Light absorption

Laser-light-absorption-instrument.jpgFor over two decades Crocker Nuclear Laboratory’s IMPROVE network measurements have included light absorption by particles collected on filters. This measurement has been conducted at a single wavelength using light of 633 nm from a He(Ne) laser.

CNL researchers have now designed and constructed a new device to allow light absorption measurements using broadband radiation throughout the visible spectrum and including the near-infrared and the ultraviolet. Most aerosol light absorption is typically due to carbonaceous or crustal particles. Using this new instrument (which we have named BITS—Broadband Integrating Transmittance/Reflectance Spectrometer) to make measurements over a broad spectrum will allow data analysts to distinguish among different types of particles that absorb in different parts of the spectrum.