Fluid inclusion depth and thickness estimates using a Na nuclear reaction resonance and Si elastic scattering

Abstract

An important aspect of quantitative fluid inclusion analysis using X-ray emission techniques concerns a knowledge of fluid inclusion depth and geometry to establish reliable absorption correction procedures. The aim of this study is to assess the potential performance of the nuclear reaction 23Na(p, p′γ)23Na in estimating inclusion depth. Na was chosen because of its common occurrence in natural fluids. The nuclear reaction displays a characteristic, low energy resonance peak at 1.283 MeV in its cross-section which, together with recognition that the energy of the incident particles traversing matter decreases predictably with depth, allow estimation of the thickness of quartz traversed by the beam and hence the inclusion depth. Results of the calculation shows accuracy on estimated fluid inclusion depths commonly better than ±0.5 μm. In addition, following the same experimental protocol as defined for Na, we show how the use of the elastic scattering reaction 28Si(p, p)28Si can provide information on the fluid inclusion thickness.