PIXE elemental analysis of air particulates and a geochemical reference sample

Particle induced x-ray emission, PIXE, has been applied for elemental analysis of air particulates from an area of Rio de Janeiro and to measure the relative concentrations of a geochemical reference sample, by using a 2 MeV proton beam produced by 4 MV Van de Graaff accelerator. Two independent methods for absolute calibration were used; (1) proton irradiation of samples containing known amounts of each elements of interest; and (2) application of a mathematical expression obtained by taking into account parameters associated with each element and parameters inherent to the system. Calibrations for each of a number of selected elements were obtained by these two methods, and the results agree within 5%. A correction factor for self absorption of x-rays was obtained as function of a parameter which is determined by the knowledge of the mass ratio of any two detected elements. This correction factor was applied to the analysis of the geochemical reference sample