Record Display for the EPA National Library Catalog


OLS Field Name OLS Field Data
Main Title X-Ray Powder Diffraction System for Chemical Speciation of Particulate Aerosol Samples.
Author Thompson, A. C. ; Jaklevic, J. M. ; O'Connor, B. H. ; Morris, C. M. ;
CORP Author California Univ., Berkeley. Lawrence Berkeley Lab. ;Western Australian Inst. of Tech., South Bentley. ;Los Alamos National Lab., NM.;Environmental Sciences Research Lab., Research Triangle Park, NC.;Department of Energy, Washington, DC. Office of Health and Environmental Research.
Year Published 1982
Report Number W-7405-ENG-48; EPA-600/J-82-028;
Stock Number PB84-174689
Additional Subjects X ray diffraction ; Chemical analysis ; Particles ; Laboratory equipment ; X ray analysis ; Aerosols ; Sampling ; Air pollution ; Concentration(Composition) ; X ray fluorescence ; Reprints ; Air pollution detection ; Dichotomous samplers ; Computer applications
Library Call Number Additional Info Location Last
NTIS  PB84-174689 Most EPA libraries have a fiche copy filed under the call number shown. Check with individual libraries about paper copy. 06/23/1988
Collation 10p
An x-ray powder diffraction system has been developed for the automated measurement and analysis of particulate aerosol samples. The system is optimized to process samples with particle loadings of about 100 micrograms/sq cm which are acquired with dichotomous air samplers. A position sensitive pressurized gas proportional chamber is used as the x-ray detector. This detector acquires information simultaneously over an angular range of up to seven degrees and increases the data acquisition rate by over 20 times compared to a conventional system. The use of a position sensitive detector also reduces spectral artifacts due to preferred particle orientations since each spectral point is measured at many goniometer settings. The on-line data analysis procedure begins with a background subtraction of the radiation scattered from the sample substrate. A spectral analysis routine then automatically finds peaks and fits them with an analytic function to determine their position and intensity. A search-match procedure is then used to determine the major chemical species present on each sample. Results from this powder diffraction analysis are then combined with an x-ray fluroescence measurement of the chemical concentrations to give quantitative analysis of the major chemical compounds present on these environmental samples.