Last modified
February 29, 2000

  Seminar Abstract
Center for Data Intensive Computing



Single Particle Laser Ablation Time-of-Flight Mass-Spectrometry

The BNL Single Particle Laser Ablation Time of Flight Mass Spectrometer (SPLAT-MS) was designed for in-situ characterization of the size and composition of individual aerosols. The aerodynamic lens aerosol-sampling inlet acts to focus particles in the 20nm to 3 micrometer size range into a well-defined beam of ~ 1mm diameter with very low divergence. Two stages of optical detection are used to indicate the presence of particles larger than 80nm and for velocity/size determination. Ablation laser synchronized with the particle’s arrival at the inlet to the TOF-MS is used at present to evaporate and ionize the components for time of flight mass spectroscopic analysis. SPLAT-MS currently utilizes a reflectron time-of-flight mass spectrometer for single particle composition analysis. Resolution of the instrument in mass-to-charge units is 1000. The TOF-MS spectra are digitized with 8-bit resolution at a rate of 50 MHz, and data is transferred to the computer. Very rapid transfer rate of 100 MB/sec allows for high-resolution mass analysis of 20 particles per second, generating 50Gb of data per day. The particle spectra must be put in context by including gas phase information, meteorology, solar flux, etc. What we are searching for is a procedure that will make it possible to visualize the data within the appropriate context so that we could look for trends, correlations, that can then lead to understanding of processes. We feel that it is essential to develop a flexible visualization, which will make it possible to device a systematic method for data analysis.

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