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

An important aspect of quantitative fluid inclusion analysis using X-ray em ission techniques concerns a knowledge of fluid inclusion depth and geometr y to establish reliable absorption correction procedures. The aim of this s tudy is to assess the potential performance of the nuclear reaction Na-23(p , p'gamma)Na-23 in estimating inclusion depth. Na was chosen because of its common occurrence in natural fluids. The nuclear reaction displays a chara cteristic, low energy resonance peak at 1.283 MeV in its cross-section whic h, together with recognition that the energy of the incident particles trav ersing matter decreases predictably with depth, allow estimation of the thi ckness of quartz traversed by the beam and hence the inclusion depth. Resul ts of the calculation shows accuracy on estimated fluid inclusion depths co mmonly better than +0.5 mu m. In addition, following the same experimental protocol as defined for Na, we show how the use of the elastic scattering r eaction Si-28(p, p)Si-28 can provide information on the fluid inclusion thi ckness. (C) 1999 Elsevier Science B.V. All rights reserved.