Chemical speciation of aerosol samples by ion beam thermography

• Ion beam thermography (IBT) is a technique for the determination of chemical compounds. The IBT setup combines the multielemental ion beam techniques PIXE, PESA, pNRA and cPESA with thermography. During thermography the temperature is gradually increased up to the order of 600 °C, causing vaporisation of chemical compounds at specific temperatures. The combination of methods display low detection limits over practically the whole periodic table, i.e. PIXE: Z > 13, PESA: C, N, O, pNRA: Li, Be, B, F, Na, Mg, cPESA: H. The analysis is undertaken with an external beam. The thermographic treatment results in a thermogram for each element i.e. the concentration as a function of the temperature of the sample. The chemical compounds are identified by the vaporisation temperature and the stoichiometric relations between the elements vaporised at that temperature. This work deals with technical improvements of the setup and evaluates the dependence on the rate of temperature increase of the vaporisation temperature of chemical compounds. An atmospheric aerosol sample was analysed to demonstrate the capabilities of this combination of IBA methods in atmospheric aerosol research. All major and several minor elements of the sample could be determined, the major inorganic compounds could be speciated and the carbonaceous constituents could be classified according to volatility.

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

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

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