A method for charged-particle activation analysis and its application to fluorine determination by the19F(p, αγ)16O reaction

Abstract

A simple method for calculating the sensitivity for detecting a nuclide distributed uniformly in any given matrix through charged particle activation is described. This method takes into account the actual values of the reaction cross section at different energies as the beam traverses through a thick target and the corresponding stopping power values. The detection sensitivity for fluorine in a number of matrices through the19F(p, αγ)16O reaction have been calculated as a function of the energy from threshold to 4.16 MeV using this method and the sensitivity curves plotted. The sensitivity values (dps/ppm/μA) for a thick or thin target and even for a layer of known thickness at a particular depth within a sample can be directly read from these curves for known bombarding conditions. The comparator methods for charged particle activation analysis of RICCI1 and of CHAUDHRI,2 especially when the matrices of the sample and standard are different, have been compared in the case of F determination through the19F(p, αγ)16O reaction. It has been found that the errors are reduced by almost a factor of two when the latter method is used compared to the former one. The fluorine concentration in animal bones and teeth, apatite crystal, and rocks have been determined through the19F(p, αγ)16O reaction using the Melbourne University Pelletron.