10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Particle Detection Using the Dual-vaporizer Configuration of the Soot Particle Aerosol Mass Spectrometer
ANITA AVERY, Edward Fortner, Leah Williams, Wade Robinson, Timothy Onasch, Aerodyne Research, Inc.
Abstract Number: 1443 Working Group: Instrumentation
Abstract The Soot Particle-Aerosol Mass Spectrometer (SP-AMS) can operate with one of two particle vaporizers: (1) the standard AMS resistively heated tungsten vaporizer for traditional detection of non-refractory particulate matter (NR-PM), and (2) an intracavity laser vaporizer for detection of absorbing, refractory materials, including black carbon (rBC) and metal nanoparticles, and associated NR-PM. The SP-AMS can also be operated with both vaporizers simultaneously, by sequentially turning the laser vaporizer on and laser off over the course of sampling. While each vaporizer has been shown to be effective when operated separately (with respective constraints), the use of both simultaneously is complicated by the different collection efficiencies (CE) of the two vaporizers and can strongly affect the measured NR-PM signals from both rBC-containing and non-rBC-containing particles. This work describes a systematic investigation of NR-PM (rBC-containing or not) detection, including chemical ion signatures and CE, while using dual vaporizers in the SP-AMS. The results from the combined vaporizers are compared with expected signal for laboratory generated particles and with the results from the vaporizers operated separately. Differences in detection are explained based on the separate collection efficiencies of the two vaporizers and the observed interference between the two vaporizers due to excess laser energy heating the other AMS components (e.g. the ion cage).