Investigation of lithium and fluorine content in geological materials using Nuclear Reaction Analysis (NRA)

Sammanfattning: This work focuses on the optimization of the Nuclear Reaction Analysis (NRA) technique to determine the content of lithium and fluorine in geological materials. Measuring low concentration of these isotopes is of great relevance in many fields such as geological, astrophysical, biological and material sciences. Light elements as lithium and fluorine are considered as geochemical tracers in various geological processes such as the crust-mantle recycling. In these applications, precise measurements are required.Our interest in geological applications is part of an interdisciplinary collaboration with geologists who provide us with samples and are interested in our results. The development of this project has enabled the Lund Ion Beam Analysis Facility (LIBAF) group to establish a technique for lithium and fluorine measurements that can be used in many fields.NRA is part of a family of analysis techniques known as Ion Beam Analysis (IBA). The advantages offered by IBA techniques are non-destructiveness, short measurement time, and very good sensitivity over the hole periodic table. Equipment such as particle accelerators and radiation detectors are needed to carry out IBA techniques. These types of equipment have been utilized at the LIBAF in order to perform NRA using Li-bearing and F-bearing materials. In NRA, the samples are scanned by energetic ions such as protons or deuterons to induce reactions with the sample elements. Many reactions can take place producing charged particles, X-rays and gamma rays. The 7Li(p,α)4He and 19F(p,α)16O reactions were utilized to obtain lithium and fluorine detection limits below 1~ppm and 50~ppm respectively.