Introducing the CRROPC Project
CRROPC stands for the Community Ruggedised/Repackaged Optical Particle Counter. It is a project born out of the larger Mid Life Upgrade project of the Facility for Airbourne Atmospheric Measurements. The project is building a new instrument that will measure the atmospheric aerosol size distribution. It draws in an air sample and passes it through a laser beam. It then measures the tiny flashes of light as individual aerosol particles pass through the beam. This type of instrument in general is called an OPTICAL PARTICLE COUNTER. Our intention is to build an instrument which will fulfil a similar role to the Passive Cavity Aerosol Spectrometer Probe, offered by Droplet Measurement Technology, but with more modern components.
The Ethos
This project was borne out of some very specific aims that form the ethos of the project.
Improvements in detector and laser technology have been colossal since the first iteration of the PCASP in the 70s. We should therefore be able to build a much simpler and more RUGGED instrument, but with similar performance.
The designs should be open source. In the past we lost support for instruments because they were built by a University or small business, then a key person left or production stopped. Everything should be open source so that anyone in the COMMUNITY can build an identical or similar instrument and can share experience.
The instrument should be built as much as possible from off the shelf components. This makes it more accessible for other members of the COMMUNITY to duplicate our efforts.
We should consider REPACKAGING another instrument or reusing parts of another instrument as a way to keep costs relatively low.
The starting point and our way forward
The project has gotten underway, with two older benchtop optical particle counters acting as initial donor instruments. A Passive Cavity Aerosol Spectrometer Probe and an Active Scattering Aerosol Spectrometer Probe. We have been working our way through the components, replacing them with more modern equivalents and in the end we should have a new fully functional instrument.
Where we are at
You can keep up to date with the project by checking out our blog. The CRROPC posts can be seen here.
Phil Rosenberg
