STANDARDLESS SEMI-QUANTITATIVE ANALYSIS BY PIXE

T. RODRIGUEZ; P. PÉREZ; J. TRINCAVELLI

Sao Paulo

Otro; XIX Escola de Verao Jorge André Swieca de Física Nuclear Experimental; 2016

Particle induced x-ray emission (PIXE) is a powerful non-destructive analytical technique used in different fields of science and industry. One of the main advantages of this technique is its very low detection limit, which allows for trace element characterisation. The PAMPA program (Parameter Assesment Method for PIXE Analysis) was developed for standardless semi-quantitative PIXE analysis of thick and thin samples. Inthis work, the first results of PAMPA are presented for the characterisation of synthetic and mineral samples.PAMPA is based on an optimisation algorithm of the atomic and experimental parameters involved in a proton induced x-ray spectrum. The method consists in minimising a function which represents the quadratic differences between an experimental x-ray spectrum Ii and an analytical function Ii proposed to describe it [1]. This function takes into account the characteristic peaks, the continuumbackground [2] and instrumental features:p { margin-bottom: 0.25cm; line-height: 120%; }where B accounts for the continuum background, G is the Gaussian profile for the detected peaks, and P denotes their intensity; the subindices j y q represent the corresponding element and line, while E i is the energy of channel i. The spectra induced by 2 MeV protons impinging on thick samples were analysed by PAMPA. The results obtained for the mass concentrations were compared with fluorescence x-ray analysesperformed by a wavelength dispersive spectrometer and also with a consolidated software for PIXE analysis.