Activation Analysis of Oxygen in Aluminium by Using α- and ³He-particles

Abstract

The dosage of trace oxygen in aluminium is very interesting, because its chemical behavior is important for chemical and physical properties of the metal. The chemical methods and the vacuum fusion method for determining oxygen in aluminium seem to have many difficulties.
The nondestructive activation analysis of oxygen in aluminium was carried out by means of ¹⁶O (α, pn) ¹⁸F, ¹⁶O (α, d) ¹⁸F ¹⁶O (α, 2n) ¹⁸Ne β⁺→¹⁸F, ¹⁶O (³He, n) ¹⁸F, and ¹⁶O (³He, p) ¹⁸Ne β⁺→¹⁸F reactions. As the calculation of content in charged particle activation is not so simple, we used the equivalent thickness method proposed by C. Engelmann, which is much simpler than the absolute method. The possible interfering nuclear reactions by aluminium and its impurities are examined. The analytical sensitivity in α- and ³He-activation is very high and the half-life of ¹⁸F is long enough to eliminate the surface contamination and the oxide film. The detection limits in our experimental conditions are compared with those by ¹⁶O (γ, n) ¹⁵O and ¹⁶O (n, p) ¹⁶N reactions. The activation analysis by ³He is found to be the best method for the analysis of oxygen in aluminium.