition of Signal Processing Package-200 (SPP-200) data interface

Example(s) of Measurement

Two examples of differential size distributions from the FRAPPE project:

Contacts

Lead Contact:

Mike Reeves

Alternate Contact:

Jorgen Jensen

Status/Plans