Estudo e desenvolvimento de um sistema de colimação de raios x para um equipamento de SAXS

Abstract

The increasing use of nanomaterials requires the creation of techniques, and the associated equipments, to allow the property evaluation at the nanometer scale. The SAXS (Small Angle X-Ray Scattering) technique allows the analysis of nanomaterials and the determination of various parameters such as nanoparticle size, density and morphology of nanoparticles. This project contributes in the construction of fundamental equipment for the study of the nanometric characteristics of new materials, which are being used widely in the industry to present different properties in comparison with the microscopic properties. Normally, X-rays pass through the sample (transmission mode) and each nanoparticle interacts with the X-ray emitting a signal which is detected and analyzed. As in other areas of research, there are major challenges associates to the development of instrumentation for the application of this technique. The challenges of this work are the optical part of the project, from the platform of conventional X-ray diffraction equipment. In a SAXS, the X-ray beam must have the least possible attenuation in the path between the X-ray tube and the detector and this condition is obtained by evacuating the entire optical path. 3D CAD software was used in the design and development of the entire optical assembly and evacuation of the system that compound the device. All the instrumentation has been manufactured in the Laboratório de Instrumentação e Tecnologia Mecânica (LITMec) of the CBPF (Centro Brasileiro de Pesquisas Físicas) and in the LNA (Laboratório Nacional de Astrofísica). Tests were performed on the optical system of the equipment in order to evaluate the dimensions of the collimated beam using slits of 5 mm and 1 mm, which presented an error of 8.9% and 2.5%, respectively, compared to the theoretical analyzes performed in 3D software. All the equipment is subject to a patent, because the technology used in position sensitive detectors developed in the CBPF holds an international patent and the configuration of all the instrumentation that will make up the SAXS establishes a new equipment model.