Dependence of X-ray yields on different parameters for light element matrices in thick target PIXE and use of standards for calibration in such analysis

Abstract

Matrix, beam energy and geometry dependent effects in PIXE analysis of thick samples have been investigated in light element matrix in the proton energy range 2.61–4.22 MeV. The experimental results have been compared with the results of numerical calculations using different prescriptions for cross sections. It is shown that experimental sensitivities as a function of atomic number of elements and beam energy can be accurately reproduced by some prescriptions. It is also shown that modification of intensity ratios of K X-ray lines obtained experimentally can be explained as due to absorption in matrix and absorbers. It is further shown that calibration using multielement standards and numerical calculations can be fruitfully utilized to reduce the uncertainties in thick target PIXE analysis. The sources of these uncertainties and limitations of the use of standards are discussed in the light of experimental results and calculations.