Ion-beam thermography analysis of the H2SO4-(NH4)2SO4 system in aerosol samples

• Ion-beam thermography (IBT) is used to determine the chemical composition of atmospheric aerosols. The aerosols are analyZed by a combination of four ion-beam techniques PIXE, PESA, pNRA and cPESA during thermography. These techniques monitor the concentrations of the available elements during the stepwise heating of the sample. For each element a thermogram, i.e., the concentration vs. temperature, is obtained. Vaporization of chemical compounds generated during heating will result in a decrease in concentration in the thermograms at temperatures that are characteristic for the compounds. The compounds are identified by the stoichiometric ratios and the characteristic vaporization temperatures (CVT). This paper deals with the analysis of five different laboratory-produced aerosols with the following compositions: (NH4)2SO4, (NH4)1.5H0.5SO4, NH4HSO4, (NH4)0.5H1.5SO4 and H2SO4. All compounds were readily separated with respect to response in IBT analysis and the amount of water bound to the two most acidic compounds could be quantified.

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NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

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